| 摘要 |
PURPOSE:To facilitate designing and to attain miniaturization and cost reduction by making elements of a chopper circuit and an inverter circuit be shared and also by separating a switching element operating at a high frequency from a switching element operating at a low frequency. CONSTITUTION:Receiving a DC voltage from a DC power source 1, third and fourth switching elements Q3 and Q4 repeat ON-OFF alternately at a low frequency and first and second switching elements Q1 and Q2 repeat ON-OFF alternately at a high frequency. Now, when Q3 is in an ON state, Q1 is turned ON and energy is accumulated in an inductance L3. Before a time point when Q1 is turned OFF, Q2 is turned ON, a voltage generated by the inductance L3 is added to the DC voltage of the DC power source 1 and a desired power is supplied to a load 2. This operation is repeated for a period of a half cycle of the low frequency. In the next period of the half cycle, a series circuit of a bridge circuit is changed, Q4 is put in an ON state and the same operation is executed. |
