Low cost energy optimized control strategy for a variable speed three-phase induction motor

A simple energy optimized control strategy for a 3-phase induction motor (IM) is presented in this paper. The control strategy is referred to as DPF control as it aims to control the displacement power factor (DPF) of the IM in quasi steady state operation. DPF control is suited for applications with low demands on the dynamic performance. It is ideal for open loop speed applications as a speed measurement or speed estimation is not required. Throughout the paper DPF control is compared to the reported energy optimized control strategy "constant rotor frequency" using a 50 W IM fed by a VSI PWM DC-link inverter.