CA1190278A - Drive circuit for step motor - Google Patents
Drive circuit for step motorInfo
- Publication number
- CA1190278A CA1190278A CA000395230A CA395230A CA1190278A CA 1190278 A CA1190278 A CA 1190278A CA 000395230 A CA000395230 A CA 000395230A CA 395230 A CA395230 A CA 395230A CA 1190278 A CA1190278 A CA 1190278A
- Authority
- CA
- Canada
- Prior art keywords
- winding
- step motor
- series
- capacitor
- diode
- 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.)
- Expired
Links
- 238000004804 winding Methods 0.000 claims abstract description 48
- 239000003990 capacitor Substances 0.000 claims abstract description 23
- 238000000034 method Methods 0.000 claims description 4
- 230000001012 protector Effects 0.000 claims description 3
- 230000000875 corresponding effect Effects 0.000 claims 5
- 238000010276 construction Methods 0.000 abstract description 2
- 238000010304 firing Methods 0.000 abstract description 2
- 238000010791 quenching Methods 0.000 description 3
- 230000000903 blocking effect Effects 0.000 description 2
- 230000033001 locomotion Effects 0.000 description 2
- 230000000171 quenching effect Effects 0.000 description 2
- XUIMIQQOPSSXEZ-UHFFFAOYSA-N Silicon Chemical compound [Si] XUIMIQQOPSSXEZ-UHFFFAOYSA-N 0.000 description 1
- 239000004020 conductor Substances 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 238000007639 printing Methods 0.000 description 1
- 230000035939 shock Effects 0.000 description 1
- 229910052710 silicon Inorganic materials 0.000 description 1
- 239000010703 silicon Substances 0.000 description 1
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
- H02P8/00—Arrangements for controlling dynamo-electric motors rotating step by step
- H02P8/14—Arrangements for controlling speed or speed and torque
Landscapes
- Engineering & Computer Science (AREA)
- Power Engineering (AREA)
- Control Of Stepping Motors (AREA)
Abstract
DRIVE CIRCUIT FOR STEP MOTOR
Abstract:
A drive circuit for a step motor, where the stator windings of the step motor are in each case connected in series to a diode and where a capacitor is connected in parallel to the series of diode and winding. The above element is provided with power from a d.c. source via a thyristor switch. The circuit provides that upon firing of a thyristor the previously current conducting thyristor is switched off. This construction allows the reliable operation of step motors and a holding current can still flow up to the moment of switching to another winding.
Abstract:
A drive circuit for a step motor, where the stator windings of the step motor are in each case connected in series to a diode and where a capacitor is connected in parallel to the series of diode and winding. The above element is provided with power from a d.c. source via a thyristor switch. The circuit provides that upon firing of a thyristor the previously current conducting thyristor is switched off. This construction allows the reliable operation of step motors and a holding current can still flow up to the moment of switching to another winding.
Description
_SCRIPTION
BACKGROUND OF THE INVENTION
1 Field of the Invention .
The present invention relates to a drive circuit for a step motor employing thyristors.
BACKGROUND OF THE INVENTION
1 Field of the Invention .
The present invention relates to a drive circuit for a step motor employing thyristors.
2. Brief Description of the Background of the Invention Including Prior Art The application of a step motor with a relatively low self holding torque results in the advantage of a correspondingly low energy requirement for performing each step. For avoiding of undesired motions caused by mechanical disturbances such as for example small shocks the self holding torque can be supported by an additional magnetic field, which can be generated from a current flowing in the rest position in a stator winding.
The switching on of the stator windings is performed by way of thyristors connected in series to corresponding windings, where the conducting state of the thyristors is maintained in each case by the current flowing through them. In the context .~
of the present invention a thyristor refers generically to thyratronlike solid-state devices such as silicon controlled rectifiers and in particular pnpn type bistable semi.conductor devices having anode, cathode and gate terminals and useable as an electronic switch.
For switching off of a stator winding the corresponding thyristor has to be switched off and in general a special quench device has to be provided for this purpose. It is an advantage~ if the switchi.ng on step of another stator winding can be employed for at the same time quenching said thyristor to switch off the current flow.
SUMMARY OF THE INVENTION
1. Purposes of the Invention -It is an object of the present invention to provide a particularly simple drive circuit employing thyristors for a step motor, where a current flowing through a stator winding of the step motor is switched off as rapidly as possible and under low losses and another winding is switched on.
It is another object of the present i.nvention to provide a drive circuit for a step motor where a thyristor of a winding to be switched on effects quenching the previously conducting thyristor.
