Multi-phase voltage controlled PWM frequency converter for AC motor control has rectifier bridge connected to inverter without use of capacitor and inductor to act respectively as intermediate energy store and current peak value limiter

摘要

The frequency converter has a control unit (23) and a rectifier bridge (20) connected to a three phase supply. An inverter bridge (21) supplies a three phase load (22) with an AC voltage of varying magnitude and frequency. The inverter bridge also has PWM controlled semiconductor switches like IGBT (V11-V16) in parallel with diodes (D11-D16). The rectifier bridge (20) is connected to the inverter bridge (21) directly without a DC capacitor to act as an intermediate storage Also, no inductor is necessary to limit current peak wave.