US20010045812A1 - Semiconductor integrated circuit for brushless motor drive control and brushless motor dirve control apparatus - Google Patents
Semiconductor integrated circuit for brushless motor drive control and brushless motor dirve control apparatus Download PDFInfo
- Publication number
- US20010045812A1 US20010045812A1 US09/893,549 US89354901A US2001045812A1 US 20010045812 A1 US20010045812 A1 US 20010045812A1 US 89354901 A US89354901 A US 89354901A US 2001045812 A1 US2001045812 A1 US 2001045812A1
- Authority
- US
- United States
- Prior art keywords
- circuit
- phase
- current
- motor
- field coil
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Granted
Links
Images
Classifications
-
- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02P—CONTROL OR REGULATION OF ELECTRIC MOTORS, ELECTRIC GENERATORS OR DYNAMO-ELECTRIC CONVERTERS; CONTROLLING TRANSFORMERS, REACTORS OR CHOKE COILS
- H02P6/00—Arrangements for controlling synchronous motors or other dynamo-electric motors using electronic commutation dependent on the rotor position; Electronic commutators therefor
- H02P6/20—Arrangements for starting
- H02P6/22—Arrangements for starting in a selected direction of rotation
Definitions
- the present invention relates to a technique for drive control of a brushless motor and a technique effective when applied to a method for determining phases (a pair of phases) at which to start current conduction when starting the motor, and particularly concerns a technique effective when used in a drive control apparatus of a spindle motor for rotating a disk-type storage medium, such as a HDD (hard disk drive) device.
- a technique for drive control of a brushless motor and a technique effective when applied to a method for determining phases (a pair of phases) at which to start current conduction when starting the motor
- a technique effective when used in a drive control apparatus of a spindle motor for rotating a disk-type storage medium such as a HDD (hard disk drive) device.
- HDD hard disk drive
- this control method is such that phases at which current conduction is started are determined by determining the rotor position based on detection results obtained by detection of differences in inductance by making use of a phenomenon that the inductance of the field coils varies whether the direction of the magnetic field is the same or not between the field coils and the rotor magnet (that is to say, whether magnetic saturation occurs or not) (Refer to JP-A-3-207250 published on Sep. 10, 1991 which corresponds to U.S. Ser. No. 413311 filed on Sep. 27, 1989).
- the stopped position of the rotor is determined by applying a diagnosis signal of a frequency higher than the frequency of an exciting signal applied when the motor is started, to a single coil or two or more coils connected in series and detecting an induced voltage of one of the serially-connected coils (Refer to JP-A-7-274585 published on Oct. 20, 1995).
- the maximum amplitude value depends on variations in winding in the field coils of the stator, for which reason detection errors occur due to very small winding variations that are unavoidable in the manufacturing process.
- the control method that determines a pair of phases, where current conduction is started by detecting the rotor position based on differences in current rise time constant, because a phenomenon of magnetic saturation is used, differences in time constant do not become conspicuous unless a fairly large current is passed, and therefore it is difficult to detect differences in the time constant when a current passed is so small as the rotor does not react to it.
- Another problem with this control method is that the point of reversal of the large-small relation among the time constants that occurs when the direction of a current is reversed does not coincide with the point of magnetic saturation, resulting in errors in determination results.
- the present invention has as its object to provide a brushless motor drive control technique that can prevents reverse rotation of the motor at starting by detecting the position of the rotor relative to the stator with fewer errors and determining a field coil pair at which current conduction is started.
- a pair of phases for current conduction to start the motor is determined by passing a pulse current with a duration so short as the rotor does not react through the field coil of any phase of the motor in first and second, mutually opposite, directions sequentially, and detecting induced voltages in the non-conducting phase by a pulse current in two opposite directions, combining voltages induced by a pulse current in the first direction and a pulse current in the second direction, detecting the polarities of combination results, and determining a pair of phases for current conduction when starting the motor based on polarity detection results related to a plurality of the conducting phases.
- FIGS. 1 a and 1 b are schematic diagrams illustrating the principle of a rotor position detecting method according to one embodiment of the present invention, in each of which diagrams the rotor is at a standstill with the border between an S pole and an N pole of the magnet of the rotor coincident with the center of the field coil Lv of the stator;
- FIGS. 2 a and 2 b are schematic diagrams illustrating the principle of a rotor position detecting method according to one embodiment of the present invention, in each of which diagrams the rotor is at a standstill with the border between an S pole and an N pole of the magnet of the rotor shifted a little from the center of the field coil Lv to the field coil Lw of the stator.
- FIGS. 3 a and 3 b are schematic diagrams illustrating the principle of a rotor position detecting method according to one embodiment of the present invention, in each of which diagrams the rotor is at a standstill with the border between an S pole and an N pole of the magnet of the rotor shifted a little from the center of the field coil Lv to the field coil Lu of the stator;
- FIGS. 4 a and 4 b are graphs showing the relation between the position of the rotor relative to the stator and induced voltages at the non-conducting phases, obtained by an experiment conducted by the present inventors;
- FIG. 5 is a waveform diagram with respect to a three-phase motor, showing a relation between detection results on the positive and negative polarities of induced voltages Eu, Ev and Ew detected at the field coils Lu, Lv and Lw and leakage fluxes to the non-conducting phases, and showing a relation between leakage fluxes to the non-conducting phases and torques (back electromotive forces) of the respective field coils Lu, Lv and Lw when the motor is rotating;
- FIG. 6 is a block diagram of brushless motor drive control apparatus according to one embodiment of the present invention in a motor driver unit used in a hard disk storage device;
- FIG. 7 is a block diagram of a brushless motor drive control apparatus according to one embodiment of the present invention in a motor driver unit used in a hard disk storage device;
- FIG. 8 is a flowchart showing the operation procedure of the apparatus in FIG. 7;
- FIG. 9 is a timing chart showing the operation of the apparatus in FIG. 7 determining the rotor position by conducting a pulse current through the field coils of respective phases and detecting induced voltages at the non-conducting phases according to the procedure shown in FIG. 8;
- FIG. 10 is a block diagram for explaining the motor driver unit, which is used in a hard disk storage device and which includes the brushless motor drive control apparatus according to one embodiment of the present invention
- FIG. 11 is a flowchart showing a control procedure from starting the motor till a constant speed operation in a motor driver unit including the brushless motor drive control apparatus according to one embodiment of the present invention.
- FIG. 12 is a block diagram showing a representative configuration of the hard disk device as an example of a system using the motor driver unit including the brushless motor drive control apparatus according to one embodiment of the present invention.
- FIGS. 1 a , 1 b , 2 a , 2 b , 3 a and 3 b These figures schematically illustrate the relation of any three field coils Lu, Lv and Lw representing 3 ⁇ n (n is a positive integer) coils with respect to the rotor magnet in order to explain the positional relation of the field coils of the stator with respect to the rotor magnet MG in a three-phase type polyphase brushless motor.
- the PIO denotes a phase current output circuit to pass currents through the field coils Lu, Lv and Lw.
- This phase current output circuit outputs a total of six currents (including currents in mutually opposite directions) to conduct them through any pair of field coils according to a specified sequence to thereby rotate the rotor.
- the rotor magnet MG and the stator field coils Lu, Lv and Lw are arranged linearly but they are arranged coaxially in a real motor.
- FIG. 1 a shows that the rotor is at a standstill with the border between an S pole and an N pole of the magnet MG of the rotor coincident with the center of the field coil Lv of the stator.
- the magnetic lines DMu of the field coil Lu is in a direction opposite to the direction of the magnetic lines DMw of the field coil Lw. Because the border between the S pole and the N pole of the magnet MG coincides with the center of the field coil Lv of the stator, the leakage flux from the field coil Lu to the field coil Lv is the same in magnitude with and opposite in direction from the leakage flux from the field coil Lw to the field coil Lv and therefore they cancel each other, so that the induced voltage in the field coil Lv is zero.
- the magnetic lines DMu produced by the field coil Lu is in the same direction as the above-mentioned flux (magnetic lines) emerging from that portion of the rotor magnet MG which faces the field coil Lu and then passing through the field coil Lu, and the magnetic lines DMw produced by the field coil Lw is also in the same direction as the above-mentioned flux (magnetic lines) emerging from that portion of the rotor magnet MG which faces the field coil Lw and then passing through the field coil Lw.
- the leakage flux ML 1 from the field coil Lu to the field coil Lv is larger than the leakage flux ML 2 from the field coil Lw to the field coil Lv, so that a voltage is induced in the field coil according to the difference in leakage flux.
- the directions of the magnetic lines produced by the field coils Lu and Lw are opposite to the directions of the magnetic lines emerging from the N poles and going into the S poles of the magnet MG of the rotor that respectively face the field coils.
- the magnetic lines of the field coil Lu are set off by the N pole of the rotor magnet MG to a greater extent than the magnetic lines of the field coil Lw are set off by the S pole. Therefore, the leakage flux ML 1 from the field coil Lu to the field coil Lv is smaller than the leakage flux ML 2 from the field coil Lw to the field coil Lv, but because the directions of the leakage fluxes ML 1 and LM 2 are reverse from those in FIG. 2 a , the polarity of the voltage induced in the Lv by the difference in leakage flux is the same as in FIG. 2 a.
- the voltage induced in the field coil Lv is greater when a current is sent such that the magnetic lines produced by the field coils Lu and Lv are in the same direction as the magnetic lines of the rotor magnet MG as in FIG. 2 a than when a current is sent such that the magnetic lines produced by the field coils Lu and Lv are in the opposite direction to the direction of the magnetic lines of the rotor magnet MG. Therefore, by passing a current through the field coils Lu and Lw alternately in opposite directions, detecting and comparing the voltage induced in the field coil Lv, it is possible to determine which poles are close to which field coils and whether the poles are north or south.
- FIG. 3 a shows the state that the rotor is at a standstill with the border between an S pole and an N pole of the magnet MG of the rotor being shifted a little away from the center of the field coil Lv of the stator to the field coil Lu.
- the S pole of the rotor magnet MG squarely faces the front side of the field coil Lw
- the density of the flux emerging from that portion of the rotor magnet MG which faces the field coil Lw and then passing through the field coil Lw is higher than the density of the flux emerging from that portion of the rotor magnet MG which faces the field coil Lu and passing through the field coil Lu.
- the magnetic lines DMw produced by field coil Lw are in the same direction as the above-mentioned flux (magnetic lines) emerging from that portion of the rotor magnet MG which faces the field coil Lw and passing through the field coil Lw and also the magnetic lines DMu produced by the field coil Lu are in the same direction as the above-mentioned flux (magnetic lines) emerging from that portion of the rotor magnet MG which faces the field coil Lu and passing through the field coil Lu.
- the leakage flux ML 2 from the field coil Lw to the field coil Lv is larger than the flux ML 1 from the field coil Lu to the field coil Lv and the voltage is induced in the field coil Lv according to the difference in leakage flux.
- the voltage induced in the field coil Lv in FIG. 3 a is opposite in polarity to the voltage induced in the field coil Lv in FIGS. 2 a and 2 b.
- the density of the flux emerging from the rotor magnet MG and passing through the field coil Lw is the same as the density of the flux emerging from the rotor magnet MG and passing through the field coil Lu as in FIG. 3 a , but the magnetic lines produced by the field coils Lw and Lu are respectively opposite in direction to the magnetic lines from the S and the N poles of the rotor magnet MG facing those field coils.
- the magnetic lines produced by the field coil Lw are set off by the S pole of the rotor magnet MG to a greater extent than the magnetic lines produced by the field coil Lu are set off by the N pole of the rotor magnet MG. Therefore, though the leakage flux ML 2 from the field coil Lw to the field coil Lv is smaller than the leakage flux ML 1 from the field coil Lu to the field coil Lv, because the direction of the magnetic lines ML 1 and ML 2 is opposite to that in FIG. 3 a , the polarity of the voltage induced in the field coil Lv according to the difference in leakage flux is the same as in FIG. 3 a.
- the voltage induced in the field coil Lv is larger when a current is supplied such that the magnetic lines produced are in the same direction as the magnetic lines of the rotor magnet MG as shown in FIG. 3 a as in FIGS. 2 a and 2 b than when a current is supplied such that the magnetic lines produced by the field coils Lu and Lv are respectively opposite in direction to the magnetic lines of the rotor magnet MG as shown in FIG. 3 b . Therefore, also in this case, by passing a current through the field coils Lu and Lw alternately in opposite directions, detecting and comparing the voltage induced in the field coil Lv, it is possible to determine which poles are close to which field coils and whether the poles are north or south. Note that the polarity of the greater one of the leakage fluxes detected is opposite to that detected in the case of FIG. 2.
- FIG. 4 a shows a result of a test conducted by the inventors.
- the vertical axis indicates the detected values of the induced voltage and the horizontal axis indicates the position of the rotor with respect to the stator expressed in electrical angles.
- a mechanical angle of 60 degrees corresponds to an electrical angle of 360 degrees.
- FIG. 4 a shows the result of measurement of voltages induced in the field coil Lv by passing a current through the field coils Lu and Lw alternately in opposite directions.
- the solid line A indicates the induced voltage in the field coil Lv when a current is conducted from the field coil Lw to the field coil Lu
- the broken line B indicates the induced voltage in the field coil Lv when a current is conducted from the field coil Lu to the field coil Lw.
