| 摘要 |
PROBLEM TO BE SOLVED: To obtain a cooling appliance capable of reducing a loss of a high-frequency power source. SOLUTION: A frequency conversion circuit 12 is composed by connecting in series a heating coil 15, and IGBT 16, 17 having mutually reverse current- carrying directions between both terminals of a bypass capacitor 18. Reflux diodes 22, 23 are connected in reverse parallel on the IGBT 16, 17 respectively, and switched by the same gate signal SG. During a positive voltage period of an alternating-current power source 14, a current is flowed from the bypass capacitor 18 through the heating coil 15, the IGBT 16 and the reflux diode 23 by ON-switching, and a resonance current is flowed by OFF-switching. During a negative voltage period, a current is flowed from the bypass capacitor 18 through the IGBT 17, the reflux diode 22 and the heating coil 15 by ON- switching, and a resonance current is flowed by OFF-switching. |
