基于不平衡电网条件下的整流器预测直接功率控制

Predictive direct power control of rectifier under unbalanced grid condition

电网不平衡时,传统控制方法会加重网侧谐波以及直流侧电压不稳定等问题。通过对PWM整流器建模分析,获得静止坐标系下的预测功率控制模型;使单位周期内的有功功率和无功功率等于给定的参考值,获得控制电压的矢量表达式,并推导出可以满足不平衡电网条件下整流器控制要求的功率补偿,从而实现不平衡条件下的整流器控制。该方法具有拓扑结构简单,动态响应较快,能够有效地实现网侧电流正弦化,单位功率因数,稳定直流侧电压等优点,通过在Simulink环境下搭建其仿真模型充分验证了该方法的正确性和有效性。

If the power grid becomes unbalanced,the traditional control methods may increase the grid-side harmonics and make the DC-side voltage instable. The PWM rectifier is modeled and analyzed to obtain the predictive power control model in the stationary coordinate system. It makes that the active power and reactive power within the unit period are equal to the given reference values to get the vector expression of the controlled voltage. The power compensation which satisfies the requirement of rectifier control under the unbalance grid condition is deduced to realize the rectifier control under unbalanced condition. This method has simple topology structure and fast dynamic response,and can realize the sinusoidal gird-side current effectively,unitize the power factor and stabilize the DC-side current. The correctness and effectiveness of the method are verified by means of simulation model built under Simulink environment.