电压畸变和不平衡状态下无锁相环UPQC补偿量检测方法

针对电网电压畸变和不平衡状态下采用锁相环所带来的缺陷,提出一种无锁相环UPQC补偿量检测方法。该方法基于同步坐标变换理论,在DSP内部建立的虚拟正余弦函数表基础上对三相电网电压进行同步坐标变换并获取单位基波正序电压分量,直接求取电压补偿量,随后利用已得结果进行基波正序有功电流的分离,无需对三相电压进行锁相和对电网电流进行同步坐标变换,同时与现有无锁相环方法相比,运算得以进一步简化,可以更加可靠、快速和准确地检测电压、电流补偿量。仿真和实验结果证实该方法用于UPQC电压、电流补偿量检测具有良好的可行性和有效性。

Compensation detection for UPQC without PLL under voltage distortion and unbalance

Aiming at the limitations of PLL under voltage distortion and unbalance of power grid,a kind of compensation detection without PLL is proposed for UPQC,which,based on the list of virtual sine and cosine functions built in DSP,carries out the synchronous coordinates transformation for three-phase voltage of power grid to get the positive-sequence voltage component of unity fundamental,and then calculates the compensating voltage and separates the positive-sequence active current component of fundamental.Both the PLL of grid voltage and the synchronous coordinates transformation for grid current are cancelled,compared with existing PLL-less detection,it is simpler,faster,more accurate and reliable.Its effectiveness and applicability to UPQC are verified by simulative and experimental results.