MONITORING AND CONTROL OF POWER CONVERTERS

• US 20090309567A1
• Filed: 06/12/2009
• Published: 12/17/2009
• Est. Priority Date: 06/13/2008
• Status: Active Grant

• Current Assignee: The Board of Regents of the University of Colorado (University of Colorado System)
• Original Assignee: The Board of Regents of the University of Colorado (University of Colorado System)
• Inventors: Maksimovic, Dragan, Zane, Regan, Morroni, Jeffrey
• Granted Patent: US 7,956,592 B2
• Time in Patent Office: Days
• US Class Current: 323/283
• CPC Class Codes: H02M 3/157 with digital control

Abstract

A digital controller configured to inject a signal into a digital feedback path that facilitates regulation of a power converter and measure the corresponding phase, gain, or frequency. The digital controller may also include an adaptive tuning controller for adjusting power converter operating attributes based in part on the measurements. In an exemplary embodiment, the adaptive tuning controller uses the phase, gain, and/or frequency measurements to adjust the digital feedback signal. In an exemplary embodiment, the adaptive tuning controller compares the operating measurements with desired values and generates adjusted operating attributes. In accordance with an exemplary embodiment, the monitoring and adjusting of the digital feedback signal occurs while the digital controller is regulating a power signal in the power converter.

Claims

1. A monitoring unit associated with a digital controller configured to regulate a power signal of a power converter, the monitoring unit comprising:

a stability margin monitor; and

a summer configured to inject an injection signal into a feedback path in the digital controller;

wherein the stability margin monitor measures at least one feedback signal in the feedback path of the digital controller;

wherein the monitoring unit outputs at least one of a measured frequency, a measured phase, and a measured gain associated with a frequency response of the power converter; and

wherein the at least one of the measured frequency, the measured phase, and the measured gain is based on the at least one feedback signal.

2. The monitoring unit of claim 1, wherein the stability margin monitor measures the at least one feedback signal before the injection signal is injected in the feedback path.

3. The monitoring unit of claim 1, wherein the stability margin monitor measures the at least one feedback signal after the injection signal is injected in the feedback path.

4. The monitoring unit of claim 1, further comprising an injection amplitude controller in communication with the stability margin monitor, wherein the injection amplitude controller sets the amplitude of the injection signal.

5. The monitoring unit of claim 1, wherein the monitoring unit receives the at least one feedback signal from an analog-to-digital converter and communicates the at least one feedback signal to a digital compensator.

6. The monitoring unit of claim 1, wherein the monitoring unit receives the at least one feedback signal from a digital compensator and communicates the at least one feedback signal to a digital modulator.

7. The monitoring unit of claim 6, wherein the digital modulator is at least one of a pulse width modulator, a frequency modulator, or a phase shifted modulator.

8. The monitoring unit of claim 1, wherein the monitoring unit measures the at least one feedback signal either continuously or discontinuously.

9. The monitoring unit of claim 1, wherein the monitoring unit measures the at least one feedback signal while the digital controller is regulating the power signal of the power converter.

10. The monitoring unit of claim 1, wherein the injection signal is a variable frequency signal, and wherein the power converter is a switched-mode power supply.

11. The monitoring unit of claim 4, wherein the injection signal causes a detectable signal perturbation of +/−

one least significant bit (LSB) in amplitude of the power signal or the at least one feedback signal.

12. The monitoring unit of claim 1, wherein the measured frequency corresponds to at least one of a crossover frequency, a gain margin frequency, and a resonant frequency.

13. The monitoring unit of claim 1, wherein the measured phase corresponds to at least one of a phase margin and a phase around resonance.

14. The monitoring unit of claim 1, wherein the measured gain corresponds to at least one of a gain margin and a gain around resonance.

15. The monitoring unit of claim 1, wherein the monitoring unit is in communication with an adaptive tuning controller, and wherein the adaptive tuning controller is configured to set at least one compensator parameter of the digital compensator.

16. The monitoring unit of claim 15, wherein the setting of the at least one compensator parameter is based on at least one of the measured phase, the measured gain, and the measured frequency output by the monitoring unit.

17. The monitoring unit of claim 15, wherein the monitoring unit is in further communication with a mode selection system configured to detect a change in an operating mode of the power converter, and wherein the adaptive tuning controller is configured to set the at least one compensator parameter based on the operating mode.

18. The monitoring unit of claim 17, wherein the operating mode of the power converter is at least one of continuous conduction mode (CCM) and discontinuous conduction mode (DCM), and wherein the adaptive tuning controller comprises a CCM parameter set and a DCM parameter set corresponding to the operating mode.

19. The monitoring unit of claim 15, wherein the adaptive tuning controller and the monitoring unit form a portion of at least one of a multi-input multi-output (MIMO) control loop, a single-input multi-output control loop, or a multi-input single-output control loop.

20. A method of regulating a power signal of a power converter, the method comprising:

injecting an injection signal into a feedback path in a digital controller of the power converter;

sampling, at a monitoring unit, at least one feedback signal in the feedback path of the digital controller; and

outputting, from the monitoring unit, at least one of a measured frequency, a measured phase, and a measured gain associated with a frequency response of the power converter;

wherein the at least one of the measured frequency, the measured phase, and the measured gain is based on the at least one feedback signal.

21. The method of claim 20, further comprising sampling the at least one of the measured frequency, the measured gain, and the measured phase to generate a phase margin signal, a gain margin signal, a gain margin frequency, and a crossover frequency signal.

22. The method of claim 21, further comprising:

generating at least one of a phase margin error signal, a gain margin error signal, a gain margin frequency error signal, and a crossover frequency error signal, wherein the phase margin error signal is based on a comparison of the phase margin signal and a phase reference signal, wherein the gain margin error signal is based on a comparison of the gain margin signal and a gain reference signal, wherein the gain margin frequency error signal is based on a comparison of the gain margin frequency signal and a gain margin frequency reference signal, and wherein the crossover frequency error signal is based on a comparison of the crossover frequency signal and a crossover frequency reference signal; and

adjusting at least one operating attribute of the digital compensator based on the at least one of the phase margin error signal, the gain margin error signal, the gain margin frequency error signal, and the crossover frequency error signal.

23. The method of claim 20, further comprising generating the injection signal amplitude based on achieving a desired amplitude perturbation of the power signal or the at least one feedback signal.

24. A method of digital control of a power converter, the method comprising:

receiving operating attributes at an adaptive tuning controller, wherein the operating attributes include at least one of a crossover frequency, a gain margin frequency, a phase margin, and a gain margin;

generating adjusted operating attributes; and

transmitting the adjusted operating attributes to a digital compensator, wherein the digital compensator generates a digital feedback signal based in part on the adjusted operating attributes, and wherein the digital feedback signal modifies the regulating of a power converter.

25. The method of claim 24, wherein the modification of the regulating of the power converter occurs while the power converter is regulating a power signal.

26. The method of claim 24, wherein the adaptive tuning controller generates the adjusted operating attributes based at least in part on the determined power converter operating mode.