System, method and apparatus for controlling converters using input-output linearization

• US 9,413,235 B2
• Filed: 08/18/2014
• Issued: 08/09/2016
• Est. Priority Date: 06/18/2009
• Status: Active Grant

• Current Assignee: Cirasys, Inc., Board of Regents of the University of Texas System (University of Texas System)
• Original Assignee: Cirasys, Inc., Board of Regents of the University of Texas System (University of Texas System)
• Inventors: Hunt, Louis R., Taylor, Robert J.
• Primary Examiner(s): Berhane, Adolf
• Assistant Examiner(s): LEE III, HENRY E
• Application Number:
  US14/462,388
• Publication Number:
  US 20140354255A1
• Time in Patent Office: 722 Days
• US Class Current: 1/1
• CPC Class Codes: H02M 3/156 with automatic control of output voltage or current, e.g. switching regulators

Abstract

A system, method and apparatus for controlling boost and buck-boost converters using input-output linearization and leading-edge modulation is provided. The controller includes a summing circuit connected to the converter to create a third voltage representing a difference between the first voltage and the second voltage. A gain circuit is connected to the summing circuit to adjust the third voltage by an appropriate gain. A modulating circuit is connected to the gain circuit, the converter, the first voltage, the second voltage and the second current to create a control signal based on the first voltage, the second voltage, the adjusted third voltage, the fourth voltage and the first current. The control signal is used to control the converter. Typically, the first voltage is a converter output voltage, the second voltage is a reference voltage, the fourth voltage is a converter input voltage, and first current is a converter inductor current.

Claims

1. A system for converting an input voltage to an output voltage, comprising:

a voltage converter circuit comprising an inductor, powered by the input voltage and producing an inductor current through the inductor;

a controller connected to the voltage converter circuit, the output voltage, and the input voltage;

a reference voltage connected to the controller;

a control signal generated by the controller for the voltage converter circuit, comprising a duty cycle based on the input voltage, the output voltage, the reference voltage, and the inductor current;

whereby the voltage converter circuit generates the output voltage based on the duty ratio;

wherein the duty cycle is given by

2. The system of claim 1, wherein the controller is configured to generate the control signal based on input-output feedback linearization of a set of state variables with stable zero dynamics.

3. The system of claim 1, wherein the controller further comprises:

a summing circuit connected to the output voltage and the reference voltage;

a gain circuit connected to the summing circuit; and

,

a modulating circuit connected to the gain circuit and the output voltage, the reference voltage, the input voltage, and the inductor current, to generate the control signal.

4. The system of claim 3, further comprising:

a difference voltage generated by the summing circuit;

an adjusted voltage generated by the gain circuit from the difference voltage and the proportional gain factor; and

,

wherein the difference voltage is the difference between the reference voltage and the output voltage.

5. The system of claim 4, wherein the gain circuit further comprises:

a gain controller connected to the summing circuit;

wherein the gain controller is selected from the group consisting of a proportional controller, an integral controller, a derivative controller, and a combination controller comprising any combination of the proportional controller, the integral controller, and the derivative controller; and

,

wherein the proportional gain factor is

6. The system of claim 5, wherein the voltage converter circuit is a boost converter.

7. The system of claim 6, wherein the boost converter further comprises:

the inductor switchably connected in series with the load resistance and the input voltage; and

,

the capacitor connected in parallel with the load resistance.

8. In a system comprising a voltage converter circuit comprising an inductor, and a controller connected to the voltage converter circuit, a method for converting an input voltage to an output voltage comprising the steps of:

receiving a reference voltage;

receiving the input voltage;

receiving an inductor current;

generating a feedback output voltage;

receiving the feedback output voltage;

generating a control signal from the input voltage, the feedback output voltage, the reference voltage, and the inductor current;

applying the control signal to the voltage converter circuit; and

,

generating the output voltage based on the control signal;

wherein the step of generating a control signal comprises the steps of calculating a duty cycle and solving

9. The method of claim 8, further comprising the steps of:

creating a difference voltage from the feedback output voltage and the reference voltage; and

,

adjusting the difference voltage by the proportional gain factor to create an adjusted voltage.

