中压级联H桥换流器提高输出电能质量的锯齿载波NL-PWM策略

丁一博; 徐永海; 张雪垠; 牟杰; 龙云波

丁一博,徐永海,张雪垠,牟杰,龙云波.中压级联H桥换流器提高输出电能质量的锯齿载波NL-PWM策略[J].电测与仪表,2023,60(9):65-71.
Ding Yibo,Xu Yonghai,Zhang Xueyin,Mu Jie,Long Yunbo.An Improved Output Power Quality NL-PWM Method Based on Sawtooth Carrier for Medium Voltage Cascade H-Bridge Converter[J].Electrical Measurement & Instrumentation,2023,60(9):65-71.

中压级联H桥换流器提高输出电能质量的锯齿载波NL-PWM策略

An Improved Output Power Quality NL-PWM Method Based on Sawtooth Carrier for Medium Voltage Cascade H-Bridge Converter

DOI：10.19753/j.issn1001-1390.2023.09.010

中文关键词: 中压配电网级联H桥换流器 NL-PWM 锯齿载波谐波特性

英文关键词:medium voltage distribution network, cascaded H-bridge converter, NL-PWM, sawtooth carrier, harmonic characteristics

基金项目:

作者中文名	作者英文名	单位
丁一博	Ding Yibo	新能源电力系统国家重点实验室华北电力大学
徐永海	Xu Yonghai	新能源电力系统国家重点实验室华北电力大学
张雪垠	Zhang Xueyin	新能源电力系统国家重点实验室华北电力大学
牟杰	Mu Jie	新能源电力系统国家重点实验室华北电力大学
龙云波	Long Yunbo	新能源电力系统国家重点实验室华北电力大学

摘要点击次数: 970

中文摘要:

最近电平-脉宽调制(nearest level pulse width modulation,NL-PWM)技术是将最近电平调制(nearest level modulation, NLM)与脉冲宽度调制(pulse width modulation, PWM)有机结合的先进调制策略,适用于中压配电网级联H桥换流器,具有开关频率低和谐波特性好的优点。现有的NL-PWM调制基于三角载波,在中压配电网应用CHB子模块数较少的情况下,其输出电压的THD含量相对较高,并且其开关点随参考电压变化,不利于均压控制。由于锯齿载波具有固定的跳变点便于均压控制,通过对NL-PWM调制的基本原理的分析,推导了基于锯齿载波的NL-PWM输出电压波形的频谱；通过仿真分析了不同电平情况下锯齿载波NL-PWM的谐波特性,并将其调制性能与基于三角载波的NL-PWM调制方法进行了对比。最后,搭建了每相4个H桥模块级联的电力电子换流器进行了基于锯齿载波NL-PWM调制的实验验证。仿真和实验结果表明,锯齿载波的NL-PWM调制的输出电压和电流THD含量明显小于三角载波的NL-PWM调制。

英文摘要:

Nearest level pulse width modulation (NL-PWM) technology is an advanced modulation strategy that combines the nearest level modulation (NLM) and pulse width modulation (PWM) which can be used in cascaded H-bridge (CHB) converter . However, when the number of CHB sub-modules is small such as used in the medium-voltage distribution network, the THD of its output voltage is high, and its switching point changes with the reference voltage which is not conducive to balancing control using the existing triangular carrier NL-PWM whereas the sawtooth carrier has a fixed transition point to facilitate voltage control. This work deduces the frequency of the NL-PWM output voltage based on the sawtooth carrier; and analyzes the case of different output voltage levels through simulation. The harmonic characteristics and the modulation performance of the sawtooth carrier NL-PWM are compared with the NL-PWM method based on the triangular carrier. Finally, CHB converter with 4 modules per bridge arm was built to verify the theoretical analysis based on the sawtooth carrier NL-PWM. The simulation and experimental results show that the THD of the output voltage and current of the proposed NL-PWM is significantly reduced than that of the triangular carrier one.

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