Transport-lag compensator

• US 6,756,702 B1
• Filed: 12/18/2002
• Issued: 06/29/2004
• Est. Priority Date: 12/18/2002
• Status: Active Grant

• Current Assignee: Honeywell International Inc.
• Original Assignee: Honeywell International Inc.
• Inventors: Huggett, Colin, Kalman, Gabor
• Primary Examiner(s): Riley, Shawn
• Application Number:
  US10/323,093
• Time in Patent Office: 559 Days
• Field of Search: 307/125, 363/40, 363/39, 318/805-808, 318/812
• US Class Current: 307/125
• CPC Class Codes: H02J 3/12 for adjusting voltage in ac networks by changing a characteristic of the network load
• CPC Class Codes: H02J 3/241 The oscillation concerning frequency
• CPC Class Codes: H02M 1/12 Arrangements for reducing harmonics from ac input or output

Abstract

An electrical power system includes an electric power source providing AC power to a load. A wideband voltage controller provides a wideband control signal vector to the electric power source. A fundamental component removal module interfaces to the AC power, receiving a fundamental component Park vector of the AC voltage, and providing a resonant frequency content in Park vector format of the AC current. A narrow band voltage regulator uses a resonant component Park vector of the AC current and the resonant frequency content in Park vector format to provide a narrow band output vector signal. A dead band compensating circuit rotates narrow band output vector signal by a transport lag compensation angle to provide a compensated control signal vector to the electric power source. The wideband control signal vector and compensated control signal vector are used to regulate the AC power so that the resonant frequency content is attenuated.

Claims

1. An electrical power system comprising:

an electric power source providing AC power comprising an AC voltage and an AC resonant current to a load;

a wideband voltage controller providing a wideband control signal vector to said electric power source;

a fundamental component removal module having an interface to said AC power and receiving a fundamental component Park vector of said AC voltage, said fundamental component removal module providing a resonant frequency content in Park vector format of a resonant frequency content of said AC resonant current from said interface;

a narrow band voltage regulator receiving a resonant component Park vector of said AC resonant current and receiving said resonant frequency content in Park vector format from said fundamental component removal module, said narrow band voltage regulator using said resonant component Park vector of said AC resonant current and said resonant frequency content in Park vector format to provide a narrow band output vector signal; and

a transport lag compensating circuit that rotates said narrow band output vector signal by a transport lag compensation angle to provide a compensated control signal vector to said electric power source, said transport lag compensating circuit using said wideband control signal vector and said compensated control signal vector to regulate said AC power and attenuate said resonant frequency content in regulating said AC power.

2. The electrical power system of claim 1, further comprising a decoupling module that assures that said resonant frequency content is not included in said wideband control signal vector provided by said wideband voltage controller.

3. The electrical power system of claim 1, further comprising a gating logic module and a summer module, wherein said compensated control signal vector is combined with said wideband control signal vector by said summer module to form a control signal vector, said control signal vector is input to said gating logic module, and said gating logic module uses said control signal vector to control said electric power source.

4. The electrical power system of claim 1 wherein said fundamental component removal module comprises:

a first rotator that rotates a Park vector of said AC voltage by said fundamental component Park vector of said AC voltage to provide a signal referenced to a synchronous frame;

a high pass filter that passes said resonant frequency content in said signal referenced to said synchronous frame and blocks a fundamental component of said AC voltage; and

a second rotator that rotates said signal referenced to said synchronous frame by the negative of said fundamental component Park vector of said AC voltage to provide said resonant frequency content in Park vector format referenced to a stationary frame.

5. The electrical power system of claim 1 wherein said narrow band voltage regulator comprises:

a first rotator that rotates said resonant frequency content in Park vector format referenced to a stationary frame by said resonant component Park vector of said AC resonant current to provide a resonance signal referenced to a synchronous frame;

a PI-regulator that regulates said resonance signal referenced to said synchronous frame against a zero-valued command signal; and

a second rotator that rotates an output signal of said PI-regulator by the negative of said resonant component Park vector of said AC resonant current to provide said narrow band output vector signal in Park vector format referenced to a stationary frame.

