CN108418480B - Method for starting sensorless permanent magnet synchronous motor - Google Patents
Method for starting sensorless permanent magnet synchronous motor Download PDFInfo
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- CN108418480B CN108418480B CN201810259150.2A CN201810259150A CN108418480B CN 108418480 B CN108418480 B CN 108418480B CN 201810259150 A CN201810259150 A CN 201810259150A CN 108418480 B CN108418480 B CN 108418480B
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- 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
- H02P6/21—Open loop start
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- 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
- H02P21/00—Arrangements or methods for the control of electric machines by vector control, e.g. by control of field orientation
- H02P21/24—Vector control not involving the use of rotor position or rotor speed sensors
- H02P21/28—Stator flux based control
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- 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
- H02P21/00—Arrangements or methods for the control of electric machines by vector control, e.g. by control of field orientation
- H02P21/34—Arrangements for starting
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- 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
- H02P25/00—Arrangements or methods for the control of AC motors characterised by the kind of AC motor or by structural details
- H02P25/02—Arrangements or methods for the control of AC motors characterised by the kind of AC motor or by structural details characterised by the kind of motor
- H02P25/022—Synchronous motors
- H02P25/024—Synchronous motors controlled by supply frequency
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- 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
- H02P27/00—Arrangements or methods for the control of AC motors characterised by the kind of supply voltage
- H02P27/04—Arrangements or methods for the control of AC motors characterised by the kind of supply voltage using variable-frequency supply voltage, e.g. inverter or converter supply voltage
- H02P27/06—Arrangements or methods for the control of AC motors characterised by the kind of supply voltage using variable-frequency supply voltage, e.g. inverter or converter supply voltage using dc to ac converters or inverters
- H02P27/08—Arrangements or methods for the control of AC motors characterised by the kind of supply voltage using variable-frequency supply voltage, e.g. inverter or converter supply voltage using dc to ac converters or inverters with pulse width modulation
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- 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
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- 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
- H02P2101/00—Special adaptation of control arrangements for generators
- H02P2101/15—Special adaptation of control arrangements for generators for wind-driven turbines
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- 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
- H02P2103/00—Controlling arrangements characterised by the type of generator
- H02P2103/20—Controlling arrangements characterised by the type of generator of the synchronous type
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- Engineering & Computer Science (AREA)
- Power Engineering (AREA)
- Control Of Motors That Do Not Use Commutators (AREA)
- Motor And Converter Starters (AREA)
- Control Of Ac Motors In General (AREA)
Abstract
The invention discloses a method for starting a sensorless permanent magnet synchronous motor, which comprises the following steps: s10), after the motor winding is short-circuited, detecting the induced current of the motor by a sampling module driving the controller; s20), judging whether the motor induction current is smaller than the induction current preset value, if so, going to step S30), and if not, going to step S40); s30), open loop start control; s40), judging whether the motor is in a forward rotation state or a reverse rotation state, if so, entering the step S50), and if not, entering the step S60); s50), forward rotation closed-loop vector starting control; s60), reverse closed-loop vector start control; the invention not only ensures that the permanent magnet synchronous motor can be started quickly and efficiently with small current when the permanent magnet synchronous motor is static and tends to be static, but also realizes quick closed-loop vector control under the condition of stronger downwind or upwind, reduces energy consumption, shortens starting time and leads the motor to be started more smoothly.
Description
Technical Field
The invention belongs to the field of motor control, and particularly relates to a starting method of a sensorless permanent magnet synchronous motor.
Background
The sensorless control technology of the permanent magnet synchronous motor has the advantages of simplicity in implementation, low cost, high reliability and the like, and therefore, the sensorless control technology is widely applied to various fan systems. Because the back electromotive force of the permanent magnet synchronous motor is very small under the condition of zero speed or low speed, and the position angle of the motor rotor is difficult to accurately obtain, the existing permanent magnet synchronous motor without sensing control usually adopts open-loop starting control when being started, and the closed-loop FOC control (vector control) is switched to after the motor rotor is driven to be synchronous and reaches a certain rotating speed (more accurate rotor position angle can be obtained through estimation).
