Optimum Design of an Input-Commutated Inverter for AC Motor Control

In any forced commutated inverter scheme, a certain amount of energy is "trapped" at the end of the commutation interval. It is desirable to minimize this level of trapped energy for best circuit component utilization. An input commutation circuit, suitable for single or three-phase inverter circuits, is introduced as a model. A mathematical analysis of the circuit yields expressions for circuit component values in terms of the load impedance at the instant of commutation. Optimizing procedures produce direct expressions for the components to yield the most efficient operation and minimum trapped energy.