A Multisampling SVM Scheme for Current Source Converters with Superior Harmonic Performance

The device switching frequency of current source converters (CSCs) in high-power medium-voltage applications is usually several hundred Hz. Selective harmonic elimination (SHE) has been the dominant modulation scheme because of its capability to eliminate unwanted low-order harmonics at low switching frequencies. Conventional space vector modulation (SVM), as another CSC modulation scheme, provides variable modulation index control but its output contains low-order harmonics with high magnitudes. In this paper, a multisampling SVM (MS-SVM) is proposed to substantially suppress the low-order harmonics in practical CSC-based drives. Investigation of 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 harmonic performance 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 methods.