- the present invention is based on an idea of providing the brushless motor drive circuit with a circuit for determining a pair of phases at which current conduction is started by conducting a pulse current through two field coils alternately in opposite directions, combining (adding) the voltages induced in the non-conducting-phase field coil by respective currents and sampled and held by a sample-and-hold circuit, or integrating and then adding up the respective induced voltages, and on the basis of the sum, detecting the polarities of the induced voltages.
- FIG. 5 shows with regard to a three-phase motor the relation between detected polarities (positive and negative) of the induced voltages Eu, Ev and Ew detected at the field coils Lu, Lv and Lw and the leakage fluxes ⁇ u, ⁇ v and ⁇ w to the non-conducting-phase field coils, and the relation between the leakage fluxes ⁇ u, ⁇ v and ⁇ w to the non-conducting-phase field coils and the torque Tu, Tv and Tw, namely, the back electromotive forces of the field coils Lu, Lv and Lw while the motor was at a standstill.
- the polarity-detecting results for the detected induced voltages Eu, Ev and Ew when the motor is at a standstill are “+, +, ⁇ ” for example, by conducting a current from the u-phase field coil Lu to the v-phase field coil Lv to start the motor, the maximum torque can be obtained. It is understood from FIG. 5 that the positions where the polarities of the induced voltages are inverted coincide with the positions where the polarities of the leakage fluxes are inverted and it never occurs that detection about the polarity of induced voltages is unclear. Moreover, because the leakage flux is proportional to the flux density in the field coil, it is not always required to make magnetic saturation occur in the field coil when detecting an induced voltage.
- Table 1 shows the relation between the polarity detection results for the combined induced voltages Eu, Ev and Ew and the phases for starting current conduction. Obviously, the relation in Table 1 corresponds to the relation shown in FIG. 5.
- the motor can be started in the correct rotating direction in a shortest time regardless of the rotor position at the moment.
- the polarity (positive or negative) detection results of the induced voltages Eu, Ev and Ew can never be all “+” or all “ ⁇ ” when induced voltages are detected normally at the field coils of the respective phases.
- a current is supplied such that the magnetic lines of the field coils are in the same direction as the magnetic lines of the rotor magnet
- a current is supplies such that the magnetic lines of the field coils are in the opposite direction to the magnetic lines of the rotor magnet. Therefore, in these two cases, the voltages induced in the field coil Lv ascribable to variation in winding are mutually opposite in polarity, and when these induced voltages are added together, they cancel each other and become zero.
- FIG. 6 shows a brushless motor drive control apparatus mounted in a motor driver unit for use in a hard disk device and structured according to one embodiment of the present invention.
- reference numeral 11 denotes a phase current output circuit that supplies current to the field coils Lu, Lv and Lw in a three-phase brushless motor
- 12 denotes a phase switching control circuit that supplies a selection signal of the phases, through which a current is to be passed, to the phase current output circuit 11
- 13 denotes an induced voltage detecting circuit, connected to the output terminals U, V and W of the phase current output circuit 11 , for detecting induced voltages
- 14 a and 14 b denote sample-and-hold circuits for sampling and holding the induced voltages detected by the induced voltage output circuit 13 when the field coils are supplied with a current in two opposite directions
- 15 denotes an adder circuit that adds up the voltages held in the sample-and-hold circuits 14 a and 14 b and generates a rotor position signal.
- Reference numeral 16 denotes a polarity detecting circuit for detecting the polarity of an addition result in the adder circuit 15 , in other words, detecting whether the sum of voltages is positive or negative, and generating a polarity signal
- 17 a , 17 b and 17 c denote data latch circuits for storing polarity data representing polarity signals generated by the polarity detecting circuit 16 when a current is passed through the field coils
- 18 denotes a discriminating circuit for determining rotor position, in other words, a pair of phases through which a current is to be supplied in the first place based on polarity data stored in the data latch circuits 17 a , 17 b and 17 c , from the relation in Table 1, for example, and generating a phase selection setting signal
- 19 denotes a timing circuit that generates control signals based on a clock signal CLK, and outputs to the circuit blocks 11 to 18 .
- the timing circuit 19 supplies a phase selection switching timing signal T.CLK and a rotor position detection ON/OFF signal STR to the phase switching control circuit 12 , an ON/OFF signal SNS to the induced voltage detecting circuit 13 , a sampling timing signal SPR to the sample-and-hold circuits 14 a and 14 b , an operation timing signal ADD and a reset signal RST to the adder circuit 15 , latch timing signals LTA to LTC to the data latch circuits 17 a , 17 b and 17 c , a determination timing signal JDG to the discriminating circuit 18 .
- the circuit blocks 11 to 18 operate sequentially by control signals from the timing circuit 19 .
- this timing circuit 19 By provision of this timing circuit 19 , it becomes possible to realize a drive control apparatus which can start a brushless motor in a short time by determining by itself a pair of phases at which to start current conduction when a clock signal is only given without control signals being generated and supplied externally.
- the phase switching control circuit 12 sends a phase selection control signal to the phase current output circuit 11 to detect the rotor position and pass a small-pulse current through the field coils.
- the phase current output circuit 11 sends a pulse current, having such a short duration as the rotor does not react, to any pair of field coils Lu, Lv and Lw in one direction or in the opposite direction.
- phase switching control circuit 12 when the phase switching control circuit 12 receives a phase selection setting signal COMMST indicating the phases at which to start current conduction, from the discriminating circuit 18 , the phase switching control circuit 12 sends a phase selection control signal to the phase current output circuit 11 directing it to pass a pulse current through the set phases at which to start current conduction to rotate the motor. At this time, the ON/OFF signal STR from the timing circuit 19 is at the effective level.
- the induced voltage detecting circuit 13 has a rotor position detecting action ON/OFF signal SNS supplied from the timing circuit 19 and also has another signal, indicating which phases are being selected, supplied from the phase switching control circuit 12 . By those signals, the induced voltage detecting circuit 13 detects and amplifies the voltage induced in the non-conducting-phase coil.
- the induced voltage detecting circuit 13 if formed by a MOSFET, may include a switch (selector) to select a voltage of the non-conducting phase, where current is not flowing, out of the output terminals U, V and W of the phase current output circuit 11 and also an amplifier circuit to amplify the selected voltage.
- the induced voltage detecting circuit 13 may include three differential amplifiers that each have at one input terminal supplied with one of the voltages of the output terminals U, V and W of the phase current output circuit 11 and at the other input terminal supplied with the potential at the common connection node NO of the respective field coils.
- the circuit 13 may be configured such that any one of the differential amplifier circuits performs amplification when its current source is turned on by a phase selection control signal.
- the adder circuit 15 may be an analog adder circuit using an operational amplifier or may be a digital adder circuit. In the case of a digital adder, it is only necessary to insert an A/D converter circuit as the stage subsequent to the sample-and-hold circuits 14 a and 14 b .
- the polarity detecting circuit 16 may be an analog or digital circuit depending on the type of the adder circuit 15 . If the adder 15 is formed as a digital circuit, the polarity detecting circuit 16 may be formed by a subtractor.
- registers may be used, and an A/D converter circuit may be provided at the preceding stage to have the detected induced voltage converted into a digital value and stored as digital data in the registers.
- the discriminating circuit 18 that designates start current conduction phases from a polarity detection result is mounted together with the induced voltage detecting circuit 13 , etc.
- a microcomputer that receives polarity data from the latch circuits 17 a to 17 c , which hold data from the polarity detecting circuit 16 , and determines a pair of phases at which to start current conduction and sets the phase data in the phase switching control circuit 12 .
- FIG. 7 shows a motor drive control apparatus in a motor driver unit, which is used in a hard disk storage device and which is structured according to another embodiment of the present invention.
- This embodiment uses an integrating circuit 20 , which has replaced the sample-and-hold circuits 14 a and 14 b and the adder 15 in the embodiment shown in FIG. 6.
- This integrating circuit 20 may be formed by a well-known integrating circuit including a CR integrating circuit made of a capacitor and a resistance, or by a well-known integrating circuit including an operational amplifier and a capacitor connected between an output terminal and an inverted input terminal of the amplifier.
- the integrating circuit integrates an induced voltage which is detected at the non-conducting phase by the induced voltage detecting circuit 13 when a pulse current is passed through the field coils in one direction in the first place and, under the condition that the result of integration is maintained, also integrates an induced voltage which is detected at the non-conducting phase by the induced voltage detecting circuit 13 when a pulse current is passed through the field coils in the opposite direction.
- the polarity detecting circuit 16 is used to detect the polarity of the electric charge remaining in the capacitor as a component part of the integrating circuit (hereafter referred to as an integrating capacitor). After this determination is made, control is performed so that the integrating capacitor is reset once, and then a pulse current is passed through a subsequent pair of field coils, and the induced voltage detected is integrated.
- FIG. 8 shows the operation procedures of the phase current output circuit 11 at left and the induced current detecting circuit 13 and the integrating circuit 20 at right to show the related actions compared with each other.
- the timing circuit 19 starts to generate a control signal for detecting the rotor position.
- the capacitor of the integrating circuit 20 is reset, more simply, the capacitor discharges itself of electric charge.
- a pulse current is passed from the phase v to the phase w by the phase current output circuit 11 .
- the pulse current used has so short a duration as the rotor does not react to it.
- the induced voltage of the phase u which is non-conducting at this moment, is detected by the detecting circuit 13 , and is integrated by the integrating circuit 20 (Step S 1 ).
- step S 2 all phase terminals of the phase current output circuit 11 are opened, and for this while the voltage integrated in the integrating circuit 20 is held.
- step S 3 the phase current output circuit 11 sends a pulse current from the phase w to the phase v in the opposite direction to the current flow in the step S 1 .
- the induced voltage of the phase u in the non-conducting state is detected by the induced voltage detecting circuit 13 , and the phase-u induced voltage is integrated using the result of the previous integration as the initial value.
- the integration result of the phase-u induced voltage when a current was passed from the phase v to the phase w is added with the integration result of the phase-u induced voltage when a current was passed from the phase w to the phase v.
- step S 4 the polarity of the electric charge remaining in the integrating capacitor is detected by the polarity detecting circuit 16 , and a detection decision result u-DATA is stored in the first circuit 17 a . All the output terminals of the phase current output circuit 11 are opened, and in the integrating circuit 20 , the electric charge held in the integrating capacitor is reset.
- step S 5 the phase current output circuit 11 passes a pulse current from the phase w to the phase u. At this time, the induced voltage of the phase v, which is not conducting, is detected by the detecting circuit 13 , and the induced voltage is integrated by the integrating circuit 20 .
- a step S 6 the voltage integrated by the integrating circuit 20 is held, and all output terminals of the phase current output circuit 11 are opened.
- the phase current output circuit 11 passes a pulse current from the phase u to the w phase in the direction opposite from the the direction in the step S 5 , the induced voltage of the phase v, which is not conducting, is detected by the detecting circuit 13 , and the integrating circuit 20 integrates the phase-v induced voltage using the previous integration result as the initial value.
- a step S 8 after twice integration, the polarity of the charge remaining in the integrating capacitor is detected by the polarity detecting circuit 16 .
- the detection result v-DATA in the second data latch circuit 17 b is detected.
- all phase terminals of the phase current output circuit 11 are opened, and the charge held in the integrating capacitor in the integrating circuit 20 is reset.
- steps S 9 to S 11 as in the above-mentioned steps S 5 to S 7 , the phase current output circuit 11 passes a pulse current from the phase u to the phase v, the induced voltage of the phase w, which is not conducting, is detected by the detecting circuit 13 , and is integrated by the integrating circuit 20 . Subsequently, a reverse pulse current is passed from the phase u to the phase v, the induced voltage of the phase w, which is not conducting, is detected by the detecting circuit 13 , and the phase-w induced voltage is integrated by the integrating circuit 20 .
- next step S 12 from results of twice integration in the integrating circuit 20 , the polarity of the charge remaining in the integrating capacitor is detected by the polarity detecting circuit 16 , and a detection result w-DATA is stored in the third data latch circuit 17 c . All phase output terminals of the phase current output circuit 11 are opened, and the charge held in the integrating capacitor is reset in the integrating circuit 20 .
- the discriminating circuit 18 determines the position of the rotor based on detection results u-DATA, v-DATA and w-DATA stored in the data latch circuits 17 a , 17 b and 17 c in the steps S 3 , S 7 and S 11 . More specifically, the discriminating circuit 18 determines the rotor position according to Table 1 from three pieces of information indicating the positive or negative polarity stored in the data latch circuits 17 a , 17 b and 17 c , and, from the rotor position, determines the phases at which current conduction is started, and sends a phase selection setting signal COMMST to the phase switching control circuit 12 to initialize the current conduction phases.
- the polarity detection results (positive or negative) stored in the data latch circuits 17 a , 17 b and 17 c are all “+” (H) or all “ ⁇ ” (L) and, therefore, if such a combination of results occurs, they should be regarded as detection errors, and the process shown in FIG. 8 returns to the step S 0 to perform rotor position detection.
