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 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 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.

The invention relates to a method for determining properties of the electrical current provided to an induction heating element (2) of an induction cooking appliance (1), the induction cooking appliance (1) comprising a heating power energy unit (3) including a heating power generator (4) with at least one switching element (5) adapted to provide pulsed electric power to said induction heating element (2), the induction cooking appliance (1) further comprising an oscillating circuit (6) comprising at least one resonance capacitor (6.1, 6.2), said induction heating element (2) being electrically coupled with said heating power generator (4) and said oscillating circuit (6), the induction cooking appliance (1) further comprising a control entity (8), wherein an input of a measurement circuit (9) is coupled with a node of the heating power energy unit (3).

The invention relates to a method for determining properties of the electrical current provided to an induction heating element (2) of an induction cooking appliance (1). The induction cooking appliance (1) has a heating power energy unit (3) including a heating power generator (4) with at least one switching element (5) adapted to provide pulsed electric power to said induction heating element (2). The induction cooking appliance (1) also has an oscillating circuit (6) with at least one resonance capacitor (6.1, 6.2). The induction heating element (2) is electrically coupled with the heating power generator (4) and the oscillating circuit (6). The induction cooking appliance (1) also has a control entity (8), wherein an input of a measurement circuit (9) is coupled with a node of the heating power energy unit (3).

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.

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.

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.

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 microwave heating apparatus and a method of operating a microwave heating apparatus are provided. The microwave heating apparatus comprises a load receiving cavity, at least one microwave source, a plurality of feeding ports connected to the microwave source and the cavity for feeding microwaves to the cavity, a measuring unit and a control unit. The measuring unit measures, for at least one frequency or within a frequency range, the power of microwaves reflected back to the microwave source for at least part of the plurality of feeding ports. The control unit selects at least one of the feeding ports based on the measured powers of the reflected microwaves in order to feed microwaves to the cavity via the at least one selected feeding port during operation of the microwave heating apparatus at the at least one frequency or within the frequency range.