The forward and reverse wind start is a basic function that most outdoor fan systems must satisfy. In the case of upwind, the permanent magnet synchronous motor will reverse, and the reverse speed is in direct proportion to the wind speed. For the drive controller with the sensor, the position of the rotor can be measured in real time, so that the fan can be directly pulled back to rotate forward to be normally started through closed-loop control; however, for the sensorless permanent magnet synchronous motor driving controller, the rotor position information is difficult to obtain during starting, and if measures are not taken to inhibit the motor from rotating reversely in advance, enough starting torque is difficult to generate in the open-loop starting stage to pull the permanent magnet synchronous motor back to rotate forward and pull the permanent magnet synchronous motor to be synchronous, so that the motor cannot be started reliably under the condition of headwind; the downwind starting condition is similar to the upwind starting condition, and the normal starting process can be started only by controlling and restraining the rotating speed of the motor. Please refer to the schematic structural diagram of sampling three sampling resistors Ra, Rb and Rc of the conventional permanent magnet synchronous motor position sensorless driving controller shown in fig. 1, and the starting method thereof is as follows: firstly, driving a lower bridge arm to realize short circuit of a motor winding to generate braking torque, and then entering open-loop starting after the rotation speed of the PMSM of the motor is reduced to be close to zero speed; the technology adopts a driving controller to measure the magnitude of short-circuit current on sampling resistors of bridge arms to judge the current speed of the PMSM so as to determine the braking time and open-loop starting time.
As is known, the single-resistor sampling can reduce the cost and the volume of the motor drive controller, however, the above method cannot be directly used in the single-resistor sampling scheme, because the short-circuit current does not flow through the sampling single resistor when the lower bridge arm is short-circuited and braked, the drive controller is difficult to directly determine the rotation condition of the motor. On the other hand, from the viewpoint of energy consumption and efficiency, in normal windless starting, it is required that the drive controller is required to have a smaller open-loop starting current as well as a shorter open-loop starting time as well as to ensure reliable starting of the motor. However, under severe conditions, especially during upwind starting, the torque applied to the motor is high, and the short-circuit braking may only reduce the rotation speed of the motor to a low rotation speed and cannot completely brake the motor (i.e. reduce the rotation speed of the motor to zero).
In order to solve the technical problems, the applicant provides a method for starting a sensorless permanent magnet synchronous motor with the application number of 201710291097.X on 28/4/2017, and a prior invention patent application with the patent name of the sensorless permanent magnet synchronous motor adopts a driving controller to start a motor winding short circuit braking mode, reduces the rotating speed of the motor, and simultaneously detects the induced current of the motor by a follow current mode by applying single resistance sampling, so that the embodiment of the invention realizes reliable starting under the single resistance sampling condition, and effectively reduces the cost and the volume of the driving controller; meanwhile, the embodiment of the invention can ensure the quick and low-current efficient starting in windless conditions and the reliable starting under severe forward and backward wind conditions by adjusting the compensation open-loop starting current and/or the open-loop starting time, and can be realized on the algorithm level without adding an additional hardware structure.
With the intensive research and application of the applicant, it is found that when the forward rotation speed of the permanent magnet synchronous motor is high in the downwind condition, if the technical scheme of 201710291097.X is adopted, the motor needs to be decelerated and stopped first and then started according to the conventional closed-loop control, so that not only is large loss caused, but also the starting time is prolonged. In addition, in some practical application occasions, the motor controller is powered down, but when the motor is not completely stopped due to the inertia of the rotating speed, the controller is restarted after power supply is recovered, and the condition similar to the downwind starting condition can also occur to the motor. In the case of headwind, the permanent magnet synchronous motor rotates reversely at a high speed, and the reverse rotation speed is in a direct proportion relation to the wind speed, so that for a sensorless controller, measures must be taken to inhibit the reverse rotation of the motor (such as a motor winding short-circuit braking mode of 201710291097. X), and then sufficient starting torque is difficult to generate in an open-loop starting stage to pull the fan back to the forward rotation and pull the fan to be synchronous, so that the fan cannot be started reliably in the headwind condition. Therefore, although the technical scheme of the prior application 201710291097.X can ensure quick and low-current efficient starting in the absence of wind and reliable starting under the condition of downwind and upwind, the energy consumption in the starting process is high and the starting time is long under the condition of stronger downwind or upwind.
The applicant therefore wishes to improve on the prior application 201710291097. X.
Disclosure of Invention
In view of the above, the present invention provides a method for starting a sensorless permanent magnet synchronous motor, which detects a rotation state of the permanent magnet synchronous motor in advance, and selectively enters a specific motor start control mode according to a current rotation direction and a current rotation speed of the permanent magnet synchronous motor, so as to ensure that the permanent magnet synchronous motor can be started quickly and efficiently with a small current when the permanent magnet synchronous motor is stationary and tends to be stationary, and to realize quick closed-loop vector control under a strong downwind or upwind condition, thereby reducing energy consumption, shortening start time, and enabling the motor to be started more smoothly;
the invention also aims to provide a starting method of the sensorless permanent magnet synchronous motor, which adopts the single resistance sampling module to detect the induced current of the motor, effectively reduces the cost and the volume of the driving controller and simultaneously effectively realizes the reliable detection of the rotating state of the permanent magnet synchronous motor.
