一种基于SVPWM的三电平逆变器中点电压平衡控制策略

A Neutral Point Voltage Balance Control Strategy of Three Level Inverter Based on SVPWM

在大功率高压逆变器应用中,三电平逆变器相较于两电平逆变器具有很多的优点,然而中点电压不平衡是二极管钳位型三电平逆变器的固有问题。基于SVPWM分析了中点电压不平衡原理,提出采用滞环比较法和平衡因子法对中点电压进行平衡控制。低调制度时采用滞环比较法和平衡因子法来平衡中点电压,高调制度时只采用平衡因子法来平衡中点电压。最后在MATLAB/Simulink中搭建仿真模型,输出了高质量的中点电压波形,验证了控制策略的可行性和有效性。

The three level inverter has more advantages compared to the two level inverter in high power highvoltage inverter. However, the neutral point voltage unbalance was an inherent problem of diode clamped three levelinverter. The principle of neutral point voltage unbalance was analyzed based on SVPWM. The hysteresis comparisoncontrol method and the balance factor method were proposed to balance the neutral point voltage. Hysteresiscomparison control method and balance factor method were used to balance the neutral point voltage under lowmodulation degree, and the balance factor method was used to balance the neutral point voltage on high modulationdegree. Finally, the simulation model is built in MATLAB/Simulink. And a high quality of the neutral-point voltagewaveform was output. It verifies the feasibility and effectiveness of the control strategy.