Optimal Zero-Current Distortion Compensation Method for Vienna Rectifier to Improve Dynamic Characteristic at Driving Start-Point

This paper proposes an optimal zero-current distortion compensation (OPTM-ZDC) method for Vienna rectifier to improve dynamic characteristic at driving start-point. The conventional ZDC method has the drawback that its applicable condition is limited by modulation index. Therefore, at driving start-point where the modulation index of the output reference voltage is relatively large, the output reference voltage of certain phase enters the overmodulation area due to added ZDC components. It causes surge and distortion in the phase current, which can damage to hardware as well as reduces the stability of the system. In this paper, the OPTM-ZDC method is proposed, which re-derives the OPTM-ZDC component by considering whether overmodulation occurs. When the reference voltage of ZDC method exceeds the linear modulation area, the ZDC component applied to the specific phase is modified as OPTM-ZDC component. As a result, it is possible to reduce surge and distortion of the phase current occurred by overmodulation at driving start-point, even while maintaining the application of ZDC. The effectiveness and validity of proposed method is verified with simulation results.