The technical scheme adopted by the invention is as follows:
a starting method of a sensorless permanent magnet synchronous motor is provided, wherein the sensorless permanent magnet synchronous motor is connected with a driving controller, and the starting method comprises the following steps:
s10), after the motor winding is short-circuited, detecting a motor induction current through a sampling module driving the controller, and judging the rotation state of the motor based on the motor induction current;
s20), judging whether the motor induction current is smaller than the induction current preset value, if so, going to step S30), and if not, going to step S40);
s30), open-loop starting control, switching to closed-loop vector control after the motor rotor is pulled to be synchronous and reaches a preset target rotating speed;
s40), judging whether the motor is in a forward rotation state or a reverse rotation state, if so, entering the step S50), and if not, entering the step S60);
s50), forward rotation closed-loop vector starting control;
s60), reverse closed loop vector start control.
Preferably, the sampling module of the controller is a single resistor sampling module, the single resistor is installed and connected to the negative electrode of the dc bus, and the single resistor detects the induced current of the motor through a follow current mode.
Preferably, in the step S40), the method for determining whether the motor is in the forward rotation state or the reverse rotation state includes:
s41), the controller outputs a constant voltage vector usTriggering the single-resistor sampling module to sample, and calculating by the single-resistor sampling module to obtain a stator current vector is；
S42), based on the determined constant voltage vector usAnd stator current vector isCalculating to obtain a back electromotive force vector es；
S43), back emf vector e according to two adjacent sampling periodssAnd determining whether the motor is in a forward rotation state or a reverse rotation state.
Preferably, the single resistance sampling module reconstructs a corresponding stator current vector i through PWM phase shift processings。
Preferably, said back electromotive force vector es＝us-isRsWherein the constant voltage vector usThe amplitude ranges between 0.1-1% of the rated voltage of the motor.
Preferably, step S50a) is further included before the step S50), the step S50a) is to determine whether the motor forward rotation speed is greater than a predetermined forward rotation speed value, if so, step S50) is performed, and if not, the step S30 is performed after the short-circuit braking mode is started until the motor induced current is less than the induced current predetermined value); step S60a) is further included before the step S60), the step S60a) is to determine whether the motor reverse rotation speed is greater than a predetermined reverse rotation speed value, if so, the step S60) is performed, and if not, the step S30 is performed after the short-circuit braking mode is started until the motor induced current is less than the predetermined induced current value.
Preferably, the specific control step of starting the short circuit braking mode until the motor induced current is smaller than the induced current preset value comprises:
s30a), the driving controller starts a motor winding short circuit braking mode to reduce the rotating speed of the motor;
s30b), detecting the motor induction current through a sampling module of the drive controller;
s30c), determining whether the motor induced current is smaller than the induced current preset value, if yes, going to step S30), and if not, returning to step S30 a).
Preferably, the step S30d) is further included before the step S30), and the step S30d) is: calculating the number of times of the step S30c) returning to the step S30a), and adjusting the compensating open-loop starting current and/or the open-loop starting time according to the returning number.
Preferably, in step S50), the forward rotation closed-loop vector start control specifically includes: and the motor is accelerated to a preset target rotating speed by the torque provided by the q-axis current of the motor, and then the motor directly enters closed-loop vector control.
Preferably, in step S60), the reverse closed-loop vector start control specifically includes: the method comprises the steps of presetting a minimum target current of a q axis of a motor, wherein the minimum target current of the q axis of the motor is used for providing a forward torque, and the forward torque enables the motor to be braked in a reverse rotation mode, pulled to a forward rotation state and accelerated to a preset target rotating speed to directly enter closed-loop vector control.
Compared with the prior application 201710291097.X, the invention has the advantages that:
1. the invention detects the rotation state of the permanent magnet synchronous motor in advance, selectively enters a specific motor starting control mode according to the current rotation direction and rotation speed of the permanent magnet synchronous motor, and particularly directly enters open-loop starting control when the motor is static or tends to be static; when the motor is in a rotating state, the rotating direction and the rotating speed of the motor are judged, and the short-circuit braking and then open-loop starting control or forward rotation closed-loop vector starting control or reverse rotation closed-loop vector starting control is selectively entered, so that the invention ensures the rapid and low-current efficient starting of the permanent magnet synchronous motor when the permanent magnet synchronous motor is static and tends to be static, realizes the reliable and rapid starting when the permanent magnet synchronous motor rotates along the headwind at low speed, and also realizes the rapid closed-loop vector control under the condition of stronger tailwind or headwind, obviously reduces the starting energy consumption, shortens the starting time and leads the starting of the motor to be smoother;
2. on the basis of the above point 1, the invention adoptsThe resistance sampling module is used for detecting the induced current of the motor in a follow current mode, so that the cost and the volume of the driving controller are effectively reduced; simultaneously provides a controller artificial output constant voltage vector usTriggering the single resistance sampling module to sample, and then reconstructing a corresponding stator current vector i by the single resistance sampling module through PWM phase-shifting processingsAnd then calculating to obtain a back electromotive force vector esBased on the back-EMF vector esThe rotation direction and the rotation speed of the motor are determined, so that the technical problem that the rotation direction of the motor cannot be determined by single resistance sampling before the motor is started is well solved;
3. the invention only realizes the 1 st and 2 nd points on the algorithm level, does not need to add an additional hardware structure, has low cost and is easy to apply and popularize.
