三相四桥臂D-STATCOM电流预测控制方法研究

Research on Current Predictive Control Method for Three-phase Four-leg D-STATCOM

为了解决配电网中存在的三相电流不平衡、谐波污染等问题,本文提出了基于电流预测控制的补偿方法。采用瞬时无功功率理论,计算出所需的补偿电流,然后将电流预测控制方法运用到D-STATCOM,建立其离散化数学模型,采用遍历法推算出在全部开关函数组合分别作用下的补偿器输出电压,并用合适的价值函数来选择最优的开关组合,按照补偿电流的参考值快速输出补偿电流。在PSCAD/EMTDC仿真平台上进行了仿真验证,按照所设计的控制策略,对三相四线制下的不平衡感性负载和注入谐波两种情况进行了无功补偿和谐波消除仿真,仿真结果表明所提出的控制方法能够实现快速的无功补偿和谐波消除。

In order to solve the three-phase currents imbalance and harmonic pollution problems in distribution network,a compensation method based on the current predictive control is presented in this paper.In this paper,the instantaneous reactive power theory is used to calculate the compensation current.Then the current predictive control is applied in the D-STATCOM.Firstly,the discrete-time model of D-STATCOM is built,in which the traversal method is used to evaluate the output voltage of compensator in all switching states,and the optimal switching combination is chosen by using suitable cost function.Then the compensating current is rapidly outputted according to its reference value.In the end,simulations are carried out on the PSCAD/EMTDC platform,based on proposed control strategy,the reactive power compensation and harmonic elimination have been studied under such cases as unbalanced reactive load and input harmonic in three-phase four-wire system.The simulation results show that the proposed method can achieve rapid reactive power compensation and harmonic elimination.