Simplified configuration of GTO current source inverter for induction motor drives

A simplified current source inverter (CSI), employing gate turn-off thyristors in which one capacitor is removed from the conventional star or delta-connected bypass capacitor circuit, is presented. This simplification gives rise to an unbalanced load condition. To demonstrate the effect of this circuit, voltage and current waveforms of a simplified CSI-induction motor system under the optimal pulsewidth modulation (PWM), are compared with those of a conventional circuit. The state-space analysis is used to show that the inbalance in motor currents and the low-order torque pulsations decrease if the capacitance of bypass capacitors is relatively small.