Current control in three-phase switching converters and AC electrical machines

In this paper, the design of current control loop and selection of the switching logic for PWM three-phase switching power converters (inverters and rectifiers) and AC electrical machines are presented. The approach is based on the deliberate introduction of the sliding mode motion in the control system. It is shown that the selection of the PWM pattern is a direct result of sliding mode existence in the current control closed-loop system. The PWM pattern selection for three-phase inverters, three-phase rectifiers and AC electrical machines is the same, due to the fact that the switching matrix is the same for all plants considered. Simulation results show that the proposed algorithm has an advantage, namely that the current ripple can be set as a fraction of the reference current while the switching frequency does not increase.