High-efficiency electric motor of electronic commutation type

• US 6,163,122 A
• Filed: 10/21/1998
• Issued: 12/19/2000
• Est. Priority Date: 03/01/1996
• Status: Expired due to Term

• Current Assignee: Bitron SPA (Bitron Industrie SPA)
• Original Assignee: Bitron SPA (Bitron Industrie SPA)
• Inventors: De Filippis, Pietro
• Primary Examiner(s): Martin, David
• Assistant Examiner(s): Leykin, Rita
• Application Number:
  US09/125,934
• Time in Patent Office: 790 Days
• Field of Search: 318/254, 318/439, 318/138, 361/23, 310/184, 310/185, 310/186, 310/187, 310/188, 310/198
• US Class Current: 318/400.26
• CPC Class Codes: H02K 16/04 Machines with one rotor and two stators
• CPC Class Codes: H02K 3/28 Layout of windings or of connections between windings windings for pole-changing H02K17/06, H02K17/14, H02K19/12, H02K19/32
• CPC Class Codes: H02M 3/1584 with a plurality of power processing stages connected in parallel
• CPC Class Codes: H02P 6/08 Arrangements for controlling the speed or torque of a single motor H02P6/10, H02P6/28 take precedence
• CPC Class Codes: H02P 6/10 Arrangements for controlling torque ripple, e.g. providing reduced torque ripple

Abstract

An electronic commutation motor including a stator unit configured as a pulse-modulation driven stator unit including at least two winding circuits in which an induced electromagnetic force is produced, and a phase switching switch; and a rotor unit powered by charge stored on a capacitor, wherein the capacitor is charged by diodes coupled between the capacitor the first winding circuits of the stator unit. In this way, the stator unit, serving as a first submachine, performs the function of power supply for the rotor unit serving as a second submachine, by charging of the capacitor via the diodes.

Claims

1. An electronic commutation motor comprising:

a stator unit and a rotor unit configured as a first submachine and a second submachine;

said first submachine being pulse-modulation driven and comprising at least two first winding circuits each comprising a series combination of a winding having an inductance and a resistance and in which an induced electromotive force is produced, and a phase switching switch;

a capacitor;

at least two diodes coupled between respective of said at least two first winding circuits and said capacitor; and

said first submachine and said at least two diodes configured to charge said capacitor to a controlled voltage applied to said second submachine as a power supply for said second submachine.

2. The motor of claim 1, wherein said second submachine comprises:

at least two second winding circuits, each comprising a series combination of a winding having an inductance and a resistance and in which an induced electromotive force is produced, and a phase switching switch.

3. The motor of claim 2, wherein said at least two first winding circuits are connected in parallel and said at least two second winding circuits are connected in parallel.

4. The motor of claim 2, wherein said first and said second submachines comprise diodes connected in parallel with respective of the switches of said winding circuits.

5. The motor of claim 2, comprising:

an electronic control unit configured to control a plurality of said switches on the basis of the controlled voltage of the capacitor, a current circulating within the voltage source, a voltage across the switches of the second submachine cinematic quantities of the motor.

6. The motor of claim 1, wherein said inductors are electromagnetically decoupled from each other or have windings which are inductively separated.

7. The motor of claim 2, wherein the record submachine has a number of inductors equal to the number of inductors of the first submachine.

8. The motor of claim 2, wherein the second submachine has a number of inductors different from the number of inductors of the first submachine.

9. The motor of claim 2, wherein said inductors of the second submachine are electromagnetically coupled together.

10. The motor of claim 2, wherein said inductors of the second submachine are electromagnetically decoupled from said inductors of the first submachine.

11. The motor of claim 1, wherein the first and second submachines have respective drivers independent from each other.

12. The motor of claim 11, wherein the driver of the second submachine is selected from the group consisting of unipolar, bridging, linear and PWM drivers.

13. The motor of claim 6 or 10, wherein the stator unit comprises teeth on which said windings are wound, further comprising:

a ferromagnetic element without windings interposed between two adjacent stator teeth provided with windings.

