Based on the characteristics of multi variable,strong coupling and nonlinear in static var compensator (DSTATCOM) system,the need for improving the performance of the DSTATCOM is sensed more and more due to the importance of compensating the reactive power and negative sequence current.Hence,one of the nonlinear control methods which combining the merits of state feedback exact linearization control,sliding mode control and space vector pulse width moduation(SVPWM) in DSTATCOM system is developed.A novel control method for the DSTATCOM in compensating unbalance load is proposed also.The proposed novel control method is using instantaneous symmetrical component and delay signal cancellation (DSC) to calculate the positive and negative component of DSTATCOM output current and three phase load current.The experiment which conducted with unbalanced load verify the validity of compensation algorithm,and also show that the SVPWM based DSTATCOM can compensate reactive power and load unbalance synchronously.The total harmonic distortion(THD) of supply current is obtained below 5％ with unity power factor under different load conditions,and the grid side current is balanced that meet the requirements of national standard.%低压配电网中,通常使用静止同步补偿器(DSTATCOM)补偿无功功率和不平衡负载造成的负序电流,针对DSTATCOM具有强耦合、多变量、非线性特性,提出一种综合滑模控制、状态反馈精确线性化和空间矢量调制(SVPWM)的非线性控制方法.三相不平衡负载下,采用瞬时对称分量法和信号延迟对消(DSC)法计算出负载电流、DSTATCOM输出电流正、负序分量,然后分别对正、负序分量进行非线性控制.实验表明采用新型控制策略的DSTATCOM在不平衡负载下,有效补偿了无功电流和负序电流,实现了电网单位功率因数,电网电流总谐波畸变率(THD)低于5％,不平衡度达到国标要求.
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