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

• US 8,810,221 B2
• Filed: 06/18/2009
• Issued: 08/19/2014
• 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.
• Primary Examiner(s): Zhang, Jue
• Assistant Examiner(s): LEE III, HENRY E
• Application Number:
  US12/487,242
• Publication Number:
  US 20100320978A1
• Time in Patent Office: 1,888 Days
• Field of Search: 323/241, 323/259, 323282-285
• US Class Current: 323/283
• 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, having a voltage source to which an inductor is connected at a first polarity, the inductor having inductance L and parasitic resistance R_S further connected to a diode S2 at a first node, a load resistor of resistance R connected in series to diode S2 at a second node and to the voltage source at a second polarity, a switch S1 connected in parallel with the load resistance and diode S2 at the first node, a capacitor of capacitance C and equivalent resistance R_c connected in parallel with the load resistor at the second node, the method using a PWM modulator/controller and comprising the steps of:

receiving a first voltage y from an output of the boost converter, a second voltage y₀ from a reference voltage source, a first current x₁ from an inductor within the boost converter and a fourth voltage u₀ from the 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 gain k;

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 d defined by

2. The method as recited in claim 1, further comprising the steps of:

controlling the boost converter with a controller selected from the group consisting of a proportional controller, an integral controller, a derivative controller and a controller that is a combination of these three controllers; and

,

adjusting the third voltage by the gain k where

3. The method as recited in claim 1, further comprising the step of confining the non-linear system to operate in a stable state.

25. The method as recited in claim 1, wherein the step of creating the control signal includes creating a control signal using a first order system.

26. The method as recited in claim 1, wherein the step of creating the control signal includes creating a control signal that is independent of a stabilizing gain, a desired output voltage and a desired output trajectory.

4. A method for controlling a buck-boost converter, having a voltage source to which a switch S1 is connected in series at a first polarity, an inductor having inductance L and parasitic resistance R_S connected between the switch S1 at a first node and the voltage source at a second polarity, a diode S2 connected to the first node and to a load resistor of resistance R at a second node, the diode S2 and load resistor being connected in parallel with the inductor, a capacitor of capacitance C and equivalent resistance R_c connected in parallel with the load resistor at the second node, the method using a PWM modulator/controller comprising the steps of:

receiving a first voltage y from an output of the buck-boost converter, a second voltage y₀ from a reference voltage source, a first current x₁ from an inductor within the buck-boost converter and a fourth voltage u₀ 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 gain k;

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 d defined by

5. The method as recited in claim 4, further comprising the steps of:

controlling the buck-boost converter with a controller selected from the group consisting of a proportional controller, an integral controller, a derivative controller and a controller that is a combination of these three controllers; and

,

adjusting the third voltage by the gain k where

6. The method as recited in claim 4, further comprising the step of confining the non-linear system to operate in a stable state.

27. The method as recited in claim 4, wherein the step of creating the control signal includes creating a control signal using a first order system.

28. The method as recited in claim 4, wherein the step of creating the control signal includes creating a control signal that is independent of a stabilizing gain, a desired output voltage and a desired output trajectory.

7. An apparatus comprising one or more electrical circuits that provide a control signal to a boost converter, having a voltage source to which an inductor is connected at a first polarity, the inductor having inductance L and parasitic resistance R_S further connected to a diode S2 at a first node, a load resistor of resistance R connected in series to diode S2 at a second node and to the voltage source at a second polarity, a switch S1 connected in parallel with the load resistance and diode S2 at the first node, a capacitor of capacitance C and equivalent resistance R_c connected in parallel with the load resistor at the second node, such that a duty cycle d of the control signal is defined as

8. The apparatus as recited in claim 7, wherein the one or more electrical circuits comprise:

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

a second connection to receive the 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 the gain k; 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.

9. The apparatus as recited in claim 7, further comprising a controller selected from the group consisting of a proportional controller, an integral controller, a derivative controller and a controller that is a combination of these three controllers, and the gain k is

10. An apparatus comprising one or more electrical circuits that provide a control signal to a buck-boost converter, having a voltage source to which a switch S1 is connected in series at a first polarity, an inductor having inductance L and parasitic resistance R_S connected between the switch S1 at a first node and the voltage source at a second polarity, a diode S2 connected to the first node and to a load resistor of resistance R at a second node, the diode S2 and load resistor being connected in parallel with the inductor, a capacitor of capacitance C and equivalent resistance R_c connected in parallel with the load resistor at the second node, such that a duty cycle d of the control signal is defined as

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

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

a second connection to receive the 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 the gain k; 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.

