| 摘要 |
PURPOSE:To protect a filter capacitor from being charged with a peak voltage under no-load by controlling the conduction ratio of a control rectifier in accordance with the magnitude of a load for a power converter thereby limiting the peak level of output from a power rectifier below the peak level of output from a noncontrolled rectifier. CONSTITUTION:Upon stoppage of an induction motor 7, a rectifier control circuit 10 detects no-load state based on a drive command D and increase the conduction phase alpha of a control rectifier 31 in the range of 90 deg.<alpha<180 deg.. Consequently, output voltage from the control rectifier 31 is restricted and the peak level of output voltage E0 from a rectifier 3 is limited below the peak level of output from a rectifier 32. |
