基于控制载波自由度的级联H桥逆变器改进型PWM技术  

Improved PWM Technology of Cascaded H-Bridge Inverter Based on Control of Carrier Degree of Freedom

作　　者：叶满园 任威 李宋 魏麒文 宋桂智 Ye Manyuan;Ren Wei;Li Song;Wei Qiwen;Song Guizhi(School of Electrical Engineering East China Jiaotong University,Nanchang 330013 China)

机构地区：[1]华东交通大学电气与自动化工程学院,南昌330013

出　　处：《电工技术学报》2021年第14期3010-3021,共12页Transactions of China Electrotechnical Society

基　　金：国家自然科学基金(51767007);江西省重点研发(20202BBEL53034,20192BBEL50011)资助项目。

摘　　要：随着级联H桥(CHB)多电平逆变器输出电压与功率等级的增加,提高载波移相脉宽调制(CPS-PWM)策略下直流侧电压利用率以及改善低调制度时谐波性能比较差的问题具有重要的意义。通过对正弦波脉宽调制(SPWM)以及梯形波脉宽调制(TPWM)原理及输出电压特性的分析,该文提出一种基于控制载波自由度的改进型CPS-PWM策略,该策略基于移相载波自由度,通过周期性的循环改变三角载波的排列方式,利用改进的多载波代替原CPS-SPWM中的三角形载波进行调制,从而可以显著地提高输出电压的直流电压利用率;又能在实现各级联单元功率均衡的条件下,降低输出电压总畸变率,有效地改善低调制度时的谐波性能,且各单元开关频率和损耗相同,同时各开关管工作应力也相同,因此提高了系统的可靠性。该文给出改进型CPS-PWM策略输出电压基波幅值和功率均衡分析,同时列举三种策略并进行比较,并对该文所提策略进行仿真与实验的验证。With the increase of the output voltage and power level of the cascaded H-bridge(CHB)multilevel inverter,it is of great significance to increase the utilization ratio of DC side voltage under carrier phase shift pulse width modulation(CPS-PWM)strategy and to improve the poor harmonic performance in low-key system.By analyzing the principle and output voltage characteristics of Sinusoidal pulse width modulation(SPWM)and trapezoid wave pulse width modulation(TPWM),an improved CPS-PWM strategy based on the control of carrier freedom is proposed.According to the shape freedom of phase-shifting carrier,this strategy uses the improved multi-carrier instead of triangle carrier in original CPS-SPWM for modulation,which can significantly improve the DC voltage utilization of output voltage.This strategy can reduce the total distortion rate(THD)of the output voltage while achieving power balance of each cascade unit at all levels.In addition,the switching frequency and loss of each unit are the same,and the working stress of each switch tube is also the same,thereby improving the reliability of the system.The analysis of the fundamental amplitude and power balance of the output voltage of the improved CPS-PWM strategy is analyzed.Moreover,three strategies are listed for comparison,and the strategy is verified by simulation and experiment.

关 键 词：级联H桥多电平逆变器 改进型载波移相PWM 总谐波畸变率 直流电压利用率 

分 类 号：TM46[电气工程—电器]