Voltage controller for minimizing the utility power provided to a local load site having a local power source

• US 6,316,920 B1
• Filed: 08/02/2000
• Issued: 11/13/2001
• Est. Priority Date: 12/11/1998
• Status: Expired due to Fees

• Current Assignee: Honeywell Space Systems Incorporated
• Original Assignee: Honeywell Space Systems Incorporated
• Inventors: Huggett, Colin, Kalman, Gabor
• Primary Examiner(s): STERRETT, JEFFREY L
• Application Number:
  US09/630,521
• Time in Patent Office: 468 Days
• Field of Search: 323/205, 323/207
• US Class Current: 323/207
• CPC Class Codes: G05F 1/70 Regulating power factor; Regulating reactive current or power
• CPC Class Codes: H02M 1/44 Circuits or arrangements for compensating for electromagnetic interference in converters or inverters

Abstract

A load site voltage regulation control system. The load site receives electrical power from a utility over transmission lines. The load site also receives electrical power from a local generator unit operating with an inverter. The local generator unit and inverter are coupled to the load by an EMI filter and a transformer. Voltage at the load is controlled by adjusting the inverter voltage using an inverter voltage command. The inverter voltage command is based on load voltage, inverter voltage, EMI filter voltage, utility supplied current, and inverter current. In one embodiment, the inverter voltage is adjusted to minimize utility supplied reactive and real power and to actively dampen EMI filter voltage, with the inverter voltage command being developed though a multi-loop PPI control system.

Claims

1. A power controller adapted for load site voltage regulation, the load site receiving power signals from a distant power source and the load site including a load site source, the power controller comprising:

a real power controller receiving an indication of real power supplied from the distant power source and a reference real power signal and outputting a commanded real power signal;

a reactive power controller receiving an indication of reactive power supplied from the distant power source and a reference reactive power signal and outputting a commanded reactive power signal;

a regulator controller receiving the commanded real power signal, the commanded reactive power signal, and an indication of power at the load and outputting a regulator control signal for use in load site voltage regularization; and

a damping controller receiving a signal indicative of signal magnitude from a filter and providing a damping control signal to the regulator controller.

2. The power controller adapted for load site regulation of claim 1 wherein the reference real power signal and the reference reactive power signal are zero.

3. The power controller adapted for load site regulation of claim 2 wherein the real power controller comprises an integral plus proportional controller.

4. The power controller adapted for load site regulation of claim 3 wherein the reactive power controller comprises a first controller section and a second controller section, the first controller section forming a reactive power error signal, an indication of which is provided to the second controller section for use in forming the commanded reactive power signal.

5. The power controller adapted for load site regulation of claim 4 wherein the first controller section and the second controller section comprise proportional plus integral controllers.

6. The power controller adapted for load site regulation of claim 1 wherein the regulator control signal is a commanded inverter voltage.

7. The power controller adapted for load site regulation of claim 6 wherein the damping controller comprises an inverting amplifier.

8. A power controller adapted for load site voltage regulation, the load site receiving power from a distant power source and the load site including a load site source and a load, the power from the distance power source including a current signal having a real component and a reactive component, the load site source having a maximum power producing capability including a maximum real and reactive power producing capability, and the load having a real and a reactive power requirement, the power controller comprising:

a real current controller receiving an indication of real current supplied from the distant power source and a reference real current signal, the real current controller outputting a commanded real current amplitude signal;

a reactive current controller receiving an indication of reactive current supplied from the distant power source and a reference reactive current signal, the reactive current controller outputting a commanded voltage amplitude signal; and

an angle regulator controller receiving a difference between the commanded voltage amplitude signal and a sensed voltage amplitude at the load site, the angle regulator adjusting the angle of the commanded real current amplitude signal such that the real component of the power supplied by the distance power source is minimized.

9. A method for regulating voltage at a load site connected to a utility power source over transmission lines, the load site including a power generator unit operatively coupled to an inverter operatively coupled to a load by a path including a filter, the method comprising:

determining an indication of load voltage;

determining an indication of utility current provided by the utility power source to the load;

determining an indication of inverter current;

forming a commanded current signal using the indication of load voltage and the indication of utility current; and

forming an inverter voltage command using the indication of inverter current and the commanded current signal.