Drawings
FIG. 1 is a schematic structural diagram of three-resistor sampling of a non-position sensing drive controller of a conventional permanent magnet synchronous motor;
FIG. 2 is a schematic diagram of a single resistor sampling configuration according to an embodiment of the present invention;
FIG. 3 is a schematic diagram of the operation of an embodiment of the present invention in a short circuit condition of the motor windings;
FIG. 4 is a schematic diagram of the operation of an embodiment of the present invention in freewheel mode;
FIG. 5 is a flowchart of the method steps for starting the present invention;
fig. 6 is a flowchart of the method steps for determining whether the motor is in the forward rotation state or the reverse rotation state in step S40) of fig. 5.
Detailed Description
The embodiment of the invention discloses a starting method of a sensorless permanent magnet synchronous motor, wherein the sensorless permanent magnet synchronous motor is connected with a driving controller, and the starting method comprises the following steps: s10), after the motor winding is short-circuited, detecting the motor induction current through a sampling module of the driving controller, and judging the rotation state of the motor based on the motor induction current; s20), judging whether the induction current of the motor is smaller than the induction current preset value, if so, going to step S30), and if not, going to step S40); s30), open-loop starting control, switching to closed-loop vector control after the motor rotor is pulled to be synchronous and reaches a preset target rotating speed; s40), judging whether the motor is in a forward rotation state or a reverse rotation state, if so, entering the step S50), and if not, entering the step S60); s50), forward rotation closed-loop vector starting control; s60), reverse closed loop vector start control.
The embodiment of the invention selectively enters a specific motor starting control mode according to the current rotating direction and rotating speed of the permanent magnet synchronous motor by detecting the rotating state of the permanent magnet synchronous motor in advance, and particularly directly enters open-loop starting control when the motor is static or tends to be static; when the motor is in a rotating state, the rotating direction and the rotating speed of the motor are judged, and the short-circuit braking and then open-loop starting control or forward rotating closed-loop vector starting control or reverse rotating closed-loop vector starting control is selectively entered, so that the embodiment of the invention ensures the rapid and low-current efficient starting of the permanent magnet synchronous motor when the permanent magnet synchronous motor is static and tends to be static, realizes the reliable and rapid starting when the permanent magnet synchronous motor rotates along the headwind at low speed, realizes the rapid closed-loop vector control under the condition of stronger tailwind or headwind, obviously reduces the starting energy consumption, shortens the starting time and enables the motor to be started more smoothly.
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, it is obvious that the drawings in the following description are only some embodiments described in the present invention, and for those skilled in the art, other drawings can be obtained according to the drawings without creative efforts.
A method for starting a sensorless permanent magnet synchronous motor, where a sensorless permanent magnet synchronous motor PMSM is connected to a drive controller, as shown in fig. 2 to 4, preferably, in this embodiment, a sampling module of the drive controller is a single resistor sampling module, and specifically includes a single resistor R, where the single resistor R is installed and connected to a negative electrode DC-of a direct current bus, and the single resistor R detects a motor induced current through a follow current mode; preferably, a bridge arm switch device connected with a motor winding is arranged between a positive pole DC + and a negative pole DC-of the direct current bus, and specifically, the bridge arm switch device comprises an A-phase upper bridge arm switch device and an A-phase lower bridge arm switch device which are connected in series, a B-phase upper bridge arm switch device and a B-phase lower bridge arm switch device which are connected in series, and a C-phase upper bridge arm switch device and a C-phase lower bridge arm switch device which are connected in series, wherein a connection point between the A-phase upper bridge arm switch device and the A-phase lower bridge arm switch device is connected with an A-phase winding of the PMSM, a connection point between the B-phase upper bridge arm switch device and the B-phase lower bridge arm switch device is connected with a B-phase winding of the PMSM, and a connection point between the C-phase upper bridge arm switch device and the C-phase lower bridge arm switch device is connected with a C-; in the embodiment, a freewheeling diode is connected in parallel to the switching tube of each bridge arm switching device in an inverse manner;
referring to fig. 5, in this embodiment, a method for starting a sensorless permanent magnet synchronous motor PMSM includes the following steps:
s10), after the motor winding is short-circuited, detecting the motor induction current through a sampling module of the driving controller, and judging the rotation state of the motor based on the motor induction current;
specifically, please further refer to fig. 3, in this step S10), before the PMSM is started, the driving controller locks the upper bridge arm switching device and turns on the lower bridge arm switching device to perform short circuit on the motor winding for a short time t1, where the range of t1 may be selected to be 10-100 ms; if the motor is in a rotating state during short circuit, the counter electromotive force can generate induced current, the magnitude of the induced current depends on the magnitude of the counter electromotive force, and the magnitude of the counter electromotive force is in direct proportion to the rotating speed of the motor, so that the magnitude of the induced current of the motor can effectively reflect the magnitude of the rotating speed of the current motor before the motor is started, namely the rotating state of the current motor can be effectively reflected by detecting the magnitude of the induced current of the motor;
