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

• US 20060158910A1
• Filed: 01/20/2005
• Published: 07/20/2006
• Est. Priority Date: 01/20/2005
• 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 7,482,794 B2
• Time in Patent Office: Days
• US Class Current: 363/35
• CPC Class Codes: H02M 3/156 with automatic control of output voltage or current, e.g. switching regulators

Abstract

The present invention provides a system, method and apparatus for controlling any type of converter using input-output linearization and leading-edge modulation. 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 a proportional gain. A modulating circuit is connected to the gain circuit, the converter, the second voltage and the second current to create a control signal based on the second voltage, the adjusted third voltage, the first current and the second current. The control signal is used to control the converter. Typically, the first voltage is an output voltage from the converter, the second voltage is a reference voltage, the first current is an inductor current from the converter and the second current is a reference current.

Claims

1. A method for controlling a non-linear system comprising the steps of:

receiving a first voltage, a second voltage, a first current and a second current;

creating a third voltage representing a difference between the first voltage and the second voltage;

adjusting the third voltage by a proportional gain;

creating a control signal based on the second voltage, the adjusted third voltage, the first current and the second current; and

controlling the non-linear system using the control signal.

2. The method as recited in claim 1, wherein the first voltage is an output voltage from the converter, the second voltage is a reference voltage, the first current is an inductor current from the converter and the second current is a reference current.

3. The method as recited in claim 1, wherein the non-linear system is a boost converter or a buck-boost converter.

4. The method as recited in claim 1, wherein the non-linear system is a boost converter and a duty cycle for the control signal is defined as

$d=-\frac{\begin{array}{c}[{\mathrm{CR}}_s\end{array}}{}$

R c ⁡

( R + R c ) + L ⁡

( R + R c ) ] ⁢

x 1 + [ ( R + R c ) ⁢

R c ⁢

C + L ] ( R + R c ) R ⁢

y - ( R + R c ) ⁢

R c ⁢

Cu 0 - k ⁡

( y - y 0 ) LRx 1 + [ ( R + R c ) ⁢

R c ⁢

C ] ⁢

( R + R c ) R ⁢

y .

5. The method as recited in claim 1, wherein the non-linear system is a buck-boost converter and a duty cycle for the control signal is defined as

$d=-\frac{\begin{array}{c}[{\mathrm{RR}}_c\end{array}}{}$

C + L ] ⁢

( R + R c ) R y - [ ( R + R c ) ⁢

R c ⁢

R s ⁢

C - L ⁡

( R + R c ) ] ⁢

x 1 + k ⁡

( y - y 0 ) ( R + R c ) ⁢

R c ⁢

C ⁢

 

⁢

y + LRx 1 - ( R + R c ) ⁢

R c ⁢

Cu 0 .

6. The method as recited in claim 1, wherein the control signal provides leading-edge modulation with input-output linearization.

7. The method as recited in claim 1, wherein the control of the non-linear system cannot be unstable.

8. The method as recited in claim 1, wherein the control signal is created using a first order system.

9. The method as recited in claim 1, wherein the control signal is independent of a stabilizing gain, a desired output voltage or a desired output trajectory.

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

11. A computer program embodied within a digital signal processor for controlling a non-linear system, the computer program comprising:

a code segment for receiving a first voltage, a second voltage, a first current and a second current;

a code segment for creating a third voltage representing a difference between the first voltage and the second voltage;

a code segment for adjusting the third voltage by a proportional gain;

a code segment for creating a control signal based on the second voltage, the adjusted third voltage, the first current and the second current; and

a code segment for controlling the non-linear system using the control signal.

12. The computer program as recited in claim 11, wherein the first voltage is an output voltage from the converter, the second voltage is a reference voltage, the first current is an inductor current from the converter and the second current is a reference current.

13. The computer program as recited in claim 11, wherein the non-linear system is a boost converter or a buck-boost converter.

14. The computer program as recited in claim 11, wherein the non-linear system is a boost converter and a duty cycle for the control signal is defined as

$d=-\frac{\begin{array}{c}[{\mathrm{CR}}_s\end{array}}{}$

R c ⁡

( R + R c ) + L ⁡

( R + R c ) ] ⁢

x 1 + [ ( R + R c ) ⁢

R c ⁢

C + L ] ( R + R c ) R ⁢

y - ( R + R c ) ⁢

R c ⁢

Cu 0 - k ⁡

( y - y 0 ) LRx 1 + [ ( R + R c ) ⁢

R c ⁢

C ] ⁢

( R + R c ) R ⁢

y .

15. The computer program as recited in claim 11, wherein the non-linear system is a buck-boost converter and a duty cycle for the control signal is defined as

$d=-\frac{\begin{array}{c}[{\mathrm{RR}}_c\end{array}}{}$

C + L ] ⁢

( R + R c ) R y - [ ( R + R c ) ⁢

R c ⁢

R s ⁢

C - L ⁡

( R + R c ) ] ⁢

x 1 + k ⁡

( y - y 0 ) ( R + R c ) ⁢

R c ⁢

C ⁢

 

⁢

y + LRx 1 - ( R + R c ) ⁢

R c ⁢

Cu 0 .

