| 摘要 |
PURPOSE:To improve the controlling accuracy of an AC voltage with respect of the variation of a load by controlling the chopper reference voltage so that the ordinary output voltage of an inverter becomes constant by feeding back a chopper output voltage. CONSTITUTION:The output voltages of a chopper 2 and an inverter 3 are respectively detected by output voltage detectors 7, 8 at every prescribed time, and respectively converted by A/D converters 9, 10 into digital signals. A control circuit 11 calculates on the basis of the sampled two digital signals to control the conducting width of the switching element of the chopper 2 so that the AC output voltage of the inverter 3 coincides with the reference voltage. |
