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.

The present invention discloses a method of controlling transmitting frequencies of microwave source, which includes the following steps of: a) collecting reflection frequencies of a load according to a pre-set sampling rate; b) calculating a change rate of the reflection frequencies collected in the step a; c) setting a reflection frequency threshold and a change rate threshold; d) comparing the reflection frequencies and the change rate with the reflection frequency threshold and the change rate threshold respectively; wherein if the reflection frequencies or the change rate is less than the threshold goes to step e or returns to the step a; e) sending control signals to the microwave source and tuning the transmitting frequencies; and f) returning to step a. The present invention also discloses a microwave transmission system thereof. The present invention can be applied in controlling microwave source consists of single magnetron tube or multiple magnetron tubes.

A modular microwave power supply comprises a plurality of microwave power supply modules and a plurality of isolating diodes. To upgrade the output power of the modular microwave power supply, the plurality of microwave power supply modules are connected isolatively in common to a magnetron load by the plurality of isolating diodes, such that power combining of the plurality of microwave power supply modules is achieved, and the efficiency as well as the accumulated-heat dissipating ability of the modular microwave power supply are as good as each of the plurality of microwave power supply modules.

A magnetron filter board for a microwave oven is disclosed. In embodiments, the magnetron filter board includes a printed circuit board with a first trace and a second trace on the printed circuit board. The first trace includes a first end for connecting to a magnetron and a second end for connecting to a power supply unit. The second trace also includes a first end for connecting to the magnetron and a second end for connecting to the power supply unit. The first trace and the second trace can be configured as a radio frequency band-gap filter that mitigates noise associated with the connection between the magnetron and the power supply unit.

A system for adaptive preheating of a magnetron within a microwave oven is disclosed. In embodiments, the system includes temperature sensors for sensing a magnetron temperature. The system includes a power supply controller in communication with the microwave's power supply and the temperature sensors and including control processors. The power supply controller receives a requested power setting associated with a cooking cycle, e.g., selected by a user via a human-machine interface of the microwave oven. Before the cooking cycle commences, the power supply controller calculates a preheat time based on the sensed magnetron temperature. After starting a timer corresponding to the determined preheat time, the power supply controller preheats the filament by applying sufficient current to render the filament incandescent and so the resonant cavities may be stimulated. By preheating the filament, the system reduces operational fatigue on the filament due to cold starts.

In a heating cooking device, a machine chamber is provided adjacent to a heating chamber for housing a food product. An air supply port is provided in a partition wall that separates the heating chamber and the machine chamber. An air supply fan is provided in the machine chamber, for supplying air to the heating chamber through the air supply port. An air supply damper is provided in the machine chamber, for opening and closing the air supply port. A control unit drives the air supply fan and brings the air supply damper into an open state during high-frequency heating of the food product. The control unit brings the air supply damper into a closed state simultaneously with completion of high-frequency heating of the food product or immediately before or immediately after the completion.

A radio frequency heating system having a radio frequency amplifier supplying power to a radio frequency heating chamber and a matching network includes a controller monitoring forward and reflected power, phase and amplitude of the power supply to the heating chamber and adjusting the power supplied by the radio frequency amplifier and/or the impedance of the matching network in accordance with predetermined values of the reflected power, and/or phase and amplitude.

A driving circuit for a magnetron, and a heating device, the driving circuit includes a rectification circuit, configured to convert an alternating current into a direct current so as to supply power to the magnetron. The driving circuit includes a transformer, a primary coil of the transformer being configured to be connected to an alternating current power supply terminal or an inverter circuit, a second secondary coil of the transformer being connected to the rectification circuit, and the transformer being configured to provide an alternating current for the rectification circuit; and a component having a variable resistance value, the component is in a circuit path formed by the first secondary coil, the anode of the magnetron, and the cathode of the magnetron and configured to limit a current flowing through the magnetron. A resistance value of the component is positively correlated with the temperature of the component.

In a method for operating a household microwave appliance, a microwave treatment operation is controlled as a function of a temperature of a microwave generator. The household microwave appliance includes a cooking chamber, a microwave generator for routing microwaves to the cooking chamber, a temperature-determining apparatus for determining a temperature of the microwave generator, a microwave distribution device designed to change a field distribution in the cooking chamber during a microwave treatment operation, and a control device designed to control the microwave treatment operation as a function of the temperature of the microwave generator effected by a change in the field distribution.

An object is to prevent a no-load operation. In a heating cooking apparatus (1) of the present invention, after a determination unit (22a) determines that no food product is present in a heating chamber (13), a reading control unit (22c) causes the reading device (16) to stop a reading operation for a predetermined time, or cancels, for a predetermined time, an information code read by the reading device (16).