| 摘要 |
PURPOSE:To realize possibility of reducing any loss of a switching device by switching the capacity of a resonance condenser according to outputs from pernicipally a load detection unit and an input detection unit. CONSTITUTION:An inverter circuit 2 is provided with a heating coil 7, resonance condensers 8a and 8b, capable of being switched two switching elements 3 and 4, and two flywheel diodes. A control circuit 10 is provided with a driving unit 11 which makes two switching elements 3 and 4 conductive alternatively at a fixed frequency, a load detection unit 12 for detecting the sort of load, an input detection unit 13, a nonconforming load detection unit 15 for detecting a load which can not be heated, and a condenser switching unit 14. Then, capacities of resonant condensers 8a and 8b are switched according to outputs from the load detection unit 12 and the input detection unit 13. Accordingly, the inductance of the heating coil 7 can be increased and losses of the switching elements 3 and 4 can be reduced. |
