三电平NPC级联整流器平滑均压调制策略

Smooth Modulation Strategy for Voltage Balance Management Based on Three-level Neutral Point Clamped Cascaded Rectifier

针对多模块三电平二极管箝位型级联整流器(3LNPC-CR)直流侧电压不均衡问题,在此提出一种平滑均压调制策略,在保证正常工作的前提下,实现了直流侧电压均压过程中各模块输入电平不跳变。通过分析3LNPC-CR的基本工作原理和控制方式,基于载波移相的正弦脉宽调制算法,提出了平滑均压调制算法。最后,采用平滑均压调制算法与冗余矢量切换相结合的策略,解决了模块内电容电压不均衡与模块间直流侧电压不均衡的问题。仿真和实验结果验证了该策略的可行性。

Aim ing at the unbalanced D C voltage of multi-module three-level neutral point clamp cascaded rectifier (3LNPC-CR), a smooth voltage balance modulation strategy is proposed.By analyzing the basic working principle and control method of the 3 LNPC-CR ,a smooth voltage balance modulation based on carrier phase shift modulation is proposed. The voltage balance effect of the universal balance modulation algorithm and the smooth balance modulation algorithm are compared and analyzed.A combination of smooth voltage balance modulation algorithm and redundant vector switching is adopted to solve the problem of unbalanced capacitor voltage and unbalanced D C link voltage between modules without switch state jump.Simulation and experimental results verify the feasibility of this strategy.