Current improvement for a 3 ⊘ bi-directional inverter with wide inductance variation

This paper presents current improvement for a 3φbi-directional inverter with wide inductance variation. A bi-directional inverter fulfilling grid connection and rectification with power factor correction has been designed and implemented in the laboratory. With a digital predictive current control, the inverter can accommodate wide inductance variation, improving current distortion in high power applications significantly. However, under low current levels, inductor currents have serious distortion. To improve current distortion, this paper presents four attempts, including mid-point current sampling, smooth region transition, current interleaving, and duty splitting. Theoretical analysis and experimental results are presented to verify the discussion.