- the steps S 0 to S 13 can be finished in a time as short as 2 msec. Therefore, even if the rotor position detection is carried out over again, this has hardly any effects on the starting time of the motor that takes several tens of msec.
- FIG. 9 is a timing chart when the rotor position is detected by supplying a pulse current to the respective phases sequentially and detecting the induced voltages at the non-conducting phases according to the above-mentioned procedure.
- FIG. 9 is a timing chart when the rotor position is detected by supplying a pulse current to the respective phases sequentially and detecting the induced voltages at the non-conducting phases according to the above-mentioned procedure.
- u, v and w denote the output voltages of the phases of the phase current output circuits 11
- Iu, Iv and Iw denote the currents that flow in the field coils Lu
- Lv and Lw SNS denotes an ON/OFF control signal for integrating actions to the integrating circuit 20
- RST denotes a reset signal to discharge the charge of the integrating capacitor
- LTA, LTB and LTC denote signals for giving latch timing to the data latch circuits 17 a , 17 b and 17 c
- JDG denotes a signal for giving discrimination timing to the discriminating circuit 18
- COMMST denotes a timing signal which the discriminating circuit 18 issues to initialize the phase selection in the phase switching control circuit 12 based on a discrimination result.
- Clock cycles T 0 to T 13 in FIG. 9 respectively correspond to steps S 0 to S 13 in the flowchart in FIG. 8.
- FIG. 10 shows an example of system configuration including a motor driver unit, which includes a motor drive control apparatus according to another embodiment of the present invention, and which is used in a hard disk storage device.
- the circuit blocks and circuit elements located in a range enclosed by a broken line 210 in FIG. 10 are formed on one semiconductor substrate, such as a single crystal silicon chip, but they are not to be construed as restrictive.
- reference numeral 11 denotes a phase current output circuit that selectively and sequentially supplies current to the three-phase field coils Lu, Lv and Lw of a spindle motor to rotate the disks of a hard disk device
- 12 denotes a phase switching control circuit to supply to the phase current output circuit 11 a signal for selection of the phases through which to pass a current (phase selection control signal)
- 19 denotes a timing circuit to generate control signals to the above-mentioned circuit blocks 11 through 18 based on a clock signal CLK.
- the induced voltage detecting circuit 13 connected to the output terminals U, V and W of the phase current output circuit 11 , for detecting the induced voltages, the integrating circuit 20 (or sample-and-hold circuits 14 a and 14 b , and an adder 15 ) for integrating induced voltages detected by the induced voltage detecting circuit 13 , the polarity detecting circuit 16 for detecting the polarity of integration results (or addition results), the data latch circuits 17 a , 17 b and 17 c for storing polarity detection results, and the discriminating circuit 18 for discriminating the rotor position, that is, a pair of phases through which a current is conducted in the first place from detection results stored in the data latch circuits 17 a , 17 b and 17 c are collectively shown as a single start current conduction phase determining circuit 21 .
- the start current conduction phase determining circuit 21 is connected to external terminals P 1 and P 2 on the chip, and the terminals P 1 and P 2 are connected to an externally-mounted discrete capacitor Ci as the integrating capacitor of the integrating circuit.
- This integrating capacitor serves to eliminate noise in detected voltages in the induced voltage detecting circuit 13 that detects the induced voltages at the non-conducting phases to determine start current conduction phases with high accuracy.
- This embodiment is particularly effective in a case where the phase current output circuit 11 is formed by a bipolar transistor. This is because large noise is contained in the induced voltages at the non-conducting phases when the phase current output circuit 11 is a bipolar transistor type than when it is a MOSFET type.
- FIG. 10 23 denotes a back e.m.f. detecting circuit that monitors the voltages at the output terminals U, V and W of the phase current output circuit 11 when they are non-conducting, detects zero-cross points of the back e.m.f., and gives a phase switching timing signal to the phase switching control circuit 12 , 22 denotes a PLL (phase locked loop) circuit including a voltage-controlled oscillator (VCO) that generates an oscillating signal required to give phase switching timing to the phase switching control circuit 12 during constant-speed rotation based on an output signal of the back e.m.f.
- VCO voltage-controlled oscillator
- detecting circuit 23 , 24 denotes a brake control circuit for forcibly applying an induction brake by shorting all field coils by turning off the power supply switch Qsw of the phase current output circuit 11 when bringing the motor to a stop
- 25 denotes a speed control circuit for controlling the motor speed by detecting the current flowing in the phase current output circuit 11 , and, in response to a speed-related command signal SPNCTL from a microcomputer, increasing the rotation speed by increasing the current applied to the phase current output circuit 11 or reducing the speed by decreasing the applied current.
- the PLL circuit 22 is connected to external terminals P 3 , P 4 and P 5 provided on the chip, and the external terminals P 3 , P 4 and P 5 are connected with externally-mounted elements, such as capacitors C 0 and C 1 and a resistance R 1 , which form a loop filter of the PLL, and a capacitor C 2 and a resistance R 2 , which determine an oscillation frequency of the VCO.
- externally-mounted elements such as capacitors C 0 and C 1 and a resistance R 1 , which form a loop filter of the PLL, and a capacitor C 2 and a resistance R 2 , which determine an oscillation frequency of the VCO.
- the parts mounted on the motor driver IC chip 210 include a protecting circuit 26 for detecting the temperature of the chip and bringing the operation of the circuit to a stop, a boosting circuit 27 for boosting the gate voltage to make it possible to sufficiently drive MOSFET's used, a voltage regulator 28 to supply a power source voltage to the IC or LSI provided around the motor driver IC chip 210 , and a VCM drive control circuit 30 for driving the voice coil motor to move the magnetic heads, but they should not be construed as restrictive.
- the VCM drive control circuit 30 comprises a VCM driving circuit 31 for outputting current to drive the driving coil L VCM of the voice coil motor, a serial port 32 for serial transmission and reception to and from the microcomputer, a D/A converter circuit 33 for converting control data received from the microcomputer into an analog signal and supplying to the VCM driving circuit 31 , a back e.m.f. detecting circuit 34 for detecting the back e.m.f. of the coil L VCM to obtain speed information when starting the motor, an A/D converter circuit 35 for converting a detected back e.m.f.
- a power supply voltage monitoring circuit 36 for monitoring the levels of power supply voltages Vss and Vdd to detect power cut-off
- a head retraction drive circuit 37 for controlled driving of the coil L VCM to enable the magnetic heads to retract to outside the disk surface when power cut-off is detected.
- the above-mentioned serial port 32 sends and receives serial data DATA based on a serial clock SCLK or a load instruction signal LOAD from the microcomputer and generates control signals, such as an enable signal VCMEN to the VCM driving circuit 31 based on data received.
- the serial port 32 also sends to the microcomputer an A-D converted version of a back e.m.f. induced in the coil LVCM when the motor is started, the back e.m.f. being detected by the back e.m.f. detecting circuit 34 for obtaining speed information from the detected back e.m.f.
- the microcomputer control the motor speed by monitoring motor speed information so that the magnetic head is prevented from falling on the hard disk surface faster than a specified speed.
- the serial port 32 has a function to generate an enable EN signal to the timing generating circuit 19 of the spindle motor control system based on data received from the microcomputer, and generates control signals, such as a phase selection setting signal COMM. Note that when the phase switching control circuit 12 starts the motor by a phase selection setting signal COMMST supplied from the start current conduction phase determining circuit 21 as in the above-mentioned embodiment, it becomes unnecessary to send a phase selection setting signal COMM from the microcomputer.
- the discriminating circuit 18 for discriminating the start current conduction phases without mounting the discriminating circuit 18 for discriminating the start current conduction phases from a polarity detection result in the start current conduction phase determining circuit 21 and if it is arranged that the microcomputer receives information from the latch circuits 17 a to 17 c , which store polarity data, and determines and sets a pair of phases for start current conduction in the phase switching control circuit 12 , the above-mentioned route passing through the serial port 32 can be used to initialize the phase switching control circuit 12 .
- Vss a power source voltage
- P 7 for a power supply voltage Vdd of 12V or 5V a power terminal for a power supply voltage Vdd of 12V or 5V
- P 8 for ground potential (0V) To the power terminal P 7 , 12V is applied for use in a 3.5-inch hard disk device, or 5V is applied for use in a 2.5-inch hard disk device.
- P 11 to P 14 denote the terminals connected to the terminals of the field coils of a spindle motor.
- FIG. 11 shows a control procedure from starting of a motor till a constant speed drive in the motor driver unit, which includes the start current conduction phase determining circuit.
- step S 21 when a start signal is given by the microcomputer, the start current conduction phase determining circuit 21 detects rotor position to begin with (step S 21 ).
- This rotor position detection is performed by the steps S 1 to S 12 in the flowchart in FIG. 8, which has been described.
- a decision is made in a step S 22 whether rotor data are all “L” (low level) or all “H” (high level), if the decision result is “Yes”, which means that data are all “L” or all “H”, rotor position determination (step S 21 ) is performed again. It ought to be noted that the step S 22 corresponds to the S 13 in FIG. 8.
- step S 22 If the decision result is “No” in the step S 22 , which means that position data are neither all “L” nor all “H”, the phases for start current conduction are set in the phase switching control circuit 12 by a signal COMMST based on detection results from the start current conduction phase determining circuit 21 (step S 23 ).
- the phase switching control circuit 12 controls the phase current output circuit 11 to change over the coils that are excited sequentially to conduct a drive current to the coils of the motor, to start synchronous driving (step S 24 ).
- back e.m.f develops in the non-conducting phases, and a decision is made in the next step S 25 whether the back e.m.f. detecting circuit 23 detected back e.m.f. If the back e.m.f. was not detected, a decision is made that the motor has not started, and the process returns to the step 21 to perform rotor position detection again. On the other hand, if back e.m.f.
- step S 26 back e.m.f. driving is performed which switches over the conducting phases according to timing of the zero-cross points detected by the back e.m.f. detecting circuit 23 and the rotation is accelerated by an increase of current passed through the coils, and the motor enters constant-speed driving (step S 27 ).
- FIG. 12 is a block diagram of an example of a hard disk device as a system including a motor driver unit according to one embodiment of the present invention.
- reference numeral 100 denotes a recording medium such as a magnetic disk
- 110 denotes a spindle motor to drive the magnetic disk 100
- 120 denotes a magnetic head including a write head and a read head
- 130 denotes a voice coil motor to move the arm assembly with the magnetic heads 120
- Reference numeral 210 denotes a motor driver unit that can be realized by embodying the present invention, and the motor driver unit 210 drives both the spindle motor 110 and the voice coil motor 130 .
- Reference numeral 220 denotes a read/write amplifier for amplifying a current, produced according to magnetic changes detected by the magnetic head 120 to transmit a readout signal to a data channel processor 230 , and for amplifying a write pulse signal from the data channel processor 230 to supply a drive current to the magnetic head 120 .
- Reference numeral 240 denotes a hard disk controller for receiving readout data RDT sent from the data channel processor 230 , performing an error correcting process thereon and performing an error correction coding process on write data from the host computer to supply the processed data to the data channel processor 230 .
- the data channel processor 230 performs a modulation/demodulation process suitable for digital magnetic recording and carries out a signal process, such as waveform shaping or the like taking magnetic recording characteristics into account.
- Reference numeral 250 denotes an interface controller that controls exchange of data between this system and external equipment, and the hard disk controller 240 mentioned above is connected to a host computer, such as the microcomputer of a personal computer, through the interface controller 250 .
- Reference numeral 260 denotes a microcomputer that performs a comprehensive control of the whole system and calculates a sector position from address information supplied from the hard disk controller 240 , and 270 denotes a buffer cache memory for temporarily storing read data read at high speed from the magnetic disk.
- the microcomputer 260 determines the operation mode from a signal sent by the hard disk controller 240 , and controls the related parts of the system according to the operation mode.
- the motor driver unit 210 comprises a spindle motor drive part and a voice coil motor drive part.
- the spindle motor drive part is servo-controlled to make the relative speed of the heads constant and the voice coil motor drive part is servo-controlled to make the center of the head coincident with the center of a truck.
- the hard disk control system 200 is formed by the motor driver unit 210 , the read/write amplifier 220 , the data channel processor 230 , the hard disk controller 240 , the interface controller 250 , the microcomputer 260 , and the cache memory 270 .
- the hard disk device is formed by the control system 200 , the magnetic disks 100 , the spindle motor 110 , the magnetic heads 120 , and the voice coil motor 130 .
Landscapes
- Engineering & Computer Science (AREA)
- Power Engineering (AREA)
- Control Of Motors That Do Not Use Commutators (AREA)
Abstract
Description
- The present invention relates to a technique for drive control of a brushless motor and a technique effective when applied to a method for determining phases (a pair of phases) at which to start current conduction when starting the motor, and particularly concerns a technique effective when used in a drive control apparatus of a spindle motor for rotating a disk-type storage medium, such as a HDD (hard disk drive) device.
- With hard disk devices, there has been a strong demand for higher speed in writing and reading information on a magnetic disk, namely, quicker access speed. To this end, it is required that the spindle motor be made much faster. In addition, demand is also mounting for reductions in size, power consumption and production cost of the drive control apparatuses. In conventional hard disk devices, DC polyphase brushless motors are generally used for their spindle motor to rotate the magnetic disks at high speed, and information is written or read on the rotating magnetic disk by bringing the read/write magnetic heads into contact with or in close vicinity to the disk.
