An apparatus for heating a load with microwave energy is provided. The microwave energy is applied by the apparatus at frequencies wherein the load's dielectric constant is within a predetermined range. The apparatus may include a microwave power source configured to supply microwave energy at the applied frequencies; and a radiating plate. The radiating plate may include an electrically conductive structure that includes a plurality of radiating elements; and a feeding port, connecting the electrically conductive structure to the microwave power source. The radiating plate is configured so that most of the power fed from the microwave source through the feeding port returns towards the power source when no load is contacting the radiating plate, and most of the power fed from the microwave source through the feeding port is absorbed by the load to be heated by the apparatus when the load is contacting the radiating plate, even in absence of a microwave cavity that encloses the radiating plate and the load.

A method and device for regulating a temperature of a magnetron, a controller, a variable-frequency power supply, a system for regulating a temperature of a magnetron, and a microwave apparatus are provided. Wherein, the method for regulating the temperature of the magnetron includes: determining an anode current flowing through the magnetron or an input power of a variable-frequency power supply or an anode voltage applied to two ends of the magnetron, the input power or an output power of the variable-frequency power supply being configured to drive the magnetron to operate; regulating the output power of the variable-frequency power supply according to the anode current or the input power or the anode voltage.

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 microwave treatment apparatus includes a treatment chamber, a microwave supply, and a resonator unit. The treatment chamber is surrounded by a plurality of walls, and accommodates a heating target. The microwave supply supplies a microwave to the treatment chamber. The resonator unit is provided on one wall of the plurality of walls, and the resonator unit has a resonance frequency in a frequency band of the microwave. In this embodiment, the impedance of the surface of the resonator unit can be changed by controlling the frequency of the microwave supplied to the treatment chamber. This makes it possible to control the standing wave distribution within the treatment chamber, that is, the microwave energy distribution within the treatment chamber. As a result, in the cases where a plurality of heating targets need to be heated simultaneously, desired dielectric heating is conducted for each of the heating targets.

A microwave oven including a frozen food defrost mode and a food drying function according to the present invention includes: a body formed with a space therein; a humidity sensor measuring a humidity value of the space; a magnetron emitting microwaves towards the space; a power transformer supplying power for operating a heater of the magnetron; a high voltage transformer providing power for operating a resonator of the magnetron; a power supply unit supplying power to the power transformer and the high voltage transformer; an output adjusting unit for selecting and adjusting so that the magnetron outputs any one of a plurality of set output levels; and a control unit controlling an output of the microwave according to the output level selected in the output adjusting unit, blocking the power supplied to the magnetron when the humidity value input from the humidity sensor remarkably increases in short time.

An apparatus and a method for heating a load using microwaves is disclosed. The apparatus includes a transmission line, configured to transmit microwaves from a microwave generator to a cavity. A sensing device configured to measure a standing wave for providing information about the phase and the amplitude of a reflection coefficient that represents a ratio between the amount of microwaves reflected back towards the microwave generator and the amount of microwaves transmitted in the transmission line from the microwave generator. A control unit configured to detect whether the measured standing wave correspond to a reflection coefficient having a phase within a certain interval of phases and an amplitude within a certain interval of amplitudes. Additionally, certain intervals of phases and amplitudes correspond to an operating region of the microwave generator. The control unit controls feeding of microwaves to the cavity based on this detection.

An apparatus and a method for heating a load using microwaves is disclosed. The apparatus includes a transmission line, configured to transmit microwaves from a microwave generator to a cavity. A sensing device configured to measure electromagnetic field strengths for providing information about the phase and the amplitude of a reflection coefficient that represents a ratio between the amount of microwaves reflected back towards the microwave generator and the amount of microwaves transmitted in the transmission line from the microwave generator. A control unit configured to detect whether the measured electromagnetic field strengths correspond to a reflection coefficient having a phase within a certain interval of phases and an amplitude within a certain interval of amplitudes. Additionally, certain intervals of phases and amplitudes correspond to an operating region of the microwave generator. The control unit controls feeding of microwaves to the cavity based on this detection.

In certain examples, a food processing machine for processing a food product includes a housing defining a cavity, a conveyor with a belt comprising metal for conveying the food product through the cavity in a longitudinal direction, and a convection heating system for heating air in the cavity such that heated air heats the food product as the food product is conveyed through the cavity. A microwave launch box system is configured to emit microwave energy into the cavity in a lateral direction transverse to the longitudinal direction to thereby further heat the food product as the food product is conveyed through the cavity.

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.

An apparatus for heating a load with microwave energy is provided. The microwave energy is applied by the apparatus at frequencies wherein the load's dielectric constant is within a predetermined range. The apparatus may include a microwave power source configured to supply microwave energy at the applied frequencies; and a radiating plate. The radiating plate may include an electrically conductive structure that includes a plurality of radiating elements; and a feeding port, connecting the electrically conductive structure to the microwave power source. The radiating plate is configured so that most of the power fed from the microwave source through the feeding port returns towards the power source when no load is contacting the radiating plate, and most of the power fed from the microwave source through the feeding port is absorbed by the load to be heated by the apparatus when the load is contacting the radiating plate, even in absence of a microwave cavity that encloses the radiating plate and the load.