It is a further object of the present invention to employ a capacitor for accepting the energy remaining in the winding after switching off of the corresponding thyristor.
These and other features and advantages of the present invention will become evident from the description which follows.
2. Brief Description of the Invention The present inver,tion provides a drive circuit for a step motor comprising: a constant current power supply; stator windings of the step motor; diodes each connected in series to a corresponding winding; capacitors each connected in parallel to a corresponding series of a diode connected to the winding and also connected on one side to one terminal of the constant current power supply;
thyristors each connected to a corresponding capacitor on the side not connected to the constant current power supply and connected to the second terminal of the constant current power supply; and a control device connected to the gate inputs of the thyristors~
There is also provided a method for providing power to a step motor comprising: charging a capacitor;
energizing a winding connected in series to a diode with the series connection of the diode and the winding being in parallel to the capacitor; interrupting the current flow by instituting a corresponding cycle at a second winding;
and charging with reverse polarity the capacitor with the energy remaining in the switched off winding and preventing current flow in the opposite direction by connecting a diode in series to the corresponding winding.
The novel features which are considered as characteristic for the invention are set forth in particular in the appended claims. The invention itself, however, both as to its construction and its method of operation, together with additional objects and advantages thereof, will be best understood from the following descrip~ion of specific embodiments when read in connection with the accompanying drawing.
BRIEF DESCRIPTION OF THE DRAWING
In the accompanying drawing in which is shown one of the various possible embodiments of the present invention, Fig. 1 is a view of a schematic diagram of a drive circuit for a step motor according to the present invention.
DESCRIPTION OF INVENTION AND PREFERRED EMBODIME~TS
In accordance with the present invention there is provided a drive circuit where in series to each stator winding there is connected a diode in each case and where in parallel to each of said series connection there is connected a capacitor in each case. Thyristors (Thl ? Th2, Th3) are connected in series to the windings (Ll,L2, L3), the diodes (Dl, D2, D3) and the capacitors (Cl, C2, C3~
in each case. Such a drive circuit can advantageously be employed for driving a step motor operating a printer for teletype equipment or for other printing machines For reasons of simplifying the representation in the drawing only three windings Ll, L2, and L3 are shown of the step motor. The dashed lines indicate in Fig. 1, that the motoremployed in each case can be provided with a larger number of windings. Since also the spacial arrangement of the windings with respect to each other does not have an immediate influence on the functioning of the circuit shown, also the possibility of employing this drive circuit in other types of motors exists,e.g. linear motors.
Also, the movable element of such motor not shown here takes a position corresponding to the windings controlled in each case. The movable element is in general a rotor and the magnetic Eield of a current containing winding interac~s with the rotor.
The windings Ll, L2, L3 can be connected to the power supply 10 via corresponding in series disposed thyristors Thl, Th2, Th3. A constant current source serves as a power supply~ In order to avoid damaging overvoltages at the output terminals of the constant current souree a surge protector 12 is provided in Fig. lo The switching pulses for the gate electrodes of the thyristors Thl, Th2 and Th3 are generated by the control device 11.
The diodes Dl, D2, D3 are eonneeted in series with the windings Ll, L2, L3. The eapacitors Cl, C2, C3 are conneeted in each case parallel to the resulting series conneetions.
Upon switching on of the eircuit the voltage generated by the constant current souree L0 is initially limited to the value predetermined by the surge protector 12, since in the eonnected eircuit no elosed eircuit paths are present for the current as long as the thyristors Thl, Th2, and Th3 are switched off. Initially the eapacitors Cl, C2 and C3 are in a discharged state.
The thyristor Th2 is switched on if the rotor is to be brought in the pvsition determined by the magnetie ~L~
fi.eld of the winding L2. The current flows via this thyristor Th2 into the capacitor C2, such that the voltage of the constant current source 10 collapses. With increasing charge on the capacitor C2 the voltage increases again~
If the voltage surpasses the threshold voltage of the diode D2, then additional current flows via the winding L2 of the step motor disposed in parallel to the capacitor C2. Since the winding L2 cannot initially accept the current in total, the capacitor C2 ~urther accepts the current difference between the current coming from the constant current source 10 and the momentary value of the current passing through the winding L2, until the winding L2 has completely accepted all the current coming from the constant current source 10. The desired motion is now provided by the magnetic field generated by the winding L2.
Furthermore, in addition the current through the winding L2 flows via the switched on thyristor Th2 and generates the desired holding moment.
