Tracking converters with input output linearization control

• US 9,252,683 B2
• Filed: 07/10/2013
• Issued: 02/02/2016
• Est. Priority Date: 06/18/2009
• Status: Active Grant

• Current Assignee: Cirasys, Inc.
• Original Assignee: Cirasys, Inc.
• Inventors: Hunt, Louis R.
• Primary Examiner(s): Finch, III, Fred E
• Application Number:
  US13/938,333
• Publication Number:
  US 20130301321A1
• Time in Patent Office: 937 Days
• US Class Current: 1/1
• CPC Class Codes: H02M 1/0012 Control circuits using digital or numerical techniques in DC/DC converters H02M3/157, H02M3/33515; in DC-AC converters H02M7/53873
• CPC Class Codes: H02M 1/009 having two or more independently controlled outputs for DC-DC converter with intermediate AC H02M3/33561
• CPC Class Codes: H02M 3/156 with automatic control of output voltage or current, e.g. switching regulators
• CPC Class Codes: H02M 3/158 including plural semiconductor devices as final control devices for a single load
• CPC Class Codes: H02M 3/1582 Buck-boost converters H02M3/1584 takes precedence
• CPC Class Codes: H02M 7/5395 by pulse-width modulation
• CPC Class Codes: H03K 7/08 Duration or width modulation ; Duty cycle modulation

Abstract

In a preferred embodiment, a voltage inverter comprises a voltage converter circuit and a controller. The voltage inverter produces a time-varying output voltage from an input voltage, which can be a DC input voltage or an AC input voltage. The controller provides a control signal at a duty ratio determined dynamically by a set of signals. The set of signals include the time-varying output voltage, a predetermined output voltage, a gain factor and an inductor current in the voltage converter circuit. The predetermined output voltage can have an AC waveform or an arbitrary time-varying waveform. The voltage inverter operates to match the time-varying output voltage to the predetermined output voltage. Input-output linearization is used to design a buck inverter, and input-output linearization with leading edge modulation is used to design boost and buck-boost inverters under conditions where left half plane zero effects are present.

Claims

1. A tracking inverter for converting an input voltage to a time-varying output voltage comprising:

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

a predetermined output voltage that varies with time;

a controller, connected to the voltage converter circuit, configured to apply a control signal to the voltage converter circuit;

the control signal having a duty ratio based on the predetermined output voltage, the time-varying output voltage, the input voltage, a gain factor and the inductor current;

whereby the voltage converter circuit generates the time-varying output voltage to match the predetermined output voltage; and

,

wherein;

the voltage converter circuit is characterized by a set of circuit parameters;

the duty ratio is given by

2. The tracking inverter of claim 1 wherein the controller is configured to generate the control signal for leading edge modulation.

3. The tracking inverter 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.

4. The tracking inverter of claim 1 wherein the gain factor includes at least one of the group consisting of a proportional gain, an integral gain and a derivative gain.

5. The tracking inverter of claim 1 wherein the predetermined output voltage varies sinusoidally in time.

6. The tracking inverter of claim 1 wherein the input voltage varies in time with a first waveform and the time-varying output voltage varies in time with a second waveform different than the first waveform.

7. The tracking inverter of claim 1 wherein the input voltage is sinusoidal at a first frequency and the time-varying output voltage is sinusoidal at a second frequency different than the first frequency.

8. The tracking inverter of claim 1 wherein the input voltage has a first frequency spectrum and the predetermine output voltage has a second frequency spectrum different than the first frequency spectrum.

9. The tracking inverter of claim 1 wherein the voltage converter circuit comprises a buck converter circuit.

10. The tracking inverter of claim 1 wherein:

the voltage converter circuit comprises a buck converter circuit;

the buck converter circuit further comprises the inductor connected in series with a load resistance, the input voltage and a switch;

a capacitor is connected in parallel with the load resistance;

11. The tracking inverter of claim 1 wherein the voltage converter circuit comprises a boost converter circuit.

12. The tracking inverter of claim 1 wherein the voltage converter circuit comprises a buck-boost converter circuit.

13. A tracking inverter for converting an input voltage to a time-varying output voltage comprising:

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

a predetermined output voltage that varies with time;

a controller, connected to the voltage converter circuit, configured to apply a control signal to the voltage converter circuit;

the control signal having a duty ratio based on the predetermined output voltage, the time-varying output voltage, the input voltage, a gain factor and the inductor current;

whereby the voltage converter circuit generates the time-varying output voltage to match the predetermined output voltage;

wherein the voltage converter circuit comprises a boost converter circuit;

wherein;

the boost converter circuit further comprises the inductor switchably connected in series with a load resistance and the input voltage;

a capacitor is connected in parallel with the load resistance;

the duty ratio is given by

14. A tracking inverter for converting an input voltage to a time-varying output voltage comprising:

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

a predetermined output voltage that varies with time;

a controller, connected to the voltage converter circuit, configured to apply a control signal to the voltage converter circuit;

the control signal having a duty ratio based on the predetermined output voltage, the time-varying output voltage, the input voltage, a gain factor and the inductor current;

whereby the voltage converter circuit generates the time-varying output voltage to match the predetermined output voltage;

wherein the voltage converter circuit comprises a buck-boost converter circuit;

wherein;

the buck-boost converter circuit further comprises the inductor switchably connected in series with a load resistance;

