Multiphase Open-End Winding Induction Machine Drive With the Floating Capacitor

A comprehensive control scheme is presented for the multiphase open-end winding induction machine drive topology, where the main inverter (MI) and floating inverter (FI) are supplied by a dc power source and a capacitor, respectively. Under the proposed method, the MI can work with the unity power factor, while the FI provides all the reactive power. Besides, the current waveform quality is improved by the harmonic suppression and current balance control. Moreover, the voltage of the floating capacitor is adjusted to keep the modulation ratio of the FI near one during the operation, which helps to reduce the switching losses of the system. Experimental results are presented to verify that the proposed control scheme is practical in controlling this open-end drive topology and suitable for expansion to high-phase-number occasions.