14. The motor of claim 13, wherein the windings of the first submachine are formed such that the respective phases are wound on different teeth separated by a ferromagnetic element without windings.

15. The motor of claim 2, wherein said inductors of the second submachine are electromagnetically decoupled from said inductors of the first submachine, and the stator unit comprises teeth on which said windings are wound, further comprising:

a ferromagnetic element without windings interposed between two adjacent stator teeth provided with windings; and

the windings of the second submachine being formed such that the respective phases are wound on the same teeth.

16. The motor of claim 6 or 10, wherein the stator unit comprises teeth on which said windings are wound, further comprising:

a ferromagnetic element without windings interposed between two adjacent stator teeth provided with windings wherein each stator tooth provided with windings is split into a fork, between the ends of which is interposed said ferromagnetic element without windings.

17. The motor of claim 16, wherein the windings of the first submachine are formed such that the respective phases are wound on the forked ends of two adjacent teeth, said ends being separated by said ferromagnetic element without windings.

18. The motor of claim 1, comprising a power source selected from the group consisting of a d.c. voltage generator, a storage battery, and a rectified a.c. voltage generator and configured to apply a voltage to said first submachine.

19. The motor of claim 11, comprising a power source selected from the group consisting of a d.c. voltage generator, a storage battery, and a rectified a.c. voltage generator and configured to apply a voltage to said first submachine, wherein the driver of the first submachine comprises a current hysteresis driver configured to act on the windings of said first submachine to maintain the current circulating through said power source within a required range.

20. The motor of claim 19, wherein a switching frequency of the switches of said first submachine depends on electrical parameters of said first submachine.

21. The motor of claim 5, comprising:

a power source configured to apply a voltage to said first submachine;

a diode connected in series between the power source and the first submachine; and

a first switch controlled by the electronic control unit and connected in parallel with diode between the power source and said first submachine, said electronic control unit sensing a switch-on current and controlling said switch to bypass said diode when the sensed switch-on current falls below a predetermined value.

22. The motor of claim 21, comprising:

a resistor connected in series with said diode with the series combination of said diode and said first switch connected in parallel with said first switch.

23. The motor of claim 22, comprising:

said electronic control unit configured to sense said switch-on current by detecting a voltage across said resistor.

24. The motor of claim 21, comprising:

an L-C filter interposed between said power source and said first submachine.

25. The motor of claim 22, comprising:

an L-C filter interposed between said power source and said first submachine.

26. The motor of claim 23, comprising:

an L-C filter interposed between said power source and said first submachine.

27. The motor of claim 2, comprising:

a power source configured to apply a voltage to said first submachine;

wherein the controlled voltage to which said capacitor is charged is equal to 1.5 times the value of the voltage across said power source, the windings of said first submachine are formed by positioning in parallel a number of wires equal to three times a number of wires used for windings of said second submachine and have the same cross-section as wires used for windings of said second submachine.

28. The motor of claim 21, wherein the controlled voltage to which said capacitor is charged is equal to 1.5 times the value of the voltage across said power source, the windings of said first submachine are formed by positioning in parallel a number of wires equal to three times a number of wires used for windings of said second submachine and have the same cross-section as wires used for windings of said second submachine.

29. The motor of claim 26, wherein the controlled voltage to which said capacitor is charged is equal to 1.5 times the value of the voltage across said power source, the windings of said first submachine are formed by positioning in parallel a number of wires equal to three times a number of wires used for windings of said second submachine and have the same cross-section as wires used for windings of said second submachine.

30. The motor of claim 2, configured as a unipolar two-phase electrical machine with four inductor windings, in which two of said windings are inductively separated from each other to form the first submachine and the other two are inductively coupled together to form the second submachine, further comprising a driver having at least two MOS transistors having parasitic diodes and configured to drive said second submachine via said at least two MOS transistors so as to utilize the parasitic diodes for energy recovery.

