A Multi-sampling SVM Scheme for Current Source Converter with Superior Harmonic Performance

The device switching frequency of current source converters (CSC) in high power medium voltage applications is usually several hundred hertz. Selective harmonic elimination (SHE) has been the dominant modulation scheme because of its ability to eliminate unwanted low order harmonics at low switching frequency. Conventional space vector modulation (SVM), as another CSC modulation method, provides variable modulation index but its output contains low order harmonics with high magnitudes. In this paper, a multi-sampling SVM (MS-SVM) is proposed which substantially suppresses the low order harmonics. Investigation on the switching frequency of the proposed modulation method is carried out and methods to reduce additional switchings are developed. The proposed MS-SVM method exhibits a superior low order harmonics profile comparable to that of SHE and provides the same fast and flexible control capability as the conventional SVM. Simulation and experimental results are provided to verify the proposed method.