基于矢量空间解耦调制的级联双三相电流源逆变器共模电压抑制方法

Common-mode voltage (CMV) is a critical performance indicator for power electronic converters. Excessive CMV can compromise motor system insulation, induce bearing leakage currents, and generate electromagnetic interference (EMI), ultimately affecting the reliability and lifespan of motor systems. In this article, a vector space decoupling (VSD) modulation strategy is proposed for the cascaded dual three-phase current-source-inverter (DTP-CSI)-fed motor drive system to reduce the common-mode current (CMC) and EMI. The DTP-CSI-fed motor drives with the proposed modulation strategy can fully retain the advantages of current-source converters, e.g., low voltage variation rate (dv/dt) and high short-circuit current tolerance. The proposed strategy conducts comprehensive comparisons of CMV magnitudes under all feasible current vector states, systematically selecting the vector combination corresponding to the minimum CMV amplitude. As an offline selection scheme, this approach eliminates the need for real-time capacitive voltage comparisons, thereby ensuring enhanced robustness and reliability. The performance of total harmonic distortion (THD) and dc bus current utilization can be maintained satisfactorily with the proposed strategy. Finally, the validity of the proposed CMV reduction strategy for DTP-CSI is verified through experimental results.