A Matrix Reactance Frequency Converter SVPWM Method with Common Mode Voltage Elimination Based on Rotating Vectors

This paper proposes a new SVPWM method (named as RSVPWM) based on Matrix Reactance Frequency Converter (MRFC) fixed length but rotating vectors (RVs, RV0 RV6), which can be considered to eliminate the output common mode voltage (CMV) in theory for better load motor maintenance and electromagnetic interference level. The proposed modulation method can be composed of two parts: the output voltage vectorial angle and the magnitude: the angle can be combined by the rotating input voltage vectors in 3*3 switching source matrix, while the output voltage magnitude can be controlled by the PWM in switching load matrix. Therefore, the new method has both zero CMV and wide voltage transfer rate (VTR) range at the same time. MRFC commutation is the point to implement the proposed modulation method. Coinciding the 3-phase IGBT’s commutation moments will not only guarantee the currents transferring safety, but also eliminate the dynamic CMV when transferring between RVs. Moreover, a linear compensation to the based vectors rotation has also been discussed due to the sampling intervals. The proposed RSVPWM feasibility and effectivity have been verified by the experiments on a new designed prototype: the proposed modulation on MRFC has sinusoidal input and output voltage or current waveforms, less CMV level, larger VTR range, and less output current total harmonic distortion.