Research on Neutral Point Potential Balance of Three-Level Inverter

Abstract

With the rapid development of new energy and the energy-saving technology, three-level inverter has gradually become the core of power conversion because of its large output capacity, good dynamic performance, low harmonic content and high inversion efficiency. In the view of the inherent problem of uneven DC side voltage distribution in T type three-level inverter, this paper analyzes the influence factors of neutral point potential imbalance based on SVPWM (Space Vector Pulse width Modulation method), and establishes the midpoint average current mathematical model. According to the current state of the midpoint under different types of vector action, a self-adaptive distribution factor method is proposed, which can self-adjust according to the potential difference of the midpoint, and the expected effect is obtained in the simulation.