Variable PFC and grid-tied bus voltage control

• US 8,081,019 B2
• Filed: 11/21/2008
• Issued: 12/20/2011
• Est. Priority Date: 11/21/2008
• Status: Active Grant

• Current Assignee: Flextronics America LLC (Flextronics International Limited)
• Original Assignee: Flextronics America LLC (Flextronics International Limited)
• Inventors: Jungreis, Aaron
• Primary Examiner(s): Donovan, Lincoln
• Assistant Examiner(s): Poos, John
• Application Number:
  US12/292,721
• Publication Number:
  US 20100127737A1
• Time in Patent Office: 1,124 Days
• Field of Search: 327/119, 327/122, 327/333, 363/34, 363/37, 363/67
• US Class Current: 327/122
• CPC Class Codes: H02J 2300/24 of photovoltaic origin
• CPC Class Codes: H02J 3/381 Dispersed generators
• CPC Class Codes: H02M 1/12 Arrangements for reducing harmonics from ac input or output
• CPC Class Codes: H02M 1/15 using active elements
• CPC Class Codes: H02M 1/4208 Arrangements for improving power factor of AC input
• CPC Class Codes: Y02B 70/10 Technologies improving the efficiency by using switched-mode power supplies [SMPS], i.e. efficient power electronics conversion e.g. power factor correction or reduction of losses in power supplies or efficient standby modes
• CPC Class Codes: Y02E 10/56 Power conversion systems, e.g. maximum power point trackers

Abstract

An apparatus for generating a compensation signal for a power converter where the second harmonic ripple on the voltage bus is substantially removed from the compensation signal. The apparatus comprises a frequency-locked clock generator, a bus voltage data generator, a stack, and a compensation signal generator. The frequency-locked clock is coupled to the power converter voltage bus that contains harmonics of the AC line frequency. The clock generator frequency locks to the second harmonic of the AC line frequency and creates a system clock which is used for the synchronous operations throughout the apparatus. The bus-voltage data generator inputs a power converter scaled-bus voltage, generates bus-voltage data at a sampling rate which is determined by the coupled system clock. The output of the bus-voltage generator is input into a stack. The output of the stack is coupled to a summer to remove the second harmonic ripple, and is used by a modified PID′ filter to generate a compensation signal for a power converter controller.

Claims

1. A device for generating a compensation signal for a power converter comprising:

a) a frequency-locked clock, coupled to an AC-line having an AC-line voltage frequency, generating a frequency that is frequency locked to an integral multiple of the AC-line voltage frequency, wherein the frequency-locked clock is a phase-locked-loop configured to selectively lock to twice the AC-line voltage frequency;

b) a bus-voltage sampler, operatively coupled to the frequency-locked clock and coupled to a power converter bus having a bus-voltage, generating bus-voltage data at the frequency;

c) a stack of the bus-voltage data, operatively coupled to the bus-voltage sampler, wherein the stack is structured to contain the bus-voltage data sampled from a time interval of one-half cycle of an AC-line voltage; and

d) a compensation module, operatively coupled to the stack and configured to generate from the bus-voltage data a compensation signal, and wherein the compensation module is configured to produce the compensation signal in which frequency components at even multiples of AC-line voltage frequency are minimized.

2. The device of claim 1, wherein the frequency-locked clock is configured to only lock to frequencies between 64 hertz and 140 hertz.

3. The device of claim 1, wherein the stack comprises a charged coupled array.

4. The device of claim 1, wherein the compensation module comprises:

a means for summing the bus-voltage data wherein the bus-voltage data was sampled over a time period of one or more complete half-cycles of the AC-line voltage coupled to the stack producing a summer output;

a computational module comprising one or more of;

a scaled proportional component coupled to the summer output having a scaled proportional output;

a scaled integral component coupled to the summer output having a scaled integral output; and

a scaled derivative component coupled to the stack and configured to process two bus-voltage data samples separated by a second time period of one or more complete half-cycles of the AC-line voltage having a scaled proportional output; and

a PID summer configured to sum the scaled proportional output, the scaled integral output, and the scaled derivative output, forming a compensation signal.

5. The device of claim 4, wherein the compensation module further comprises a scaled feed-forward component having an input coupled to the power converter bus, having a feed-forward output coupled to the PID summer, wherein the compensation signal further comprises a scaled feed-forward signal component.

6. The device of claim 4, wherein the compensation signal module implements computation digitally.

7. The device of claim 6, further comprising a converter module having a converter input configured to receive the compensation signal, wherein the converter input is digital, and wherein the converter converts the digital compensation signal to an analog compensation signal provided on a converter output.

8. The device of claim 7, further comprising a power converter controller configured to receive the converter'"'"'s analog output.

9. The device of claim 4, wherein the compensation signal module processes signals with analog components and has an analog compensation signal output.

10. The device of claim 9, further comprising a power converter controller having a compensation signal input, configured to receive an analog compensation signal and coupled to a converter module.

11. The device of claim 1, wherein the bus-voltage sampler generates data-samples that represent a scaled difference between a target-voltage and the bus-voltage.

12. The device of claim 1, wherein the bus-voltage sampler generates analog bus-voltage data and the stack uses analog charged coupled devices to store the analog bus-voltage data.

13. The device of claim 1, wherein the bus-voltage sampler generates digital bus-voltage data and the stack stores the digital bus-voltage data.

14. The device of claim 1, wherein the device is implemented in an ASIC, and wherein the phase-locked-loop comprises phase-locked-loop filter components that can be external to the ASIC.

