电网电压不平衡时星接链式SVG控制算法

Control Strategy of Star-connected Cascade SVG Under Unbalanced Grid Condition

建立了星接链式静止无功发生器(SVG)在三相静止坐标系和双同步旋转坐标系下的数学模型,分析了电网电压不平衡对星接链式SVG运行产生的影响。提出在双同步旋转坐标系下对星接链式SVG进行电流闭环控制,并通过注入负序电流指令以实现SVG三相输入有功功率平衡。通过相量分析的方法推导了正、负序电流指令的计算公式,所得结果简洁易实现。最后搭建了6 kV星接链式SVG的RTDS实验模型,实验验证了所提控制算法的正确性和可行性。

The mathematical model of star-connected cascade static var generator （SVG） in three-phase stationary fra- me and dual synchronous rotating frame is established.Currents closed-loop control strategy in dual synchronous rotat- ing frame is proposed, and the balance of three-phase input active power will be realized by the injection of negative sequence current reference.The expressions of positive and negative sequence current reference are also derived by vec- tor analysis method,the results seems simple and easy to implement.RTDS simulation model of 6 kV star-configuration cas-cade SVG is built up, the simulation results prove the correctness and feasibility of the proposed control strategy.