文章摘要
张雪垠,徐永海,徐少博,等.不对称规则采样CPS-PWM的基波近似模型及其频率特性[J].电力系统自动化. DOI: 10.7500/AEPS20190328001.
ZHANG Xueyin,XU Yonghai,XU Shaobo, et al.Fundamental Approximation Model and Frequency Characteristics of CPS-PWM with Asymmetric Regular Sampling[J].Automation of Electric Power Systems. DOI: 10.7500/AEPS20190328001.
不对称规则采样CPS-PWM的基波近似模型及其频率特性
Fundamental Approximation Model and Frequency Characteristics of CPS-PWM with Asymmetric Regular Sampling
DOI:10.7500/AEPS20190328001
关键词: 多电平换流器  载波移相脉冲宽度调制  不对称规则采样  基波近似模型  频率特性
KeyWords: Multilevel converter  CPS-PWM  asymmetric regular sampling  fundamental approximation model  frequency characteristic
上网日期:2019-09-04
基金项目:北京市自然科学基金
作者单位E-mail
张雪垠 华北电力大学电气与电子工程学院新能源电网研究所 elec_zhang@foxmail.com 
徐永海 华北电力大学电气与电子工程学院新能源电网研究所 yonghaixu@263.net 
徐少博 华北电力大学电气与电子工程学院新能源电网研究所 13021085107@163.com 
肖湘宁 华北电力大学电气与电子工程学院新能源电网研究所 xxn@ncepu.edu.cn 
摘要:
      中压多电平换流器常采用模块化结构,可应用于交/直流配电网。配电网电压较低,换流器子模块数较少,常采用载波移相脉冲宽度调制(carrier phase shift pulse width modulation, CPS-PWM)提升等效开关频率。建立CPS-PWM模型是换流器系统级建模的基础。调制环节非线性,常分析其基波。现有CPS-PWM基波近似模型以桥臂等效开关频率为准,在不对称规则采样下模型延时偏低、误差较大。本文以子模块为基础,通过子模块输出叠加建立了零阶保持器(zero order holder, ZOH)经纯延时近似、不近似以及纯延时环节经Padé近似的三种形式CPS-PWM基波近似模型,更准确的反映了CPS-PWM的频率特性。仿真研究验证了理论分析的正确性。
Abstract:
      Medium-voltage multilevel converters usually adopt a modular structure. They can be used in AC/DC distribution networks. As a result of the relatively low voltage in distribution networks, the number of converter sub-modules is small. Therefore, carrier phase shift pulse width modulation (CPS-PWM) is widely used to increase the equivalent switching frequency. The modeling of CPS-PWM is one of the fundamentals of converter system modeling. The modulation stage is nonlinear, and thus, only the fundamental frequency component is usually considered. The existing fundamental approximation model of CPS-PWM is based on equivalent switching frequency, hence the low time delay and large errors when asymmetric regular sampling is adopted. In this work, the following three forms of fundamental approximation models of CPS-PWM are established: zero order holder (ZOH) delay approximation, ZOH no approximation, and delay Padé approximation. These models are developed by combining the outputs of sub-models on the basis of a sub-module. The proposed models more accurately reflect the frequency characteristics of CPS-PWM than the traditional one. A simulation study verifies the correctness of the theoretical analysis.
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