Granted Patent B2

US 6,876,169 · App. 10/341,997 · Granted Apr 5, 2005

Abstract

Claims (107)

1. A method for controlling current in an electric machine comprising:

receiving a state vector time signal from a space vector modulator indicative of a time interval when a switching state vector is activated;

comparing the received state vector time signal to a commanded state vector time signal; and

using the result of the comparison to regulate a direct axis current signal input to a machine controller.

2. The current control method of claim 1 , wherein the electric machine is a vector controlled machine.

3. The current control method of claim 1 , wherein the electric machine is a power converter controlled machine.

4. The current control method of claim 1 , wherein the state vector time signal comprises a zero vector time signal indicative of a time interval when a zero vector is activated.

5. The current control method of claim 1 , wherein the state vector time signal comprises a sum of a first and second space vector time signals indicative of a respective time interval when the first and second space vectors are activated.

6. The current control method of claim 1 , further comprising filtering the received state vector time signal.

7. The current control method of claim 1 , further comprising using the received state vector time signal as a feedback signal in a commanded direct axis current control loop.

8. The current control method of claim 1 , further comprising generating a state vector time error signal.

9. The current control method of claim 8 , wherein generating a state vector time error signal further comprises subtracting the received state vector time signal from the commanded state vector time signal.

10. The current control method of claim 8 , wherein generating a state vector time error signal further comprises subtracting the commanded state vector time signal from the received state vector time signal.

11. The current control method of claim 8 , further comprising:

generating a proportional-integral state vector error signal comprising proportional and integral components;

detecting a condition when the proportional-integral state vector error signal has a value equal to or greater than a commanded direct axis current signal; and

applying the commanded direct axis current signal to the direct axis current input of the machine controller when the proportional-integral state vector error signal has a value equal to or greater than the commanded direct axis current signal.

12. The current control method of claim 11 , further comprising:

limiting the proportional-integral state vector error signal to generate a direct axis current signal; and

applying the direct axis current signal to the direct axis current input of the machine controller.

13. The current control method of claim 12 , wherein limiting the proportional-integral state vector error signal further comprises limiting the proportional-integral state vector error signal to a value of less than the commanded direct axis current signal.

14. A method for controlling current in an electric machine comprising:

receiving a state vector time signal indicative of a time interval when a switching state vector is activated;

comparing the received state vector time signal to a commanded state vector time signal;

using the result of the comparison to regulate a direct axis current signal input to a machine controller;

generating a state vector time error signal;

generating a proportional-integral state vector error signal comprising proportional and integral components;

detecting when the proportional-integral state vector error signal has a negative value;

generating a direct axis current signal by adding the proportional-integral state vector error signal to the commanded direct axis current signal; and

applying the direct axis current signal to the direct axis current input of the machine controller when the proportional-integral state vector error signal has a negative value.

15. A method for controlling current in an electric machine comprising:

receiving a state vector time signal indicative of a time interval when a switching state vector is activated;

comparing the received state vector time signal to a commanded state vector time signal;

using the result of the comparison to regulate a direct axis current signal input to a machine controller;

generating a state vector time error signal;

generating a proportional-integral state vector error signal comprising proportional and integral components;

detecting when the proportional-integral state vector error signal has a negative value;

generating a direct axis current signal by adding the proportional-integral state vector error signal to the commanded direct axis current signal;

applying the direct axis current signal to the direct axis current input of the machine controller when the proportional-integral state vector error signal has a negative value; and

wherein applying the direct axis current signal further comprises closing a commanded direct axis current control loop.

16. A method for controlling current in an electric machine comprising:

receiving a state vector time signal indicative of a time interval when a switching state vector is activated;

comparing the received state vector time signal to a commanded state vector time signal;

using the result of the comparison to regulate a direct axis current signal input to a machine controller;

generating a state vector time error signal;

generating a proportional-integral state vector error signal comprising proportional and integral components;

detecting when the proportional-integral state vector error signal has a positive value; and

applying a commanded direct axis current signal to the direct axis current input of the machine controller when the proportional-integral state vector error signal has a positive value or zero value.

17. A method for controlling current in an electric machine comprising:

receiving a state vector time signal indicative of a time interval when a switching state vector is activated;

comparing the received state vector time signal to a commanded state vector time signal;

using the result of the comparison to regulate a direct axis current signal input to a machine controller;

generating a state vector time error signal;

generating a proportional-integral state vector error signal comprising proportional and integral components;

detecting when the proportional-integral state vector error signal has a positive value;

applying a commanded direct axis current signal to the direct axis current input of the machine controller when the proportional-integral state vector error signal has a positive value or zero value;

generating a proportional-integral state vector error signal comprising proportional and integral components;

limiting the proportional-integral state vector error signal to generate a limited proportional-integral state vector error signal;

generating a direct axis current signal by adding the limited proportional-integral state vector error signal to a commanded direct axis current signal; and

applying the direct axis current signal to the direct axis current input of the machine controller.