If now the thyristor Thl is switched on, then the current flows through -the capacitor Cl still being in a discharged state, as a result of which the voltage at the constant current source collapses and blocks the thyristor Th2. In the circui,t belonging to the thyristor Thl the process described above for the circuit of the thyristor Th2 now runs and generates in the winding Ll the desired magnetic field.
By blocking the thyristor Th2 the outer connection of the current circuit for the winding L2 is interrupted.
However, the current in the winding L2 remains effective in the original direction and flows now to the capacitor C2, whereby the capacitor C2 is charged with reverse polarity.
Backflow of the charge from the capacitor C2 into the wind-ing L2 is preYented by the diode D2, such that the charge state generated this way remains effective until a renewed firing of the thyristor Th2. Thereby, the thyristor Th2 is safely kept in a blocking state for the current.
If now the thyristor Th2 is again fired, then the voltage at the capacitor C2 acts as a countervoltage to which the voltage of the constant current source 10 falls such that the previously fired thyristor Thl blocks rapidly and reliably.
It is to be understood that each of the elements described above, or two or more together, may also find a useful application in other types of motor configurations and electromechanical power converters differing from the types described above.
While the invention has been illustrated and described in the context of a step motor, it is not intended to be limited to the details shown, since various modifications and structural changes may be made without departing in any way from the spirit of the present invention.
Without further analysis 7 the foregoing will so fully reveal the gist of the present invention that others can, by applying current knowledge, readily adapt it for various applications without omi.tting features that, from the standpoint of prior art, fairly constitute essential characteristics of the generi.c or specific aspects of this invention.
W~lat is claimed as new and desired to be protected by Letters Patent is set forth in the appended claims.
The switching on of the stator windings is performed by way of thyristors connected in series to corresponding windings, where the conducting state of the thyristors is maintained in each case by the current flowing through them. In the context .~
of the present invention a thyristor refers generically to thyratronlike solid-state devices such as silicon controlled rectifiers and in particular pnpn type bistable semi.conductor devices having anode, cathode and gate terminals and useable as an electronic switch.
For switching off of a stator winding the corresponding thyristor has to be switched off and in general a special quench device has to be provided for this purpose. It is an advantage~ if the switchi.ng on step of another stator winding can be employed for at the same time quenching said thyristor to switch off the current flow.
SUMMARY OF THE INVENTION
1. Purposes of the Invention -It is an object of the present invention to provide a particularly simple drive circuit employing thyristors for a step motor, where a current flowing through a stator winding of the step motor is switched off as rapidly as possible and under low losses and another winding is switched on.
It is another object of the present i.nvention to provide a drive circuit for a step motor where a thyristor of a winding to be switched on effects quenching the previously conducting thyristor.
It is a further object of the present invention to employ a capacitor for accepting the energy remaining in the winding after switching off of the corresponding thyristor.
These and other features and advantages of the present invention will become evident from the description which follows.
2. Brief Description of the Invention The present inver,tion provides a drive circuit for a step motor comprising: a constant current power supply; stator windings of the step motor; diodes each connected in series to a corresponding winding; capacitors each connected in parallel to a corresponding series of a diode connected to the winding and also connected on one side to one terminal of the constant current power supply;
thyristors each connected to a corresponding capacitor on the side not connected to the constant current power supply and connected to the second terminal of the constant current power supply; and a control device connected to the gate inputs of the thyristors~
There is also provided a method for providing power to a step motor comprising: charging a capacitor;
energizing a winding connected in series to a diode with the series connection of the diode and the winding being in parallel to the capacitor; interrupting the current flow by instituting a corresponding cycle at a second winding;
and charging with reverse polarity the capacitor with the energy remaining in the switched off winding and preventing current flow in the opposite direction by connecting a diode in series to the corresponding winding.
The novel features which are considered as characteristic for the invention are set forth in particular in the appended claims. The invention itself, however, both as to its construction and its method of operation, together with additional objects and advantages thereof, will be best understood from the following descrip~ion of specific embodiments when read in connection with the accompanying drawing.
BRIEF DESCRIPTION OF THE DRAWING
In the accompanying drawing in which is shown one of the various possible embodiments of the present invention, Fig. 1 is a view of a schematic diagram of a drive circuit for a step motor according to the present invention.
