An Optimized Loss Balancing Control of Five-Level ANPC H-Bridge Converter

Five-level neutral point clamped H-bridge (NPCH) converter has been found practical application due to its low EMI and high output capacity. However, the unbalanced loss distribution of semiconductor devices in NPCH converter would limit the lifetime and the output capacity. In this paper, a five-level active neutral point clamped H-bridge (ANPCH) converter topology is studied, which is composed two three-level active neutral point clamped phase legs with H-bridge connection. Compared with the conventional NPCH, the ANPCH topology has more redundant switching states. The operation principle and loss distribution of every switching pattern are described in detail, and a loss-balancing control scheme is presented. Simulation and experimental results show that the loss distribution can be well balanced in ANPCH converter, resulting that the output power can be substantially increased or the total harmonic distortion of output current would be reduced effectively.