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

a capacitor is connected in parallel with the load resistance;

the duty ratio is given by

15. A method of converting an input voltage into a time-varying output voltage comprising:

providing a voltage converter circuit;

powering the voltage converter circuit with the input voltage;

producing an inductor current through an inductor in the voltage converter circuit;

defining a predetermined output voltage that varies with time;

applying a control signal to the voltage converter circuit;

determining a duty ratio of the control signal based on the predetermined output voltage, the time-varying output voltage, the input voltage, a gain factor and the inductor current;

generating the time-varying output voltage to match the predetermined output voltage;

measuring a set of circuit parameters for the voltage converter circuit; and

,

determining the duty ratio according to the formula

16. The method of claim 15 further comprising the step of determining the duty ratio of the control signal based on leading edge modulation.

17. The method of claim 15 further comprising the step of determining the duty ratio of the control signal based on input-output feedback linearization of a set of state variables with stable zero dynamics.

18. The method of claim 15 further comprising the step of determining the gain factor from at least one of the group consisting of a proportional gain, an integral gain and a derivative gain.

19. The method of claim 15 further comprising the step of defining the predetermined output voltage to be a sinusoidal function of time.

20. The method of claim 15 further comprising the steps of:

powering the voltage converter circuit with the input voltage that varies in time with a first waveform;

producing the time-varying output voltage that varies in time with a second waveform different than the first waveform.

21. The method of claim 15 further comprising the steps of:

powering the voltage converter circuit with the input voltage that varies sinusoidally with time at a first frequency; and

,

producing the time-varying output voltage that varies sinusoidally with time at a second frequency different than the first frequency.

22. The method of claim 15 further comprising the steps of:

powering the voltage converter circuit with the input voltage that has a first frequency spectrum; and

,

producing the time-varying output voltage that has a second frequency spectrum different than the first frequency spectrum.

23. The method of claim 15 further comprising the step of providing a buck converter circuit for the voltage converter circuit.

24. The method of claim 15 further comprising the step of providing a boost converter circuit for the voltage converter circuit.

25. The method of claim 15 further comprising the step of providing a buck-boost converter circuit for the voltage converter circuit.

26. The method of claim 15 further comprising:

measuring a set of circuit parameters for the voltage converter circuit;

determining the gain factor based on the set of circuit parameters;

applying the control signal with the duty ratio to the voltage converter circuit;

adjusting the duty ratio of the control signal based on the set of circuit parameters, the predetermined output voltage, the time-varying output voltage, the input voltage, the gain factor and the inductor current; and

,

stopping the method if a directive to stop the controller is received.

27. The method of claim 15 further comprising the steps of:

providing a multiple output voltage converter circuit;

defining a plurality of predetermined output voltages;

defining a plurality of control signals with a plurality of duty ratios and a plurality of gain factors;

applying the plurality of control signals to the multiple output voltage converter circuit;

generating a plurality of time-varying output voltages from the input voltage to match the plurality of predetermined output voltages.

28. A method of converting an input voltage into a time-varying output voltage comprising:

providing a voltage converter circuit;

powering the voltage converter circuit with the input voltage;

producing an inductor current through an inductor in the voltage converter circuit;

defining a predetermined output voltage that varies with time;

applying a control signal to the voltage converter circuit;

determining a duty ratio of the control signal based on the predetermined output voltage, the time-varying output voltage, the input voltage, a gain factor and the inductor current;

generating the time-varying output voltage to match the predetermined output voltage;

providing a buck converter circuit for the voltage converter circuit wherein the buck converter circuit comprises the inductor connected in series with a load resistance, the input voltage and a switch, and, a capacitor connected in parallel with the load resistance;

determining the duty ratio according to the formula

29. A method of converting an input voltage into a time-varying output voltage comprising:

providing a voltage converter circuit;

powering the voltage converter circuit with the input voltage;

producing an inductor current through an inductor in the voltage converter circuit;

defining a predetermined output voltage that varies with time;

applying a control signal to the voltage converter circuit;

determining a duty ratio of the control signal based on the predetermined output voltage, the time-varying output voltage, the input voltage, a gain factor and the inductor current;

generating the time-varying output voltage to match the predetermined output voltage;

providing a boost converter circuit for the voltage converter circuit, wherein the boost converter circuit comprises the inductor switchably connected in series with a load resistance and the input voltage, and, a capacitor connected in parallel with the load resistance;

defining the duty ratio according to the formula

30. A method of converting an input voltage into a time-varying output voltage comprising:

providing a voltage converter circuit;

powering the voltage converter circuit with the input voltage;

producing an inductor current through an inductor in the voltage converter circuit;

defining a predetermined output voltage that varies with time;

applying a control signal to the voltage converter circuit;

determining a duty ratio of the control signal based on the predetermined output voltage, the time-varying output voltage, the input voltage, a gain factor and the inductor current;

generating the time-varying output voltage to match the predetermined output voltage;

providing a buck-boost converter circuit for the voltage converter circuit, wherein the buck-boost converter comprises the inductor switchably connected in series with a load resistance, the input voltage switchably connected in parallel with the inductor, and, a capacitor connected in parallel with the load resistance;

defining the duty ratio according to the formula