DESCRIPTION OF INVENTION AND PREFERRED EMBODIME~TS
In accordance with the present invention there is provided a drive circuit where in series to each stator winding there is connected a diode in each case and where in parallel to each of said series connection there is connected a capacitor in each case. Thyristors (Thl ? Th2, Th3) are connected in series to the windings (Ll,L2, L3), the diodes (Dl, D2, D3) and the capacitors (Cl, C2, C3~
in each case. Such a drive circuit can advantageously be employed for driving a step motor operating a printer for teletype equipment or for other printing machines For reasons of simplifying the representation in the drawing only three windings Ll, L2, and L3 are shown of the step motor. The dashed lines indicate in Fig. 1, that the motoremployed in each case can be provided with a larger number of windings. Since also the spacial arrangement of the windings with respect to each other does not have an immediate influence on the functioning of the circuit shown, also the possibility of employing this drive circuit in other types of motors exists,e.g. linear motors.
Also, the movable element of such motor not shown here takes a position corresponding to the windings controlled in each case. The movable element is in general a rotor and the magnetic Eield of a current containing winding interac~s with the rotor.
The windings Ll, L2, L3 can be connected to the power supply 10 via corresponding in series disposed thyristors Thl, Th2, Th3. A constant current source serves as a power supply~ In order to avoid damaging overvoltages at the output terminals of the constant current souree a surge protector 12 is provided in Fig. lo The switching pulses for the gate electrodes of the thyristors Thl, Th2 and Th3 are generated by the control device 11.
The diodes Dl, D2, D3 are eonneeted in series with the windings Ll, L2, L3. The eapacitors Cl, C2, C3 are conneeted in each case parallel to the resulting series conneetions.
Upon switching on of the eircuit the voltage generated by the constant current souree L0 is initially limited to the value predetermined by the surge protector 12, since in the eonnected eircuit no elosed eircuit paths are present for the current as long as the thyristors Thl, Th2, and Th3 are switched off. Initially the eapacitors Cl, C2 and C3 are in a discharged state.
The thyristor Th2 is switched on if the rotor is to be brought in the pvsition determined by the magnetie ~L~
fi.eld of the winding L2. The current flows via this thyristor Th2 into the capacitor C2, such that the voltage of the constant current source 10 collapses. With increasing charge on the capacitor C2 the voltage increases again~
If the voltage surpasses the threshold voltage of the diode D2, then additional current flows via the winding L2 of the step motor disposed in parallel to the capacitor C2. Since the winding L2 cannot initially accept the current in total, the capacitor C2 ~urther accepts the current difference between the current coming from the constant current source 10 and the momentary value of the current passing through the winding L2, until the winding L2 has completely accepted all the current coming from the constant current source 10. The desired motion is now provided by the magnetic field generated by the winding L2.
Furthermore, in addition the current through the winding L2 flows via the switched on thyristor Th2 and generates the desired holding moment.
If now the thyristor Thl is switched on, then the current flows through -the capacitor Cl still being in a discharged state, as a result of which the voltage at the constant current source collapses and blocks the thyristor Th2. In the circui,t belonging to the thyristor Thl the process described above for the circuit of the thyristor Th2 now runs and generates in the winding Ll the desired magnetic field.
By blocking the thyristor Th2 the outer connection of the current circuit for the winding L2 is interrupted.
However, the current in the winding L2 remains effective in the original direction and flows now to the capacitor C2, whereby the capacitor C2 is charged with reverse polarity.
Backflow of the charge from the capacitor C2 into the wind-ing L2 is preYented by the diode D2, such that the charge state generated this way remains effective until a renewed firing of the thyristor Th2. Thereby, the thyristor Th2 is safely kept in a blocking state for the current.
If now the thyristor Th2 is again fired, then the voltage at the capacitor C2 acts as a countervoltage to which the voltage of the constant current source 10 falls such that the previously fired thyristor Thl blocks rapidly and reliably.
It is to be understood that each of the elements described above, or two or more together, may also find a useful application in other types of motor configurations and electromechanical power converters differing from the types described above.
While the invention has been illustrated and described in the context of a step motor, it is not intended to be limited to the details shown, since various modifications and structural changes may be made without departing in any way from the spirit of the present invention.
Without further analysis 7 the foregoing will so fully reveal the gist of the present invention that others can, by applying current knowledge, readily adapt it for various applications without omi.tting features that, from the standpoint of prior art, fairly constitute essential characteristics of the generi.c or specific aspects of this invention.
W~lat is claimed as new and desired to be protected by Letters Patent is set forth in the appended claims.
