| 摘要 |
In order to provide a control technology for an inverter circuit with which switching loss can be reduced and a high power factor can be maintained regardless of load deviations, the direct current voltage supplied to an inverter (4) is controlled in accordance with the voltage of the load, thereby controlling the output power of the inverter (4). Thus, the output power of the inverter (4) can be adjusted without changing the output voltage pulse width of the inverter in accordance with load deviations. The drive frequency of the inverter (4) is controlled so as to be higher, exactly by a prescribed value, than the resonant frequency of a resonance circuit that includes the load (8). Thus, soft switching can be achieved. The pulse width of the output power of the inverter (4) is constant regardless of whether the load (8) is heavy or light, so it is not necessary for the phase of the current pulse to be delayed significantly with respect to the phase of the voltage pulse, and a high power factor can be maintained. |