31. The motor of claims 5, wherein the electronic control unit provides control of the controlled voltage across the capacitor such that:

space="preserve" listing-type="equation">V.sub.c ≧

V.sub.b +E.sub.f1 +E.sub.m1,

where V_b is the feed voltage of a power source applied to said first submachine, E_f1 is the emf per half wave of each of the windings of the submachine, and E_m1 is the induced emf due to the undersirable coupling between the windings of the submachine.

32. The motor of claim 1, comprising:

a power source configured to apply a voltage to said first submachine;

wherein the controlled voltage to which said capacitor is charged is more than 1.5 times the value of the voltage across said power source (V_b); and

an electronic circuit configured to control the current in a phase being switched off.

33. The motor of claims 21, wherein the controlled voltage to which said capacitor is charged is more than 1.5 times the value of the voltage across said power source, further comprising:

an electronic circuit configured to control the current in a phase being switched off.

34. The motor of claims 26, wherein the controlled voltage to which said capacitor is charged is more than 1.5 times the value of the voltage across said power source, further comprising:

an electronic circuit configured to control the current in a phase being switched off.

35. The motor of claim 32, wherein said electronic circuit applies a pulse wave modulated signal to control the phase switching switch of the winding circuit being switched off to artificially prolong the conduction interval of each phase of submachine.

36. The motor of claim 33, wherein said electronic circuit applies a pulse wave modulated signal to control the phase switching switch of the winding circuit being switched off to artificially prolong the conduction interval of each phase of submachine.

37. The motor of claims 35, comprising:

a circuit provided to definitively switch off said pulse wave modulated signal once the current in said winding circuit being switched off reaches zero.

38. The motor of claims 36, comprising:

a circuit provided to definitively switch off said pulse wave modulated signal once the current in said winding circuit being switched off reaches zero.

39. A circuit for applying power from a power source to a motor, comprising:

an input terminal configured to receive a start signal;

a diode connected in series between the power source and said motor;

a control unit configured to control application of power from the power source to the motor via a first switch controlled by the control unit and connected in parallel with said diode between the power source and said motor; and

said control unit configured to control said first switch to become conductive and bypass said diode upon receipt of said start signal at said input terminal and upon an initial current applied to the motor via said diode falling below a predetermined value.

40. The circuit according to claim 39, comprising:

a resistor connected in series with said diode, said control unit configured to control said first switch to be conductive when a voltage across the resistor falls below a predetermined value after receipt of said start signal.

41. The circuit according to claim 39, comprising:

an L-C filter interposed between said power source and said motor.

42. The circuit according to claim 39, comprising:

a second switch connected to the input terminal to initiate application of said start signal to said input terminal.

43. The circuit according to claim 39, comprising:

a second switch connected to the input terminal to initiate application of said start signal to said input terminal.

44. A method for applying power from a power source to a motor, comprising:

providing a diode in series between the power source and the motor,

initiating application of power from the power source to the motor via said diode upon receipt of a start signal;

sensing a switch-on current from the power source to the motor; and

bypassing said diode when the sensed switch-on current drops below a predetermined value.

45. The method of claim 44, comprising:

limiting current to said motor by connecting a resistor is series with the diode; and

bypassing both said diode and said resistor when the sensed switch-on current drops below a predetermined value.

46. The method of claim 45, wherein said sensing step comprises:

sensing a voltage across said resistor connected in series with the diode.

47. A circuit for applying power from a power source to a motor, comprising:

means for receiving a start signal;

a diode connected in series between the power source and said motor; and

control means for controlling application of power from the power source to the motor via a first switch connected in parallel with the diode between the power source and the motor, said control means controlling said first switch to bypass said diode when a switch-on current applied to the motor falls below a predetermined value.

48. The circuit according to claim 47, comprising:

a resistor connected in series with said diode, said control means controlling said first switch to be conductive when a voltage across the resistor falls below a predetermined value after receipt of said start signal.

49. The circuit according to claim 47, comprising:

an L-C filter interposed between said power source and said motor.

50. The circuit according to claim 48, comprising:

a second switch connected to the input terminal to initiate application of said start signal to said input terminal.