| 摘要 |
PURPOSE:To perform smooth switching in a pulse width modulation type inverter by deciding the switching point from an open loop operation to a closed loop operation in response to the amplifier output signal level of a voltage control system and the output voltage command signal level of a function generator. CONSTITUTION:The amplitude relationship between the signal amplified from an error voltage of a voltage detection signal inputted from a rectifier 5 from the voltage command signal inputted from an A/D converter 8 under the open loop voltage control is monitored by a coincidence detector 23. When the coincidence of the both signals is detected by the detector 23, a contact S1 is opened based on the detection signal, a contact S2 is closed, thereby switching the prescribed voltage control from the open loop to the closed loop operation. |
