Instantaneous Power Decoupling Control Strategy for T-type Three-level Rectifier with Independent Double Loads

In some applications, two independent loads are connected to the upper and lower DC-link capacitors, and the T-type three-level rectifier operates in the dual output mode. In these applications, the DC-link voltages control, power exchange relationship and modulation method are quite different from that in single output mode. The instantaneous power exchange principle in the dual output mode is analyzed in this letter. Based on that, an instantaneous power decoupling control (IPDC) is proposed. The proposed method adopts respective regulators for the upper and lower DC-link voltages, and the zero-sequence voltage (ZSV) is injected to decouple the input power. Under balanced or unbalanced DC-link voltages and loads, DC-link voltages and exchanged power can be well controlled with the proposed method. From the analysis of the output voltage of the upper or lower capacitor, buck type rectifier is realized, which improves the operating range of the T-type three-level rectifier, especially in the field of electric vehicle charging. Finally, the feasibility and superiority of the proposed method are verified by experiments.