一种三电平逆变器中点电位控制方法仿真研究  

Simulation of Three Level Inverter Neutral Point Potential Control Based on Three Level DC/DC Converter

作　　者：夏鲲[1] 李肖迪 丁晓波[1] 曾彦能 王一鸣 许颇 

机构地区：[1]上海理工大学光电信息与计算机工程学院电气系,上海200093 [2]宁波锦浪新能源科技有限公司,宁波315712

出　　处：《系统仿真学报》2016年第1期235-241,共7页Journal of System Simulation

基　　金：宁波市科委重大科技攻关项目(2012B100 31);沪江基金(B14002/D14002)

摘　　要：二极管中点钳位型三电平逆变器直流侧中点电位偏移不仅会导致交流侧输出性能变差,严重时会减少直流支撑电容寿命甚至损坏功率器件。提出了基于三电平直流变换器的三电平逆变器直流侧中点电压平衡控制方法,依据开关管关断时间之和决定母线电压、关断时间之比决定中点电位的约束条件,调节开关管工作状态,从而使中点电位在系统所允许的范围内波动。在MATLAB/Simulink环境下构建了仿真模型,实现了双闭环调节控制算法,完成了系统仿真分析。仿真结果表明,该设计可减小三电平逆变器直流侧中点电位偏移量达93%以上。The DC capacitor voltage unbalancing of NPC three-level inverter not only makes the AC output performance worse, but also reduces the DC capacitors＇ service life and even damages the power devices. A method based on three-level DC/DC converter was put forward to control the neutral point potential of three-level inverter. This method realized power conversion with three-level DC/DC converter topology, boosting voltage and stabilizing the neutral point potential of DC link at the same time. It would regulate switches working states according to the constraint rules on the sum of switches off time deciding bus voltage and the ratio of switches off time deciding neutral point potential, so that the voltage fluctuations of two capacitors would keep in the range which was permitted by the system. Under the MATLAB/Simulink environment, the simulation model of three level inverter based on three level DC/DC converter to inhibit DC link midpoint potentials offset was built. The double closed loop control algorithm was achieved and the system simulation analysis was accomplished. The simulation results show that the three level inverter＇s DC link neutral point potential offset could be reduced to more than 93%.

关 键 词：三电平直流变换器 三电平逆变器 中点电位平衡 双闭环控制 

分 类 号：TM464[电气工程—电器]