ANPC⁃5L逆变器电容电压平衡的优化算法

Optimization Algorithm for Capacitor Voltage Balance of ANPC⁃5L Inverter

针对有源中点钳位五电平(ANPC⁃5L)逆变器在g-h坐标系的空间矢量脉宽(SVPWM)算法下的悬浮电容电压和直流电容中点电压发散问题,提出了一种建立边沿触发脉冲控制开关状态时间的方法,降低悬浮电容电压波动,减小直流侧电容电压偏移。通过悬浮电容电流波动导致悬浮电容电压偏移的原理,依据不同开关状态下输出相同的电平,且不同开关状态导致悬浮电容电流方向相反的原理,在一个完整周期内,使得悬浮电容电流相互抵消,降低悬浮电容电压波动。建立一种主动功率流动模型,通过减小悬浮电容电压波动来实现直流侧电容中点电压的平衡。最后,通过搭建仿真平台,对比应用所提方法前后ANPC⁃5L的电容电压平衡情况,使方法的有效性得到验证。

A method for establishing edge triggered pulse control switch state time was proposed to address the divergence of floating capacitor voltage and DC capacitor midpoint voltage in a 5-level active neutral point clamped(ANPC-5L)inverter using the space vector pulse width(SVPWM)algorithm in the g-h coordinate system.The fluctuation of floating capacitor voltage and the offset of DC side capacitor voltage were reduced.The principle that the fluctuation of the floating capacitor current causes the voltage deviation of the floating capacitor was used.Based on the principle that the same level is output under different switch states,and different switch states cause the current direction of the floating capacitor to be opposite,within a complete cycle,the floating capacitor current cancels out each other,reducing the voltage fluctuation of the floating capacitor.An active power flow model was established to balance the midpoint voltage of the DC side capacitor by reducing the voltage fluctuation of the floating capacitor.Finally,by building a simulation platform and comparing the capacitor voltage balance of ANPC-5L before and after the application of the proposed method,the validity of the method was verified.