注入3次谐波控制的共模电压分析  

Research on common-mode voltage with third-order harmonic injection

作　　者：黄守道[1] 葛照强[1] 肖慧慧[1] 叶光辉[1] 

机构地区：[1]湖南大学电气与信息工程学院,湖南长沙410082

出　　处：《电力自动化设备》2006年第9期8-11,共4页Electric Power Automation Equipment

摘　　要：由于功率器件仅有2个开关状态,输出电压只能离散变化,造成中性点存在共模电压,对电机的运行产生负面效应。以传统两电平变频器和级联型高压变频器为例,分析了共模电压产生机理和3次谐波注入理论,在此基础上,分析注入3次谐波在提高直流电压利用率的同时,对输出共模电压造成的影响。经对比发现,共模电压新增加了3次谐波电压成分,当调制比取最大值时,共模电压中3次谐波电压幅值达到最大,加剧了共模电压对电机可靠运行的影响。通过Matlab仿真,验证了理论分析的正确性,并进一步说明了,对采用同相调制算法的变频器,注入3次谐波将导致共模电压增加。Power devices have only two states,their output voltage is common-mode voltage exists in the neutral point,which will cause negative tion. With traditional two-level inverter and cascade high-voltage inverter as e discontinuous and the effect on motor operaxamples,the mechanism of common-mode voltage generation and the theory of third-order harmonic injection are studied. When the third-order harmonic is injected to raise the usage factor of DC voltage,its influence on common-mode voltage is analyzed. There is third-order harmonic component added in common -mode voltage. When maximal modulation ratio is selected,the amplitude of the third- order harmonic voltage in common-mode voltage also reaches the maximum,which may further affect the reliable operation of generators. Simulations with Matlab prove the correctness of theoretic analysis and illuminate that the third- order harmonic injection into inverter controlled by in- phase modulation will increase common-mode voltage.

关 键 词：共模电压 3次谐波 高压变频器 级联 

分 类 号：TM714.2[电气工程—电力系统及自动化]