Control system for an electric heater
First Claim
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1. A control system for an electric heater, comprising:
- a current sensor positioned to sense a heating current through a heating element of an electric heater;
a voltage sensor positioned across the heating element to sense a heating voltage;
a switching element including a control terminal, wherein the switching element is coupled between the heating element and a power supply to interrupt the heating current through the heating element responsive to a control signal on the control terminal; and
a control circuit coupled to the current sensor, the voltage sensor and the control terminal of the switching element, wherein the control circuit varies the control signal to maintain a temperature of the heating element within a predetermined temperature range.
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Abstract
A control system for an electric heater, e.g., an electric catalyst heater (ECH), includes a current sensor, a voltage sensor, a switching element, and a control circuit. The control circuit is coupled to the current sensor, the voltage sensor and a control terminal of the switching element and varies a control signal on the control terminal to maintain the temperature of the heating element within a predetermined temperature range.
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Citations
20 Claims
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1. A control system for an electric heater, comprising:
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a current sensor positioned to sense a heating current through a heating element of an electric heater;
a voltage sensor positioned across the heating element to sense a heating voltage;
a switching element including a control terminal, wherein the switching element is coupled between the heating element and a power supply to interrupt the heating current through the heating element responsive to a control signal on the control terminal; and
a control circuit coupled to the current sensor, the voltage sensor and the control terminal of the switching element, wherein the control circuit varies the control signal to maintain a temperature of the heating element within a predetermined temperature range. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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9. An auxiliary power unit (APU), comprising:
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a fuel reformer, including;
an electric heater; and
a control system for monitoring a temperature of the electric heater, the control system including;
a current sensor positioned to sense a heating current through a heating element of the electric heater;
a voltage sensor positioned across the heating element to sense a heating voltage;
a switching element including a control terminal, wherein the switching element is coupled between the heating element and a power supply to interrupt the heating current through the heating element responsive to a control signal on the control terminal; and
a control circuit coupled to the current sensor, the voltage sensor and the control terminal of the switching element, wherein the control circuit varies the control signal to maintain the temperature of the heating element within a predetermined temperature range; and
a solid oxide fuel cell receiving reformate from the fuel reformer. - View Dependent Claims (10, 11, 12, 13, 14, 15, 16)
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17. An automotive control system for an electric catalyst heater (ECH), comprising:
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a current sensor positioned to sense a heating current through a heating element of an ECH;
a voltage sensor positioned across the heating element to sense a heating voltage;
a switching element including a control terminal, wherein the switching element is coupled between the heating element and a power supply to interrupt the heating current through the heating element responsive to a control signal on the control terminal; and
a control circuit coupled to the current sensor, the voltage sensor and the control terminal of the switching element, wherein the control circuit varies the control signal to maintain a temperature of the heating element within a predetermined temperature range. - View Dependent Claims (18, 19, 20)
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Specification