s20), judging whether the induction current of the motor is smaller than the induction current preset value, if so, going to step S30), and if not, going to step S40);
specifically, please refer to fig. 4In step S20), the switching tubes of all the bridge arm switching devices are locked by the driving controller, the motor induced current flows from the DC bus cathode DC-to the DC bus anode DC + through the single resistor R and the freewheeling diode, and the driving controller obtains the motor induced current by sampling and detecting the current flowing through the single resistor R by the freewheeling; further preferably, during freewheel mode, the drive controller samples the current of the freewheel flowing through the single resistor R a plurality of times and calculates an average sampled current IavTaking the average sampled current value IavAs the detected motor induced current, the sampling accuracy of the motor induced current is ensured, and certainly, in other embodiments of the present invention, single sampling may also be adopted; preferably, the time t2 of the single freewheel mode is 0.01-6ms, which effectively ensures that the induced current of the motor does not suddenly change during the freewheel mode, and of course, in other embodiments of the present invention, a person skilled in the art may set the time t2 of the single freewheel mode according to actual needs;
specifically, in the present embodiment, the induced current predetermined value may be set to 0 or a smaller current value (for example, set to 0.04A), and in other embodiments of the present invention, a person skilled in the art may define the pre-induced current predetermined value according to specific actual requirements; if the average sampling current IavWhen the current is less than the preset value of the induction current, the motor is considered to be in a static state and a static trend state, the open-loop starting control of the step S30) is directly carried out, the high-efficiency starting of the motor with fast and small current when the motor is in the static state and the static trend state is ensured, and if the average sampling current I is smaller than the preset value of the induction current, the average sampling current IavIf the current is larger than the predetermined value, the motor is considered to be in a rotating state, and the process proceeds to step S40) to further determine the rotating direction of the motor.
S30), open-loop starting control, switching to closed-loop vector control after the motor rotor is pulled to be synchronous and reaches a preset target rotating speed; specifically, in this embodiment, open-loop start VF control (i.e., variable-voltage variable-frequency control) may be adopted, and after the motor rotor is pulled to be synchronous and reaches a certain rotation speed, the open-loop start VF control is switched to closed-loop FOC control (i.e., vector control).
S40), judging whether the motor is in a forward rotation state or a reverse rotation state, if so, entering the step S50), and if not, entering the step S60);
referring to fig. 2, since the single resistance sampling module is adopted in the present embodiment, it is clear to those skilled in the art that before the motor is started, when the motor rotates, the topology structure of the single resistance sampling module cannot realize that the three-resistance sampling structure shown in fig. 1 can obtain the three-phase stator current of the motor in a bridge arm short circuit manner, and therefore, in the prior art, the single resistance sampling module cannot obtain the three-phase stator current of the motor in a rotating state before the motor is started. In order to solve the technical problem, the applicant particularly proposes a technical scheme that: in the positive and reverse rotation detection stage of the motor, the controller is set to output a smaller constant voltage vector usThe controller and the motor loop are communicated to trigger single-resistor AD sampling, meanwhile, the corresponding stator current of the motor is reconstructed by particularly applying a single-resistor sampling phase-shifting processing technology, and the technical problem is solved completely through a control algorithm.
Referring to fig. 6, in the present embodiment, preferably, in step S40), the method for determining whether the motor is in the forward rotation state or the reverse rotation state includes:
s41), the controller outputs a constant voltage vector usThe constant voltage vector usConstant voltage vector u for communicating controller and motor loop to trigger single resistor sampling module to samplesShould be chosen to be smaller, wherein preferably the constant voltage vector usThe amplitude ranges between 0.1-1% of the rated voltage of the motor, in particular, in the present embodiment, the constant voltage vector usThe amplitude is 0.5% of the rated voltage of the motor, and the angle is 45 degrees; of course, in other embodiments, those skilled in the art can perform specific setting according to actual needs, and the single-resistor sampling module reconstructs the corresponding stator current vector i through PWM phase shift processings；
It should be particularly noted that the PWM phase shift processing reconstruction of stator current during single resistance sampling proposed by the present invention is a common technique in the field of motor control starting, which is beneficial to obtain accurate motor stator current by calculation, and belongs to the common knowledge of technicians in the field.
