一种抑制三相两电平逆变器电流纹波的变零矢量分配PWM方法

Variable Zero-vector Distribution PWM Method for Current Ripple Suppression of Three-phase Two-level Inverter

三相两电平逆变器广泛应用于交流电机驱动、电能变换等领域。由于逆变器的输出电流含有纹波成分,会给系统带来损耗增加、性能下降等问题。在脉冲位置居中对称的前提下推导了电流纹波模型,分析了脉冲宽度调制PWM(pulse width modulation)技术中开关周期、脉冲占空比和脉冲位置对电流纹波的影响,并提出了一种改变脉冲占空比抑制电流纹波的PWM方法,即变零矢量分配脉冲宽度调制VZDPWM(variable zero-vector distribution pulse width modulation)技术。最后,通过仿真和实验验证了VZDPWM抑制电流纹波的有效性。

The three-phase two-level inverter is widely applied in fields such as AC motor drive and power conversion.Due to the ripple component in the output current from the inverter,some problems will arise in the system,including the increase in loss and performance degradation.On the premise that the position of pulse is symmetrical with respect to its center,a current ripple model is deduced,and the influences of switching period,pulse duty cycle and pulse position in the pulse width modulation(PWM)technology on the current ripple are analyzed.In addition,a variable zerovector distribution pulse width modulation(VZDPWM)technology is proposed,which suppresses the current ripple by changing the pulse duty cycle.Finally,the effectiveness of VZDPWM for current ripple suppression was verified by simulation and experimental results.