Reduction of harmonic distortions of VSI-fed induction motor with direct self-control

A novel PWM strategy for direct self-control was proposed in this paper which reduces distortion in the inverter output current. This is achieved by increasing the stator flux corner and choose appropriate flux trajectory to form a stator flux trajectory which closer to circular compared with the classic DSC flux hexagon, It greatly improve the switching frequency and make the output current closer to sinusoidal. The method does not require on-line calculation, and is based on logic circuits and an EPROM look-up table, The theoretical analysis and experimental results show that the proposed method retain the advantages of concise in classic DSC and improved the control performance to a great extent.