10. The method of claim 9, wherein the step of calculating a duty cycle further comprises the step of implementing input-output linearization.

11. The method of claim 9, wherein the step of generating a control signal further comprises the step of creating the control signal based on the output voltage, the reference voltage, the adjusted voltage, the input voltage, and the duty cycle.

12. The method of claim 9, further comprising the step of providing a boost converter for the voltage converter circuit, wherein the boost converter further comprises:

the inductor switchably connected in series with the load resistance and the input voltage; and

,

the capacitor connected in parallel with the load resistance.

13. A system for converting an input voltage to an output voltage, comprising:

a voltage converter circuit comprising an inductor, powered by the input voltage and producing an inductor current through the inductor;

a controller connected to the voltage converter circuit, the output voltage, and the input voltage;

a reference voltage connected to the controller;

a control signal generated by the controller for the voltage converter circuit, comprising a duty cycle based on the input voltage, the output voltage, the reference voltage, and the inductor current;

whereby the voltage converter circuit generates the output voltage based on the duty ratio;

wherein the duty cycle is given by

14. The system of claim 13, wherein the controller is configured to generate the control signal based on input-output feedback linearization of a set of state variables with stable zero dynamics.

15. The system of claim 13, wherein the controller further comprises:

a summing circuit connected to the output voltage and the reference voltage;

a gain circuit connected to the summing circuit; and

,

a modulating circuit connected to the gain circuit and the output voltage, the reference voltage, the input voltage, and the inductor current, to generate the control signal.

16. The system of claim 15, further comprising:

a difference voltage generated by the summing circuit;

an adjusted voltage generated by the gain circuit from the difference voltage and the proportional gain factor; and

,

wherein the difference voltage is the difference between the reference voltage and the output voltage.

17. The system of claim 16, wherein the gain circuit further comprises:

a gain controller connected to the summing circuit;

wherein the gain controller is selected from the group consisting of a proportional controller, an integral controller, a derivative controller, and a combination controller comprising any combination of the proportional controller, the integral controller, and the derivative controller; and

,

wherein the proportional gain factor is

18. The system of claim 17, wherein the voltage converter circuit is a buck-boost converter.

19. The system of claim 18, wherein the buck-boost converter further comprises:

the inductor switchably connected in series with a load resistance;

the input voltage switchably connected in parallel with the inductor; and

,

the capacitor connected in parallel with the load resistance.

20. In a system comprising a voltage converter circuit comprising an inductor, and a controller connected to the voltage converter circuit, a method for converting an input voltage to an output voltage comprising the steps of:

receiving a reference voltage;

receiving the input voltage;

receiving an inductor current;

generating a feedback output voltage;

receiving the feedback output voltage;

generating a control signal from the input voltage, the feedback output voltage, the reference voltage, and the inductor current;

applying the control signal to the voltage converter circuit; and

,

generating the output voltage based on the control signal;

wherein the step of generating a control signal comprises the steps of calculating a duty cycle and solving

21. The method of claim 20, further comprising the steps of:

creating a difference voltage from the feedback output voltage and the reference voltage; and

,

adjusting the difference voltage by the proportional gain factor to create an adjusted voltage.

22. The method of claim 21, wherein the step of calculating a duty cycle further comprises the step of implementing input-output linearization.

23. The method of claim 21, wherein the step of generating a control signal further comprises the step of creating the control signal based on the output voltage, the reference voltage, the adjusted voltage, the input voltage, and the duty cycle.

24. The method of claim 21, further comprising the step of providing a buck-boost converter for the voltage converter circuit, wherein the buck-boost converter further comprises:

the inductor switchably connected in series with the load resistance;

the input voltage switchably connected in parallel with the inductor; and

,

the capacitor connected in parallel with the load resistance.