级联H桥换流器避免窄脉冲的NL-PWM策略  

NL-PWM Strategy Without Narrow Pulses for Cascaded H-bridge Converter

作　　者：牟杰 徐永海 丁一博 龙云波 MU Jie;XU Yong-hai;DING Yi-bo;LONG Yun-bo(State Key Laboratory of Alternate Electrical Power System With Renewable Energy Sources(North China Electric Power University),Beijing 102206,China)

机构地区：[1]新能源电力系统国家重点实验室(华北电力大学),北京102206

出　　处：《电力电子技术》2021年第10期90-94,共5页Power Electronics

基　　金：北京市自然科学基金(3172036);新能源电力系统国家重点实验室(华北电力大学)自主研究课题项目(LAPS2019-20)。

摘　　要：最近电平-脉宽调制(NL-PWM)是将最近电平调制(NLM)和脉宽调制(PWM)结合的混合调制方法,在级联H桥(CHB)型换流器中具有广泛的应用前景,但其在实施过程中会出现窄脉冲,对CHB工作效率、输出电压质量和功率器件的安全运行产生不利影响。此处分析了传统NL-PWM窄脉冲问题的产生机理,提出了一种能够避免窄脉冲的改进型NL-PWM策略,分析了其避免窄脉冲原理并对其进行频谱分析。研究表明改进型NL-PWM在有效避免窄脉冲的同时,谐波特性优于传统NL-PWM。仿真和实验验证了理论分析的正确性。Nearest level pulse width modulation(NL-PWM) is a hybrid modulation method which combines nearest level modulation(NLM) and pulse width modulation(PWM).NL-PWM has a broad prospect of application in the cascaded H-bridge(CHB) converter but it will produce narrow pulses in the process of implementation,which has a negative impact on CHB efficiency,output voltage quality and safe operation of power devices.The generation mechanism of narrow pulses is analyzed,an improved NL-PWM which can avoid narrow pulses is proposed,and its principle and spectrum is analyzed.The results show that the improved NL-PWM can effectively avoid narrow pulses and its harmonic characteristics is better than traditional NL-PWM.Theoretical research is verified by simulation and experiment.

关 键 词：级联H桥换流器 最近电平-脉宽调制 窄脉冲 

分 类 号：TM46[电气工程—电器]