Power converter for a thermal system

A control system for controlling a heater, the heater comprising a plurality of resistive heating elements, the control system comprising:

• a plurality of power converters, each of the plurality of power converters being a step-down voltage converter operable to generate an output voltage that is adjustable to one or more resistive heating elements from among the plurality of resistive heating elements;
• a plurality of sensor circuits, wherein a given sensor circuit from among the plurality of sensor circuits is electrically coupled between a given power converter from among the plurality of power converters and the one or more resistive heating elements from among the plurality of resistive heating elements and the given sensor circuit is configured to measure at least one of a voltage or an electric current of the one or more resistive heating elements from among the plurality of resistive heating elements;
• and
• a controller connected to the plurality of power converters and the plurality of sensor circuits, wherein, for the given power converter, the controller is configured to:
• determine an input parameter based on the at least one of the voltage or the electric current from the given sensor circuit, wherein the input parameter is indicative of a temperature of the one or more resistive heating elements;
• determine an operational state of the heater based on the input parameter, wherein the heater is configured to operate in a plurality of operational states comprising a start-up mode, a soft-start mode in which the output voltage is gradually increased, a rate mode in which the output voltage is increased at a rate higher than that of the soft-start mode, and a hold mode,
• set the output voltage for the one or more resistive heating elements based on the input parameter and a desired setpoint, wherein the desired setpoint is based on the operational state of the heater, and
• operate a power switch of the given power converter to generate the output voltage.

A method for controlling a heater, the heater comprising a resistive heating element operable to emit heat and operable as a sensor, the method comprising:

• measuring at least one of a voltage or an electric current of the resistive heating element;
• determining an input parameter based on the at least one of the voltage or the electric current, wherein the input parameter is indicative of a temperature of the resistive heating element;
• determining an operational state of the heater based on the input parameter, wherein the heater is configured to operate in a plurality of operational states comprising a start-up mode, a soft-start mode in which the output voltage is gradually increased, a rate mode in which the output voltage is increased at a rate higher than that of the soft-start mode, and a hold mode;
• setting an output voltage for the resistive heating element based on the input parameter and a desired setpoint, wherein the desired setpoint is based on the operational state of the heater;
• generating, using a power converter having a power switch, the output voltage by operating the power switch, wherein the power converter is a step-down voltage converter and the output voltage is adjustable;
• determining a resistance of the resistive heating element, as the input parameter, based on the at least one of the voltage or the electric current;
• and
• adjusting the output voltage based on the resistance such that the output voltage is proportional to a change in the resistance.