Inductor type synchronous motor driving system for minute control of the position and the rotation angle of the motor

• US 4,321,518 A
• Filed: 05/25/1978
• Issued: 03/23/1982
• Est. Priority Date: 03/28/1975
• Status: Expired due to Term

• Current Assignee: Mitsubishi Denki Kabushiki Kaisha (Mitsubishi Electric Corporation)
• Original Assignee: Mitsubishi Denki Kabushiki Kaisha (Mitsubishi Electric Corporation)
• Inventors: Akamatsu, Masahiko
• Primary Examiner(s): Truhe, J. V.
• Assistant Examiner(s): Moose, Richard M.
• Application Number:
  US05/909,493
• Time in Patent Office: 1,398 Days
• Field of Search: 318/138, 318/696, 318/341, 318/810, 318/701, 310/49, 310/162-164
• US Class Current: 318/696
• CPC Class Codes: H02P 25/024 controlled by supply frequency
• CPC Class Codes: Y10S 174/16 in a motive power system, e.g. electric motor control system

Abstract

A system for driving an inductor type synchronous motor for minute control thereof which includes an inductor type synchronous motor having a circuit for driving m phases of driving windings and first magnetic teeth. A second group of magnetic teeth is provided facing the first group of magnetic teeth. Apparatus is provided for feeding electric current from a DC power source to the driving windings of the respective phases. The driving winding for one phase intersects the flux of a partial set of first magnetic teeth or at least two magnetic teeth to provide a flux-interlink. A group of solid state switches are interposed between the source for producing the electric current and the driving windings of the respective phases. A distribution pattern generator generates patterns in response to a command signal and controls the on-off states of the solid-state switches with the noted patterns to thereby form the electric current into trigonometric-functional-patterns. The minute control characterized with an electrical resolution number R, per electrical angle 2π (2π being one fundamental cycle) of the apparatus for feeding electric current, is equal to or larger than 3m per electrical cycle. The minute control is thereby determined to be stepless.

Claims

1. A system for driving an inductor-type synchronous motor for minute control comprising:

an inductor-type synchronous motor having a first means equipped with driving windings of m numbers of phases and first magnetic teeth, and second means equipped with second magnetic teeth face to face with said first magnetic teeth; and

a power feed means for feeding electric power to said driving windings of said m numbers of phases from a DC power source through solid-state switching means interposed therebetween;

wherein said driving windings for one of said phases intersect flux of a portion of said first magnetic teeth and said portion includes at least two magnetic teeth having different fluxes in electrical phase which results in said first means forming a non-distortion electromagnetic construction thereby providing a sinusoidalized internal velocity electromotive force; and

wherein said power feed means comprises a distribution pattern generator for generating patterns in response to a command signal from a system control means, and comprises a switching control device for generating on-off signals for on-off control of said solid-state switching means in response to said pattern; and

said fed electric power being formed into trigonometric-functional patterns by said distribution pattern generator to provide AC components of said fed electric power which has an electric vector rotation angle which is accurately coincident with a balance point of magnetomotive force produced by said driving winding;

whereby minute control is provided which is characterized by an electrical resolution number per electrical angle aπ

of said power feed means which is equal or larger than three times m points.

2. A system for driving an inductor type synchronous motor for minute control as in claim 1 wherein the flux of at least one of said first magnetic teeth interlinks the driving windings of a plurality of said m numbers of phases.

3. A system for driving an inductor type synchronous motor for minute control as in claim 1 wherein a composite of the magneto-motive force of said plural phases acts on a gap formed between a portion of said first and second teeth.

4. A system for driving an inductor type synchronous motor for minute control as in claim 1 wherein the magnetic teeth of one phase of said m numbers of phases comprises at least two magnetic teeth whose fluxes interlink said driving winding of one phase.

5. A system for driving an inductor type synchronous motor for minute control as in claim 1 wherein said first means has a group of unit magnetic paths for forming paths to said driving windings, the group of unit magnetic paths having a unit magnetic path divided by slots and which has a plurality of unit magnetic teeth installed opposite to second magnetic teeth, the unit magnetic teeth belonging to said first magnetic teeth, and said first means further has a group of unit coils intersecting the flux of at least one of said magnetic paths, and each phase of said driving windings is formed of at least one of said unit coils in series-parallel connection.

6. A system for driving an inductor type synchronous motor for minute control as in claim 5 wherein at least two magnetic teeth of one of said magnetic paths are different in kind from each other.