- In brushless motors, there has been used a motor drive control method by which to prevent reverse rotation of the motor by detecting the positional relation of the rotor and the stator by means of Hall elements and by, from the detected positional relation, determining field-coil phases at which current conduction is to be started. Because mounting a rotor position detector using Hall elements in the motor increases the difficulty of downsizing the motor, sensorless motors have come to be used in large numbers in the hard disk devices. However, if the magnetic disk is driven by a sensorless motor, the rotor is likely to make a reverse rotation for an instant with a probability of ½ when the disk starts to rotate.
- With the rapidly multiplying storage density of the magnetic disks in hard disk devices in recent years, the magnetic read/write heads have been sharply reduced in size. Consequently, in the hard disk devices with the magnetic heads miniaturized to such an extent, there is a problem that if the rotor is turned in reverse even for an instant, the magnetic heads may suffer a fatal damage. To solve this problem, a control method has been proposed in which a pulse current of so short a duration as not to cause the rotor to react is supplied to the field coils of the stator, and the field coils where the amplitude is at the maximum value, in other words, the phases, where the field of the rotor magnet in the same direction as the generated field of the coils, causing magnetization to be saturated to make current flow most easily, are determined as the phases at which to start current conduction (Refer to JP-A-63-694895 published on Mar. 29, 1988 which corresponds to U.S. Ser. No. 880754 filed on Jul. 1, 1986).
- Another control method has been proposed in which a pulse current is conducted through the field coils of the stator and then the pulse current is conducted in the opposite direction, and differences in current rise time constant are detected at respective field coils where the current is passed through, and according to detection results, the position of the rotor is determined to determine a pair of phases at which current conduction is started. In other words, this control method is such that phases at which current conduction is started are determined by determining the rotor position based on detection results obtained by detection of differences in inductance by making use of a phenomenon that the inductance of the field coils varies whether the direction of the magnetic field is the same or not between the field coils and the rotor magnet (that is to say, whether magnetic saturation occurs or not) (Refer to JP-A-3-207250 published on Sep. 10, 1991 which corresponds to U.S. Ser. No. 413311 filed on Sep. 27, 1989).
- In addition to the above inventions, another invention has been proposed that the stopped position of the rotor is determined by applying a diagnosis signal of a frequency higher than the frequency of an exciting signal applied when the motor is started, to a single coil or two or more coils connected in series and detecting an induced voltage of one of the serially-connected coils (Refer to JP-A-7-274585 published on Oct. 20, 1995).
- However, the present inventors have revealed that the prior art described above suffer problems as follows.
- In the control method that determines a pair of phases, where current conduction is started, by passing a pulse current and detecting the maximum amplitude value, the maximum amplitude value depends on variations in winding in the field coils of the stator, for which reason detection errors occur due to very small winding variations that are unavoidable in the manufacturing process. In the control method that determines a pair of phases, where current conduction is started, by detecting the rotor position based on differences in current rise time constant, because a phenomenon of magnetic saturation is used, differences in time constant do not become conspicuous unless a fairly large current is passed, and therefore it is difficult to detect differences in the time constant when a current passed is so small as the rotor does not react to it. Another problem with this control method is that the point of reversal of the large-small relation among the time constants that occurs when the direction of a current is reversed does not coincide with the point of magnetic saturation, resulting in errors in determination results.
- The present invention has as its object to provide a brushless motor drive control technique that can prevents reverse rotation of the motor at starting by detecting the position of the rotor relative to the stator with fewer errors and determining a field coil pair at which current conduction is started.
- According to an aspect of the present invention, a pair of phases for current conduction to start the motor is determined by passing a pulse current with a duration so short as the rotor does not react through the field coil of any phase of the motor in first and second, mutually opposite, directions sequentially, and detecting induced voltages in the non-conducting phase by a pulse current in two opposite directions, combining voltages induced by a pulse current in the first direction and a pulse current in the second direction, detecting the polarities of combination results, and determining a pair of phases for current conduction when starting the motor based on polarity detection results related to a plurality of the conducting phases.
- The above-mentioned and other objects and features of the present invention will become obvious from the following description of this specification and the accompanying drawings.
- FIGS. 1a and 1 b are schematic diagrams illustrating the principle of a rotor position detecting method according to one embodiment of the present invention, in each of which diagrams the rotor is at a standstill with the border between an S pole and an N pole of the magnet of the rotor coincident with the center of the field coil Lv of the stator;
- FIGS. 2a and 2 b are schematic diagrams illustrating the principle of a rotor position detecting method according to one embodiment of the present invention, in each of which diagrams the rotor is at a standstill with the border between an S pole and an N pole of the magnet of the rotor shifted a little from the center of the field coil Lv to the field coil Lw of the stator.
- FIGS. 3a and 3 b are schematic diagrams illustrating the principle of a rotor position detecting method according to one embodiment of the present invention, in each of which diagrams the rotor is at a standstill with the border between an S pole and an N pole of the magnet of the rotor shifted a little from the center of the field coil Lv to the field coil Lu of the stator;
- FIGS. 4a and 4 b are graphs showing the relation between the position of the rotor relative to the stator and induced voltages at the non-conducting phases, obtained by an experiment conducted by the present inventors;
- FIG. 5 is a waveform diagram with respect to a three-phase motor, showing a relation between detection results on the positive and negative polarities of induced voltages Eu, Ev and Ew detected at the field coils Lu, Lv and Lw and leakage fluxes to the non-conducting phases, and showing a relation between leakage fluxes to the non-conducting phases and torques (back electromotive forces) of the respective field coils Lu, Lv and Lw when the motor is rotating;
- FIG. 6 is a block diagram of brushless motor drive control apparatus according to one embodiment of the present invention in a motor driver unit used in a hard disk storage device;
- FIG. 7 is a block diagram of a brushless motor drive control apparatus according to one embodiment of the present invention in a motor driver unit used in a hard disk storage device;
- FIG. 8 is a flowchart showing the operation procedure of the apparatus in FIG. 7;
- FIG. 9 is a timing chart showing the operation of the apparatus in FIG. 7 determining the rotor position by conducting a pulse current through the field coils of respective phases and detecting induced voltages at the non-conducting phases according to the procedure shown in FIG. 8;
- FIG. 10 is a block diagram for explaining the motor driver unit, which is used in a hard disk storage device and which includes the brushless motor drive control apparatus according to one embodiment of the present invention;
- FIG. 11 is a flowchart showing a control procedure from starting the motor till a constant speed operation in a motor driver unit including the brushless motor drive control apparatus according to one embodiment of the present invention; and
- FIG. 12 is a block diagram showing a representative configuration of the hard disk device as an example of a system using the motor driver unit including the brushless motor drive control apparatus according to one embodiment of the present invention.
- Embodiments will be described with reference to the accompanying drawings.
- Before proceeding with the description of the embodiments of the present invention, explanation will be made of the principle of rotor position detection, on which those embodiments are based, by referring to FIGS. 1a, 1 b, 2 a, 2 b, 3 a and 3 b. These figures schematically illustrate the relation of any three field coils Lu, Lv and Lw representing 3×n (n is a positive integer) coils with respect to the rotor magnet in order to explain the positional relation of the field coils of the stator with respect to the rotor magnet MG in a three-phase type polyphase brushless motor. The PIO denotes a phase current output circuit to pass currents through the field coils Lu, Lv and Lw. This phase current output circuit outputs a total of six currents (including currents in mutually opposite directions) to conduct them through any pair of field coils according to a specified sequence to thereby rotate the rotor. In FIGS. 1a, 1 b, 2 a, 2 b, 3 a and 3 b, the rotor magnet MG and the stator field coils Lu, Lv and Lw are arranged linearly but they are arranged coaxially in a real motor.
- FIG. 1a shows that the rotor is at a standstill with the border between an S pole and an N pole of the magnet MG of the rotor coincident with the center of the field coil Lv of the stator. Under this condition, when a short pulse current Iw is supplied from a phase current output terminal W, to which the field coil Lw is connected, to a phase current output terminal U, to which the field coil Lu is connected, the magnetic lines DMu produced by the field coil Lu are almost in the same direction as the magnetic lines DMr1 from the N pole of the magnet MG of the rotor facing the field coil Lu and, moreover, the magnetic lines DMw produced by the field coil Lw are almost in the same direction as the magnetic lines DMr2 of the S pole of the magnet MG of the rotor facing the field coil Lw. However, the magnetic lines DMu of the field coil Lu is in a direction opposite to the direction of the magnetic lines DMw of the field coil Lw. Because the border between the S pole and the N pole of the magnet MG coincides with the center of the field coil Lv of the stator, the leakage flux from the field coil Lu to the field coil Lv is the same in magnitude with and opposite in direction from the leakage flux from the field coil Lw to the field coil Lv and therefore they cancel each other, so that the induced voltage in the field coil Lv is zero.
- Under this condition, to pass a current through the field coils Lu and Lw in reverse direction, a short pulse current Iu is supplied from the phase current output terminal U to the phase current output terminal W as shown in FIG. 1b, the magnetic lines produced by the field coils Lu and Lw are respectively opposite in direction to the magnetic lines emerging from the N poles and going into the S poles of the magnet MG of the rotor which respectively face the field coils Lu and Lw. Therefore, the flux densities in the field coils Lu and Lw are lower than in FIG. 1a, and the leakage fluxes from the field coils Lu and Lw to the field coil Lv are small but are the same in magnitude and opposite in direction as in FIG. 1a, so that they cancel each other and the induced voltage in the field coil Lv is zero.
- Description will now be made of the state that the rotor is at a standstill with the border of an S pole and an N pole of the magnet MG of the rotor being located a little shifted from the center of the field coil Lv to the field coil Lw as in FIG. 2a. Under this condition, because the N pole of the magnet MG squarely faces the front side of the field coil Lu, the density of the flux emerging from that portion of the magnet MG of the rotor which faces the field coil Lu and then passing through the field coil Lu is higher than the density of the flux emerging from that portion of the rotor magnet MG which faces the field coil Lw and then passing through the field coil Lw. Therefore, if a short pulse current Iu is supplied from the phase current output terminal W to the phase current output terminal U, the magnetic lines DMu produced by the field coil Lu is in the same direction as the above-mentioned flux (magnetic lines) emerging from that portion of the rotor magnet MG which faces the field coil Lu and then passing through the field coil Lu, and the magnetic lines DMw produced by the field coil Lw is also in the same direction as the above-mentioned flux (magnetic lines) emerging from that portion of the rotor magnet MG which faces the field coil Lw and then passing through the field coil Lw. However, due to the above-mentioned difference in flux density, the leakage flux ML1 from the field coil Lu to the field coil Lv is larger than the leakage flux ML2 from the field coil Lw to the field coil Lv, so that a voltage is induced in the field coil according to the difference in leakage flux.
- On the other hand, as in FIG. 2a, under the condition that the rotor is at a standstill with the border between an S pole and an N pole of the rotor magnet MG being shifted a little from the center of the field coil Lv to the field coil Lw of the stator, the direction in which the current is supplied is reversed, and a short pulse current Iu is conducted from the phase current output terminal U to the phase current output terminal W as shown in FIG. 2b. Though the density of the flux emerging from the rotor magnet MG and then passing through the field coil Lu and the density of the flux emerging from the rotor magnet MG and then passing through the field coil Lw are the same as in FIG. 2a, the directions of the magnetic lines produced by the field coils Lu and Lw are opposite to the directions of the magnetic lines emerging from the N poles and going into the S poles of the magnet MG of the rotor that respectively face the field coils. In addition, the magnetic lines of the field coil Lu are set off by the N pole of the rotor magnet MG to a greater extent than the magnetic lines of the field coil Lw are set off by the S pole. Therefore, the leakage flux ML1 from the field coil Lu to the field coil Lv is smaller than the leakage flux ML2 from the field coil Lw to the field coil Lv, but because the directions of the leakage fluxes ML1 and LM2 are reverse from those in FIG. 2a, the polarity of the voltage induced in the Lv by the difference in leakage flux is the same as in FIG. 2a.
- Moreover, in the above case, the voltage induced in the field coil Lv is greater when a current is sent such that the magnetic lines produced by the field coils Lu and Lv are in the same direction as the magnetic lines of the rotor magnet MG as in FIG. 2a than when a current is sent such that the magnetic lines produced by the field coils Lu and Lv are in the opposite direction to the direction of the magnetic lines of the rotor magnet MG. Therefore, by passing a current through the field coils Lu and Lw alternately in opposite directions, detecting and comparing the voltage induced in the field coil Lv, it is possible to determine which poles are close to which field coils and whether the poles are north or south.
