SYSTEM, METHOD AND APPARATUS FOR CONTROLLING CONVERTERS USING INPUT-OUTPUT LINEARIZATION

• US 20100320978A1
• Filed: 06/18/2009
• Published: 12/23/2010
• Est. Priority Date: 06/18/2009
• Status: Active Grant

• Current Assignee: Board of Regents of the University of Texas System (University of Texas System)
• Original Assignee: Board of Regents of the University of Texas System (University of Texas System)
• Inventors: Hunt, Louis R., Taylor, Robert J.
• Granted Patent: US 8,810,221 B2
• Time in Patent Office: Days
• US Class Current: 323/282
• 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 method for controlling a boost converter using a PWM modulator/controller comprising the steps of:

receiving a first voltage from an output of the boost converter, a second voltage from a reference voltage source, a first current from an inductor within the boost converter and a fourth voltage from a voltage source providing an input voltage to the boost converter at the PWM modulator/controller;

creating a third voltage representing a difference between the first voltage from the output of the boost converter and the second voltage from the reference voltage source;

adjusting the third voltage by a proportional gain;

creating a control signal that provides leading-edge modulation with input-output linearization based on the first voltage from the output of the boost converter, the second voltage from the reference voltage source, the adjusted third voltage, the fourth voltage from the voltage source or the input of the converter, and the first current from the inductor within the boost converter, wherein the control signal has a duty cycle defined by

2. The method as recited in claim 1, further comprising the step of controlling the boost converter with a proportional (P) controller, an integral (I) controller, or a derivative (D) controller or a controller that is a combination of these three by replacing k(y₀−

y) in the equation defining the duty cycle d with

3. The method as recited in claim 1, wherein:

the control of the non-linear system cannot be unstable;

the control signal is created using a first order system;

or

the control signal is independent of a stabilizing gain, a desired output voltage or a desired output trajectory.

4. A boost converter controlled in accordance with the method of claim 1.

5. A method for controlling a buck-boost converter using a PWM modulator/controller comprising the steps of:

receiving a first voltage from an output of the buck-boost converter, a second voltage from a reference voltage source, a first current from an inductor within the buck-boost converter and a fourth voltage from a voltage source providing an input voltage to the buck-boost converter at the PWM modulator/controller;

creating a third voltage representing a difference between the first voltage from the output of the buck-boost converter and the second voltage from the reference voltage source;

adjusting the third voltage by a proportional gain;

creating a control signal that provides leading-edge modulation with input-output linearization based on the first voltage from the output of the buck-boost converter, the second voltage from the reference voltage source, the adjusted third voltage, the fourth voltage from the voltage source or the input of the buck-boost converter, and the first current from the inductor within the buck-boost converter, wherein the control signal has a duty cycle defined by

6. The method as recited in claim 5, further comprising the step of controlling the buck-boost converter with a proportional (P) controller, an integral (I) controller, or a derivative (D) controller or a controller that is a combination of these three by replacing k(y₀−

y) in the equation for the duty cycle d with

7. The method as recited in claim 5, wherein:

the control of the non-linear system cannot be unstable;

the control signal is created using a first order system;

or

the control signal is independent of a stabilizing gain, a desired output voltage or a desired output trajectory.

8. A buck-boost converter controlled in accordance with the method of claim 5.

9. An apparatus comprising one or more electrical circuits that provide a control signal to a boost converter such that a duty cycle of the control signal is defined as

10. The apparatus as recited in claim 9, wherein the one or more electrical circuits comprise:

a first connection to receive an output voltage from the boost converter;

a second connection to receive a reference voltage;

a third connection to receive an inductor current from the boost converter;

a fourth connection to receive an input voltage from the boost converter;

a fifth connection to output the control signal;

a summing circuit connected to the first connection and the second connection to create a third voltage representing a difference between the first voltage from the output of the boost converter and the second voltage from the reference voltage source;

a gain circuit connected to the summing circuit to adjust the third voltage by a proportional gain; and

a modulating circuit connected to the gain circuit, the second connection, the third connection, the fourth connection and the fifth connection, the modulation circuit creating the control signal based on the first voltage, the second voltage, the adjusted third voltage, the fourth voltage, and the first current.

11. The apparatus as recited in claim 9, further comprising a proportional (P) controller, an integral (I) controller, or a derivative (D) controller or a controller that is a combination of these three by replacing k(y₀−

y) in the equation for the duty cycle d with

12. An apparatus comprising one or more electrical circuits that provide a control signal to a buck-boost converter such that a duty cycle of the control signal is defined as

13. The apparatus as recited in claim 12, wherein the one or more electrical circuits comprise:

a first connection to receive an output voltage from the buck-boost converter;

a second connection to receive a reference voltage;

a third connection to receive an inductor current from the buck-boost converter;

a fourth connection to receive an input voltage from a voltage source to the buck-boost converter;

a fifth connection to output a control signal;

a summing circuit connected to the first connection and the second connection to create a third voltage representing a difference between the first voltage from the output of the buck-boost converter and the second voltage from the reference voltage source;

a gain circuit connected to the summing circuit to adjust the third voltage by a proportional gain; and

a modulating circuit connected to the gain circuit, the second connection, the third connection, the fourth connection and the fifth connection, the modulation circuit creating the control signal based on the first voltage, the second voltage, the adjusted third voltage, the fourth voltage, and the first current.

