三电平逆变器因其输出电压谐波小、开关应力低等优点被用于中压大功率船舶电气领域。然而传统独立的虚拟空间矢量调制或断续脉宽调制方法均难以在全工况内实现中点电位平衡和开关损耗综合优化控制。针对需计及复杂工况下开关损耗的三电平逆变器中点平衡控制难题，本文通过深入分析不同PWM调制下三电平逆变器控制机理，给出2种传统调制方法的中点可控区域，并提出一种基于中点电位平衡的断续脉宽调制和虚拟空间矢量调制的开关序列切变策略（Modulation Based Switching Pulse Width Modulation，MBSPWM），在保证中点电压平衡条件下最大程度降低开关损耗。最后搭建考虑器件结温的三电平逆变器损耗计算仿真模型，对逆变器桥臂损耗数据进行统计分析。仿真实验结果表明，与传统独立的断续脉宽调制和虚拟空间矢量调制方法相比，基于特定调制切换策略的三电平逆变器可实现全调制度以及全负载功率因数角下中点电位波动、输出电压THD和开关损耗性能指标综合较优。
The three-level inverter is used in the field of medium voltage and high power ship electrical because of its advantages of low harmonic output voltage and low switching stress. However, the traditional independent VSVPWM or DPWM methods are difficult to achieve the balance of midpoint potential and the comprehensive optimal control of switching loss in all working conditions. Aiming at the problem of midpoint balance control of three-level inverters that need to account for switching loss under complex working conditions, this paper gives the midpoint controllable area of two traditional modulation methods by deeply analyzing the control mechanism of three-level inverters under different PWM modulation. A Modulation Based Switching Pulse Width Modulation (MBSPWM) based on midpoint potential balance and virtual space vector modulation is proposed to minimize the switching loss under the condition of guaranteeing midpoint voltage balance. Finally, a three-level inverter loss calculation simulation model was built considering the device junction temperature, and the loss data of the bridge arm of the inverter were statistically analyzed. The simulation experiment results showed that compared with the traditional independent DPWM and VSVPWM methods, The three-level inverter based on the specific modulation switching strategy can realize the full modulation system, and the performance index of the full load power factor is better than the midpoint potential fluctuation, output voltage THD and switching loss.
2025,47(20): 156-164 收稿日期：2024-10-31
DOI：10.3404/j.issn.1672-7649.2025.20.024
分类号：U662；TM46
基金项目：湖北省自然科学基金资助项目（2021CFB030）；武汉市重点研发计划项目（2023010402010584）
作者简介：刘江(1987-),男,博士,讲师,研究方向为电力电子与电力传动
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