Alternating Sequence and Zero Vector Modulation with Reduced Switching Losses and Common-Mode Voltage in Current Source Inverters

This paper proposes an alternating sequence and zero modulation (ASZM) algorithm for current source inverters (CSIs) that simultaneously reduces the switching losses and common-mode voltages (
$v_{CM}$
). The PWM sequence and the zero current vectors are altered based on the CSI output voltage conditions, and the optimal PWM options are selected to achieve the minimum switching losses and
$v_{CM}$
. In addition, the proposed ASZM algorithm inherently achieves zero-voltage (or near-zero-voltage) switching conditions during the zero current vector transitions, leading to a further reduction of the switching losses. Experimental results exhibit significant reductions of
$v_{CM}$
by as much as 95% over a wide frequency range and up to 57% reduction of the CSI losses compared to the baseline CSI modulation algorithm, confirming the predicted advantages of the proposed ASZM algorithm.