Single-Stage Three-Phase AC-AC Isolated Inertialess Converter (IIC) for Industrial Drives

Industrial drive systems require large, heavy, and costly drive filter and transformer subsystems in order to mitigate EMI, harmonics, and other converter interactions. This paper proposes a bidirectional, single-stage, three-phase AC-AC matrix-type converter with high frequency isolation to consolidate the variable speed drive, drive transformer, and drive filter subsystems to lower size, cost, and weight. Previously, this topology has been experimentally characterized using PWM and SVM-based modulation at low power, but results have shown problems with THD, efficiency, and transformer saturation. This paper expands on previous work by providing a more thorough explanation of the SVM-based modulation and discussing and validating a power factor control for the topology. The SVM-based modulation is validated in simulation with parasitics and a four-step commutation, with an input and output current THD of 2.7% and 0.2%. In addition, the impact of modulation, parasitics, and commutation on transformer saturation is analyzed, which is an important challenge that has not been previously discussed for this topology.