10. The method for regulating voltage at a load site of claim 9 wherein the indication of load voltage, the indication of utility current, the indication of inverter current and the inverter voltage command are park vectors.

11. The method for regulating voltage at a load site of claim 10 wherein forming a commanded current signal using the indication of load voltage and the indication of utility current comprises:

determining a real component of utility current;

comparing the real component of utility current to a reference signal to form a commanded amplitude of current;

determining a reactive component of utility current;

comparing the reactive component of utility current to an indication of load voltage for form a commanded angle of current; and

combining the commanded amplitude of current and the commanded angle of current to for the commanded current signal.

12. The method for regulating voltage at a load site of claim 11 further comprising determining

an indication of filter voltage and modifying the commanded current signal using the indication of filter voltage.

13. The method for regulating voltage at a load site of claim 12 wherein the indication of filter voltage is a park vector.

14. The method for regulating voltage at a load site of claim 13 wherein the indication of filter voltage is about a resonant frequency of the filter.

15. The method for regulating voltage at a load site of claim 14 wherein the commanded current signal is modified by the indication of filter voltage by subtracting a multiple of the indication of filter voltage as compared against a commanded filter voltage.

16. An apparatus including a multiloop control system for voltage regulation for load sites at the end of feeder lines, the load sites including a load coupled to the feeder lines and local power generation units with voltage regulators coupled to the feeder lines, the apparatus comprising:

means for determining a commanded amplitude of current using an indication of a real component of feeder line current;

means for determining a commanded angle of current using an indication of a reactive component of feeder line current and an indication of load voltage, said means for determining a commanded angle including means for limiting the angle of the commanded angle of current to one or more predefined quadrants; and

means for determining a voltage regulator control signal controlling operation of the voltage regulator using the commanded amplitude of current and the commanded angle of current.

17. The apparatus including a multiloop control system for voltage regulation for load sites at the end of feeder lines of claim 16 further comprising means for determining a damping control signal, the damping control signal, the damping control signal additionally being used by the means for determining a voltage regulator control signal.

18. A power controller adapted for load site voltage regulation, the load site receiving power from a distant power source and the load site including a load site source, the power from the distance power source including a current signal having a real component and a reactive component, the power controller comprising:

a real current controller receiving an indication of the real current supplied from the distant power source and a reference real current signal, the real current controller outputting a commanded real current amplitude signal;

a reactive current controller receiving an indication of the reactive current supplied from the distant power source and a reference reactive current signal, the reactive current controller outputting a commanded reactive current signal;

a regulator controller for receiving the commanded real current signal, the commanded reactive current signal, and an indication of power at the load, the regulator controller outputting a regulator control signal for use in load site voltage regularization; and

a damping controller receiving a signal indicative of current magnitude from a filter, and providing a damping control signal to the regulator controller.

19. A power controller adapted for load site voltage regulation, the load site receiving power signals from a distant power source and the load site including a load site source and a load, the load site source having a maximum power producing capability including a maximum real and reactive power producing capability, and the load having a real and a reactive power requirement, the power controller comprising:

a real power controller receiving an indication of real power supplied from the distant power source and a reference real power signal and outputting a commanded real power signal;

a reactive power controller receiving an indication of reactive power supplied from the distant power source and a reference reactive power signal and outputting a commanded reactive power signal; and

a regulator controller receiving the commanded real power signal, the commanded reactive power signal, and an indication of power at the load, the regulator controller allowing the load site source to provide a predetermined portion of the real power required by the load up to the maximum real power producing capability of the load site source, after which the regulator controller allowing the distance power source to provide any remaining real power required by the load.

20. A power controller according to claim 19 wherein the regulator controller causes the load site source to provide substantially all of the real power required by the load up to the maximum real power producing capability of the load site source, after which the regulator controller causes the distance power source to provide any remaining real power required by the load.

