Novel mid-point balancing for ANPC converter and assessing future DC to MV power converter architectures

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Schneider Electric has established the research goal of introducing a novel mid-point voltage balancing for ANPC converters and assessing future DC to MV power converter architectures. Although the worldwide headquarters of Schnieder Electric's Solar Business is Burnaby, BC, they do not have the in-house expertise to address the research challenges. This Engage Grant will establish a research collaboration which will hopefully provide the foundation for future interactions, and maintain Canada's position as a leader in this field.The use of renewable distributed energy resources (DERs) offers a variety of economic, environmental and technological benefits compared to conventional large scale generating units. Grid-tie DC/AC inverters are commonly used to feed the renewable energy into the grid by converting direct current (DC) electricity into alternating sinusoidalcurrent (AC). This AC voltage is generated by switch-mode power converters. Major concerns in grid-tie inverters are their weight, size, efficiency, reliability and life time. Technically, inverter topologies, materials, control methods and interior design layouts are major tools to address these concerns. Medium-voltage, high-power DC/AC grid-tie inverters are a future trend for high power renewable energy. Neutral-Point-Clamped (NPC) inverters, due to their unique characteristics, have proven to be among the best choices for Medium-voltage high-power DC/AC converters. However, mid-point voltage balancing and symmetrical semiconductor loss distribution are major goals that must be achieved. In Active Neutral-Point-Clamped (ANPC) inverters clamping diodes are replaced by controlled bi-directional switches to provide redundancy in switching. However, voltage balancing in APNCs is still a challenging issue that requires further investigation. In this research, we are looking for a novel control scheme and switching methodology to improve output voltage quality of grid-connected APNCs with balanced DC-side voltages for the whole range of power transfer.