Motor Drive Voltage-Boost Control

• US 20080265808A1
• Filed: 07/08/2005
• Published: 10/30/2008
• Est. Priority Date: 07/10/2004
• Status: Active Grant

• Current Assignee: TRW Limited (Zeppelin - Stiftung der Stadt Friedrichshafen)
• Original Assignee: TRW Limited (Zeppelin - Stiftung der Stadt Friedrichshafen)
• Inventors: Williams, Connel Brett, Coles, Jeffrey Ronald, Sparey, Malcolm Eric, White, Graham William, Szabo, Adrian, Chen, Yangsheng
• Granted Patent: US 8,004,220 B2
• Time in Patent Office: Days
• US Class Current: 318/139
• CPC Class Codes: H02P 2201/09 Boost converter, i.e. DC-DC step up converter increasing the voltage between the supply and the inverter driving the motor
• CPC Class Codes: H02P 6/16 Circuit arrangements for detecting position
• CPC Class Codes: H02P 6/182 using back-emf in windings

Abstract

A drive system for a motor having a rotor and a phase winding (a, b, c) comprises; a drive circuit including switch means associated with the winding a, b, c for varying the current passing through the winding; rotor position sensing means arranged to sense the position of the rotor; control means arranged to provide drive signals to control the switch means; a power input for connection to a power supply at a nominal voltage; and boost means in electric communication with the power input and power output, and controllable to boost the nominal voltage to a higher voltage for application to the winding.

Claims

1. A drive system for a motor having a rotor and a phase winding, the system comprising:

a drive circuit including switch means associated with the winding for varying the current passing through the winding;

rotor position sensing means arranged to sense the position of the rotor;

control means arranged to provide drive signals to control the switch means;

a power input for connection to a power supply at a nominal voltage; and

boost means in electric communication with the power input, and controllable to boost the nominal voltage to a higher boosted voltage for application to the winding;

in which the control means is arranged to define a current demand and a required phase advance of the current passing through the winding relative to the magnetic field of the rotor, to control the potential difference applied to the winding to achieve the demanded current and the required phase advance, and to control the boosted voltage output by the boost means.

2. A system according to claim 1 wherein the control means is arranged to provide voltage boost for motor speeds above a predetermined boost introduction speed.

3. A system according to claim 2 wherein the control means is arranged to increase the voltage boost in a stepped manner when the motor speed reaches the boost introduction speed.

4. A system according to claim 2 wherein the control means is arranged to increase the voltage boost with increasing motor speeds over a range of motor speeds from the boost introduction speed to a higher full boost speed.

5. A system according to any foregoing claim wherein the control means is arranged to control the phase of the current to produce a varying phase advance of the current relative to the rotor position.

6. A system according to claim 5 wherein the control means is arranged to increase the phase advance with increasing motor speed for speeds above a phase advance introduction speed.

7. A system according to claim 6 wherein the control means is arranged to set the phase advance to zero over at least a range of zero phase advance motor speeds below the phase advance introduction speed.

8. A system according to claim 6 or claim 7 wherein the control means is arranged to provide a non-zero phase advance over a range of increased phase advance motor speeds below the phase advance introduction speed.

9. A system according to claim 8 wherein the control means is arranged, within the range of increased phase advance motor speeds, to provide a phase advance that increases with motor speed up to a maximum phase advance.

10. A system according to claim 9 wherein the control means is arranged within the range of increased phase advance motor speeds to provide a phase advance that decreases with motor speed from the maximum phase advance.

11. A system according to claim 6 when dependent on any of claims 2 to 4 wherein the phase advance introduction speed is greater than the boost introduction speed.

12. A system according to any of claims 8 to 10 when dependent on any of claims 2 to 4 wherein the range of increased phase advance motor speeds includes a range of speeds immediately below the boost introduction speed.

13. A system according to claim 12 wherein the range of increased phase advance motor speeds includes the boost introduction speed.

14. A system according to claim 13 wherein the range of increased phase advance motor speeds includes a range of speeds immediately above the boost introduction speed.

15. A drive system for a motor having a rotor and a phase winding, the system comprising:

a drive circuit including switch means associated with the winding for varying the current passing through the winding;

control means arranged to provide drive signals to control the switch means;

a power input for connection to a power supply at a nominal voltage;

in which the control means is arranged to control at least one control parameter of the motor thereby to limit the magnitude of the current from the power supply to a maximum.

16. A system according to claim 15 wherein the at least one parameter includes phase advance.

17. A system according to claim 15 or claim 16 further comprising boost means in electric communication with the power input, power output, and controllable to boost the nominal voltage to a higher boosted voltage for application to the winding, wherein the at least one parameter includes the level of boost provided by the boost means.

18. A system according to any of claims 15 to 17 wherein the at least one parameter includes at least one of q-axis current limit, phase current limit, and over-modulation level.

19. A drive system for a motor having a rotor and a phase winding, the system comprising:

an input arranged to receive a battery current from a battery switch means associated with the winding for varying the current passing through the winding;

a dc link arranged to provide an input current to the switch means;

a current sensor arranged to measure the current in the dc link;

a low pass filter arranged to average the output from the current sensor, and

control means arranged to determine the battery current from said output.

20. A drive system according to claim 19 wherein at least one system component is provided between the input and the dc link, and the control means is arranged to determine the battery current from said output using a factor related to the system component.

21. A drive system according to claim 20 wherein the factor is the efficiency of the component.

22. A drive system according to claim 20 or claim 21 wherein the system component is a voltage booster.

23. A drive system according to any of claims 19 to 22 wherein the control means arranged to determine the factor on the basis of at least one operating parameter of the system.

24. A drive system according to claim 23 wherein the parameter comprises the input voltage of the booster, the output voltage of the booster, the link current, or temperature.

25. A push-pull voltage boost circuit comprising a bifilar wound component having two windings on a common magnetic core, each having one end connected to a common first potential, two active switches arranged to be switched on alternately to connect a respective one of the windings to a second potential thereby to produce a boosted voltage across the pair of windings, and two further switches arranged to be switched on alternately to connect a respective one of the windings to an output thereby to apply the boosted voltage to the output.

26. A circuit according to claim 25 wherein the switches can all be switched to an off state such that the circuit operates in a passive mode in which current can flow through both of the windings to the output.

27. A circuit according to claim 25 or claim 26 wherein the further switches can be switched on to reduce their resistance while the active switches are switched off, so that current can flow through both of the windings to the output through further switches with reduced losses.

28. A circuit according to any of claims 25 to 27 wherein the active switches can be turned off and the further switches turned on such that regenerative current can flow from the output through the circuit.