A novel control scheme of a parallel current-controlled PWM inverter

A parallel technique for current-controlled pulse-width-modulated (PWM) inverters is described. Two voltage source inverters, the output terminals of which are connected in parallel through current balancers, are used as a main circuit. In this scheme, excellent characteristics both in steady states and in transient states are obtained, keeping the average values of the cross current and zero sequence current at zero level. This current control scheme is applicable to large-capacity GTO inverters because good performance is attained even if the switching frequency is only a few hundred hertz, as is shown in the experimental results.<
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