US 2003/0164373 A1Published application

Induction heating apparatus

AssigneeMatsushita Electric Industrial Co., Ltd.

InventorsIzuo Hirota, Atsushi Fujita, Takahiro Miyauchi, Takeshi Kitaizumi, Yuji Fujii, Kouji Niiyama, Hideki Omori

Life of this patent

Estimating the term…

Loading patent…

Abstract

An induction heating apparatus can heat aluminum pot etc. with pot vibration noise being suppressed. During a turn-on time of second switching device 57, an energy is accumulated at choke coil 54, and at the same time a resonant current with a shorter period than the turn-on time of second switching device 57 or a driving time of first switching device 55 is generated at heating coil 59, so that during turn-off of second switching device 57, i.e., during on-time of first switching device 55, the energy accumulated at choke coil 54 is transferred to second smoothing capacitor 62. And then the output power is supplied from smoothing capacitor 62 to heating coil 59, thereby reducing the pot vibration noise, which is caused by pulsating current of input voltage.

Claims14

Dependent claims

An induction heating apparatus comprising:

an inverter having a switching device, a reverse conducting device connected to the switching device in parallel, a heating coil for heating a load by generating a magnetic field and a resonant capacitor unit, wherein the inverter generates a resonant current passing through the heating coil by turning on the switching device;
a control circuit for controlling a turn-on time of the switching device, and
a boosting and smoothing circuit for boosting and smoothing an input DC voltage to provide the boosted and smoothed DC voltage to the inverter,
wherein, in case the load is a material of a high conductivity and a low permeability, the resonant current passing through the switching device or the reverse conducting device resonates with a shorter period than the turn-on time of the switching device and an amplitude of the resonant current is maintained to be equal to or higher than a predetermined value during the turn-on time.

1 more element

An induction heating apparatus comprising:

an inverter including a resonant circuit having a first series connector containing a first switching device and a second switching device connected in series, a first reverse conducting device connected to the first switching device in parallel, a second reverse conducting device connected to the second switching device in parallel, and a second series connector containing a heating coil for heating a load by generating a magnetic field and a resonant capacitor unit connected to the first or the second switching device in parallel, wherein the inverter resonates by turning on the first and the second switching device;
a control circuit for exclusively turning on the first and the second switching device;
and
a boosting and smoothing circuit for boosting and smoothing an input DC voltage to provide the boosted and smoothed DC voltage to the inverter,
wherein, in case the load is material of a high conductivity and a low permeability, the resonant current passing through the first switching device or the first reverse conducting device resonates with a shorter period than a turn-on time of the first switching device and an amplitude of the resonant current is maintained to be equal to or higher than a predetermined value during the turn-on time.

2 more elements

Dependencies are inferred from the claim text.