基于混合箝位五电平拓扑的三相PWM整流器研究.pdf

AbstractDue to the particular advantages，multilevel PWM rectifier has been a researchhotspot in the field of high-voltage and high—power active AC-DC conversion·However．for the diode．clamped(Neutral—Point—Clamped，NPC)topology,theproblem of DC．1ink capacitor voltages imbalance has been the difficult point．For the虹lree．1evel topology,mature solutions have been put forward，and wide applicationscan be seen in the industrial field．Unfortunately,there are no practical methodssolving this problem in the topology of higher than three-level，consequently,theresearch of PWM rectifier has been mostly limited to three·level．This paper adopts a hybrid—clamped five—level topology applying in PWMrectifier'which Can balance the dc．1ink capacitors voltages naturally,SO the controlalgorithm call be simplified greatly，and the mature control method for two-level orthree．1evel PWM rectifier Can be applied in the five-level PWM rectifier．The paper firstly analyzes the operating principle of hybrid-clamped five-levelPWM rectifier and the circuit working modes when it is working in the condition ofunit power factor．In allusion to the selection of ac—side input inductance，which is animportant parameter for voltage．source rectifier(VSR)，the paper deduces thetlleoretical equation based on the particular alternative hybrid PWM(AHPWM)modulation metllod．Meanwhile，due to the existence of the switched。

capacitor c沁u沁different capacitance of the dc．1ink will be presented in a three-phase system．Thepaper deduces the function equation between the dc-link equivalent capacitanceandthe modulation index．Based on the hybrid．clamped five·level topology，the paper analyzes thematllematical model of PWM rectifier,and deduces the control algorithm of directcurrent corln?01．Then the control principle of two—loop control is expounded，and thedesign procedure of the control system is presented，moreover,the strategy of inputvoltage feedforward control for limiting start inrush current is analyzed．Furthermore，the paper analyzes the commutation modes of the hybrid‘clampedTTunder the condition of unit power factor control ale divided into fNe types，and thereason of voltage and current overshoots on the devices caused by commutation isanalyzed based on the experimental data．Then the paper summarizes all thecommuta-tion modes and analyzes the factors influencing reliable operation of thesystem·A prototype of the three．phase hybrid-clamped five·level PWM rectifier was builtup in the lab，and the experiments were carried out under the resister load and inverter10ad(back．to．back converter)．The experimental results show that the five‘level PWMrectifier designed in this paper Call guarantee the dc·link capacitor voltages balancedand stable．restrain the distortion of the ac—side input current effectively and realizepower factor correction．Key words：hybrid．clamped fNe-level topology,PWM rectifier,capacitors voltagebalance，switched．capacitor circuit，dual·loop control，modes conversionIII浙江大学硕士学位论文 目录目录摘|喜………………………………………………………………………………………………………………．．IAbstract…………………………………………………………………………………………………………．II第一章绪论………………………………………………………………………．-1-1．1课题研究背景及意义……………………………………………………．-卜1．2多电平PWM整流器研究现状…………………………………………．．2．1．2．1多电平变换器发展现状…………………………………………．．．2．1．2．2 PWM整流器的拓扑结构及控制技术……………………………．3．1．3本文研究的主要内容……………………………………………………．．4-第二章混合箝位五电平PWM整流器的工作原理……………………………．6．2．1混合箝位五电平拓扑的基本工作原理…………………………………．6．2．2混合箝位五电平PWM整流器的工作模态分析………………………．．8．2．2．1 PWM整流器的工作状态分析……………………………………．8．2．2．2单位功率因数下混合箝位五电平PWM整流器的工作模态…．．9．第三章储能元件的分析与设计…………………………………………………．12．3．1混合箝位五电平PWM整流器进线电感设计………………………．．．12．3．1．1抑制输入电流纹波的要求………………………………………．12．3．1．2满足快速跟踪指令电流的要求…………………………………．15．3．1．3满足功率传输指标的要求………………………………………．-16．3．2混合箝位五电平PWM整流器等效直流母线电容分析………………．1 6．第四章混合箝位五电平PWM整流器的数学模型与控制策略………………．20．4．1混合箝位五电平PWM整流器的数学模型…………………………一20．4．1．1开关函数描述的一般数学模型…………………………………．20．4．1．2采用占空比描述的一般数学模型………………………………．21．4．1．3 dq坐标系下的数学模型…………………………………………．22．4．2混合箝位五电平PWM整流器的控制策略…………………………．．．23．4．2．1静止坐标系下直接电流控制控制算法…………………………．23．4．2．2 dq坐标系下直接电流控制控制算法……………………………．24．4．3控制系统环路设计……………………………………………………．．．26．IV浙江大学硕士学位论文 目录4．3．1电流内环的设计…………………………………………………．26．4．3．2电压外环的设计…………………………………………………．29．4．3．3数字锁相环的设计………………………………………………．32．4．4启动限流策略分析………………………………………………………．34．第五章混合箝位五电平PWM整流器非理想特性下模态转换测试与分析…．37．5．1混合箝位五电平PWM整流器的换流回路…………………………．．．37．5．2非理想特性下换流模态分析…………………………………………．．．38．5．2．1第一类换流模态…………………………………………………．39．5．2．2第二类换流模态…………………………………………………．43．5．2．3第三类换流模态…………………………………………………．47．5．2．4第四类换流模态…………………………………………………．50．5．2．5第五类换流模态…………………………………………………．53．5．2．6换流模态总结及系统可靠性分析………………………………．55．5．3加吸收电容后的回路RC充放电分析………………………………．．．56．第六章样机搭建与实验结果……………………………………………………．59．6．1交流进线配电设计………………………………………………………．59．6．2控制系统概述……………………………………………………………．60．6．3采样调理电路设计………………………………………………………．61．6．4实验结果及分析…………………………………………………………．6卜6．4．1阻性负载实验结果………………………………………………．62．6．4．2逆变器负载实验结果……………………………………………．64．第七章总结与展望………………………………………………………………．．66．7．1总结……………………………………………………………………………………………。

．66．7．2展望……………………………………………………………………………………………．．．66．参考文献…………………………………………………………………………．．68．攻读硕士学位期间发表的论文…………………………………………………．．72．。