Characteristics of independent two induction motor drives fed by a four-leg inverter

This paper presents the experimental results of the independent drive characteristics of two three-phase induction motors (IMs) fed by a four-leg inverter (FLI). The FLI is a single inverter that can drive two three-phase AC motors independently. The inverter consists of four legs and two capacitors connected in a series. The U and V phases of both motors are connected in each leg respectively whereas the W phase of both motors is connected in the neutral point of two-sprit capacitors. The PWM technique in three-phase voltage source inverter (three-VSI) is not directly applicable for the FLI because only two phases must be modulated. Then, the paper also analyzes about potential in the neutral point of two-sprit capacitors and inverter output voltage. Next, modulation technique in the FLI is also shown. The PWM strategy may apply carrier-based PWM. Experimental results demonstrate the characteristics of two IM independent drives and the validity of those analytic results.