Claims (3)
1. A drive circuit for a step motor comprising:
a constant current power supply;
stator windings of the step motor;
diodes each connected in series to a corresponding winding;
capacitors each connected in parallel to a correspond-ing series of a diode connected to the winding and also connected on one side to one terminal of the constant current power supply;
thyristors each connected to a corresponding capacitor on the side not connected to the constant current power supply and connected to the second terminal of the constant current power supply; and a control device connected to the gate inputs of the thyristors.
a constant current power supply;
stator windings of the step motor;
diodes each connected in series to a corresponding winding;
capacitors each connected in parallel to a correspond-ing series of a diode connected to the winding and also connected on one side to one terminal of the constant current power supply;
thyristors each connected to a corresponding capacitor on the side not connected to the constant current power supply and connected to the second terminal of the constant current power supply; and a control device connected to the gate inputs of the thyristors.
2. The drive circuit for a step motor according to claim 1 further comprising:
a surge protector connected in parallel to the constant current power supply.
a surge protector connected in parallel to the constant current power supply.
3. A method for providing power to a step motor comprising:
charging a capacitor;
energizing a winding connected in series to a diode with the series connection of the diode and the winding being in parallel to the capacitor;
interrupting the current flow by instituting a corres-ponding cycle at a second winding; and charging with reverse polarity the capacitor with the energy remaining in the switched off winding and preventing current flow in the opposite direction by connecting a diode in series to the corresponding winding.
charging a capacitor;
energizing a winding connected in series to a diode with the series connection of the diode and the winding being in parallel to the capacitor;
interrupting the current flow by instituting a corres-ponding cycle at a second winding; and charging with reverse polarity the capacitor with the energy remaining in the switched off winding and preventing current flow in the opposite direction by connecting a diode in series to the corresponding winding.
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
DE19813103097 DE3103097C2 (en) | 1981-01-30 | 1981-01-30 | Circuit arrangement for a stepper motor |
DEP3103097.1-32 | 1981-01-30 |
Publications (1)
Publication Number | Publication Date |
---|---|
CA1190278A true CA1190278A (en) | 1985-07-09 |
Family
ID=6123649
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
CA000395230A Expired CA1190278A (en) | 1981-01-30 | 1982-01-29 | Drive circuit for step motor |
Country Status (5)
Country | Link |
---|---|
EP (1) | EP0057378B1 (en) |
JP (1) | JPS57145598A (en) |
CA (1) | CA1190278A (en) |
DE (1) | DE3103097C2 (en) |
IN (1) | IN156138B (en) |
Families Citing this family (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JP4875777B1 (en) * | 2011-05-19 | 2012-02-15 | アタカ大機株式会社 | Aeration stirrer |
Family Cites Families (8)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
GB950337A (en) * | 1961-06-15 | 1964-02-26 | Int Computers & Tabulators Ltd | Improvements in or relating to switching apparatus for inductive circuits |
US3247433A (en) * | 1962-12-12 | 1966-04-19 | Bendix Corp | Reversible silicon controlled rectifier ring counter for stepper motor drive |
GB1010571A (en) * | 1963-01-24 | 1965-11-17 | Ass Elect Ind | Improvements in or relating to the speed control of electric motors |
US3392293A (en) * | 1964-12-29 | 1968-07-09 | Teletype Corp | Electromagnetic stepping motor |
GB1112455A (en) * | 1966-08-03 | 1968-05-08 | Kabushikikaisha Tokyo Keiki Se | Power source device for driving step motor of gyro |
CA902167A (en) * | 1967-09-22 | 1972-06-06 | Fairchild Camera And Instrument Corporation | Stepper motor control system |
DE2009752C3 (en) * | 1969-03-07 | 1975-03-06 | Institutul Politehnic, Cluj (Rumaenien) | Circuit arrangement for controlling the speed of a three-phase asynchronous motor |
DE2829685C2 (en) * | 1978-07-06 | 1982-09-09 | Danfoss A/S, 6430 Nordborg | Motor fed by DC voltage |
-
1981
- 1981-01-30 DE DE19813103097 patent/DE3103097C2/en not_active Expired
-
1982
- 1982-01-21 EP EP19820100397 patent/EP0057378B1/en not_active Expired
- 1982-01-29 JP JP1194982A patent/JPS57145598A/en active Pending
- 1982-01-29 CA CA000395230A patent/CA1190278A/en not_active Expired
- 1982-03-01 IN IN236/CAL/82A patent/IN156138B/en unknown
Also Published As
Publication number | Publication date |
---|---|
JPS57145598A (en) | 1982-09-08 |
EP0057378B1 (en) | 1984-03-28 |
DE3103097C2 (en) | 1985-01-24 |
DE3103097A1 (en) | 1982-08-12 |
IN156138B (en) | 1985-05-18 |
EP0057378A1 (en) | 1982-08-11 |
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Legal Events
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