6. The electrical power system of claim 1 wherein said transport lag compensating circuit comprises:

a transport lag angle module that adjusts said transport lag compensation angle to be commensurate with said resonant frequency content; and

a transport lag rotator that rotates said narrow band output vector signal by said transport lag compensation angle to provide said compensated control signal vector.

7. The electrical power system of claim 1 wherein said fundamental component Park vector of said AC voltage is provided by a phase locked loop.

8. The electrical power system of claim 1 wherein said resonant component Park vector of said AC resonant current is provided by a phase locked loop.

9. An electrical power system comprising:

an electric power source that provides AC power comprising an AC voltage and an AC resonant current to a load;

a wideband voltage controller that provides a wideband control signal vector to said electric power source;

a fundamental component removal module having an interface to said AC power and receiving a fundamental component Park vector of said AC voltage, said fundamental component removal module providing a resonant frequency content in Park vector format of a resonant frequency content of said AC resonant current from said interface;

a narrow band voltage regulator receiving a resonant component Park vector of said AC resonant current and receiving said resonant frequency content in Park vector format from said fundamental component removal module, said narrow band voltage regulator using said resonant component Park vector of said AC resonant current and said resonant frequency content in Park vector format to provide a narrow band output vector signal;

a dead band compensating circuit that rotates said narrow band output vector signal by a transport lag compensation angle to provide a compensated control signal vector;

a decoupling module that assures that said resonant frequency content is not included in said wideband control signal vector provided by said wideband voltage controller; and

a gating logic module and a summer module, wherein said compensated control signal vector is combined with said wideband control, signal vector by said summer module to form a control signal vector, said control signal vector is input to said gating logic module, and said gating logic module uses said control signal vector to control said electric power source so as to regulate said AC power and attenuate said resonant frequency content in regulating said AC power.

10. The electrical power system of claim 9 wherein said fundamental component removal module comprises:

a first rotator that rotates a Park vector of said AC voltage by said fundamental component Park vector of said AC voltage to provide a signal referenced to a fundamental synchronous frame;

a high pass filter that passes said resonant frequency content in said signal referenced to said fundamental synchronous frame and blocks a fundamental component of said AC voltage; and

a second rotator that rotates said signal referenced to said fundamental synchronous frame by the negative of said fundamental component Park vector of said AC voltage to provide said resonant frequency content in Park vector format referenced to a stationary frame.

11. The electrical power system of claim 9 wherein said narrow band voltage regulator comprises:

a first rotator that rotates said resonant frequency content in Park vector format referenced to a stationary frame by said resonant component Park vector of said AC resonant current to provide a resonance signal referenced to a resonant synchronous frame;

a PI-regulator that regulates said resonance signal referenced to said resonant synchronous frame against a zero-valued command signal; and

a second rotator that rotates an output signal of said PI-regulator by the negative of said resonant component Park vector of said AC resonant current to provide said narrow band output vector signal in Park vector format referenced to a stationary frame.

12. The electrical power system of claim 9 wherein:

said electric power source comprises an inverter; and

said dead band compensating circuit comprises;

a transport lag angle module that adjusts said transport lag compensation angle to compensate for a transport lag caused by an inverter update rate at a resonant frequency of said resonant frequency content; and

a transport lag rotator that rotates said narrow band output vector signal by said transport lag compensation angle to provide said compensated control signal vector.

13. The electrical power system of claim 9 wherein said fundamental component Park vector of said AC voltage is provided by a phase locked loop and said resonant component Park vector of said AC resonant current is provided by a phase locked loop.

14. The electrical power system of claim 9 further comprising an inverter and a space vector modulation module that converts said control signal vector to signals that said gating logic module uses to form gating commands that control said inverter.

