An optimized modulation method for a five-leg-inverter for dual Induction motor drives

In order to satisfy the requirements of common leg for both motors at the same time, an optimized modulation method is proposed for a five-leg voltage source inverter for dual Induction motor drives. In this method, pulse widths of voltage vectors are calculated according to space vector pulse width modulation (SVPWM) theory, and the distribution of vectors is adjusted and optimized, especially the extra zero vectors are considered and inserted while the needs of the common leg for both motors collide. Simulation results show that two motors operate at different speeds with different loads, which means the five-leg-inverter is controlled effectively by using the proposed method. Moreover, compared with the conventional half-cycle PWM method, switching frequency of the inverter is reduced and the driving capability of the dual induction motor drive system fed by a five-leg-inverter is improved by the proposed method.