7. A system for driving an inductor type synchronous motor for minute control as in claim 5 wherein the driving winding of at least one phase intersects the fluxes of at least two unit magnetic paths and said portion of first magnetic teeth of one phase are installed on different unit magnetic paths.

8. A system for driving an inductor type synchronous motor for minute control as in claim 5 wherein the flux of at least one of said group of magnetic paths intersects said driving windings of plural phases.

9. A system for driving an inductor type synchronous motor for minute control as in claim 1 wherein pitch of said first magnetic teeth is differentiated from that of said second magnetic teeth on one of said unit magnetic paths.

10. A system for driving an inductor type synchronous motor for minute control as in claim 1 wherein either said group of first magnetic teeth or said second magnetic teeth are sequentially shifted in the direction perpendicular to a relative moving direction of the first and second magnetic teeth.

11. A system for driving an inductor type synchronous motor for minute control as in claim 1 wherein at least two of said first magnetic teeth have tooth widths different from each other.

12. A system for driving an inductor type synchronous motor for minute control as in claim 1 wherein a DC field means for providing a DC field is disposed between said first magnetic teeth and said second magnetic teeth whereby the linearity of a current-torque characteristic is improved.

13. A system for driving an inductor type synchronous motor for minute control as in claim 1 wherein said power feed means feeds current or applies voltages which are proportional to the currents or voltages of the driving windings of the m numbers of phases.

14. A system for driving an inductor type synchronous motor for minute control as in claim 1 including power control means for controlling said electric power accordingly to a desired torque.

15. A system for driving an inductor type synchronous motor for minute control as in claim 1 wherein said power feed means is a pure AC power feed device for bipolar power feed to the driving windings of the m numbers of phases.

16. A system for driving an inductor type synchronous motor for minute control as in claim 1 wherein said pattern generator forms said fed electric power into a trapezoidal wave or a polygonal-line-approximated sine wave or a pattern wave of time-ratio-modulated wave representing said trapezoidal wave or representing said polygonal-line approximated sine wave, and being unipolar or bipolar.

17. A system for driving an inductor type synchronous motor for minute control as in claim 16 wherein said fed power is bipolar.

18. A system for driving an inductor type synchronous motor for minute control as in claim 12 wherein said power feed means feeds power in a trigonometric functional mode in the low speed region for minute control, and releases minute control during operation in a high speed region.

19. A system for driving an inductor type synchronous motor for minute control as in claim 18 wherein said power feed means feeds a voltage or a current of the square wave or stepped wave type during operations in a high speed region.

20. A system for driving an inductor type synchronous motor for minute control as in claim 12 wherein said power feed means provides a switching mode control performing time-ratio-modulation, thus feeding said motor with voltage or current of sine wave or approximate sine wave, unipolar or bipolar wave.

21. A system for driving an inductor type synchronous motor for minute control as in claim 20 wherein said power feed means comprises:

a distribution pattern generator for generating a waveform pattern in response to a digital command pulse from a digital command pulse generator, and said waveform pattern has the form of a trigonometric functional mode wave or approximately trigometric functional mode wave or said time-ratio-modulated wave representing the trigonometric or approximately-trigometric functional mode wave, and a power control device for generating an output of substantial power-amplified quantity of said waveform pattern.

22. A system for driving an inductor type synchronous motor for minute control as in claim 21 wherein said distribution pattern generator generates a time-ratio-modulated wave, and said time-ratio-modulated distribution pattern is an on-off control signal for on-off control of at least one of said solid-state switching means of said power feed means.

23. A system for driving an inductor type synchronous motor for minute control as in claim 21 wherein said distribution pattern generator has a frequency signal generator and a signal converter;

the frequency signal generator being capable of generating at least two frequency signals, at least one of which is variable in frequency responding to said digital command pulse, and the signal converter receiving said two frequency signals and generating a distribution pattern.

