An improved modulation strategy to reduce common-mode voltage for two-stage matrix converter

Aiming at the large instantaneous common-mode voltage in traditional space vector modulation strategy for two-stage matrix converter (TSMC), on the basis of analyzing the laws of common-mode voltage, an improved modulation strategy to reduce common-mode voltage was proposed. To suppress common-mode voltage effectively, the sector of rectifier stage was doubled into twelve sectors from six sectors, according to the sector of the reference current vector and dc-side voltage, the switching state points of inverter stage were redefined and reallocated, and zero vectors of inverter were reselected and redistributed reasonably without affecting on valid vectors. Finally the peak value of common-mode voltage was reduced to 57.7% of the original value meanwhile exhibits lower harmonic components of CMV, without any sacrifice in the voltage transfer ratio and introducing additional hardware. The feasibility and validity of the proposed method has been verified by simulation results.