Precise Inductor Current Ripple Distribution of Three-Level Active Neutral-Point-Clamped Inverter

In power electronic converters, the inductor current ripple affects the system power loss and should be minimized. This paper studies in detail the output filter inductor current ripple distribution of a three-level active neutral-point-clamped (3L-ANPC)inverter. The peak-to-peak current ripple per line cycle is precisely derived according to the modulation index. Then, the maximum current ripple is identified, and the concept of average current ripple is proposed to quantify the overall ripple level. An optimal operating point with minimum ripple level is found, and it is chosen as the nominal operation condition of the 3L-ANPC inverter. Simulations are performed in a case study to confirm the theoretical expectations.