- FIG. 3a shows the state that the rotor is at a standstill with the border between an S pole and an N pole of the magnet MG of the rotor being shifted a little away from the center of the field coil Lv of the stator to the field coil Lu. Under this condition, because the S pole of the rotor magnet MG squarely faces the front side of the field coil Lw, the density of the flux emerging from that portion of the rotor magnet MG which faces the field coil Lw and then passing through the field coil Lw is higher than the density of the flux emerging from that portion of the rotor magnet MG which faces the field coil Lu and passing through the field coil Lu. Therefore, when a short pulse current Iw is supplied from the phase current output terminal W to the phase current output terminal U, the magnetic lines DMw produced by field coil Lw are in the same direction as the above-mentioned flux (magnetic lines) emerging from that portion of the rotor magnet MG which faces the field coil Lw and passing through the field coil Lw and also the magnetic lines DMu produced by the field coil Lu are in the same direction as the above-mentioned flux (magnetic lines) emerging from that portion of the rotor magnet MG which faces the field coil Lu and passing through the field coil Lu. However, owing to the above-mentioned difference in flux density, the leakage flux ML2 from the field coil Lw to the field coil Lv is larger than the flux ML1 from the field coil Lu to the field coil Lv and the voltage is induced in the field coil Lv according to the difference in leakage flux. The voltage induced in the field coil Lv in FIG. 3a is opposite in polarity to the voltage induced in the field coil Lv in FIGS. 2a and 2 b.
- When the direction of current flow is reversed and a short pulse current is conducted from the phase current output terminal U to the phase current output terminal W as shown in FIG. 3b, the density of the flux emerging from the rotor magnet MG and passing through the field coil Lw is the same as the density of the flux emerging from the rotor magnet MG and passing through the field coil Lu as in FIG. 3a, but the magnetic lines produced by the field coils Lw and Lu are respectively opposite in direction to the magnetic lines from the S and the N poles of the rotor magnet MG facing those field coils. Moreover, the magnetic lines produced by the field coil Lw are set off by the S pole of the rotor magnet MG to a greater extent than the magnetic lines produced by the field coil Lu are set off by the N pole of the rotor magnet MG. Therefore, though the leakage flux ML2 from the field coil Lw to the field coil Lv is smaller than the leakage flux ML1 from the field coil Lu to the field coil Lv, because the direction of the magnetic lines ML1 and ML2 is opposite to that in FIG. 3a, the polarity of the voltage induced in the field coil Lv according to the difference in leakage flux is the same as in FIG. 3a.
- In addition, the voltage induced in the field coil Lv is larger when a current is supplied such that the magnetic lines produced are in the same direction as the magnetic lines of the rotor magnet MG as shown in FIG. 3a as in FIGS. 2a and 2 b than when a current is supplied such that the magnetic lines produced by the field coils Lu and Lv are respectively opposite in direction to the magnetic lines of the rotor magnet MG as shown in FIG. 3b. Therefore, also in this case, by passing a current through the field coils Lu and Lw alternately in opposite directions, detecting and comparing the voltage induced in the field coil Lv, it is possible to determine which poles are close to which field coils and whether the poles are north or south. Note that the polarity of the greater one of the leakage fluxes detected is opposite to that detected in the case of FIG. 2.
- FIG. 4a shows a result of a test conducted by the inventors. The vertical axis indicates the detected values of the induced voltage and the horizontal axis indicates the position of the rotor with respect to the stator expressed in electrical angles. For example, in a motor with a 12-pole rotor, a mechanical angle of 60 degrees corresponds to an electrical angle of 360 degrees. In other words, FIG. 4a shows the result of measurement of voltages induced in the field coil Lv by passing a current through the field coils Lu and Lw alternately in opposite directions.
- In FIG. 4a, the solid line A indicates the induced voltage in the field coil Lv when a current is conducted from the field coil Lw to the field coil Lu and the broken line B indicates the induced voltage in the field coil Lv when a current is conducted from the field coil Lu to the field coil Lw. From FIG. 4a, one of the zero-cross points of the two curves (A and B) is not clear, in other words, it is difficult to uniquely determine the positional relation between the rotor and the stator from induced voltages detected when a current was sent in one direction. Therefore, if an attempt is made to determine the rotor position from induced voltages by a current supplied in one direction, errors are likely to occur. So, the inventors combined (add up) the above two curves by way of trial, and found as indicated by the broken line C in FIG. 4b that the zero-cross points became clear and the rotor position can be determined with high accuracy.
- According to an aspect of the present invention, the present invention is based on an idea of providing the brushless motor drive circuit with a circuit for determining a pair of phases at which current conduction is started by conducting a pulse current through two field coils alternately in opposite directions, combining (adding) the voltages induced in the non-conducting-phase field coil by respective currents and sampled and held by a sample-and-hold circuit, or integrating and then adding up the respective induced voltages, and on the basis of the sum, detecting the polarities of the induced voltages.
- FIG. 5 shows with regard to a three-phase motor the relation between detected polarities (positive and negative) of the induced voltages Eu, Ev and Ew detected at the field coils Lu, Lv and Lw and the leakage fluxes φu, φv and φw to the non-conducting-phase field coils, and the relation between the leakage fluxes φu, φv and φw to the non-conducting-phase field coils and the torque Tu, Tv and Tw, namely, the back electromotive forces of the field coils Lu, Lv and Lw while the motor was at a standstill.
- If the polarity-detecting results for the detected induced voltages Eu, Ev and Ew when the motor is at a standstill are “+, +, −” for example, by conducting a current from the u-phase field coil Lu to the v-phase field coil Lv to start the motor, the maximum torque can be obtained. It is understood from FIG. 5 that the positions where the polarities of the induced voltages are inverted coincide with the positions where the polarities of the leakage fluxes are inverted and it never occurs that detection about the polarity of induced voltages is unclear. Moreover, because the leakage flux is proportional to the flux density in the field coil, it is not always required to make magnetic saturation occur in the field coil when detecting an induced voltage. Therefore, it is possible to make this determination by passing a smaller pulse current as compared with one of the conventional control methods in which a determination is made on a pair of phases at which to start current conduction by detecting the rotor position based on differences in current rise time constant.
- Table 1 shows the relation between the polarity detection results for the combined induced voltages Eu, Ev and Ew and the phases for starting current conduction. Obviously, the relation in Table 1 corresponds to the relation shown in FIG. 5. After the polarity detection result is obtained, by arranging for a determination to be made on a pair of phases at which to start current conduction with reference to Table 1, the motor can be started in the correct rotating direction in a shortest time regardless of the rotor position at the moment. The polarity (positive or negative) detection results of the induced voltages Eu, Ev and Ew can never be all “+” or all “−” when induced voltages are detected normally at the field coils of the respective phases. Therefore, if such detection results are given, this should be regarded as caused by detection errors and detection should be carried out over again.
TABLE 1 START CURRENT CONDUCTION PHASES INDUCED VOLTAGE (DIRECTION OF EU Ev EW CURRENT FLOW) DETECTION negative negative positive phase v → phase u RESULT positive negative positive phase w → phase u positive negative negative phase w → phase v positive positive negative phase u → phase v negative positive negative phase u → phase w negative positive positive phase v → phase w - Meanwhile, in a real motor, even if the rotor and the stator are in the positional relation shown in FIGS. 1a and 1 b, in other words, even if the center of the field coil Lv coincides with the border between an S pole and an N pole of the rotor, when a current is passed through the field coils Lu and Lw, the leakage flux from either one of those field coils to the field coil Lv is greater than the leakage flux from the other coil due to, for example, variation in winding of the coils, and a voltage proportional to a difference in leakage flux is induced in the field coil Lv. However, in FIG. 1a, a current is supplied such that the magnetic lines of the field coils are in the same direction as the magnetic lines of the rotor magnet, whereas, in FIG. 1b, a current is supplies such that the magnetic lines of the field coils are in the opposite direction to the magnetic lines of the rotor magnet. Therefore, in these two cases, the voltages induced in the field coil Lv ascribable to variation in winding are mutually opposite in polarity, and when these induced voltages are added together, they cancel each other and become zero.
- FIG. 6 shows a brushless motor drive control apparatus mounted in a motor driver unit for use in a hard disk device and structured according to one embodiment of the present invention.
- In FIG. 6,
reference numeral 11 denotes a phase current output circuit that supplies current to the field coils Lu, Lv and Lw in a three-phase brushless motor, 12 denotes a phase switching control circuit that supplies a selection signal of the phases, through which a current is to be passed, to the phasecurrent output circuit current output circuit 11, for detecting induced voltages, 14 a and 14 b denote sample-and-hold circuits for sampling and holding the induced voltages detected by the inducedvoltage output circuit 13 when the field coils are supplied with a current in two opposite directions, and 15 denotes an adder circuit that adds up the voltages held in the sample-and-hold circuits 14 a and 14 b and generates a rotor position signal. -
Reference numeral 16 denotes a polarity detecting circuit for detecting the polarity of an addition result in theadder circuit 15, in other words, detecting whether the sum of voltages is positive or negative, and generating a polarity signal, 17 a, 17 b and 17 c denote data latch circuits for storing polarity data representing polarity signals generated by thepolarity detecting circuit 16 when a current is passed through the field coils, 18 denotes a discriminating circuit for determining rotor position, in other words, a pair of phases through which a current is to be supplied in the first place based on polarity data stored in the data latchcircuits - The
timing circuit 19 supplies a phase selection switching timing signal T.CLK and a rotor position detection ON/OFF signal STR to the phase switchingcontrol circuit 12, an ON/OFF signal SNS to the inducedvoltage detecting circuit 13, a sampling timing signal SPR to the sample-and-hold circuits 14 a and 14 b, an operation timing signal ADD and a reset signal RST to theadder circuit 15, latch timing signals LTA to LTC to the data latchcircuits circuit 18. The circuit blocks 11 to 18 operate sequentially by control signals from thetiming circuit 19. - By provision of this
timing circuit 19, it becomes possible to realize a drive control apparatus which can start a brushless motor in a short time by determining by itself a pair of phases at which to start current conduction when a clock signal is only given without control signals being generated and supplied externally. - When the ON/OFF signal STR issued from the
timing circuit 19 is at its effective level, the phase switchingcontrol circuit 12 sends a phase selection control signal to the phasecurrent output circuit 11 to detect the rotor position and pass a small-pulse current through the field coils. In response to the phase selection control signal from the phase-switchingcontrol circuit 12, the phasecurrent output circuit 11 sends a pulse current, having such a short duration as the rotor does not react, to any pair of field coils Lu, Lv and Lw in one direction or in the opposite direction. On the other hand, when the phase switchingcontrol circuit 12 receives a phase selection setting signal COMMST indicating the phases at which to start current conduction, from the discriminatingcircuit 18, the phase switchingcontrol circuit 12 sends a phase selection control signal to the phasecurrent output circuit 11 directing it to pass a pulse current through the set phases at which to start current conduction to rotate the motor. At this time, the ON/OFF signal STR from thetiming circuit 19 is at the effective level. - The induced
voltage detecting circuit 13 has a rotor position detecting action ON/OFF signal SNS supplied from thetiming circuit 19 and also has another signal, indicating which phases are being selected, supplied from the phase switchingcontrol circuit 12. By those signals, the inducedvoltage detecting circuit 13 detects and amplifies the voltage induced in the non-conducting-phase coil. The inducedvoltage detecting circuit 13, if formed by a MOSFET, may include a switch (selector) to select a voltage of the non-conducting phase, where current is not flowing, out of the output terminals U, V and W of the phasecurrent output circuit 11 and also an amplifier circuit to amplify the selected voltage. If formed by a bipolar transistor, the inducedvoltage detecting circuit 13 may include three differential amplifiers that each have at one input terminal supplied with one of the voltages of the output terminals U, V and W of the phasecurrent output circuit 11 and at the other input terminal supplied with the potential at the common connection node NO of the respective field coils. When the inducedvoltage detecting circuit 13 is formed by three differential amplifier circuits, thecircuit 13 may be configured such that any one of the differential amplifier circuits performs amplification when its current source is turned on by a phase selection control signal. - The
adder circuit 15 may be an analog adder circuit using an operational amplifier or may be a digital adder circuit. In the case of a digital adder, it is only necessary to insert an A/D converter circuit as the stage subsequent to the sample-and-hold circuits 14 a and 14 b. Thepolarity detecting circuit 16 may be an analog or digital circuit depending on the type of theadder circuit 15. If theadder 15 is formed as a digital circuit, thepolarity detecting circuit 16 may be formed by a subtractor. In place of the sample-and-hold circuits 14 a and 14 b, registers may be used, and an A/D converter circuit may be provided at the preceding stage to have the detected induced voltage converted into a digital value and stored as digital data in the registers. - In the above embodiment, the discriminating
circuit 18 that designates start current conduction phases from a polarity detection result is mounted together with the inducedvoltage detecting circuit 13, etc. However, it is possible to provide a microcomputer that receives polarity data from thelatch circuits 17 a to 17 c, which hold data from thepolarity detecting circuit 16, and determines a pair of phases at which to start current conduction and sets the phase data in the phase switchingcontrol circuit 12. - FIG. 7 shows a motor drive control apparatus in a motor driver unit, which is used in a hard disk storage device and which is structured according to another embodiment of the present invention.
