Linear, inductance based control of regulated electrical properties in a switch mode power supply of a thermal processing system

1. A method for providing linear control of a regulated electrical property in a switch mode power supply of a thermal processing system including an inductive element and at least one switching element, the method comprising a computing device performing the steps of:

generating a first nonlinear model for predicting values for a regulated electrical property of the inductive element in the switch mode power supply of the thermal processing system based on a given duty cycle of the at least one switching element; and

generating a second nonlinear model for determining a duty cycle for the at least one switching element based on the first nonlinear model for the regulated electrical property, the second nonlinear model determining the duty cycle such that a linear relationship results between the regulated electrical property and a selected value regardless of variations in electrical inputs and outputs of the switch mode power supply.

2. The method of claim 1 further comprising:

determining the duty cycle to achieve the selected value for the regulated electrical property from the second nonlinear model for determining the duty cycle.

3. The method of claim 1 wherein the regulated electrical property of the inductive element is current or voltage.

4. The method of claim 1 wherein the switch mode power supply includes a boost converter, a buck converter, a buck-boost converter, a boost-buck converter, a Cuk converter, a Zeta converter, or a SEPIC converter.

5. A method for providing linear control of a regulated electrical property in a switch mode power supply of a thermal processing system including an inductive element and at least one switching element, the method comprising a computing device performing the steps of:

generating a first nonlinear model for predicting values for a regulated electrical property of the inductive element in the switch mode power supply of the thermal processing system based on a given duty cycle of the at least one switching element; and

generating a second nonlinear model for determining a duty cycle for the at least one switching element based on the first nonlinear model for the regulated electrical property, the second nonlinear model determining the duty cycle such that a linear relationship results between the regulated electrical property and a selected value;

wherein generating the first nonlinear model comprises:

generating a third nonlinear, predictive model for predicting discrete values of inductive current in a circuit mode based on present values of duty cycle, applied voltage and inductive current; and

generating a fourth nonlinear, predictive model for predicting average values of inductive current in the circuit mode based on the present and predicted values for inductive current;

wherein generating the second nonlinear model comprises:

generating a fifth nonlinear, predictive model for determining a duty cycle from the third nonlinear predictive model and the fourth nonlinear predictive model, the fifth nonlinear predictive model determining the duty cycle such that a linear relationship results between an average value for inductive current and a selected value in the circuit mode.

6. The method of claim 5 wherein the circuit mode is Continuous Current Mode (CCM) or Discontinuous Current Mode (DCM).

7. A method for providing linear control of a regulated electrical property in a switch mode power supply of a thermal processing system including an inductive element and at least one switching element, the method comprising a computing device performing the steps of:

generating a first nonlinear model for predicting values for a regulated electrical property of the inductive element in the switch mode power supply of the thermal processing system based on a given duty cycle of the at least one switching element;

generating a second nonlinear model for determining a duty cycle for the at least one switching element based on the first nonlinear model for the regulated electrical property, the second nonlinear model determining the duty cycle such that a linear relationship results between the regulated electrical property and a selected value;

wherein generating the first nonlinear model comprises:

generating, based on present values of duty cycle, applied voltage and inductive current, a plurality of third nonlinear models for predicting discrete values of inductive current in each circuit mode or transition between circuit modes; and

generating, based on the present and predicted values for inductive current, a plurality of fourth nonlinear models for predicting average values of inductive current in each circuit mode or transition between circuit modes;

wherein generating the second nonlinear model comprises:

generating, based on the plurality of third nonlinear models and the plurality of fourth nonlinear models, a plurality of fifth nonlinear, predictive models for determining a duty cycle such that a linear relationship results between an average value for inductive current and a selected value in each circuit mode or transition between circuit modes.

8. The method of claim 7 further comprising:

determining a circuit mode or transition being entered during a subsequent switching period;

selecting one of the plurality of fifth nonlinear predictive models for determining the duty cycle that corresponds to the determined circuit mode or transition; and

determining the duty cycle for the selected value from the selected model.

9. The method of claim 7 wherein the circuit mode includes Continuous Current Mode (CCM) or Discontinuous Current Mode (DCM).

10. The method of claim 7 wherein the transition between circuit modes includes CCM to DCM or DCM to CCM.

11. An apparatus for providing linear control of a regulated electrical property in a switch mode power supply of a thermal processing system including an inductive element and at least one switching element, the apparatus comprising:

means for generating a first nonlinear model for predicting values for a regulated electrical property of the inductive element in the switch mode power supply of the thermal processing system based on a given duty cycle of the at least one switching element; and

means for generating a second nonlinear model for determining a duty cycle for the at least one switching element based on the first nonlinear model for the regulated electrical property, the second nonlinear model determining the duty cycle such that a linear relationship results between the regulated electrical property and a selected value;

wherein the means for generating the first nonlinear model comprises:

means for generating a third nonlinear, predictive model for predicting discrete values of inductive current in a circuit mode based on present values of duty cycle, applied voltage and inductive current; and

means for generating a fourth nonlinear, predictive model for predicting average values of inductive current in the circuit mode based on the present and predicted values for inductive current;

wherein the means for generating the second nonlinear model comprises:

means for generating a fifth nonlinear, predictive model for determining a duty cycle from the third nonlinear predictive model and the fourth nonlinear predictive model, the fifth nonlinear predictive model determining the duty cycle such that a linear relationship results between an average value for inductive current and a selected value in the circuit mode.