S42) due to stator current vector isThe most part of the components come from the current generated by the rotary back electromotive force of the permanent magnet synchronous motor and are based on a determined constant voltage vector usAnd stator current vector isCalculating to obtain a back electromotive force vector esPreferably, the back electromotive force vector es＝us-isRsWherein R issIs the motor winding resistance due to the constant voltage vector usIs very small, and u thus obtaineds-isRsCan be approximately considered as being equal to the back electromotive force vector e generated by the rotation of the permanent magnet motors；
S43), back emf vector e according to two adjacent sampling periodssThe difference value delta theta is changed, and whether the motor is in a forward rotation state or a reverse rotation state is judged;
in the invention, the counter electromotive force vector e can be obtained in the above motor positive and negative rotation detection stagesThe counter electromotive force vector e can be obtainedsThe electromotive force vector esIs equal to the electrical angular velocity at which the motor rotates. As described in the background of the present invention, for a sensorless permanent magnet synchronous motor based on a flux linkage observation control technique, the higher the motor rotation speed, the more accurate the calculation of the back electromotive force, and the higher the accuracy of estimating the rotor position angle.
That is to say, when the forward and reverse rotation speed of the motor is high enough, the motor flux observer in the forward and reverse rotation detection stage can obtain more accurate rotor flux position information, so that the open-loop starting is not needed after the motor flux observer is braked and decelerated to the target rotation speed firstly, and the closed-loop vector control can be directly carried out, so that the starting energy consumption can be obviously reduced, the starting time can be shortened, and the motor can be started more smoothly. Conversely, when the motor rotates forward and backwardBack electromotive force vector e obtained in the detection stagesAnd when the rotor flux linkage estimation accuracy (namely, the accuracy of the estimated rotor position angle) is not high, the closed-loop vector control cannot be directly performed, and at the moment, the starting method provided by 201710291097.X is adopted, namely, the open-loop control starting in the step S30 is performed after the short-circuit braking mode is started until the induced current of the motor is smaller than the induced current preset value, so that the motor can be reliably and quickly started under the condition of lower forward and backward wind.
Preferably, in this embodiment, step S50a) is further included before step S50), and step S50a) is to determine whether the motor forward rotation speed is greater than a predetermined forward rotation speed value, where the predetermined forward rotation speed value is specifically selected according to actual needs and is set to 60RPM in this embodiment; if yes, the step S50) is carried out, if not, the step S30 is carried out after the short-circuit braking mode is started until the motor induction current is smaller than the induction current preset value;
s50), forward rotation closed-loop vector starting control; preferably, in step S50), the forward rotation closed-loop vector start control specifically includes: the motor positively rotates and accelerates to a preset target rotating speed by the torque provided by the q-axis current of the motor, and then the motor directly enters closed-loop vector control; when the motor is restarted after power failure, the embodiment of the invention can directly accelerate to the target rotating speed on the basis of the inertia rotating speed of the motor to realize quick start without braking and stopping, thereby reducing energy consumption and shortening starting time;
preferably, in this embodiment, step S60a) is further included before step S60), and step S60a) is to determine whether the motor reverse rotation speed is greater than a predetermined reverse rotation speed value, where the predetermined forward rotation speed value is specifically selected according to actual needs and is set to 100RPM in this embodiment; if yes, the step S60) is carried out, if not, the step S30 is carried out after the short-circuit braking mode is started until the motor induction current is smaller than the induction current preset value;
s60), reverse closed-loop vector start control; preferably, in the step S60), the reverse closed-loop vector start control specifically includes: presetting a minimum target current of a q axis of a motor, wherein the minimum target current of the q axis of the motor is used for providing a forward torque, and the forward torque enables the motor to be braked in a reverse rotation mode, pulled to a forward rotation state and accelerated to a preset target rotating speed and then directly enters closed-loop vector control; in the present embodiment, the lowest motor q-axis minimum target current is required to ensure that sufficient forward torque is provided; the implementation mode has extremely strong upwind reliable starting capability;
preferably, in this embodiment, the specific control step of turning on the short-circuit braking mode until the motor induced current is smaller than the induced current predetermined value includes:
s30a), the driving controller starts a motor winding short circuit braking mode to reduce the rotating speed of the motor;
s30b), detecting the motor induction current through a sampling module of the drive controller;
s30c), judging whether the induction current of the motor is smaller than the preset value of the induction current, if so, entering the step S30), and if not, returning to the step S30 a); further preferably, the step S30) is preceded by a step S30d), and the step S30d) is: calculating the number of times of the step S30c) returning to the step S30a), and adjusting the compensating open-loop starting current and/or the open-loop starting time according to the returning number.
