System and method for controlling output ripple of DC-DC converters with leading edge modulation control using current injection

• US 9,690,308 B2
• Filed: 12/19/2012
• Issued: 06/27/2017
• Est. Priority Date: 12/20/2011
• 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: Taylor, Robert Jewell, Hunt, Louis R., Paduvalli, Vikas V.
• Primary Examiner(s): Tran, Nguyen
• Assistant Examiner(s): Mata, Monica
• Application Number:
  US13/720,850
• Publication Number:
  US 20130154586A1
• Time in Patent Office: 1,651 Days
• Field of Search: None
• CPC Class Codes: G05F 1/468 characterised by reference voltage circuitry, e.g. soft start, remote shutdown
• CPC Class Codes: H02M 1/0025 Arrangements for modifying reference values, feedback values or error values in the control loop of a converter
• CPC Class Codes: H02M 1/14 Arrangements for reducing ripples from dc input or output
• CPC Class Codes: H02M 3/156 with automatic control of output voltage or current, e.g. switching regulators
• CPC Class Codes: H02M 3/157 with digital control
• CPC Class Codes: H03K 7/08 Duration or width modulation ; Duty cycle modulation

Abstract

In a preferred embodiment, a voltage converter comprises a voltage converter circuit, an output adjuster and a controller. The controller provides a control signal at a duty ratio determined dynamically by a set of input signals. The dynamic output adjuster determines the set of input signals by adjusting the ac component of an output voltage based on a gain Q. The dynamic output adjuster alleviates dependence on the value of R_c under leading edge modulation in either analog or digital converter systems. In addition to delivering the desired left half plane zero effects, dynamic output adjustment reduces the value of the output ripple. As a result, modern control methods such as input-output linearization can be used to design both boost and buck-boost PWM converters if only left half plane zero effects are present.

Claims

1. A voltage converter for converting an input voltage to an output voltage across a load resistance comprising:

a voltage converter circuit having an inductor;

an output adjuster, connected to the voltage converter circuit, configured to generate an adjusted output voltage based on the output voltage and a time varying component of an inductor current through the inductor, scaled by a first adjustable gain factor;

a controller, connected to the output adjuster and the voltage converter circuit, configured to generate a control signal to the voltage converter circuit;

the control signal having a duty ratio based on the adjusted output voltage, the input voltage, a desired output voltage, a second gain factor, the inductor current and the first adjustable gain factor;

whereby the voltage converter circuit changes the output voltage to match the desired output voltage; and

,

wherein the adjusted output voltage is generated according to

2. The voltage converter of claim 1 wherein the voltage converter circuit comprises:

a boost converter circuit where the inductor is connected to a first polarity of the input voltage in series with a series resistance;

the boost converter circuit further comprising;

a first switch connected in series with the inductor and a second polarity of the input voltage and controlled by the control signal;

a second switch connected between the inductor and a capacitor;

the capacitor connected by a capacitive resistance to the second polarity of the input voltage;

the load resistance connected in parallel to the capacitor and the capacitive resistance; and

,

the duty ratio of the control signal is given by the formula;

3. The voltage converter of claim 2 wherein the duty ratio of the control signal is given by the formula:

4. The voltage converter of claim 2 wherein the duty ratio of the control signal is given by the formula:

5. The voltage converter of claim 1 wherein the voltage converter circuit comprises:

a buck converter circuit further comprising;

a first switch connected in series with a first polarity of the input voltage and controlled by the control signal;

the inductor having a series resistance connected in series with the first switch and a second polarity of the input voltage;

a second switch connected between the first switch and a capacitor;

the capacitor connected by a capacitive resistance to the second polarity of the input voltage;

the load resistance connected in parallel to the capacitor and the capacitive resistance; and

,

the duty ratio of the control signal is given by the formula;

6. The voltage converter of claim 5 wherein the duty ratio of the control signal is given by the formula:

7. The voltage converter of claim 5 wherein the duty ratio of the control signal is given by the formula:

8. A voltage converter for converting an input voltage to an output voltage across a load resistance comprising:

a voltage converter circuit having an inductor;

an output adjuster, connected to the voltage converter circuit, configured to generate an adjusted output voltage based on the output voltage and a time varying component of an inductor current through the inductor, scaled by a first adjustable gain factor;

a controller, connected to the output adjuster and the voltage converter circuit, configured to generate a control signal to the voltage converter circuit;

the control signal having a duty ratio based on the adjusted output voltage, the input voltage, a desired output voltage, a second gain factor, the inductor current and the first adjustable gain factor;

whereby the voltage converter circuit changes the output voltage to match the desired output voltage; and

,

wherein;

the voltage converter circuit further comprises a capacitor having a capacitive resistance and connected in parallel to the load resistance; and

,

the adjusted output voltage is generated according to

9. A voltage converter for converting an input voltage to an output voltage across a load resistance comprising:

a voltage converter circuit having an inductor;

an output adjuster, connected to the voltage converter circuit, configured to generate an adjusted output voltage based on the output voltage and a time varying component of an inductor current through the inductor, scaled by a first adjustable gain factor;

a controller, connected to the output adjuster and the voltage converter circuit, configured to generate a control signal to the voltage converter circuit;

the control signal having a duty ratio based on the adjusted output voltage, the input voltage, a desired output voltage, a second gain factor, the inductor current and the first adjustable gain factor;

whereby the voltage converter circuit changes the output voltage to match the desired output voltage; and

,

wherein the adjusted output voltage is generated according to

10. The voltage converter of claim 9 wherein the voltage converter circuit comprises:

a buck-boost converter circuit further comprising;

a first switch connected in series with a first polarity of the input voltage and controlled by the control signal;

the inductor having a series resistance connected in series with the first switch and a second polarity of the input voltage;

a second switch connected between the first switch and a capacitor;

the capacitor connected by a capacitive resistance to the second polarity of the input voltage;

the load resistance connected in parallel to the capacitor and the capacitive resistance; and

,

the duty ratio of the control signal is given by the formula;

11. The voltage converter of claim 10 wherein the duty ratio of the control signal is given by the formula:

12. The voltage converter of claim 10 wherein the duty ratio of the control signal is given by the formula:

13. A method of converting an input voltage into an output voltage across a load resistance comprising:

providing a voltage converter circuit having the input voltage as a voltage source and producing the output voltage;

providing an inductor current flowing through an inductor in the voltage converter circuit, the inductor current having a time varying component;

providing an output adjuster connected to the voltage converter circuit;

generating an adjusted output voltage which depends on the output voltage and the time varying component of the inductor current scaled by a first adjustable gain factor;

providing a controller connected to the output adjuster and to the voltage converter circuit;

generating a control signal with a duty ratio that controls the voltage converter circuit;

dynamically determining the duty ratio from the adjusted output voltage, the input voltage, a desired output voltage, a second gain factor, the inductor current and the first adjustable gain factor;

whereby the voltage converter circuit produces the output voltage to match the desired output voltage; and

,

generating the adjusted output voltage according to one of a first equation, a second equation, a third equation, and a fourth equation,

the first equation comprising