21. A power controller according to claim 19 wherein the regulator controller attempts to match the real power provided by the load site source with the real power required by the load when the real power required by the load is less than the power producing capability of the local site source.

22. The power controller according to claim 19, wherein the regulator controller adjusts the angle of the power provided to the load by the local site source such that the reactive power required from the distant power source is minimized.

23. The power controller according to claim 22, wherein the regulator controller uses any excess power producing capability of the local site source to adjust the angle of the power provided to the load by the local site source such that the reactive power required from the distant power source is minimized.

24. An apparatus including a multiloop control system for voltage regulation for load sites at the end of feeder lines, the load sites including a load coupled to the feeder lines and local power generation units with associated voltage regulators coupled to the feeder lines, the load site source having a maximum power producing capability including a maximum real and reactive power producing capability, and the load having a real and a reactive power requirement, the apparatus comprising:

means for determining a commanded amplitude of current using an indication of a real power component of feeder line current;

means for determining a commanded angle of current using an indication of a reactive component of feeder line current and an indication of load voltage; and

means for determining a voltage regulator control signal controlling operation of the voltage regulator using the commanded amplitude of current and the commanded angle of current, the voltage regulator control signal directing the voltage regulator to allow the load site source to provide a predetermined portion of the real power required by the load up to the maximum real power producing capability of the load site source, after which the voltage regulator control signal directing the voltage regulator to allow the distance power source to provide any remaining real power required by the load.

25. A power controller adapted for load site voltage regulation, the load site receiving power from a distant power source and the load site including a load site source and a load, the power including current and voltage signals from the distance power source which are coupled to the load, the load site source having a maximum power producing capability including a maximum real and reactive power producing capability, and the load having a real and a reactive power requirement, the power controller comprising:

a regulator controller coupled between the local site source and the load, the regulator controller allowing the load site source to provide a predetermined portion of the real power required by the load up to the maximum real power producing capability of the load site source, after which the regulator controller allowing the distance power source to provide any remaining real power required by the load.

26. A power controller according to claim 25 wherein the regulator controller causes the load site source to provide substantially all of the real power required by the load up to the maximum real power producing capability of the load site source, after which the regulator controller causes the distance power source to provide any remaining real power required by the load.

27. A power controller according to claim 25 wherein the regulator controller attempts to match the real power provided by the load site source with the real power required by the load when the real power required by the load is less than the power producing capability of the local site source.

28. The power controller according to claim 25, wherein the regulator controller adjusts the angle of the power provided to the load by the local site source such that the reactive power required from the distant power source is minimized.

29. The power controller according to claim 28, wherein the regulator controller uses any excess power producing capability of the local site source to adjust the angle of the power provided to the load by the local site source such that the reactive power required from the distant power source is minimized.

30. A method for regulating the voltage of load site, the load site receiving power from a distant power source and the load site including a load site source and a load, the power including current and voltage signals from the distance power source which are coupled to the load, the load site source having a maximum power producing capability including a maximum real and reactive power producing capability, and the load having a real and a reactive power requirement, the method comprising:

allowing the load site source to provide a predetermined portion of the real power required by the load up to the maximum real power producing capability of the load site source; and

allowing the distance power source to provide any remaining real power required by the load if the maximum real power producing capability of the load site source are exceeded.

31. A method according to claim 30, further comprising allowing the load site source to provide substantially all of the real power required by the load up to the maximum real power producing capability of the load site source.

32. A method according to claim 30, further comprising attempting to match the real power provided by the load site source with the real power required by the load when the real power required by the load is less than the power producing capability of the local site source.

33. A method according to claim 30, wherein the local site source provides voltage and current signals to the load, where the current signal has an angle, the method further comprising the step of adjusting the angle of the current signal provided to the load by the local site source such that the reactive power required from the distant power source is minimized.

34. A method according to claim 33 further comprising using any excess power producing capability of the local site source to adjust the angle of the current signal provided to the load by the local site source such that the reactive power required from the distant power source is minimized.