变频器参数及调制方式对共模电压的影响  

Influences of Converter Parameters and Modulation Methods on Common-mode Voltage

作　　者：刘瑞芳[1] 孟延停 康强[1] LIU Ruifang MENG Yanting KANG Qiang(School of Electrical Engineering,Beijing Jiaotong University,Beijing 100044, China)

机构地区：[1]北京交通大学电气工程学院,北京100044

出　　处：《电源学报》2017年第3期71-77,共7页Journal of Power Supply

基　　金：国家自然科学基金资助项目(51107004)~~

摘　　要：PWM变频器被广泛应用于在电机驱动系统中,但其输出电压中的共模电压会产生许多负面效应,因此确定影响共模电压的各种因素对提出有效的共模电压抑制策略有重要的意义。采用解析、仿真和实验验证的方法围绕变频器参数和调制方式对共模电压的影响展开研究,研究结果表明:变频器参数中直流母线电压利用率增大时共模电压减小;载波比变化时共模电压基本不变;死区时间增加时共模电压增大;不同调制方式SPWM和SVPWM在相同直流母线电压利用率下的共模电压大小相近。进一步讨论了在VVVF控制调速时直流母线利用率和载波比同时变化时共模电压的变化规律,实验表明低速时共模电压更大,应当重视电机低速时共模电压产生的危害。Pulse width modulation（PWM） inverters are widely used in the motor driving systems,but the common mode voltage from the output voltage induces lots of negative effects. Analysis of the influential factors of the common mode voltage is very important to proposing common mode voltage suppression strategies. Through analytical solution, simulation and experiment,this paper studies the influence of the inverter parameters and the modulation mode on the common mode voltage. The results show that with the increase of utilization of DC voltage rate,the common-mode voltage decreases; the common mode voltage is basically unchanged when the carrier ratio changes; with the increase of dead time,the common-mode voltage also increases. Under the different modulation modes,the common mode voltages of sinusoidal pulse width modulation（SPWM） and space vector pulse width modulation（SVPWM） are similar under same utiliza-tion of DC voltage rate. This paper has a further discussion of the common mode voltage on VVVF control when both utilization of DC voltage rate and carrier ratio change simultaneously. The experimental results show that the common mode voltage is larger while the motors are under low speed than high speed, and the suppression should be given attention on motors at low speed.

关 键 词：PWM变频器 共模电压 SPWM SVPWM 

分 类 号：TM315[电气工程—电机]