Soft-switching inverter investigation for three-phase IM drive as wind turbine emulator design

Abstract

Thanks to their high reliability, minimum maintenance and reduced cost, induction motors (IM) are commonly used in industry applications especially in renewable energy field. In this paper, a three-phase IM drive based on soft-switching structure is investigated for wind profile emulation. A specific space vector modulation (SVM) for the four-switch three-phase inverter (FSTPI) is applied to select the appropriate three vectors which synthesize the desired output voltage. Although this technique seems to be complicated in terms of hardware implementation since no zero vector is used and only three active vectors are considered, it has less total harmonic distortion, larger linear modulation range and better DC bus use. The proposed approach based on compensation, which ensures a feasible alternative for low-cost motor drives, fed the IM to react effectively as a wind turbine emulator in research laboratory by controlling the speed waveform. Software and hardware results show that the system has a good static and dynamic performance. The presented curves demonstrate the control scheme accuracy for trajectory tracking under sudden load variation.