24. A fine control system for driving an inductor type synchronous motor comprising:

an inductor type synchronous motor having a first inductor equipped with driving windings corresponding to m phases and a group of first magnetic teeth, and a second inductor equipped with a group of second magnetic teeth, m representing a positive interger;

a DC power supply;

a plurality of switches connected between the DC power supply and said driving winding for distributing the DC power supply voltage to said driving windings of said m phases, wherein said driving windings for one of said phases intersect flux of a portion of said first magnetic teeth and said portion includes at least two magnetic teeth having different fluxes in electrical phase which results in said first inductor forming a non-distortion electromagnetic construction thereby providing a sinusoitalized internal velocity electromotive force;

control means for generating command pulse trains which denote positive and negative rotation and fine control mode command pulse trains; and

distribution pattern generator means connected to said control means and responsive to the generation of a fine control mode command pulse train for controlling the on-off operation of said plurality of switches to cause a mean value of said supply voltage to said driving windings of said m phases to assume a trapezoidal waveform to provide AC components of said fed electric power which has an electric vector rotation angle which is accurately coincident with a balance point of magnetomotive force produced by said driving winding;

whereby minute control is provided which is characterized by an electrical resolution number per electrical angle 2π

which is larger than 2 m.

25. A fine control system for driving an inductor type synchronous motor comprising:

an inductor type synchronous motor having a first phases and a group of first magnetic teeth, and a second inductor equipped with a group of second magnetic teeth, m representing a positive interger;

a DC power supply;

a plurality of switches connected between the DC power supply and said driving winding for distributing the DC power supply voltage to said driving winding of said m phases, wherein said driving windings for one of said phases intersect flux of a portion of said first magnetic teeth and said portion includes at least to magnetic teeth having different fluxes in electrical phase which results in said first inductor forming a non-distortion electromagnetic construction thereby providing a sinusoidalizer internal velocity electromotive force;

control means for generating command pulse trains which denote positive and negative rotation and fine control mode command pulse trains; and

distribution pattern generator means connected to said control means and responsive to the generation of a fine control mode command pulse train for controlling the on-off operation of said plurality of switches to cause a mean value of said supply voltage to said driving windings of said m phases to assume a square waveform to provide AC components of said fed electric power which has an electric vector rotation angle which is accurately coincident with a balance point of magnetomotive force produced by said driving windings;

whereby minute control is provided which is characterized by an electrical resolution number per electrical angle 2π

which is larger than 2 m.

26. A fine control system for driving an inductor type synchronous motor comprising:

an inductor type synchronous motor having a first inductor equipped with driving winding corresponding to m phases and a group of first magnetic teeth, and a second inductor equipped with a group of second magnetic teeth, m representing a positive interger;

a DC power supply;

a plurality of switches connected between the DC power supply and said driving winding for distributing the DC power supply voltage to said driving winding of said m phases, wherein said driving windings for one of said phases intersect flux of a portion of said first magnetic teeth and said portion includes at least two magnetic teeth having different fluxes in electrical phase which results in said first inductor forming a non-distortion electromagnetic construction thereby providing a sinusoitalized internal velocity electromotive force;

control means for generating command pulse trains which denote positive and negative rotation and fine control mode command pulse trains; and

distribution pattern generator means connected to said control means and responsive to the generation of a fine control mode command pulse train for controlling the on-off operation of said plurality of switches to cause a means current to said driving windings of said m phases to assume a trapezoidal waveform to provide AC components of fed electrical power which has an electric vector rotation angle which is accurately coincident with a balance point of magnetomotive force produced by said driving windings;

whereby minute control is provided which is characterized by an electrical resolution number per electrical angle 2π

which is larger than 2 m.

27. A fine control system for driving an inductor type synchronous motor comprising:

an inductor type synchronous motor having a first inductor equipped with driving winding corresponding to m phases and a group of first magnetic teeth, and a second inductor equipped with a group of second magnetic teeth, m representing a positive interger;

a DC power supply;

a plurality of switches connected between the DC power supply the said driving winding for distributing the DC power supply voltage to said driving windings of said m phases, wherein said driving windings for one of said phases intersect flux of a portion of said first magnetic teeth and said portion includes at least two magnetic teeth having different fluxes in electrical phase which results in said first inductor forming a non-distortion electromagnetic construction thereby providing a sinusoidalized internal velocity electromotive force;

control means for generating command pulse trains which denote positive and negative rotation and fine control mode command pulse trains; and

distribution pattern generator means connected to said control means and responsive to the generation of a fine control mode command pulse train for controlling the on-off operation of said plurality of switches to cause a mean value of mean current to said driving winding of said m phases to assume a polygonal line approximation sign waveform to provide AC components of said fed electrical power which has an electric vector rotation angle which is accurately coincident with a balance point of magnetomotive force produced by said driving windings;

whereby minute control is provided which is characterized by an electrical resolution number per electrical angle 2π

which is larger than 2 m.