Low losses modulation algorithm for dual cascaded inverters

A low losses modulation technique for dual cascaded inverter feeding open-end induction motor is presented in this paper. It allows to optimize the converter performances in terms of power losses and harmonic content. On the basis of the actual position of the reference voltage space vector, a proper pattern selection of both the inverter of the cascaded structure is selected, in order to reduce the commutation losses. This is achieved by means of a combined hysteresis/space vector modulation of the two cascaded inverters. In this way, performances and efficiency of the power conversion process are optimized. A numerical analysis and an experimental implementation on a laboratory prototype fully confirm the validity of the proposed modulation technique.