- This embodiment uses an integrating
circuit 20, which has replaced the sample-and-hold circuits 14 a and 14 b and theadder 15 in the embodiment shown in FIG. 6. This integratingcircuit 20 may be formed by a well-known integrating circuit including a CR integrating circuit made of a capacitor and a resistance, or by a well-known integrating circuit including an operational amplifier and a capacitor connected between an output terminal and an inverted input terminal of the amplifier. - In this embodiment, by a control signal from the
timing circuit 19, the integrating circuit integrates an induced voltage which is detected at the non-conducting phase by the inducedvoltage detecting circuit 13 when a pulse current is passed through the field coils in one direction in the first place and, under the condition that the result of integration is maintained, also integrates an induced voltage which is detected at the non-conducting phase by the inducedvoltage detecting circuit 13 when a pulse current is passed through the field coils in the opposite direction. Thepolarity detecting circuit 16 is used to detect the polarity of the electric charge remaining in the capacitor as a component part of the integrating circuit (hereafter referred to as an integrating capacitor). After this determination is made, control is performed so that the integrating capacitor is reset once, and then a pulse current is passed through a subsequent pair of field coils, and the induced voltage detected is integrated. - Description will be made of the operation of the motor drive control apparatus in FIG. 7 with reference to a flowchart in FIG. 8. FIG. 8 shows the operation procedures of the phase
current output circuit 11 at left and the induced current detectingcircuit 13 and the integratingcircuit 20 at right to show the related actions compared with each other. - When the enable signal EN (Refer to FIGS. 9 and 10) from a control circuit is asserted to the low level, the
timing circuit 19 starts to generate a control signal for detecting the rotor position. With this action got started, in the first step S0, while the output terminals of the phasecurrent output circuit 11 are in high impedance state in which the terminals are all opened, that is, no current is output from any phase output terminal, the capacitor of the integratingcircuit 20 is reset, more simply, the capacitor discharges itself of electric charge. Next, a pulse current is passed from the phase v to the phase w by the phasecurrent output circuit 11. The pulse current used has so short a duration as the rotor does not react to it. The induced voltage of the phase u, which is non-conducting at this moment, is detected by the detectingcircuit 13, and is integrated by the integrating circuit 20 (Step S1). - Subsequently, in a step S2, all phase terminals of the phase
current output circuit 11 are opened, and for this while the voltage integrated in the integratingcircuit 20 is held. In the next step S3, the phasecurrent output circuit 11 sends a pulse current from the phase w to the phase v in the opposite direction to the current flow in the step S1. At this time, the induced voltage of the phase u in the non-conducting state is detected by the inducedvoltage detecting circuit 13, and the phase-u induced voltage is integrated using the result of the previous integration as the initial value. Accordingly, in the integrating capacitor, the integration result of the phase-u induced voltage when a current was passed from the phase v to the phase w is added with the integration result of the phase-u induced voltage when a current was passed from the phase w to the phase v. - In the step S4, the polarity of the electric charge remaining in the integrating capacitor is detected by the
polarity detecting circuit 16, and a detection decision result u-DATA is stored in thefirst circuit 17 a. All the output terminals of the phasecurrent output circuit 11 are opened, and in the integratingcircuit 20, the electric charge held in the integrating capacitor is reset. In a step S5, the phasecurrent output circuit 11 passes a pulse current from the phase w to the phase u. At this time, the induced voltage of the phase v, which is not conducting, is detected by the detectingcircuit 13, and the induced voltage is integrated by the integratingcircuit 20. - In a step S6, the voltage integrated by the integrating
circuit 20 is held, and all output terminals of the phasecurrent output circuit 11 are opened. In the next step S7, the phasecurrent output circuit 11 passes a pulse current from the phase u to the w phase in the direction opposite from the the direction in the step S5, the induced voltage of the phase v, which is not conducting, is detected by the detectingcircuit 13, and the integratingcircuit 20 integrates the phase-v induced voltage using the previous integration result as the initial value. - Subsequently, in a step S8, after twice integration, the polarity of the charge remaining in the integrating capacitor is detected by the
polarity detecting circuit 16. The detection result v-DATA in the seconddata latch circuit 17 b. In addition, all phase terminals of the phasecurrent output circuit 11 are opened, and the charge held in the integrating capacitor in the integratingcircuit 20 is reset. - In steps S9 to S11, as in the above-mentioned steps S5 to S7, the phase
current output circuit 11 passes a pulse current from the phase u to the phase v, the induced voltage of the phase w, which is not conducting, is detected by the detectingcircuit 13, and is integrated by the integratingcircuit 20. Subsequently, a reverse pulse current is passed from the phase u to the phase v, the induced voltage of the phase w, which is not conducting, is detected by the detectingcircuit 13, and the phase-w induced voltage is integrated by the integratingcircuit 20. - In the next step S12, from results of twice integration in the integrating
circuit 20, the polarity of the charge remaining in the integrating capacitor is detected by thepolarity detecting circuit 16, and a detection result w-DATA is stored in the thirddata latch circuit 17 c. All phase output terminals of the phasecurrent output circuit 11 are opened, and the charge held in the integrating capacitor is reset in the integratingcircuit 20. - After this, in a step S13, the discriminating
circuit 18 determines the position of the rotor based on detection results u-DATA, v-DATA and w-DATA stored in the data latchcircuits circuit 18 determines the rotor position according to Table 1 from three pieces of information indicating the positive or negative polarity stored in the data latchcircuits control circuit 12 to initialize the current conduction phases. - In determining the rotor position in the step S13, it is improbable that the polarity detection results (positive or negative) stored in the data latch
circuits - FIG. 9 is a timing chart when the rotor position is detected by supplying a pulse current to the respective phases sequentially and detecting the induced voltages at the non-conducting phases according to the above-mentioned procedure. In FIG. 9, u, v and w denote the output voltages of the phases of the phase
current output circuits 11, Iu, Iv and Iw denote the currents that flow in the field coils Lu, Lv and Lw, SNS denotes an ON/OFF control signal for integrating actions to the integratingcircuit 20, RST denotes a reset signal to discharge the charge of the integrating capacitor, LTA, LTB and LTC denote signals for giving latch timing to the data latchcircuits circuit 18, and COMMST denotes a timing signal which the discriminatingcircuit 18 issues to initialize the phase selection in the phase switchingcontrol circuit 12 based on a discrimination result. Clock cycles T0 to T13 in FIG. 9 respectively correspond to steps S0 to S13 in the flowchart in FIG. 8. - FIG. 10 shows an example of system configuration including a motor driver unit, which includes a motor drive control apparatus according to another embodiment of the present invention, and which is used in a hard disk storage device. The circuit blocks and circuit elements located in a range enclosed by a
broken line 210 in FIG. 10 are formed on one semiconductor substrate, such as a single crystal silicon chip, but they are not to be construed as restrictive. - In FIG. 10, the circuits designated by the same reference numerals as in FIG. 7 are the circuits, which have or include the same functions. Specifically,
reference numeral 11 denotes a phase current output circuit that selectively and sequentially supplies current to the three-phase field coils Lu, Lv and Lw of a spindle motor to rotate the disks of a hard disk device, 12 denotes a phase switching control circuit to supply to the phase current output circuit 11 a signal for selection of the phases through which to pass a current (phase selection control signal), 19 denotes a timing circuit to generate control signals to the above-mentioned circuit blocks 11 through 18 based on a clock signal CLK. - In this embodiment, out of the circuit blocks shown in FIG. 7 (or FIG. 6), the induced
voltage detecting circuit 13, connected to the output terminals U, V and W of the phasecurrent output circuit 11, for detecting the induced voltages, the integrating circuit 20 (or sample-and-hold circuits 14 a and 14 b, and an adder 15) for integrating induced voltages detected by the inducedvoltage detecting circuit 13, thepolarity detecting circuit 16 for detecting the polarity of integration results (or addition results), the data latchcircuits circuit 18 for discriminating the rotor position, that is, a pair of phases through which a current is conducted in the first place from detection results stored in the data latchcircuits phase determining circuit 21. - In this embodiment, the start current conduction
phase determining circuit 21 is connected to external terminals P1 and P2 on the chip, and the terminals P1 and P2 are connected to an externally-mounted discrete capacitor Ci as the integrating capacitor of the integrating circuit. This integrating capacitor serves to eliminate noise in detected voltages in the inducedvoltage detecting circuit 13 that detects the induced voltages at the non-conducting phases to determine start current conduction phases with high accuracy. This embodiment is particularly effective in a case where the phasecurrent output circuit 11 is formed by a bipolar transistor. This is because large noise is contained in the induced voltages at the non-conducting phases when the phasecurrent output circuit 11 is a bipolar transistor type than when it is a MOSFET type. - In FIG. 10, 23 denotes a back e.m.f. detecting circuit that monitors the voltages at the output terminals U, V and W of the phase
current output circuit 11 when they are non-conducting, detects zero-cross points of the back e.m.f., and gives a phase switching timing signal to the phase switchingcontrol circuit control circuit 12 during constant-speed rotation based on an output signal of the back e.m.f. detectingcircuit current output circuit 11 when bringing the motor to a stop, and 25 denotes a speed control circuit for controlling the motor speed by detecting the current flowing in the phasecurrent output circuit 11, and, in response to a speed-related command signal SPNCTL from a microcomputer, increasing the rotation speed by increasing the current applied to the phasecurrent output circuit 11 or reducing the speed by decreasing the applied current. - The
PLL circuit 22 is connected to external terminals P3, P4 and P5 provided on the chip, and the external terminals P3, P4 and P5 are connected with externally-mounted elements, such as capacitors C0 and C1 and a resistance R1, which form a loop filter of the PLL, and a capacitor C2 and a resistance R2, which determine an oscillation frequency of the VCO. The parts mounted on the motordriver IC chip 210 include a protectingcircuit 26 for detecting the temperature of the chip and bringing the operation of the circuit to a stop, a boostingcircuit 27 for boosting the gate voltage to make it possible to sufficiently drive MOSFET's used, avoltage regulator 28 to supply a power source voltage to the IC or LSI provided around the motordriver IC chip 210, and a VCMdrive control circuit 30 for driving the voice coil motor to move the magnetic heads, but they should not be construed as restrictive. - The VCM
drive control circuit 30 comprises aVCM driving circuit 31 for outputting current to drive the driving coil L VCM of the voice coil motor, aserial port 32 for serial transmission and reception to and from the microcomputer, a D/A converter circuit 33 for converting control data received from the microcomputer into an analog signal and supplying to theVCM driving circuit 31, a back e.m.f. detectingcircuit 34 for detecting the back e.m.f. of the coil L VCM to obtain speed information when starting the motor, an A/D converter circuit 35 for converting a detected back e.m.f. into a digital signal, a power supplyvoltage monitoring circuit 36 for monitoring the levels of power supply voltages Vss and Vdd to detect power cut-off, and a headretraction drive circuit 37 for controlled driving of the coil L VCM to enable the magnetic heads to retract to outside the disk surface when power cut-off is detected. - The above-mentioned
serial port 32 sends and receives serial data DATA based on a serial clock SCLK or a load instruction signal LOAD from the microcomputer and generates control signals, such as an enable signal VCMEN to theVCM driving circuit 31 based on data received. Theserial port 32 also sends to the microcomputer an A-D converted version of a back e.m.f. induced in the coil LVCM when the motor is started, the back e.m.f. being detected by the back e.m.f. detectingcircuit 34 for obtaining speed information from the detected back e.m.f. Thus, the microcomputer control the motor speed by monitoring motor speed information so that the magnetic head is prevented from falling on the hard disk surface faster than a specified speed. - Further, the
serial port 32 has a function to generate an enable EN signal to thetiming generating circuit 19 of the spindle motor control system based on data received from the microcomputer, and generates control signals, such as a phase selection setting signal COMM. Note that when the phase switchingcontrol circuit 12 starts the motor by a phase selection setting signal COMMST supplied from the start current conductionphase determining circuit 21 as in the above-mentioned embodiment, it becomes unnecessary to send a phase selection setting signal COMM from the microcomputer. However, without mounting the discriminatingcircuit 18 for discriminating the start current conduction phases from a polarity detection result in the start current conductionphase determining circuit 21 and if it is arranged that the microcomputer receives information from thelatch circuits 17 a to 17 c, which store polarity data, and determines and sets a pair of phases for start current conduction in the phase switchingcontrol circuit 12, the above-mentioned route passing through theserial port 32 can be used to initialize the phase switchingcontrol circuit 12. - Meanwhile, in the motor driver unit in this embodiment, there are provided a power terminal P6 for a power source voltage Vss of 5V for example, a power terminal P7 for a power supply voltage Vdd of 12V or 5V, and a set of power terminals P8 for ground potential (0V). To the power terminal P7, 12V is applied for use in a 3.5-inch hard disk device, or 5V is applied for use in a 2.5-inch hard disk device. P11 to P14 denote the terminals connected to the terminals of the field coils of a spindle motor.
- FIG. 11 shows a control procedure from starting of a motor till a constant speed drive in the motor driver unit, which includes the start current conduction phase determining circuit.