15. An electrical power system comprising:

an electric power source that provides AC power comprising an AC voltage and an AC resonant current to a load;

a wideband voltage controller that provides a wideband control signal vector to said electric power source;

a fundamental component removal module having an interface to said AC power and receiving a fundamental component Park vector of said AC voltage, said fundamental component removal module providing a resonant frequency content in Park vector format of a resonant frequency content of said AC resonant current from said interface, wherein said fundamental component removal module comprises;

a first rotator that rotates a Park vector of said AC voltage by said fundamental component Park vector of said AC voltage to provide a signal referenced to a fundamental synchronous frame;

a high pass filter that passes said resonant frequency content in said signal referenced to said fundamental synchronous frame and blocks a fundamental component of said AC voltage; and

a second rotator that rotates said signal referenced to said fundamental synchronous frame by the negative of said fundamental component Park vector of said AC voltage to provide said resonant frequency content in Park vector format referenced to a stationary frame;

a narrow band voltage regulator receiving a resonant component Park vector of said AC resonant current and receiving said resonant frequency content in Park vector format from said fundamental component removal module, said narrow band voltage regulator using said resonant component Park vector of said AC resonant current and said resonant frequency content in Park vector format to provide a narrow band output vector signal, wherein said narrow band voltage regulator comprises;

a third rotator that rotates said resonant frequency content in Park vector format referenced to said stationary frame by said resonant component Park vector of said AC resonant current to provide a resonance signal referenced to a resonant synchronous frame;

a PI-regulator that regulates said resonance signal referenced to said resonant synchronous frame against a zero-valued command signal, and

a fourth rotator that rotates an output signal of said PI-regulator by the negative of said resonant component Park vector of said AC resonant current to provide said narrow band output vector signal in Park vector format referenced to said stationary frame;

a transport lag compensating circuit that rotates said narrow band output vector signal by a transport lag compensation angle to provide a compensated control signal vector, wherein said transport lag compensating circuit comprises;

a transport lag angle module that adjusts said transport lag compensation angle to be commensurate with said resonant frequency content; and

a transport lag rotator that rotates said narrow band output vector signal by said transport lag compensation angle to provide said compensated control signal vector;

a decoupling module that assures that said resonant frequency content is not included in said wideband control signal vector provided by said voltage controller; and

a gating logic module and a summer, wherein said compensated control signal vector is combined with said wideband control signal vector by said summer to form a control signal vector, said control signal vector is input to said gating logic module, and said gating logic module uses said control signal vector to control said electric power source so as to regulate said AC power and attenuate said resonant frequency content in regulating said AC power.

16. A method comprising steps of:

supplying electric power to a load from an electric power source, said electric power being in the form of AC power comprising an AC voltage and an AC resonant current;

providing a wideband control signal vector for controlling said electric power source;

removing a fundamental frequency component from said AC voltage and providing a resonant frequency content in Park vector format of a resonant frequency content of said AC resonant current using a fundamental component Park vector of said AC voltage;

providing a narrow band output vector signal using said resonant frequency content in Park vector format and a resonant component Park vector of said AC resonant current;

rotating said narrow band output vector signal by a transport lag compensation angle to provide a compensated control signal vector;

decoupling said resonant frequency content from said wideband control signal vector using said resonant frequency content in Park vector format;

combining said compensated control signal vector with said wideband control signal vector to form a control signal vector; and

logically processing said control signal vector to control said electric power source so as to regulate said AC power and attenuate said resonant frequency content in regulating said AC power.

17. The method of claim 16 wherein said removing step comprises:

rotating a Park vector of said AC voltage by said fundamental component Park vector of said AC voltage to provide a signal referenced to a synchronous frame;

passing said resonant frequency content in said signal referenced to said synchronous frame through a high pass filter and blocking a fundamental component of said AC voltage using said high pass filter; and

rotating said signal referenced to said synchronous frame by the negative of said fundamental component Park vector of said AC voltage to provide said resonant frequency content in Park vector format referenced to a stationary frame.

18. The method of claim 16 wherein said step of providing a narrow band output vector signal comprises:

rotating said resonant frequency content in Park vector format referenced to a stationary frame by said resonant component Park vector of said AC resonant current to provide a resonance signal referenced to a synchronous frame;

using a PI-regulator to regulate said resonance signal referenced to said synchronous frame against a zero-valued command signal; and

rotating an output signal of said PI-regulator by the negative of said resonant component Park vector of said AG resonant current to provide said narrow band output vector signal in Park vector format referenced to a stationary frame.

19. The method of claim 16 wherein said rotating step comprises:

adjusting said transport lag compensation angle to be commensurate with said resonant frequency content; and

rotating said narrow band output vector signal by said transport lag compensation angle to provide said compensated control signal vector.