TNPC三电平静止同步补偿器不平衡负荷控制策略

Control Strategy of TNPC Three-level STATCOM Under Unbalanced Load Conditions

负荷不平衡会导致电网损耗增大,关键设备出现过流故障甚至损坏等问题,对此主要研究了T型中点箝位(TNPC)三电平静止同步补偿器(STATCOM)对电网不平衡负荷和无功功率进行综合补偿的方法。首先建立三相三桥臂TNPC STATCOM在两相旋转坐标系下的数学模型,在双闭环控制中加入陷波器实现对负荷正序、负序和零序电流的联合控制,在此基础上完成TNPC拓扑中点平衡控制,保证零序电流控制和中点平衡控制的解耦。最后搭建TNPC静止同步补偿器实验平台,验证了控制策略的有效性。

Unbalanced load will increase the grid losses and lead to the key equipment overcurrent even damage.Based on this problem, the compensation method of T type neutral point clamped （TNPC） three-level static synchronous com- pensator（STATCOM） under grid unbalanced load is presented.Firstly, the mathematic modulation of TNPC STATCOM in rotary two-phase coordinate is established.According to adding the notch filter in double closed loop,the positive, negative and zero sequence current is controlled.Further,neutral point control of TNPC topology is accomplished that makes the zero sequence control and neutral point balance control decouple.Finally,the experimental platform of TNPC three-level STATCOM is built to verify the effectiveness of the coordination control strategy.