The specific control steps and processes of turning on the short-circuit braking mode until the induced current of the motor is less than the predetermined value of the induced current proposed in the present invention can directly follow the description of the applicant's prior application 201710291097.X, wherein, in order to realize more reliable and effective open-loop control starting, the present invention provides a compensation value I for the open-loop starting currentOFFSETAnd the compensation value T of the open loop starting timeOFFSETSetting a limit value; since the technical contents of this section do not belong to the innovative contents of the present invention, the present invention will not be repeatedly described for the sake of brevity.
It should be noted that, in other less preferred embodiments of the present invention, the current sampling detection of the motor induced current can be implemented by using the prior art (for example, by using the three-resistor sampling technique shown in fig. 1 of the background art, or by using the technique disclosed in the chinese utility model patent with the publication number of CN 205123634U), so as to further implement the above-mentioned advantage of point 1 of the present invention.
It will be evident to those skilled in the art that the invention is not limited to the details of the foregoing illustrative embodiments, and that the present invention may be embodied in other specific forms without departing from the spirit or essential attributes thereof. The present embodiments are therefore to be considered in all respects as illustrative and not restrictive, the scope of the invention being indicated by the appended claims rather than by the foregoing description, and all changes which come within the meaning and range of equivalency of the claims are therefore intended to be embraced therein. Any reference sign in a claim should not be construed as limiting the claim concerned.
Furthermore, it should be understood that although the present description refers to embodiments, not every embodiment may contain only a single embodiment, and such description is for clarity only, and those skilled in the art should integrate the description, and the embodiments may be combined as appropriate to form other embodiments understood by those skilled in the art.
Claims (7)
1. A starting method of a sensorless permanent magnet synchronous motor is characterized by comprising the following steps:
s10), after the motor winding is short-circuited, detecting a motor induction current through a sampling module driving the controller, and judging the rotation state of the motor based on the motor induction current;
s20), judging whether the motor induction current is smaller than the induction current preset value, if so, going to step S30), and if not, going to step S40);
s30), open-loop starting control, switching to closed-loop vector control after the motor rotor is pulled to be synchronous and reaches a preset target rotating speed;
s40), judging whether the motor is in a forward rotation state or a reverse rotation state, if so, entering the step S50), and if not, entering the step S60);
s50), forward rotation closed-loop vector starting control;
s60), reverse closed-loop vector start control;
the sampling module of the controller is a single-resistor sampling module, the single resistor is installed and connected to the negative electrode of the direct-current bus, and the single resistor detects the induced current of the motor in a follow current mode;
in step S40), the method for determining whether the motor is in the normal rotation state or the reverse rotation state includes:
s41), the controller outputs a constant voltage vector usTriggering the single-resistor sampling module to sample, and calculating by the single-resistor sampling module to obtain a stator current vector isThe single resistance sampling module reconstructs a corresponding stator current vector i through PWM phase-shifting processings；
S42), based on the determined constant voltage vector usAnd stator current vector isCalculating to obtain a back electromotive force vector es；
S43), back emf vector e according to two adjacent sampling periodssAnd determining whether the motor is in a forward rotation state or a reverse rotation state.
2. The method of starting a sensorless permanent magnet synchronous motor according to claim 1, wherein the back electromotive force vector es＝us-isRsWherein R issFor the motor winding resistance, the constant voltage vector usThe amplitude ranges between 0.1-1% of the rated voltage of the motor.
3. The sensorless permanent magnet synchronous motor starting method according to claim 1,
step S50a) is further included before the step S50), the step S50a) is to determine whether the motor forward rotation speed is greater than a predetermined forward rotation speed value, if so, the step S50) is performed, and if not, the step S30 is performed after the short-circuit braking mode is started until the motor induced current is less than the predetermined induced current value;
step S60a) is further included before the step S60), the step S60a) is to determine whether the motor reverse rotation speed is greater than a predetermined reverse rotation speed value, if so, the step S60) is performed, and if not, the step S30 is performed after the short-circuit braking mode is started until the motor induced current is less than the predetermined induced current value.
4. The sensorless permanent magnet synchronous motor starting method according to claim 3, wherein the specific control step of turning on the short circuit braking mode until the motor induced current is smaller than the induced current predetermined value comprises:
s30a), the driving controller starts a motor winding short circuit braking mode to reduce the rotating speed of the motor;
s30b), detecting the motor induction current through a sampling module of the drive controller;
s30c), judging whether the motor induction current is smaller than the induction current preset value, if so, entering the step S30), and if not, returning to the step S30 a).
