软开关三相逆变器磁链轨迹的研究  

RESEARCH ON LOCUS OF FLUX LINKAGE FOR THREE-PHASE ZVS INVERTER

作　　者：许春雨[1] 陈国呈[1] 孙承波[1] 屈克庆[1] 

机构地区：[1]上海大学机电与自动化学院,上海200072

出　　处：《中国电机工程学报》2004年第8期29-33,共5页Proceedings of the CSEE

基　　金：国家自然科学基金项目(59977012)~~

摘　　要：近年来零电压开关PWM变频技术受到人们的普遍关注。其基本思想是,通过零电压开关电路使逆变器主电路在各载波周期起始时刻产生谐振,确保各功率开关器件在主电路P、N极间电压为零期间进行动作切换。为了使谐振电路正常工作,通常采用正负斜率交替的锯齿波作为 载波,这使得该PWM模式的零电压矢量的作用时间较传统硬开关SPWM模式发生很大变化。该文利用空间电压矢量概念,深入分析了软开关PWM模式下磁链的运动轨迹。指出在硬开关:PWM模式下,磁链的运动速度靠零空间电压矢量调节;而在软开关PWM模式下,空间电压矢量的作用时间发生了很大变化,有时甚至没有零空间电压矢量。但该模式依靠非零空间电压矢量进行调节,使得磁链的运动速度仍然保持与硬开关时完全相等。文章还分析了软开关PWM逆变器电流波形畸变的原因,并从磁链轨迹圆出发,提出相应的补偿方法。实验证明了该方法能有效地改善逆变器的输出电流波形。Recently, more attention is paid to ZVS PWM Inverter. Its basic idea is to use ZVS circuit which makes the main circuit of inverter resonate at every beginning of carrier period, so each power devices can be commutate when the voltage of main circuit's DC bus line is zero. To ensure the resonant circuit operates properly, sawtooth with alternate slope (positive or negative) is proposed as carrier. But the action time of zero voltage vectors with such PWM pattern has great difference to that of traditional hard-switching PWM pattern. This paper discusses the locus of flux linkage under soft-switching PWM pattern by using space voltage vector in detail. It points out that under the hard-switching PWM pattern, the movement speed of flux linkage is adjusted by zero space voltage vector, but when soft-switching PWM pattern is used, effect time of space voltage vector vary greatly, sometimes even no zero space voltage vector exist. So non-zero space voltage vector has been used to make the speed of flux linkage locus equals to that of hard-switching PWM pattern. The reason of soft-switching PWM inverter's current distortion has also been discussed, according to flux linkage locus circle, corresponding compensation methods are put forward. Experiment results prove such method can effectively improve output current waveform of inverter.

关 键 词：三相逆变器 磁链轨迹 PWM 调制原理 功率开关器件 电磁干扰 软开关 

分 类 号：TM464[电气工程—电器]