High frequency heating apparatus
First Claim
1. A high frequency heating apparatus which comprises a unidirectional power source for converting input from an A.C. power source to D.C. voltage, an inverter for converting output from said unidirectional power source into high frequency power, a control circuit for said inverter, an induction heating coil for heating through electrical induction by high frequency magnetic flux, a high frequency oscillator which is energized by high voltage for radiating microwave energy, and a heating cavity in which the microwave energy from said high frequency oscillator is confined for effecting the dielectric heating, said inverter including at least one thyristor connected to a series-resonance circuit which has at least a commutation capacitor and a commutation inductor, said commutation capacitor being connected in parallel to a filter capacitor and said induction coil which are connected in series, with a step-up transformer for a high frequency oscillator being further connected in parallel to said commutation capacitor, thereby enabling said inverter to serve as a high voltage power source for applying the high voltage to said high frequency oscillator and also a high frequency power source for energizing said induction heating coil.
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Abstract
A high frequency heating apparatus in which a combination of a microwave oven for heating food through dielectric heating and a cooking device for heating metallic vessel through electrical induction is incorporated to effect efficient cooking and simultaneous formation of brown scorching on the surface of food. In the heating apparatus, power required for the magnetron of the microwave oven and also for the heating coil of the cooking device is supplied through one inverter unit, by which arrangement, an efficient cooking apparatus of compact size is presented.
32 Citations
16 Claims
- 1. A high frequency heating apparatus which comprises a unidirectional power source for converting input from an A.C. power source to D.C. voltage, an inverter for converting output from said unidirectional power source into high frequency power, a control circuit for said inverter, an induction heating coil for heating through electrical induction by high frequency magnetic flux, a high frequency oscillator which is energized by high voltage for radiating microwave energy, and a heating cavity in which the microwave energy from said high frequency oscillator is confined for effecting the dielectric heating, said inverter including at least one thyristor connected to a series-resonance circuit which has at least a commutation capacitor and a commutation inductor, said commutation capacitor being connected in parallel to a filter capacitor and said induction coil which are connected in series, with a step-up transformer for a high frequency oscillator being further connected in parallel to said commutation capacitor, thereby enabling said inverter to serve as a high voltage power source for applying the high voltage to said high frequency oscillator and also a high frequency power source for energizing said induction heating coil.
- 14. A high frequency heating apparatus which comprises a unidirectional power source for converting input from an A.C. power source to D.C. voltage, an inverter for converting output from said unidirectional power source into high frequency power, a control circuit for said inverter, an induction heating coil for heating through electrical induction by high frequency magnetic flux, a high frequency oscillator which is energized by high voltage for radiating microwave energy, and a heating cavity in which the microwave energy from said high frequency oscillator is confined for effecting the dielectric heating, said inverter including at least a set of a thyristor and a diode connected in counter-parallel to each other, with a series-resonance circuit of a commutation capacitor and a commutation inductor being connected in parallel to said set of the counter-parallel-connected thyristor and diode, thereby to form a closed loop by said thyristor, an input capacitor and a choking coil.
Specification