14. The apparatus as recited in claim 12, further comprising a proportional (P) controller, an integral (I) controller, or a derivative (D) controller or a controller that is a combination of these three by the duty cycle d with k(y₀−

y) replaced by

15. A system comprising:

a boost converter having a first voltage at an output of the boost converter, a fourth voltage at a voltage source or an input of the boost converter and a first current at an inductor within the boost converter;

a reference voltage source having a second voltage; and

a PWM modulator/controller comprising;

a summing circuit connected to the boost converter and the reference voltage source to create a third voltage representing a difference between the first voltage from the output of the boost converter and the second voltage from the reference voltage source,

a gain circuit connected to the summing circuit to adjust the third voltage by a proportional gain, and

a modulating circuit connected to the gain circuit, the boost converter, and the reference voltage source to create a control signal to control the boost converter, wherein the control signal provides leading-edge modulation with input-output linearization that is based on the first voltage from the output of the boost converter, the second voltage from the reference voltage source, the adjusted third voltage from the gain circuit, the fourth voltage from the voltage source or the input of the boost converter, the first current from the inductor within the boost converter and the second current from the reference current source, wherein the control signal is defined by

16. The system as recited in claim 15, further comprising a proportional (P) controller, an integral (I) controller, or a derivative (D) controller or a controller that is a combination of these three by replacing k(y₀−

y) in the equation for the duty cycle d with

17. The system as recited in claim 15, wherein:

the reference voltage source is integrated into the PWM modulator/controller;

or

the PWM modulator/controller is implemented using a digital signal processor or conventional electrical circuitry.

18. A system comprising:

a buck-boost converter having a first voltage at an output of the buck-boost converter, a fourth voltage at voltage source or an input of the buck-boost converter and a first current at an inductor within the buck-boost converter;

a reference voltage source having a second voltage; and

a PWM modulator/controller comprising;

a summing circuit connected to the buck-boost converter and the reference voltage source to create a third voltage representing a difference between the first voltage from the output of the buck-boost converter and the second voltage from the reference voltage source,

a gain circuit connected to the summing circuit to adjust the third voltage by a proportional gain, and

a modulating circuit connected to the gain circuit, the buck-boost converter, and the reference voltage source to create a control signal to control the buck-boost converter, wherein the control signal provides leading-edge modulation with input-output linearization that is based on the first voltage from the output of the buck-boost converter, the second voltage from the reference voltage source, the adjusted third voltage from the gain circuit, the fourth voltage from the voltage source or the input of the buck-boost converter, and the first current from the inductor within the buck-boost converter, wherein the control signal is defined by

19. The system as recited in claim 18, further comprising a proportional (P) controller, an integral (I) controller, or a derivative (D) controller or a controller that is a combination of these three by the duty cycle d with k(y₀−

y) replaced by

20. The system as recited in claim 18, wherein:

the reference voltage source is integrated into the PWM modulator/controller;

or

the PWM modulator/controller is implemented using a digital signal processor, a FPGA, or conventional electrical circuitry.

21. A kit for a PWM modulated boost converter comprising;

a digital signal processor or FPGA comprising;

a first connection to receive a first voltage from an output of the boost converter,

a second connection to receive a second voltage from a reference voltage source,

a third connection to receive a first current from an inductor within the boost converter,

a fourth connection to receive a fourth voltage from a voltage source or an input of the boost converter,

a fifth connection to output a control signal to the boost converter,

a summing circuit connected to the first connection and the second connection to create a third voltage representing a difference between the first voltage from the output of the boost converter and the second voltage from the reference voltage source,

a gain circuit connected to the summing circuit to adjust the third voltage by a proportional gain, and

a PWM modulating circuit connected to the gain circuit, the first connection, the second connection, the third connection, the fourth connection and the fifth connection, the modulation circuit creating the control signal that provides leading-edge modulation with input-output linearization based on the first voltage from the output of the boost converter, the second voltage from the reference voltage source, the adjusted third voltage from the gain circuit, the fourth voltage from the voltage source or the input of the boost converter, and the first current from the inductor within the boost converter, wherein the control signal is defined by

22. The kit as recited in claim 21, wherein the computer program further comprises one or more design tools.

23. A kit for a PWM modulated buck-boost converter comprising;

a digital signal processor or FPGA comprising;

a first connection to receive a first voltage from an output of the buck-boost converter,

a second connection to receive a second voltage from a reference voltage source,

a third connection to receive a first current from an inductor within the buck-boost converter,

a fourth connection to receive a fourth voltage from a voltage source or an input of the buck-boost converter,

a fifth connection to output a control signal to the buck-boost converter,

a summing circuit connected to the first connection and the second connection to create a third voltage representing a difference between the first voltage from the output of the buck-boost converter and the second voltage from the reference voltage source,

a gain circuit connected to the summing circuit to adjust the third voltage by a proportional gain, and

a PWM modulating circuit connected to the gain circuit, the first connection, the second connection, the third connection, the fourth connection and the fifth connection, the modulation circuit creating the control signal that provides leading-edge modulation with input-output linearization based on the first voltage from the output of the buck-boost converter, the second voltage from the reference voltage source, the adjusted third voltage from the gain circuit, the fourth voltage from the voltage source or the input of the buck-boost converter, and the first current from the inductor within the buck-boost converter, wherein the control signal is defined by

24. The kit as recited in claim 23, wherein the computer program further comprises one or more design tools.