| 摘要 |
A semi-conductor system for controlling three phase motors by voltage and/or frequency variations. An input circuit (14) provides dc power, such as a three phase full wave input bridge (28) with silicon control rectifiers (24) to provide a voltage controlled dc power output. An output inverter bridge (20) having six silicon rectifiers (34) receives dc power and converts it to three phase ac power for operating motor (12). A diverter network (18) is connected between the dc power input circuit (14) and the output inverter (20) and is activated periodically for temporarily diverting the dc power from the inverter (20) in order that the inverter rectifiers (34) may be turned off. The diverter (18) may include a tank circuit (42, 44) having a capacitor (42) and an inductor (44) connected across the dc power output through a diode (46) and a silicon control rectifier (50) is connected to the tank circuit (42, 44) for shunting the dc power from the inverter (20) and applying a reverse voltage to the inverter (20). A harmonic suppression circuit (22) is connected across the output of the inverter (20) and may include a capacitor (72) connected between each of the three phase output lines (36, 38, 40) of the inverter (20). |