- In this motor driver unit, when a start signal is given by the microcomputer, the start current conduction
phase determining circuit 21 detects rotor position to begin with (step S21). This rotor position detection is performed by the steps S1 to S12 in the flowchart in FIG. 8, which has been described. When the rotor position has been detected, a decision is made in a step S22 whether rotor data are all “L” (low level) or all “H” (high level), if the decision result is “Yes”, which means that data are all “L” or all “H”, rotor position determination (step S21) is performed again. It ought to be noted that the step S22 corresponds to the S13 in FIG. 8. If the decision result is “No” in the step S22, which means that position data are neither all “L” nor all “H”, the phases for start current conduction are set in the phase switchingcontrol circuit 12 by a signal COMMST based on detection results from the start current conduction phase determining circuit 21 (step S23). - Subsequently, the phase switching
control circuit 12 controls the phasecurrent output circuit 11 to change over the coils that are excited sequentially to conduct a drive current to the coils of the motor, to start synchronous driving (step S24). When the rotor starts to rotate normally, back e.m.f develops in the non-conducting phases, and a decision is made in the next step S25 whether the back e.m.f. detectingcircuit 23 detected back e.m.f. If the back e.m.f. was not detected, a decision is made that the motor has not started, and the process returns to thestep 21 to perform rotor position detection again. On the other hand, if back e.m.f. was detected, in a step S26, back e.m.f. driving is performed which switches over the conducting phases according to timing of the zero-cross points detected by the back e.m.f. detectingcircuit 23 and the rotation is accelerated by an increase of current passed through the coils, and the motor enters constant-speed driving (step S27). - FIG. 12 is a block diagram of an example of a hard disk device as a system including a motor driver unit according to one embodiment of the present invention.
- In FIG. 12,
reference numeral 100 denotes a recording medium such as a magnetic disk, 110 denotes a spindle motor to drive themagnetic disk magnetic heads 120.Reference numeral 210 denotes a motor driver unit that can be realized by embodying the present invention, and themotor driver unit 210 drives both thespindle motor 110 and thevoice coil motor 130. -
Reference numeral 220 denotes a read/write amplifier for amplifying a current, produced according to magnetic changes detected by themagnetic head 120 to transmit a readout signal to adata channel processor 230, and for amplifying a write pulse signal from thedata channel processor 230 to supply a drive current to themagnetic head 120.Reference numeral 240 denotes a hard disk controller for receiving readout data RDT sent from thedata channel processor 230, performing an error correcting process thereon and performing an error correction coding process on write data from the host computer to supply the processed data to thedata channel processor 230. Thedata channel processor 230 performs a modulation/demodulation process suitable for digital magnetic recording and carries out a signal process, such as waveform shaping or the like taking magnetic recording characteristics into account. -
Reference numeral 250 denotes an interface controller that controls exchange of data between this system and external equipment, and thehard disk controller 240 mentioned above is connected to a host computer, such as the microcomputer of a personal computer, through theinterface controller 250.Reference numeral 260 denotes a microcomputer that performs a comprehensive control of the whole system and calculates a sector position from address information supplied from thehard disk controller microcomputer 260 determines the operation mode from a signal sent by thehard disk controller 240, and controls the related parts of the system according to the operation mode. - The
motor driver unit 210, as described above, comprises a spindle motor drive part and a voice coil motor drive part. By a signal from themicrocomputer 260, the spindle motor drive part is servo-controlled to make the relative speed of the heads constant and the voice coil motor drive part is servo-controlled to make the center of the head coincident with the center of a truck. - The hard
disk control system 200 is formed by themotor driver unit 210, the read/write amplifier 220, thedata channel processor 230, thehard disk controller 240, theinterface controller 250, themicrocomputer 260, and thecache memory 270. The hard disk device is formed by thecontrol system 200, themagnetic disks 100, thespindle motor 110, themagnetic heads 120, and thevoice coil motor 130. - Description has been made of the embodiments made by the inventors. However, the present invention is not limited to those embodiments, but obviously many changes and modifications of the present invention may be made without departing from the spirit or scope of the invention. For example, in the above-mentioned embodiments, description has been made using a three-phase motor as an example, but the present invention is not limited to three-phase motors, but may be applied to the driving circuits of two-phase motors and four-phase or other polyphase motors. Further, in those embodiments, the motor driver unit described has been a composite type that includes not only the driving circuit of the spindle motor but also the driving circuit of the voice coil motor mounted on one semiconductor chip. However, needless to say, the present invention may be applied to a semiconductor integrated circuit having only the spindle motor driving circuit mounted on it.
- Moreover, description has centered around the field as the backdrop of the invention in which the invention made by the inventors is applied to the motor driver unit of the hard disk storage device, but the present invention is not limited to this area and may be utilized in motor driver units for driving brushless motors, such as a motor to drive the polygon mirror of a laser beam printer or a motor for an axial flow fan.
- According to the embodiments of the present invention, it is possible to realize a semiconductor integrated circuit for brushless motor drive control and a brushless motor drive control apparatus, which are capable of preventing a reverse rotation when starting the motor by detecting the rotor position relative to the stator with less errors to determine field coils at which current conduction is started.
Claims (15)
Priority Applications (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US09/893,549 US6340873B2 (en) | 2000-03-29 | 2001-06-29 | Semiconductor integrated circuit for brushless motor drive control and brushless motor drive control apparatus |
US10/025,545 US6563286B2 (en) | 2000-03-29 | 2001-12-26 | Semiconductor integrated circuit for brushless motor drive control and brushless motor drive control apparatus |
Applications Claiming Priority (4)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP2000090037A JP3673964B2 (en) | 2000-03-29 | 2000-03-29 | Brushless motor drive control semiconductor integrated circuit and brushless motor drive control device |
JP2000-090037 | 2000-03-29 | ||
US09/818,511 US6344721B2 (en) | 2000-03-29 | 2001-03-28 | Semiconductor integrated circuit for brushless motor drive control and brushless motor drive control apparatus |
US09/893,549 US6340873B2 (en) | 2000-03-29 | 2001-06-29 | Semiconductor integrated circuit for brushless motor drive control and brushless motor drive control apparatus |
Related Parent Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US09/818,511 Continuation US6344721B2 (en) | 2000-03-29 | 2001-03-28 | Semiconductor integrated circuit for brushless motor drive control and brushless motor drive control apparatus |
Related Child Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US10/025,545 Continuation US6563286B2 (en) | 2000-03-29 | 2001-12-26 | Semiconductor integrated circuit for brushless motor drive control and brushless motor drive control apparatus |
Publications (2)
Publication Number | Publication Date |
---|---|
US20010045812A1 true US20010045812A1 (en) | 2001-11-29 |
US6340873B2 US6340873B2 (en) | 2002-01-22 |
Family
ID=18605700
Family Applications (3)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US09/818,511 Expired - Lifetime US6344721B2 (en) | 2000-03-29 | 2001-03-28 | Semiconductor integrated circuit for brushless motor drive control and brushless motor drive control apparatus |
US09/893,549 Expired - Lifetime US6340873B2 (en) | 2000-03-29 | 2001-06-29 | Semiconductor integrated circuit for brushless motor drive control and brushless motor drive control apparatus |
US10/025,545 Expired - Lifetime US6563286B2 (en) | 2000-03-29 | 2001-12-26 | Semiconductor integrated circuit for brushless motor drive control and brushless motor drive control apparatus |
Family Applications Before (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US09/818,511 Expired - Lifetime US6344721B2 (en) | 2000-03-29 | 2001-03-28 | Semiconductor integrated circuit for brushless motor drive control and brushless motor drive control apparatus |
Family Applications After (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US10/025,545 Expired - Lifetime US6563286B2 (en) | 2000-03-29 | 2001-12-26 | Semiconductor integrated circuit for brushless motor drive control and brushless motor drive control apparatus |
Country Status (2)
Country | Link |
---|---|
US (3) | US6344721B2 (en) |
JP (1) | JP3673964B2 (en) |
Cited By (8)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US20100117572A1 (en) * | 2007-03-30 | 2010-05-13 | Tomomi Harada | Brushless motor control device and brushless motor control method |
US20150188464A1 (en) * | 2013-12-26 | 2015-07-02 | Chervon Intellectual Property Limited | Brushless motor and control method thereof |
US9543865B2 (en) | 2013-09-20 | 2017-01-10 | Hitachi Automotive Systems, Ltd. | Device for driving three-phase brushless motor |
EP1753124A3 (en) * | 2005-08-10 | 2017-08-23 | Mitsubishi Heavy Industries, Ltd. | Control device for electric compressor |
EP3226403A1 (en) | 2016-04-01 | 2017-10-04 | Melexis Technologies NV | Position detection of a 1-coil or 2- coil motor |
US10181773B1 (en) * | 2017-07-05 | 2019-01-15 | Anpec Electronics Corporation | Detection device and detection method of rotor position of three-phase motor |
US10381965B2 (en) | 2016-01-12 | 2019-08-13 | Hitachi Automotive Systems, Ltd. | Drive device and method for three-phase brushless motor |
US10998846B2 (en) | 2017-05-24 | 2021-05-04 | Hangzhou Sanhua Research Institute Co., Ltd. | Control system and control method |
Families Citing this family (52)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JP4223667B2 (en) | 2000-09-18 | 2009-02-12 | 株式会社日立グローバルストレージテクノロジーズ | Magnetic disk unit |
JP2002247875A (en) * | 2001-02-22 | 2002-08-30 | Japan Servo Co Ltd | Fan motor driving circuit |
JP2002343013A (en) * | 2001-05-18 | 2002-11-29 | Sanyo Electric Co Ltd | Disk drive device |
JP3998960B2 (en) * | 2001-12-12 | 2007-10-31 | 株式会社ルネサステクノロジ | Sensorless motor drive control system |
JP3932408B2 (en) * | 2002-02-01 | 2007-06-20 | ミネベア株式会社 | Brushless DC 1-phase motor pre-drive circuit |
TW200405646A (en) * | 2002-05-24 | 2004-04-01 | Virginia Tech Intell Prop | Method, apparatus, and system for drive control, power conversion, and start-up control in an SRM or PMBDCM drive system |
US7412339B2 (en) * | 2002-05-24 | 2008-08-12 | Virginia Tech Intellectual Properties, Inc. | Method and apparatus for identifying an operational phase of a motor phase winding and controlling energization of the phase winding |
JP2004040943A (en) * | 2002-07-05 | 2004-02-05 | Nec Electronics Corp | Method and device for detecting rotor stop position of sensorless motor, and method and device for starting |
JP3993502B2 (en) | 2002-10-21 | 2007-10-17 | 株式会社ルネサステクノロジ | Multi-phase DC motor rotation drive control device and start-up method |
US7157878B2 (en) * | 2002-11-19 | 2007-01-02 | Delphi Technologies, Inc. | Transient compensation voltage estimation for feedforward sinusoidal brushless motor control |
JP2004297904A (en) | 2003-03-27 | 2004-10-21 | Renesas Technology Corp | Drive control device for dc motor, rotation drive system for the dc motor and coil-driving semiconductor integrated circuit |
WO2004093306A2 (en) * | 2003-04-10 | 2004-10-28 | Prasanna Srinivasa G N | Motion control using electromagnetic forces |
JP4523765B2 (en) * | 2003-08-12 | 2010-08-11 | 特殊電装株式会社 | Rotor position detection method and position detection apparatus for permanent magnet synchronous motor |
US7292009B2 (en) * | 2003-09-17 | 2007-11-06 | Honda Motor Co., Ltd. | Hybrid type working machine |
US7514887B2 (en) * | 2003-10-24 | 2009-04-07 | A. O. Smith Corporation | Electrical machine and method of controlling the same |
JP2005204390A (en) * | 2004-01-14 | 2005-07-28 | Hitachi Global Storage Technologies Netherlands Bv | Data storage device, and apparatus and method for controlling motor |