12. An apparatus for providing linear control of a regulated electrical property in a switch mode power supply of a thermal processing system including an inductive element and at least one switching element, the apparatus comprising:

means for generating a first nonlinear model for predicting values for a regulated electrical property of the inductive element in the switch mode power supply of the thermal processing system based on a given duty cycle of the at least one switching element;

means for generating a second nonlinear model for determining a duty cycle for the at least one switching element based on the first nonlinear model for the regulated electrical property, the second nonlinear model determining the duty cycle such that a linear relationship results between the regulated electrical property and a selected value;

wherein the means for generating the first nonlinear model comprises:

means for generating, based on present values of duty cycle, applied voltage and inductive current, a plurality of third nonlinear models for predicting discrete values of inductive current in each circuit mode or transition between circuit modes; and

means for generating, based on the present and predicted values for inductive current, a plurality of fourth nonlinear models for predicting average values of inductive current in each circuit mode or transition between circuit modes;

wherein the means for generating the second nonlinear model comprises:

means for generating, based on the plurality of third nonlinear models and the plurality of fourth nonlinear models, a plurality of fifth nonlinear, predictive models for determining a duty cycle such that a linear relationship results between an average value for inductive current and a selected value in each circuit mode or transition between circuit modes.

13. The apparatus of claim 12 further comprising:

means for determining a circuit mode or transition being entered during a subsequent switching period;

means for selecting one of the plurality of fifth nonlinear models for determining the duty cycle that corresponds to the determined circuit mode or transition; and

means for determining the duty cycle for the selected value from the selected model.

14. The apparatus of claim 12 wherein the circuit mode includes Continuous Current Mode (CCM) or Discontinuous Current Mode (DCM).

15. The apparatus of claim 12 wherein the transition between circuit modes includes CCM to DCM or DCM to CCM.

16. An apparatus for providing linear control of a regulated electrical property in a switch mode power supply of a thermal processing system including an inductive element and at least one switching element, the apparatus comprising:

means for generating a first nonlinear model for predicting values for a regulated electrical property of the inductive element in the switch mode power supply of the thermal processing system based on a given duty cycle of the at least one switching element; and

means for generating a second nonlinear model for determining a duty cycle for the at least one switching element based on the first nonlinear model for the regulated electrical property, the second nonlinear model determining the duty cycle such that a linear relationship results between the regulated electrical property and a selected value regardless of variations in electrical inputs and outputs of the switch mode power supply.

17. The apparatus of claim 16 further comprising means for determining the duty cycle to achieve the selected value for the regulated electrical property from the second nonlinear model for determining the duty cycle.

18. The apparatus of claim 16 wherein the regulated electrical property of the inductive element is current or voltage.

19. The apparatus of claim 16 wherein the switch mode power supply includes a boost converter, a buck converter, a buck-boost converter, a boost-buck converter, a Cuk converter, a Zeta converter, or a SEPIC converter.

20. An apparatus for providing linear control of a regulated electrical property in a switch mode power supply of a thermal processing system including an inductive element and at least one switching element, the apparatus comprising a processor programmed with instructions to:

generate a first nonlinear model for predicting values for a regulated electrical property of the inductive element in the switch mode power supply of the thermal processing system based on a given duty cycle of the at least one switching element; and

generate a second nonlinear model for determining a duty cycle for the at least one switching element based on the first nonlinear model for the regulated electrical property, the second nonlinear model determining the duty cycle such that a linear relationship results between the regulated electrical property and a selected value regardless of variations in electrical inputs and outputs of the switch mode power supply.

21. An apparatus for providing linear control of a regulated electrical property in a switch mode power supply of a thermal processing system including an inductive element and at least one switching element, the apparatus comprising a processor programmed with instructions to:

generate a first nonlinear model for predicting values for a regulated electrical property of the inductive element in the switch mode power supply of the thermal processing system based on a given duty cycle of the at least one switching element; and

generate a second nonlinear model for determining a duty cycle for the at least one switching element based on the first nonlinear model for the regulated electrical property, the second nonlinear model determining the duty cycle such that a linear relationship results between the regulated electrical property and a selected value;

wherein the instructions to generate the first nonlinear model comprise instructions to:

generate a third nonlinear, predictive model for predicting discrete values of inductive current in a circuit mode based on present values of duty cycle, applied voltage and inductive current; and

generate a fourth nonlinear, predictive model for predicting average values of inductive current in the circuit mode based on the present and predicted values for inductive current;

wherein the instructions to generate the second nonlinear model comprise instructions to:

generate a fifth nonlinear, predictive model for determining a duty cycle from the third nonlinear predictive model and the fourth nonlinear predictive model, the fifth nonlinear predictive model determining the duty cycle such that a linear relationship results between an average value for inductive current and a selected value in the circuit mode.

22. An apparatus for providing linear control of a regulated electrical property in a switch mode power supply of a thermal processing system including an inductive element and at least one switching element, the apparatus comprising a processor programmed with instructions to:

generate a first nonlinear model for predicting values for a regulated electrical property of the inductive element in the switch mode power supply of the thermal processing system based on a given duty cycle of the at least one switching element;

generate a second nonlinear model for determining a duty cycle for the at least one switching element based on the first nonlinear model for the regulated electrical property, the second nonlinear model determining the duty cycle such that a linear relationship results between the regulated electrical property and a selected value;

wherein the instructions to generate the first nonlinear model comprise instructions to:

generate, based on present values of duty cycle, applied voltage and inductive current, a plurality of third nonlinear models for predicting discrete values of inductive current in each circuit mode or transition between circuit modes; and

generate, based on the present and predicted values for inductive current, a plurality of fourth nonlinear models for predicting average values of inductive current in each circuit mode or transition between circuit modes;

wherein the instructions to generate the second nonlinear model comprise instructions to:

generate, based on the plurality of third nonlinear models and the plurality of fourth nonlinear models, a plurality of fifth nonlinear, predictive models for determining a duty cycle such that a linear relationship results between an average value for inductive current and a selected value in each circuit mode or transition between circuit modes.