| 摘要 |
PURPOSE:To preclude generation of a beating sound in an arrangement in which a preregulator is provided at the fore-stage of an inverter circuit, wherein the sound signifies such a one as results from overshooting due to flowing of steep current in an inductor when the DC voltage given by the preregulator is going to rise. CONSTITUTION:A preregulator 3 in the voltage boosting chopper system including a switching element 6 and inductor 5 is installed at the fore-stage of an inverter circuit, wherein the arrangement is further equipped with a sensing means 9 to sense the DC voltage VDC, which is given by the preregulator 3 to the inverter circuit, a preregulator control circuit 7 which is to control the switching motion of the element 6 in accordance with the DC voltage value sensed by this sensing means 9, and a soft starting means 11 to cause the preregulator 3 to make soft starting for a certain specified period at the time the DC voltage is going to start. |
