Independent two induction motor drives with vector control method fed by a four-leg inverter

This paper presents the experimental results of the independent drives of two induction motors (IMs) fed by a four-leg inverter with vector control method. The inverter consists of four legs and two capacitors connected in a series. Recently the four-leg inverter and four switch inverter have been studied, but there are known to have several disadvantages. First, the balanced three-phase current cannot be obtained. Second, the drift phenomenon is happened by the two capacitor voltages fluctuation. This paper analyzes the cause of the unbalanced three-phase current and resolves about it by vector control method. Next, the effective compensation method to restrain the drift phenomenon is proposed and demonstrated by the experimental results. Moreover, the independent drive of two IMs fed by the four-leg inverter with the vector control method is demonstrated by the experimental results.