5. The sensorless permanent magnet synchronous motor starting method according to claim 4, wherein step S30d) is further included before entering step S30), and the step S30d) is: calculating the number of times of the step S30c) returning to the step S30a), and adjusting the compensating open-loop starting current and/or the open-loop starting time according to the returning number.
6. The method for starting a sensorless permanent magnet synchronous motor according to claim 1 or 3, wherein in step S50), the forward rotation closed-loop vector start control specifically includes: and the motor is accelerated to a preset target rotating speed by the torque provided by the q-axis current of the motor, and then the motor directly enters closed-loop vector control.
7. The method for starting a sensorless permanent magnet synchronous motor according to claim 1 or 3, wherein in step S60), the reverse closed-loop vector start control specifically includes: the method comprises the steps of presetting a minimum target current of a q axis of a motor, wherein the minimum target current of the q axis of the motor is used for providing a forward torque, and the forward torque enables the motor to be braked in a reverse rotation mode, pulled to a forward rotation state and accelerated to a preset target rotating speed to directly enter closed-loop vector control.
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| CN109323393B (en) * | 2018-09-25 | 2021-02-26 | 广东美的制冷设备有限公司 | Starting control method and device of direct current fan, outdoor unit and air conditioner |
| CN109245654B (en) * | 2018-09-25 | 2021-02-26 | 广东美的制冷设备有限公司 | Starting control method and device of direct current fan, outdoor unit and air conditioner |
| CN111064397B (en) * | 2018-10-17 | 2023-03-21 | 硕呈科技股份有限公司 | Driving method of single-phase DC brushless motor only for starting application sensor |
| CN109510525B (en) * | 2018-12-11 | 2022-05-17 | 上海肖可雷电子科技有限公司 | Method for detecting initial state of permanent magnet synchronous motor |
| CN110260484B (en) * | 2019-06-17 | 2020-12-15 | 珠海格力电器股份有限公司 | Method and device for controlling starting of fan, computer readable storage medium and air conditioner |
| CN110208697B (en) * | 2019-06-27 | 2021-07-13 | 深圳和而泰智能控制股份有限公司 | Motor state monitoring circuit and method |
| CN111555685A (en) * | 2020-04-27 | 2020-08-18 | 广东芬尼克兹节能设备有限公司 | Fan starting control circuit and control method thereof |
| CN111697879A (en) * | 2020-06-30 | 2020-09-22 | 深圳和而泰智能控制股份有限公司 | Motor starting control system and motor control method |
| CN112260601B (en) * | 2020-09-29 | 2022-03-25 | 广东工业大学 | Low-speed running single-resistor sampling permanent magnet synchronous motor phase current reconstruction method |
| CN113708344B (en) * | 2021-08-17 | 2024-03-26 | 精进电动科技股份有限公司 | Overvoltage protection method and circuit for DC bus of inverter and motor controller |
| CN113945846A (en) * | 2021-09-08 | 2022-01-18 | 深圳拓邦股份有限公司 | Motor state judgment method and motor driving device |
| CN115189597B (en) * | 2021-12-16 | 2023-04-11 | 广东华芯微特集成电路有限公司 | Method for detecting running state of brushless direct current motor |
| CN114421844A (en) * | 2022-01-18 | 2022-04-29 | 合肥美的暖通设备有限公司 | Motor control method, control device, control system and readable storage medium |
| CN115441802B (en) * | 2022-09-06 | 2023-12-01 | 江苏新安电器股份有限公司 | Software method for detecting and starting motor in forward and reverse directions |
| CN115566938B (en) * | 2022-11-24 | 2023-03-24 | 中山大洋电机股份有限公司 | Novel rotor pre-positioning method in high-speed upwind rotation state before starting of fan |
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| CN102299679B (en) * | 2011-08-30 | 2013-12-25 | 中冶南方（武汉）自动化有限公司 | Method for determining rotating speed of restarted asynchronous motor |
| CN104579106A (en) * | 2013-10-12 | 2015-04-29 | 珠海格力电器股份有限公司 | Single-resistor sampling phase-shifting compensation method and system |
| CN104811095B (en) * | 2015-04-28 | 2018-03-27 | 广东美的暖通设备有限公司 | Startup control method, device and the air conditioner of motor |
| CN104917435B (en) * | 2015-06-24 | 2018-06-05 | 广东美的暖通设备有限公司 | Startup control method, device, motor and the compressor of motor |
| CN105529967B (en) * | 2016-01-21 | 2018-11-27 | 珠海格力电器股份有限公司 | Fan starting state detection and starting control method |
| CN107317526B (en) * | 2017-04-28 | 2019-12-10 | 苏州半唐电子有限公司 | method for starting sensorless permanent magnet synchronous motor and sensorless permanent magnet synchronous motor |
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