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.

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.

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 household or commercial appliance includes a couple magnetrons having relative anodes and cathodes, and a power unit comprising a high voltage circuit. The high voltage circuit comprises: a high voltage transformer comprising a primary winding connected to an alternating voltage source and a secondary high-voltage winding providing an alternating high voltage having a period comprising two half periods, a couple of half-wave voltage doubler circuits, and first and second unidirectional conducting devices. The first and second unidirectional conducting devices being configured to cause the half-wave voltage doubler circuits to supply, during a period of the alternating high-voltage the doubled high-voltage to the cathode of the respective magnetron alternately.

An electronic transformer and a microwave cooking appliance. The electronic transformer includes 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.

A high frequency high power converter system comprises: a plurality of resonant tank circuits arranged in parallel, a plurality of transformers, each transformer having a single primary winding and a plurality of secondary windings, and a vacuum electronic device, the output of each resonant tank circuit being applied to a respective different transformer and the outputs of the transformers being arranged to drive the vacuum electronic device.

A power converter and a cooking apparatus including the same are disclosed. The power converter includes a switching unit to perform switching using a direct current (DC) voltage and to output an alternating current (AC) voltage, a driving unit to output a high-frequency voltage to a magnetron based on the AC voltage, an output voltage detector to detect an output voltage flowing to the magnetron, and a controller to calculate a frequency command value based on the detected output voltage, to generate a frequency command value by avoiding a resonance frequency when the calculated frequency command value corresponds to the resonance frequency, and to output the generated frequency command value to the switching unit. Therefore, it is possible to stably perform oscillation.

The present disclosure provides a microwave oven circuit, a control method and a control device of the microwave oven circuit, and a microwave oven. The microwave oven circuit includes a magnetron and an inverter circuit for driving the magnetron to work. The control method includes when the inverter circuit needs to be started, detecting a zero crossing point of an electric supply signal for supplying power to the microwave oven circuit, when the electric supply signal is detected to reach the zero crossing point, controlling the inverter circuit to be powered on; when the power-on time length of the inverter circuit reaches a first predetermined time length.

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.