Dynamic programming-based optimal torque control of induction machine

This paper introduces a novel optimal torque control scheme based on dynamic programming for control of inverter fed induction machines. Utilizing dynamic programming method, a cost function is minimized in order to identify optimum sequence of inverter switching operations for the whole prediction horizon at every sampling instant. The proposed optimal control strategy significantly reduces the inverter switching frequency while the stator flux and electromagnetic torque follow their reference values with much less ripple. Simulation is done on accurate model of inverter fed induction machine and the results confirm the superior performance of the introduced optimal control strategy compared to direct torque control and direct self-control strategies. Furthermore, due to short calculation time needed for this method, it is applicable for online control of inverter fed induction machine. The method is a general approach which can be applied on different types of electrical drives and adapted towards different distinct applications.