电网不平衡时三相四线整流器控制策略研究

The Control Strategy of Three-phase Four-wire Rectifier Under Unbalanced Grid Voltage

提出了一种三相四线脉宽调制(PWM)整流器在不平衡电网下的控制方法。该方法通过分析静止坐标系下三相四线PWM整流器的有功、无功、零序功率,在保证直流侧电压稳定及交流侧单位功率因数的条件下计算出指令电流。该方法外环采用传统的电压环,内环电流采用有限控制状态模型预测控制(FCS-MPC)。和传统方法相比,所提方法无需提取电网电压、电流的正负序分量,有效降低了计算的复杂性。在电网不平衡时,该方法能够减小整流器直流侧电压波动和有功功率的波动。同时,简化了在线计算过程,易于工程实践,保证了良好的动态性能和电流跟踪能力。最后通过试验对所提方法的正确性与可行性进行了验证。

This paper presents a control method of three-phase four-wire pulse width modulation （PWM） rectifier un- der unbalance grid voltage.The method analysis active power, reactive power, zero-sequence power of three-phase four- wire rectifier in stationary frame, the reference current is calculated to ensure stable DC bus voltage and unit power factor at AC side.This method uses conventional voltage outer loop, using the finite control set model predictive con- trol（FCS-MPC） of inner current.Compared with the traditional method,the proposed method does not need to extract positive-sequence and negative-sequence components of the grid voltage and current, effectively reduce the computa- tional complexity.This method can reduce the fluctuation of the rectifier DC voltage and active power.In addition it re- duces the computational diffficuhy,easy to practical application,and ensure good dynamic performance and current tracking ability.Finally, Experiment results verify the correctness and effectiveness of the proposed control method.