A New Current Source Inverter

With the application of one gate turn- off thyristor (GTO'S)and six thyristors, a new current source inverter has been developed. GTO'S is used to control commutation lime of thvristors in the inverter section. Three capacitors are connected to the AC output terminals to provide commutation and to absorb ovcrvaltage spikes and to reduce harmonics in the output current. A 2-kW induction motor is driven by the inverter. The motor valtage and current waveforms are measured and compared with those obtained when the motor is driven by a conventional current source inverter. Therefore, this new current source inverter is very suitable for AC motor variable speed drive in fans or pumps.