Study on the Leakage Current and Neutral-Point Potential Balance in TL-Boost Photovoltaic System

In this paper, TL-Boost is adopted as a front-end converter in the non-isolated photovoltaic grid-connected system, the common-mode leakage current equivalent circuit of TL-Boost circuit is established, and the calculation formula of leakage current of the system is derived. On this basis, a conclusion that the common-mode leakage current of the system can be reduced using the synchronous modulation strategy is obtained. Aiming at the problem of unbalanced neutral-point potential in the process of starting up when DC bus voltage is building up, a fuzzy control strategy based on pre-TL-Boost circuit is proposed, thus realizing the balance of two capacitors' voltage on the DC side. And the experimental results verify the theoretical analysis.