减小轻载下Vienna整流过零畸变的优化设计方法

An Optimization Method to Reduce Zero-crossing Distortion for Vienna Rectifier Under Light Load

Vienna变换器凭借高效率、高功率密度、高可靠性的优点,在工业领域得到了广泛的应用。在此分析了电感或采样延时产生过零点电流尖刺及传统七段空间矢量脉宽调制(SVPWM)在过零点断续出现过零点电流平台的原因。提出一种在过零点利用五段式SVPWM替代传统七段式SVPWM的方法,来改善过零畸变。考虑到五段式SVPWM会引入更高的电流纹波,对过零点五段式SVPWM补偿范围进行优化。最后,通过Simulink搭建了Vienna整流模型,并研制一台5 kW的原理样机,验证了过零点采用五段式SVPWM后能改善电流过零波形,轻载下效果更为显著。

Vienna rectifier has the advantages of high efficiency,high power density,high reliability,which is widely used in industrial and other fields.The zero-crossing current spike caused by inductance or sampling delay and the current platform at zero-crossing point caused by discontinuous conduction mode(DCM)with traditional seven-segment space vector pulse width modulation(SVPWM)at zero-crossing point are analyzed.A strategy is proposed to improve the zero-crossing distortion by using five-segment SVPWM instead of seven-segment SVPWM at zero-crossing point.The compensation range can be optimized,considering that five-segment SVPWM will introduce higher current ripple.Finally,the Vienna rectifier model is established in Simulink,the accuracy of the method using five-segment SVPWM at zero-crossing point to improve the zero-crossing distortion are verified by a 5 kW prototype.However,the improvement is significant under light load.