A method for regulating a temperature of a magnetron includes: determining an anode current flowing through the magnetron and an output power of a variable-frequency power supply, the output power being configured to drive the magnetron to operate; calculating an anode voltage of the magnetron according to the anode current of the magnetron and the output power of the variable-frequency power supply; calculating an anode temperature of the magnetron according to the anode voltage of the magnetron; and regulating the output power of the variable-frequency power supply according to the anode temperature of the magnetron.

A device includes an antenna configured to be disposed within a cavity of an appliance. The appliance includes an electrode and the antenna includes a sheet of conductive material having a surface area that is equal to or greater than a surface area of the electrode. The device includes a voltage sensor coupled to the antenna, an output device, and a controller coupled to the voltage sensor and the output device. The controller is configured to generate an output at the output device. The output is determined by a voltage of the antenna.

An electromagnetic cooking device and method of controlling the same is provided herein. The cooking device includes a cavity in which a liquid is placed and a plurality of RF feeds configured to introduce electromagnetic radiation into the cavity for heating the liquid. A controller is provided and is configured to analyze forward and backward power at the plurality of RF feeds to calculate efficiency; determine and monitor a coefficient of variation of the efficiency; detect a heating state in the liquid based on changes in the coefficient of variation; and adjust a power level of the electromagnetic radiation in response to detection of the heating state.

A microwave oven having a cabinet, a door, a programming interface, a magnetron tube that capable of being dynamically controlled, a controller configured to control the magnetron tube, and a microwave generating system is described. A method of dynamically controlling the magnetron tube in the microwave oven by utilizing a magnetron power supply is also described. By monitoring a current to the magnetron power supply, determining the current to the magnetron power supply at which the magnetron tube conducts, calculating a time base, and adjusting the time base as the power level required is increased, the control produces consistent power when the magnetron tube is cycled at less than a 100% power level and to compensate for a slow start of the magnetron tube during a short cook cycle.

An electronic transformer and a microwave cooking appliance. The electronic transformer comprises a rectifier device, a transformer, a switch device, and a control device. The rectifier device is connected to an alternating current source; the transformer is connected to the rectifier device; the switch device is configured to provide an on/off signal to the transformer; the control device is connected to the switch device; the control device is configured to generate a control signal according to preset power and provide the control signal to the switch device to control the switching frequency of the switch device.

An adapting circuit is connected onto the high voltage end output of a magnetron driving power supply. In the adapting circuit, the high frequency part of current in the magnetron anode loop is converted into a part of the filament driving current. The high frequency part is removed by the two primary coils of a ferret core transformer and converted into a larger current on the secondary coil, which is rectified and filtered to increase the driving current in the magnetron filament loop. Two or more power supplies connected with the adapting circuits are connected together in parallel to drive a high power and high filament driving current magnetron with a correct compensation for its filament current.

A device includes an antenna configured to be disposed within a cavity of an appliance. The appliance includes an electrode and the antenna includes a sheet of conductive material having a surface area that is equal to or greater than a surface area of the electrode. The device includes a voltage sensor coupled to the antenna, an output device, and a controller coupled to the voltage sensor and the output device. The controller is configured to generate an output at the output device. The output is determined by a voltage of the antenna.

An electromagnetic cooking device and method of controlling the same is provided herein. The cooking device includes a cavity in which a liquid is placed and a plurality of RF feeds configured to introduce electromagnetic radiation into the cavity for heating the liquid. A controller is provided and is configured to analyze forward and backward power at the plurality of RF feeds to calculate efficiency; determine and monitor a coefficient of variation of the efficiency; detect a heating state in the liquid based on changes in the coefficient of variation; and adjust a power level of the electromagnetic radiation in response to detection of the heating state.

The present invention relates to a modulator system adapted to generate high voltage pulses suitable for supply across a high voltage load having a thermionic cathode, such as a magnetron. The modulator system comprises a high voltage DC PSU connected to a switching mechanism adapted to generate high voltage pulses from the high voltage DC PSU for application to a thermionic cathode of a high voltage load. The modulator system further comprises an isolation transformer; a heater PSU adapted to be connected to a cathode heater through the isolation transformer and to provide an AC current thereto. The modulator system further comprises a controller to receive pulse instruction signals and trigger generation of corresponding high voltage pulses by the switching mechanism, to calculate the estimated arrival time of a next pulse instruction signal, based on the time between previous pulse instruction signals, and disable the heater PSU for a preset time, commencing before the estimated arrival time of the next pulse instruction signal, such that no current is supplied from the heater PSU while current is supplied from the high voltage PSU.

A method for regulating a temperature of a magnetron includes: determining an anode current flowing through the magnetron and an output power of a variable-frequency power supply, the output power being configured to drive the magnetron to operate; calculating an anode voltage of the magnetron according to the anode current of the magnetron and the output power of the variable-frequency power supply; calculating an anode temperature of the magnetron according to the anode voltage of the magnetron; and regulating the output power of the variable-frequency power supply according to the anode temperature of the magnetron.