18. A method for controlling current in an electric machine comprising:

receiving a state vector time signal indicative of a time interval when a switching state vector is activated;

comparing the received state vector time signal to a commanded state vector time signal;

using the result of the comparison to regulate a direct axis current signal input to a machine controller;

generating a state vector time error signal;

generating a proportional-integral state vector error signal comprising proportional and integral components;

detecting when the proportional-integral state vector error signal has a positive value;

applying a commanded direct axis current signal to the direct axis current input of the machine controller when the proportional-integral state vector error signal has a positive value or zero value;

generating a proportional-integral state vector error signal comprising proportional and integral components;

limiting the proportional-integral state vector error signal to generate a limited proportional-integral state vector error signal;

generating a direct axis current signal by adding the limited proportional-integral state vector error signal to a commanded direct axis current signal;

applying the direct axis current signal to the direct axis current input of the machine controller; and

wherein limiting the proportional-integral state vector error signal further comprises limiting the proportional-integral state vector error signal to a value of less than or equal to zero.

19. A current controller for an electric machine comprising:

a space vector modulator generating a state vector time signal indicative of a time interval when a switching state vector is activated;

a state vector error comparator for comparing the state vector time signal received from the space vector modulator to a commanded state vector time signal and generating a state vector time error signal; and

a control element, coupled to the state vector error comparator, for providing a direct axis current signal, responsive to the state vector time error, to a machine controller.

20. The current controller of claim 19 , wherein the electric machine is a vector controlled machine.

21. The current controller of claim 19 , wherein the electric machine is a power converter controlled machine.

22. The current controller of claim 19 , wherein the received state vector time signal comprises a zero vector time signal indicative of a time interval when a zero vector is activated.

23. The current controller of claim 19 , wherein the received state vector time signal comprises a sum of a first and second space vector time signals indicative of a respective time interval when the first and second space vectors are activated.

24. The current controller of claim 19 , further comprising a filter for filtering the received state vector time signal.

25. The current controller of claim 19 , further comprising a commanded direct axis current control loop having a state vector time signal as a feedback signal.

26. The current controller of claim 19 , wherein the state vector error comparator is a subtractor for subtracting the received state vector time signal from the commanded state vector time signal.

27. The current controller of claim 19 , wherein the state vector error comparator is a subtractor for subtracting the commanded state vector time signal from the received state vector time signal.

28. The current controller of claim 19 , wherein the controller further comprises:

a proportional-integral state vector error signal regulator for generating a proportional-integral state vector error signal comprising proportional and integral components;

a limiter, coupled to the proportional-integral state vector error signal regulator, for limiting the proportional-integral state vector error signal and providing a limited proportional-integral state vector error signal; and

a summer, coupled to the limiter, for generating a direct axis current signal responsive to the limited proportional-integral state vector error signal and the commanded direct axis current signal.

29. The current controller of claim 28 , wherein the limiter limits the output of the proportional-integral state vector error signal regulator to a value of less than zero or equal to zero.

30. The current controller of claim 19 , wherein the controller further comprises:

a proportional-integral state vector error signal regulator for generating a proportional-integral state vector error signal comprising proportional and integral components; and

a limiter, coupled to the proportional-integral state vector error signal regulator, for limiting the proportional-integral state vector error signal and providing a direct axis current signal responsive to the limited proportional-integral state vector error signal and the commanded direct axis current signal.

31. The current controller of claim 30 , wherein the limiter limits the output of the proportional-integral state vector error signal regulator to a value of less than or equal to the commanded direct axis current signal.

32. A current controller for an electric machine comprising:

a state vector error comparator for comparing a received state vector time signal to a commanded state vector time signal and generating a state vector time error signal;

a control element, coupled to the state vector error comparator, for providing a direct axis current signal, responsive to the state vector time error, to a machine controller;

a proportional-integral state vector error signal regulator, coupled to the state vector error comparator, for generating a proportional-integral state vector time error signal comprising proportional and integral components;

a zero comparator, coupled to the proportional-integral state vector error signal regulator, to determine when the proportional-integral state vector time error signal has a negative value;

a summer, for adding the proportional-integral state vector time error signal and the commanded direct axis current signal to generate a direct axis current signal; and

a switch, coupled to the zero comparator, for applying the direct axis current signal to a direct axis current input of the machine controller when the proportional-integral state vector time error signal has a negative value.

33. A current controller for an electric machine comprising:

a state vector error comparator for comparing a received state vector time signal to a commanded state vector time signal and generating a state vector time error signal:

a control element, coupled to the state vector error comparator, for providing a direct axis current signal, responsive to the state vector time error, to a machine controller;

a proportional-integral state vector error signal regulator, coupled to the state vector error comparator, for generating a proportional-integral state vector time error signal comprising proportional and integral components;

a zero comparator, coupled to the proportional-integral state vector error comparator, to determine when the proportional-integral state vector time error signal has a positive value; and

a switch, coupled to the zero comparator, for applying a commanded direct axis current signal to the direct axis current input of the machine controller when the proportional-integral state vector time error signal has a positive value or a zero value.

Assignments (6)