基于序分量法的D-STATCOM直接功率控制策略研究

摘要

将基于序分量法的 P-DPC 引入到配电网静止同步补偿器(D-STATCOM)的控制研究中，来解决传统预测直接功率控制策略只可控制补偿负荷无功功率的问题。将电网电压不对称因素考虑在内，利用瞬时对称分量法对各个采集电气量进行序分解，构建正、负序等效电路。无功和三相不平衡负荷补偿时，根据序网络等效电路分别推得正、负序功率预测模型。基于正序功率预测模型的P-DPC算法控制D-STATCOM补偿负荷无功，而基于负序功率预测模型的D-DPC算法控制补偿负荷所需负序电流。两种算法相互牵制，严格控制了D-STATCOM的输出电流，消除了装置在电网电压不对称时可能产生的过流威胁，实现了负荷无功和平衡化补偿。仿真结果表明，不论电网电压对称与否，该控制策略都能良好地补偿负荷的无功和负序电流，确保电源侧三相电流平衡且单位功率因数运行。%Predictive direct power control (P-DPC) strategy based on sequence componentmethod is introduced to control static synchronous compensator of distributionnetwork, so as to solve the incapability of compensation of three-phase unbalanced load current. Taking the influence ofnegative voltage into account, first of all, instantaneous symmetrical component method is applied to every electricalmeasurements to construct sequence equivalent circuit.Then positive andnegative sequence power predictive models can be deduced.The P-DPC based on positive power predictive model is used inD-STATCOM to compensate reactive power; and thenegative predictive model is adopted to realize the compensation ofnegative load current.Two different controlstrategies arecombined to regulate the output current of D-STATCOM strictly, as a result, thethreat of converterovercurrent caused bynegative voltage iseliminated and the compensation of reactive power andnegative load current is achieved. Simulation results verify the validity of the proposed control strategy even under unbalance voltage.