WO2005083876A1 (en) * | 2004-02-26 | 2005-09-09 | Rohm Co., Ltd. | Motor drive device and electric device using motor |
DE502005001351D1 (en) * | 2004-05-12 | 2007-10-11 | Ebm Papst St Georgen Gmbh & Co | Electronically commutated two-pulse motor and method for starting such a motor |
US7246029B2 (en) * | 2004-09-09 | 2007-07-17 | F;Visteon Global Technologies, Inc. | Electric machine with actively controlled switches |
JP4386815B2 (en) | 2004-10-04 | 2009-12-16 | パナソニック株式会社 | Motor driving apparatus and driving method |
JP4614728B2 (en) | 2004-10-14 | 2011-01-19 | ルネサスエレクトロニクス株式会社 | Motor drive control device and starting method |
US7432677B2 (en) * | 2004-12-16 | 2008-10-07 | Seagate Technology Llc | Closed-loop rotational control of a brushless dc motor |
JP4780493B2 (en) * | 2005-03-15 | 2011-09-28 | 学校法人東京電機大学 | Rotor position detection device and rotor position detection method |
JP2007068256A (en) * | 2005-08-29 | 2007-03-15 | Canon Inc | Method of controlling stage device |
US7675259B2 (en) * | 2006-01-16 | 2010-03-09 | Brother Kogyo Kabushiki Kaisha | Controller for DC motor |
US20080024028A1 (en) * | 2006-07-27 | 2008-01-31 | Islam Mohammad S | Permanent magnet electric motor |
US7543679B2 (en) * | 2006-07-28 | 2009-06-09 | Delphi Technologies, Inc. | Compensation of periodic sensor errors in electric power steering systems |
US7549504B2 (en) * | 2006-07-28 | 2009-06-23 | Delphi Technologies, Inc. | Quadrant dependent active damping for electric power steering |
JP2008095909A (en) * | 2006-10-16 | 2008-04-24 | Hitachi Ltd | Electrically driven brake device |
JP2008113506A (en) | 2006-10-31 | 2008-05-15 | Renesas Technology Corp | Motor drive controller and motor start-up method |
US7725227B2 (en) * | 2006-12-15 | 2010-05-25 | Gm Global Technology Operations, Inc. | Method, system, and apparatus for providing enhanced steering pull compensation |
WO2008120727A1 (en) * | 2007-03-30 | 2008-10-09 | Shindengen Electric Manufacturing Co., Ltd. | Brushless motor control device and brushless motor controlling method |
US8084975B2 (en) | 2007-03-30 | 2011-12-27 | Shindengen Electric Manufacturing Co., Ltd. | Brushless motor, brushless motor control system, and brushless motor control method |
US20110050209A1 (en) * | 2007-10-09 | 2011-03-03 | Rainer Nase | Method and apparatus for unambiguous determination of the rotor position of an electrical machine |
JP5175569B2 (en) | 2008-02-07 | 2013-04-03 | ルネサスエレクトロニクス株式会社 | Synchronous motor drive system |
US8237385B2 (en) * | 2008-09-15 | 2012-08-07 | Texas Instruments Incorporated | Systems and methods for detecting position for a brushless DC motor |
JP5308109B2 (en) | 2008-09-17 | 2013-10-09 | ルネサスエレクトロニクス株式会社 | Synchronous motor drive system |
US20100141191A1 (en) * | 2008-12-04 | 2010-06-10 | Chen Liyong | Systems and methods for determining a commutation state for a brushless dc motor |
US20100237817A1 (en) | 2009-03-23 | 2010-09-23 | Jingbo Liu | Method and Apparatus for Estimating Rotor Position in a Sensorless Synchronous Motor |
PT104638A (en) * | 2009-06-22 | 2010-12-22 | Alexandre Tiago Batista De Alves Martins | PROPULSION SYSTEM USING THE VACUUM ANTIGRAVITY FORCE AND APPLICATIONS. |
JP5405224B2 (en) * | 2009-07-28 | 2014-02-05 | アスモ株式会社 | Motor driving device and method for determining relative position of rotor provided in motor |
US8901867B2 (en) | 2011-04-28 | 2014-12-02 | Regal Beloit America, Inc. | Electrical machine, method of controlling an electrical machine, and system including an electrical machine |
JP5820287B2 (en) | 2012-01-31 | 2015-11-24 | ルネサスエレクトロニクス株式会社 | Motor drive control device and operation method thereof |
JP5970227B2 (en) | 2012-04-17 | 2016-08-17 | 日立オートモティブシステムズ株式会社 | Synchronous motor drive system |
DE102013206029A1 (en) * | 2013-04-05 | 2014-10-09 | Ksb Aktiengesellschaft | Method for starting a variable-speed electric motor |
US9025266B2 (en) * | 2013-06-14 | 2015-05-05 | Rohm Co., Ltd. | Semiconductor integrated circuit device, magnetic disk storage device, and electronic apparatus |
US9559623B2 (en) | 2013-08-30 | 2017-01-31 | Regal Beloit America, Inc. | Method of controlling an electrical machine |
JP6481254B2 (en) * | 2014-03-06 | 2019-03-13 | 株式会社リコー | Phase detection device, motor drive control device, and motor device |
CN105141200B (en) * | 2015-08-04 | 2019-04-09 | 矽力杰半导体技术(杭州)有限公司 | A kind of driving circuit and driving method of permanent magnet synchronous motor |
CN108931085A (en) * | 2017-05-24 | 2018-12-04 | 杭州三花研究院有限公司 | control system and control method |
WO2019056072A1 (en) | 2017-09-22 | 2019-03-28 | Janislav Sega | System and method for controlling a motor |
JP7198027B2 (en) * | 2018-10-01 | 2022-12-28 | ローム株式会社 | Motor driver device and semiconductor device |
Family Cites Families (22)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
DE3786849T2 (en) | 1986-07-01 | 1993-11-11 | Conner Peripherals Inc | Method and device for controlling electric motors. |
US4746850A (en) * | 1987-02-12 | 1988-05-24 | Westinghouse Electric Corp. | Start-up system for a synchronous motor drive |
US4892863A (en) * | 1988-09-30 | 1990-01-09 | Eastman Kodak Company | Electric machinery employing a superconductor element |
US5001405A (en) * | 1989-09-27 | 1991-03-19 | Seagate Technology, Inc. | Position detection for a brushless DC motor |
US4992710A (en) * | 1989-09-27 | 1991-02-12 | Seagate Technology, Inc. | Position detection for a brushless DC motor with sample time optimization |
US5068582A (en) * | 1990-05-29 | 1991-11-26 | A. O. Smith Corporation | Brushless pulsed D.C. motor |
US5028852A (en) * | 1990-06-21 | 1991-07-02 | Seagate Technology, Inc. | Position detection for a brushless DC motor without hall effect devices using a time differential method |
US5254914A (en) * | 1990-06-29 | 1993-10-19 | Seagate Technology, Inc. | Position detection for a brushless DC motor without Hall effect devices using a mutual inductance detection method |
US5117165A (en) * | 1990-06-29 | 1992-05-26 | Seagate Technology, Inc. | Closed-loop control of a brushless DC motor from standstill to medium speed |
US5258695A (en) * | 1990-12-19 | 1993-11-02 | Integral Peripherals, Inc. | Spin motor control system for a hard disk assembly |
US5113125A (en) * | 1991-05-01 | 1992-05-12 | Westinghouse Electric Corp. | AC drive with optimized torque |
JPH0696518A (en) * | 1992-06-08 | 1994-04-08 | Hewlett Packard Co <Hp> | Dipole disk torque system for disk drive for freeing fixed transducer |
JP3207250B2 (en) | 1992-06-16 | 2001-09-10 | 株式会社名南製作所 | Turning method of raw wood in veneer lace |
JPH06165567A (en) * | 1992-11-17 | 1994-06-10 | Hitachi Ltd | Semiconductor integrated circuit device |
JPH07274585A (en) | 1994-03-30 | 1995-10-20 | Hokuto Seigyo Kk | Method for detecting stop position of, and control equipment for drive of, brushless motor |
US5841252A (en) * | 1995-03-31 | 1998-11-24 | Seagate Technology, Inc. | Detection of starting motor position in a brushless DC motor |
US5569990A (en) * | 1995-03-31 | 1996-10-29 | Seagate Technology, Inc. | Detection of starting motor position in a brushless DC motor |
JP3419157B2 (en) * | 1995-07-20 | 2003-06-23 | 株式会社日立製作所 | Motor driving method and electric equipment using the same |
KR0158614B1 (en) * | 1995-11-28 | 1998-12-15 | 김광호 | Morse-start circuit and control method |
JP2858692B2 (en) * | 1996-12-05 | 1999-02-17 | 株式会社安川電機 | Sensorless control method and device for permanent magnet type synchronous motor |
US5982571A (en) * | 1997-06-30 | 1999-11-09 | Quantum Corporation | Disk drive with closed loop commutator and actuator oscillator |
US6369534B1 (en) * | 2000-04-26 | 2002-04-09 | Stmicroelectronics, Inc. | Circuit and method for detecting backward spin of a spindle motor for a disk drive |
-
2000
- 2000-03-29 JP JP2000090037A patent/JP3673964B2/en not_active Expired - Fee Related
-
2001
- 2001-03-28 US US09/818,511 patent/US6344721B2/en not_active Expired - Lifetime
- 2001-06-29 US US09/893,549 patent/US6340873B2/en not_active Expired - Lifetime
- 2001-12-26 US US10/025,545 patent/US6563286B2/en not_active Expired - Lifetime
Cited By (11)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
EP1753124A3 (en) * | 2005-08-10 | 2017-08-23 | Mitsubishi Heavy Industries, Ltd. | Control device for electric compressor |
US20100117572A1 (en) * | 2007-03-30 | 2010-05-13 | Tomomi Harada | Brushless motor control device and brushless motor control method |
US8106612B2 (en) | 2007-03-30 | 2012-01-31 | Shindegen Electric Manufacturing Co., Ltd. | Brushless motor control device and brushless motor control method |
US9543865B2 (en) | 2013-09-20 | 2017-01-10 | Hitachi Automotive Systems, Ltd. | Device for driving three-phase brushless motor |
US20150188464A1 (en) * | 2013-12-26 | 2015-07-02 | Chervon Intellectual Property Limited | Brushless motor and control method thereof |
US9590542B2 (en) * | 2013-12-26 | 2017-03-07 | Chervon Intellectual Property Limited | Brushless motor and control method thereof |
US10381965B2 (en) | 2016-01-12 | 2019-08-13 | Hitachi Automotive Systems, Ltd. | Drive device and method for three-phase brushless motor |
EP3226403A1 (en) | 2016-04-01 | 2017-10-04 | Melexis Technologies NV | Position detection of a 1-coil or 2- coil motor |
US10066967B2 (en) | 2016-04-01 | 2018-09-04 | Melexis Technologies Nv | Position detection of a 1-coil or 2-coil motor |
US10998846B2 (en) | 2017-05-24 | 2021-05-04 | Hangzhou Sanhua Research Institute Co., Ltd. | Control system and control method |
US10181773B1 (en) * | 2017-07-05 | 2019-01-15 | Anpec Electronics Corporation | Detection device and detection method of rotor position of three-phase motor |
Also Published As
Publication number | Publication date |
---|---|
US6563286B2 (en) | 2003-05-13 |
US6340873B2 (en) | 2002-01-22 |
US20020079860A1 (en) | 2002-06-27 |
JP2001275387A (en) | 2001-10-05 |
JP3673964B2 (en) | 2005-07-20 |
US20010050542A1 (en) | 2001-12-13 |
US6344721B2 (en) | 2002-02-05 |
Similar Documents
Publication | Publication Date | Title |
---|---|---|
US6344721B2 (en) | Semiconductor integrated circuit for brushless motor drive control and brushless motor drive control apparatus | |
JP3993502B2 (en) | Multi-phase DC motor rotation drive control device and start-up method | |
US7750586B2 (en) | Drive control device of motor and a method of start-up | |
US7230785B2 (en) | Drive control device of motor and disk rotation system | |
JPH11122977A (en) | Sensorless/brushless dc motor rotation control method and device | |
US8497647B1 (en) | Motor spindle control system and method | |
US20020167290A1 (en) | Apparatus for driving three-phase brushless motor | |
JP4890796B2 (en) | Motor drive circuit and disk device using the same | |
US5038232A (en) | Spindle motor control circuit | |
US6163118A (en) | Method and apparatus for controlling a motor in a mass storage device | |
JP3804019B2 (en) | Brushless motor drive control method | |
USRE42113E1 (en) | Control system of motors for rotating a disk and for positioning heads of a mass storage disk device | |
JP2000134982A (en) | Method for starting spindle motor and device utilizing the same | |
JP2006081396A (en) | Rotary drive controller for three-phase motor | |
JP2006262569A (en) | Rotor position detection device and rotor position detection method | |
US7049770B2 (en) | Current control circuit and motor drive circuit that can accurately and easily control a drive current | |
JPH10271881A (en) | Motor and method for controlling the same | |
JP2001186788A (en) | Drive circuit of brushless motor | |
US6320343B1 (en) | Fine phase frequency multipiler for a brushless motor and corresponding control method | |
JP2666468B2 (en) | Motor drive | |
JP3537633B2 (en) | Magnetic recording / reproducing device | |
JPH05146192A (en) | Driving circuit for dc brushless motor | |
JPS60128887A (en) | Controller of brushless motor | |
JP2004215341A (en) | Sensorless brushless motor | |
JPH06119707A (en) | Magnetic disk device |
Legal Events
Date | Code | Title | Description |
---|---|---|---|
STCF | Information on status: patent grant |
Free format text: PATENTED CASE |
|
FEPP | Fee payment procedure |
Free format text: PAYER NUMBER DE-ASSIGNED (ORIGINAL EVENT CODE: RMPN); ENTITY STATUS OF PATENT OWNER: LARGE ENTITY |
|
FEPP | Fee payment procedure |
Free format text: PAYOR NUMBER ASSIGNED (ORIGINAL EVENT CODE: ASPN); ENTITY STATUS OF PATENT OWNER: LARGE ENTITY |
|
FPAY | Fee payment |
Year of fee payment: 4 |
|
FEPP | Fee payment procedure |
Free format text: PAYOR NUMBER ASSIGNED (ORIGINAL EVENT CODE: ASPN); ENTITY STATUS OF PATENT OWNER: LARGE ENTITY |
|
FPAY | Fee payment |
Year of fee payment: 8 |
|
AS | Assignment |
Owner name: RENESAS ELECTRONICS CORPORATION, JAPAN Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNOR:HITACHI, LTD.;REEL/FRAME:026109/0528 Effective date: 20110307 |
|
FPAY | Fee payment |
Year of fee payment: 12 |
|
AS | Assignment |
Owner name: RENESAS ELECTRONICS CORPORATION, JAPAN Free format text: CHANGE OF ADDRESS;ASSIGNOR:RENESAS ELECTRONICS CORPORATION;REEL/FRAME:044928/0001 Effective date: 20150806 |