15. The device of claim 14, further comprising a power converter controller as part of the ASIC.

16. A method of generating a compensation signal for a power converter comprising the steps:

a) generating a frequency-locked clock having a frequency that is locked to an integral multiple of an AC-line voltage frequency, wherein the frequency-locked clock is a phase-locked-loop configured to selectively lock to twice the AC-line voltage frequency;

b) generating bus-voltage data at the frequency, from a power converter bus-voltage;

c) queuing the bus-voltage data, wherein a stack is structured to contain the bus-voltage data spanning a time interval of one-half cycle of an AC-line voltage; and

d) compensating the bus-voltage data and forming a compensation signal, wherein the compensating minimizes frequency components in the compensation signal that are at even multiples of the AC-line voltage frequency.

17. The method of claim 16, wherein the frequency-locked clock is configured to only lock to frequencies between 64 hertz and 140 hertz.

18. The method of claim 16, wherein the queuing is within an analog delay line, and wherein the queuing is for one or more half-cycles of the AC-line voltage.

19. The method of claim 16, wherein the compensating forms the compensation signal comprising at least one of a scaled derivative component signal, a scaled proportional component signal, and a scaled integral component signal from the bus-voltage data.

20. The method of claim 19, wherein the compensating further comprises a scaled feed-forward component signal in forming the compensation signal.

21. The method of claim 16, wherein the compensation signal is digital.

22. The method of claim 21, further comprising converting the compensation signal to an analog signal.

23. The method of claim 16, wherein the compensation signal is analog.

24. The method of claim 16, wherein the generating of a bus-voltage data represents a scaled difference between a target-voltage and the bus-voltage.

25. The method of claim 16, wherein the generation of bus-voltage data is analog, and the queuing bus-voltage data uses analog charged coupled devices to store data-samples.

26. The method of claim 16, wherein the generating bus-voltage data provides digital bus-voltage data and the queuing uses a digital stack.

27. The method of claim 16, further comprising the step of power factor correction.

28. A method of manufacturing a device for generating a compensation signal for a power converter, comprising the steps:

a) providing a frequency-locked clock coupled to an AC-line having an AC-line voltage frequency, wherein the clock is configured to generate a frequency that is frequency locked to an integral multiple of the AC-line voltage frequency, wherein the frequency-locked clock is a phase-locked-loop configured to selectively lock to twice the AC-line voltage frequency;

b) providing a bus-voltage sampler coupled to the frequency-locked clock and coupled to a power converter bus having a bus-voltage and generating bus-voltage data at the frequency;

c) providing a stack coupled to the bus-voltage sampler, wherein the stack is structured to contain bus data-samples spanning a time interval of one-half cycle of an AC-line voltage; and

d) providing a compensation module, operatively coupled to the stack, and configured to generate from the bus-voltage data a compensation signal, and wherein the compensation signal module is configured to produce the compensation signal in which frequency components at even multiples of the AC-line voltage frequency are minimized.

29. The method of manufacturing of claim 28, wherein the frequency-locked clock is configured to only lock to frequencies between 64 hertz and 140 hertz.

30. The method of manufacturing of claim 28, wherein the stack comprises a charged coupled array.

31. The method of manufacturing of claim 28, wherein the compensation module comprises:

a means for summing the bus-voltage data sampled over one or more complete half cycles of the AC-line voltage coupled to the stack producing a summer output,

a computational module comprising one or more of;

a scaled proportional component coupled to the summer output having a scaled proportional output;

a scaled integral component coupled to the summer output having a scaled integral output; and

a scaled derivative component coupled to the stack and configured to process two bus-voltage data samples separated by the one or more complete half cycles of the AC-line voltage having a scaled proportional output; and

a PID summer configured to sum the scaled proportional output, the scaled integral output, and the scaled derivative output, forming a compensation signal.

32. The method of manufacturing of claim 31, with a scaled feed-forward component coupled to a feed-forward signal, wherein the compensation signal further comprises a scaled feed-forward component signal.

33. A device for generating a compensation signal for a power converter comprising:

a) a frequency-locked clock, coupled to an AC-line having an AC-line voltage frequency, generating a frequency that is frequency locked to an integral multiple of the AC-line voltage frequency;

b) a bus-voltage sampler, operatively coupled to the frequency-locked clock and coupled to a power converter bus having a bus-voltage, generating bus-voltage data at the frequency and data-samples that represent a scaled difference between a target-voltage and the bus-voltage;

c) a stack of the bus-voltage data, operatively coupled to the bus-voltage sampler, wherein the stack is structured to contain the bus-voltage data sampled from a time interval of one-half cycle of an AC-line voltage; and

d) a compensation module, operatively coupled to the stack and configured to generate from the bus-voltage data a compensation signal, and wherein the compensation module is configured to produce the compensation signal in which the frequency components at even multiples of AC-line voltage frequency are minimized.

34. A method of generating a compensation signal for a power converter comprising the steps:

a) generating a frequency-locked clock having a frequency that is locked to an integral multiple of an AC-line voltage frequency;

b) generating bus-voltage data at the frequency, from a power converter bus-voltage, wherein the bus-voltage data represents a scaled difference between a target-voltage and the bus-voltage;

c) queuing the bus-voltage data, wherein a stack is structured to contain the bus-voltage data spanning a time interval of one-half cycle of an AC-line voltage; and

d) compensating the bus-voltage data and forming a compensation signal, wherein the compensating minimizes frequency components in the compensation signal that are at even multiples of the AC-line voltage frequency.