16. 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

$d=-\frac{\begin{array}{c}[{\mathrm{CR}}_s\end{array}}{}$

R c ⁡

( R + R c ) + L ⁡

( R + R c ) ] ⁢

x 1 + [ ( R + R c ) ⁢

R c ⁢

C + L ] ( R + R c ) R ⁢

y - ( R + R c ) ⁢

R c ⁢

Cu 0 - k ⁡

( y - y 0 ) LRx 1 + [ ( R + R c ) ⁢

R c ⁢

C ] ⁢

( R + R c ) R ⁢

y .

17. 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

$d=-\frac{\begin{array}{c}[{\mathrm{RR}}_c\end{array}}{}$

C + L ] ⁢

( R + R c ) R y - [ ( R + R c ) ⁢

R c ⁢

R s ⁢

C - L ⁡

( R + R c ) ] ⁢

x 1 + k ⁡

( y - y 0 ) ( R + R c ) ⁢

R c ⁢

C ⁢

 

⁢

y + LRx 1 - ( R + R c ) ⁢

R c ⁢

Cu 0 .

18. An apparatus comprising:

a first connection to receive a first voltage;

a second connection to receive a second voltage;

a third connection to receive a first current;

a fourth connection to receive a second current;

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 and the second voltage;

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 a control signal based on the second voltage, the adjusted third voltage, the first current and the second current.

19. The apparatus as recited in claim 18, wherein the first voltage is an output voltage from the converter, the second voltage is a reference voltage, the first current is an inductor current from the converter and the second current is a reference current.

20. The apparatus as recited in claim 18, wherein the control signal controls a boost converter or a buck-boost converter.

21. The apparatus as recited in claim 18, wherein the control signal controls a boost converter and has a duty cycle defined as

$d=-\frac{\begin{array}{c}[{\mathrm{CR}}_s\end{array}}{}$

R c ⁡

( R + R c ) + L ⁡

( R + R c ) ] ⁢

x 1 + [ ( R + R c ) ⁢

R c ⁢

C + L ] ( R + R c ) R ⁢

y - ( R + R c ) ⁢

R c ⁢

Cu 0 - k ⁡

( y - y 0 ) LRx 1 + [ ( R + R c ) ⁢

R c ⁢

C ] ⁢

( R + R c ) R ⁢

y .

22. The apparatus as recited in claim 18, wherein the control signal controls a buck-boost converter and has a duty cycle defined as

$d=-\frac{\begin{array}{c}[{\mathrm{RR}}_c\end{array}}{}$

C + L ] ⁢

( R + R c ) R ⁢

y - [ ( R + R c ) ⁢

R c ⁢

R s ⁢

C - L ⁡

( R + R c ) ] ⁢

x 1 + k ⁡

( y - y 0 ) ( R + R c ) ⁢

R c ⁢

Cy + LRx 1 - ( R + R c ) ⁢

R c ⁢

Cu 0 .

23. A system comprising:

a converter having a first voltage and a first current;

a second voltage source;

a second current source; and

a PWM modulator/controller comprising;

a summing circuit connected to the converter and the second voltage source to create a third voltage representing a difference between the first voltage and the second voltage,

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 converter, the second voltage second and the second current source to create a control signal based on the second voltage, the adjusted third voltage, the first current and the second current, and to the converter to control the converter with the control signal.

24. The system as recited in claim 23, wherein the second voltage source and second current source are integrated into the PWM modulator/controller.

25. The system as recited in claim 23, wherein the PWM modulator/controller is implemented using a digital signal processor or conventional electrical circuitry.

26. The system as recited in claim 23, wherein the first voltage is an output voltage from the converter, the second voltage is a reference voltage, the first current is an inductor current from the converter and the second current is a reference current.

27. The system as recited in claim 23, wherein the control signal controls a boost converter or a buck-boost converter.

28. The system as recited in claim 23, wherein the control signal controls a boost converter and has a duty cycle defined as

$d=-\frac{\begin{array}{c}[{\mathrm{CR}}_s\end{array}}{}$

R c ⁡

( R + R c ) + L ⁡

( R + R c ) ] ⁢

x 1 + [ ( R + R c ) ⁢

R c ⁢

C + L ] ( R + R c ) R ⁢

y - ( R + R c ) ⁢

R c ⁢

Cu 0 - k ⁡

( y - y 0 ) LRx 1 + [ ( R + R c ) ⁢

R c ⁢

C ] ⁢

( R + R c ) R ⁢

y .

29. The system as recited in claim 23, wherein the control signal controls a buck-boost converter and has a duty cycle defined as

$d=-\frac{\begin{array}{c}[{\mathrm{RR}}_c\end{array}}{}$

C + L ] ⁢

( R + R c ) R y - [ ( R + R c ) ⁢

R c ⁢

R s ⁢

C - L ⁡

( R + R c ) ] ⁢

x 1 + k ⁡

( y - y 0 ) ( R + R c ) ⁢

R c ⁢

Cy + LRx 1 - ( R + R c ) ⁢

R c ⁢

Cu 0 .

30. A kit for a PWM modulated converter comprising;

a digital signal processor comprising;

a first connection to receive a first voltage,

a second connection to receive a second voltage,

a third connection to receive a first current,

a fourth connection to receive a second current,

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 and the second voltage,

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 a control signal based on the second voltage, the adjusted third voltage, the first current and the second current; and

a computer program embodied on a computer readable medium for programming the digital signal processor to control the PWM modulated converter.

31. The kit as recited in claim 30, wherein the computer program further comprises one or more design tools.