A microwave appliance includes a cabinet defining a cooking chamber, a magnetron, a temperature sensor directed toward the cooking chamber, and a controller. The controller is configured to measure a raw temperature of the cooking chamber, determine a calibrated temperature from the raw temperature and a conversion model, determine a preheat power level for the magnetron, and operate the magnetron at the preheat power level. The controller is further configured to determine a calibrated chamber temperature using a chamber temperature and a preheat conversion model and determine the calibrated chamber temperature has reached a target temperature. The controller is further configured to monitor a calibrated cooking temperature, based on a cooking temperature and a cooking conversion model, and operate the magnetron to a cooking power level to maintain the calibrated cooking temperature at the target temperature. A method of operating a microwave appliance with a temperature sensor is also disclosed.

An electromagnetic cooking device and method of controlling the same is provided herein. The cooking device includes a cavity in which a food load is placed and a plurality of RF feeds configured to introduce electromagnetic radiation into the cavity for heating the food load. A controller is provided and is configured to: (a) measure resonances in the cavity; (b) generate a resonance map resulting from the measured resonances; (c) conditionally repeat steps (a) and (b); (d) detect a melting state of the food load based on variations between the resonance maps; and (e) adjust a power level of the electromagnetic radiation in response to detection of the melting state.

A system and a method for adjusting a power of an inverter of a microwave oven, and a microwave oven are provided. The system (100) includes: a storage module (101), configured to store an index table comprising periodic counting values and identification numbers; a control module (102), configured to look up an identification number corresponding to a power request signal in the index table according to the power request signal, to look up a periodic counting value corresponding to the identification number in the index table, and to output a frequency signal according to the periodic counting value; and a communication module (104), configured to output a power control signal to the inverter (106) of the microwave oven according to the frequency signal. The inverter (106) outputs a power to a magnetron (108) of the microwave oven according to the power control signal.

High frequency heating device is provided with heater disposed adjacent to mount base on which object to be heated is mounted and having a plurality of surface wave transmission lines electrically isolated from each other, and first and second high frequency power generators, each of which generates high frequency power having different frequency. Surface wave transmission lines receive at least one of the high frequency power generated by first high frequency power generator and the high frequency power generated by second high frequency power generator. According to this aspect, interference between the high frequency powers is not occurred and electromagnetic field coupling is not occurred. As a result, in the high frequency heating device provided with the surface wave transmission line using a periodic structure, uneven baking caused by the electromagnetic field coupling can be suppressed, and a heating state of an object to be heated can be easily controlled.

An electromagnetic cooking device and method of controlling the same is provided herein. The cooking device has 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 specified temperature of 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 specified temperature.

A solid state radio frequency generation system is provided for an electromagnetic cooking device having an enclosed cavity. The radio frequency generation system includes: an RF feed for introducing electromagnetic radiation into the cavity to heat a food load; a high-power RF amplifier coupled to the RF feed, the amplifier comprising at least one amplifying stage configured to output a signal that is amplified in power with respect to an input RF signal; a small signal generator for supplying the input RF signal to the amplifier; and a switching power supply unit including a single DC-DC converter that converts AC mains power to low voltage DC for supply to the amplifier, and a controller configured to adapt an input current from the AC mains power to form a predefined periodic waveform with the same frequency as the AC mains power for supply to the small signal generator.

An RF generation system is provided for an electromagnetic cooking device having a cavity. The system includes: a signal generator for generating an input RF signal; an RF feed configured to introduce electromagnetic radiation into the cavity and to receive reflected electromagnetic radiation from the cavity; and a high-power amplifier coupled between the signal generator and the RF feed. The high-power amplifier including an amplifying stage configured to output a signal that is amplified in power, and a circulator for directing the amplified output signal to the RF feed and for redirecting any reflected radiation received from the RF feed to a dummy load. The system further includes a hardware protection component for detecting backward power in the reflected radiation and for reducing power supplied to the amplifying stage if the backward power exceeds a power threshold within a time scale that prevents damage to the circulator.

An electromagnetic cooking device includes a cavity in which a food load is placed, a plurality of RF feeds for introducing electromagnetic radiation into the enclosed cavity, and a controller configured to detect asymmetries and select rotations that compensate for the asymmetries; select a heating target including a plurality of resonant modes that are rotated using the selected rotations in the preceding step; generate a heating strategy based on the heating target to determine a sequence of desired heating patterns; cause the RF feeds to output a radio frequency signal to thereby excite the enclosed cavity with a selected set of phasors for a set of frequencies; and monitor the created heating patterns based on the forward and backward power measurements at the RF feeds to use closed-loop regulation to selectively modify the sequence of resonant modes into the enclosed cavity based on the desired heating patterns as

A method for diagnosing an electromagnetic cooking device includes selecting a frequency from a set of frequencies in a bandwidth of radio frequency electromagnetic waves; setting a subset of a set of radio frequency feeds to output a radio frequency signal of the selected frequency; measuring a forward power level for the subset of the set of radio frequency feeds that is outputting the radio frequency signal; measuring a forward and backward power level for the set of radio frequency feeds; and processing the measurements of the forward and backward power levels to determine an operating condition of the electromagnetic cooking device based on the processing of the measurements of the forward and backward power levels.

An electromagnetic cooking device includes a cavity in which a food load is placed, a plurality of RF feeds for introducing electromagnetic radiation into the enclosed cavity, and a controller configured to select a heating target including a plurality of unrotated resonant modes; detect asymmetries of the food load relative to a center of the enclosed cavity and select rotations for the plurality of unrotated resonant modes that compensate for the detected asymmetries of the food load to generate a plurality of optimized resonant modes; generate a heating strategy having a selected sequence of the optimized resonant modes; cause the RF feeds to excite the enclosed cavity with a selected set of phasors for a set of frequencies corresponding to each resonant mode of the selected sequence of optimized resonant modes; and monitor the created heating patterns using closed-loop regulation to selectively modify the sequence of optimized resonant modes.