12. The apparatus as recited in claim 10, further comprising a controller selected from the group consisting of a proportional controller, an integral controller, a derivative controller and a controller that is a combination of these three controllers, and the gain k is

13. A system comprising:

a boost converter, comprising a voltage source to which an inductor is connected at a first polarity, the inductor having inductance L and parasitic resistance R_S further connected to a diode S2 at a first node, a load resistor of resistance R connected in series to diode S2 at a second node and to the voltage source at a second polarity, a switch S1 connected in parallel with the load resistance and diode S2 at the first node, a capacitor of capacitance C and equivalent resistance R_c connected in parallel with the load resistor at the second node;

the boost converter having a first voltage y at an output of the boost converter, a fourth voltage u₀ at an input of the boost converter and a first current x₁ through the inductor;

a reference voltage source having a second voltage y₀; 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 gain k, 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, where the duty cycle d of the control signal is defined by

14. The system as recited in claim 13, further comprising a controller selected from the group consisting of a proportional controller, an integral controller, a derivative controller and a controller that is a combination of these three controllers, and the gain k is

15. The system as recited in claim 13, wherein the reference voltage source is integrated into the PWM modulator/controller.

29. The system as recited in claim 13, wherein the PWM modulator/controller is implemented using at least one of the group of:

a digital signal processor, an FPGA, an ASIC, and a combination thereof.

16. A system comprising:

a buck-boost converter comprising a voltage source to which a switch S1 is connected in series at a first polarity, an inductor having inductance L and parasitic resistance R_S connected between the switch S1 at a first node and the voltage source at a second polarity, a diode S2 connected to the first node and to a load resistor of resistance R at a second node, the diode S2 and load resistor being connected in parallel with the inductor, a capacitor of capacitance C and equivalent resistance R_e connected in parallel with the load resistor at the second node;

the buck-boost converter having a first voltage y at an output of the buck-boost converter, a fourth voltage u₀ at an input of the buck-boost converter and a first current x₁ through the inductor;

a reference voltage source having a second voltage y_o; 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 gain k, 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 duty cycle d of the control signal is defined by

17. The system as recited in claim 16, further comprising a controller selected from the group consisting of a proportional controller, an integral controller, a derivative controller and a controller that is a combination of these three controllers, and, the gain k is

18. The system as recited in claim 16, wherein the reference voltage source is integrated into the PWM modulator/controller.

30. The system as recited in claim 16, wherein the PWM modulator/controller is implemented using at least one of the group of:

a digital signal processor, an FPGA, an ASIC, and a combination thereof.

19. A PWM modulated boost converter comprising:

a kit for assembly of the PWM modulated boost converter including a programmable component with memory and a boost converter having a voltage source to which an inductor is connected at a first polarity, the inductor having inductance L and parasitic resistance R_S further connected to a diode S2 at a first node, a load resistor of resistance R connected in series to diode S2 at a second node and to the voltage source at a second polarity, a switch S1 connected in parallel with the load resistance and diode S2 at the first node, a capacitor of capacitance C and equivalent resistance R_c connected in parallel with the load resistor at the second node;

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

a second connection to receive a second voltage y₀ from a reference voltage source,

a third connection to receive a first current x₁ from an inductor within the boost converter,

a fourth connection to receive a fourth voltage u₀ 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 gain k, 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 duty cycle d of the control signal is defined by

20. The PWM modulated boost converter as recited in claim 19, wherein the computer program further comprises one or more design tools.

23. The PWM modulated boost converter of claim 19 wherein the programmable component is selected from the group consisting of a digital signal processor, an FPGA and a combination thereof.

21. A PWM modulated buck-boost converter comprising;

a kit for assembly of the PWM modulated buck-boost converter including a programmable component with memory and a buck-boost converter having a voltage source to which a switch S1 is connected in series at a first polarity, an inductor having inductance L and parasitic resistance R_S connected between the switch S1 at a first node and the voltage source at a second polarity, a diode S2 connected to the first node and to a load resistor of resistance R at a second node, the diode S2 and load resistor being connected in parallel with the inductor, a capacitor of capacitance C and equivalent resistance R_c connected in parallel with the load resistor at the second node;

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

a second connection to receive a second voltage y₀ from a reference voltage source,

a third connection to receive a first current x₁ from an inductor within the buck-boost converter,

a fourth connection to receive a fourth voltage u₀ 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 gain k, 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 duty cycle d of the control signal is defined by

22. The PWM modulated buck-boost converter as recited in claim 21, wherein the computer program further comprises one or more design tools.

24. The PWM modulated buck-boost converter of claim 21 wherein the programmable component is selected from the group consisting of a digital signal processor, an FPGA and a combination thereof.