A compensation method for sequential current sampling in multi-phase AC motor control

All-phase current sensing is an effective method to enhance robustness of a motor control system when current sensor error is taken into account. However, sequential sampling has to be used for controllers having less number of analog-to-digital converters than that of phases. A difference in sampling timing may lead to unbalance between phases and thus toque ripple at high speeds. Based on theoretical analysis of the phenomenon, this paper proposes a compensation algorithm to solve the problem. Simulation and experiment have been carried out to validate the proposed method.