A Novel Modulation Strategy for Active Neutral-Point-Clamped Grid-Connected Inverter

This is the authors' abstract. We don't add key points for this paper.

With the development of renewable energy power generation, the neutral point clamped three-level inverter has gained widespread application, due to its advantages such as low device stress and output characteristics. However, due to the different working styles of the power switches, there are significant differences in losses and thermal stresses. The active neutral point clamped three-level topology provides more freewheeling paths for grid-in current, which allows for changing the working styles of switches. Thus, it offers the structural foundation for optimizing the loss distribution and thermal stresses. Furthermore, it is still necessary to employ novel modulation strategies to balance the losses. For this purpose, a novel modulation strategy with a more balanced loss distribution is proposed for active neutral point clamped gridconnected inverter in this paper. Two traditional modulation strategies are overviewed in brief. Based on the commutating process and the switching losses distribution in the conventional modulation strategies, the commutating paths are combined in the novel modulation strategy. The comparison between the proposed modulation strategy and the traditional modulation strategies is conducted by numerical calculation. The results demonstrate the performance in achieving a balanced loss distribution by the proposed strategy. Furthermore, experimental validation is performed to verify the effectiveness of the proposed modulation strategy.