随着电力电子装置等非线性负载的广泛使用，公用电网中的谐波污染问题越来越严重，造成电能质量不断下降，因此治理谐波污染改善电能质量就显得尤为迫切。目前，有源电力滤波器是一种能够实现动态补偿谐波的理想装置，对降低电网总谐波畸变率，改善电能质量有着重要意义。 谐波补偿的前提是需要实时而准确地检测出电网电流中的谐波电流，由于有源电力滤波器大多采用基于瞬时无功功率理论的谐波检测算法，尤其在采用该理论下的 谐波检测算法进行谐波电流检测时，需要锁相环在电网电压非理想工况下也能够准确获取电网频率和相位信息。针对该要求，利用二阶广义积分器和在αβ坐标系下的对称分量法对传统的SRF-SPLL进行改进，设计了一种DSOGI-SPLL，它既可准确获取电网正序分量的相位和频率，又可避免电网电压三相不平衡和谐波的影响。通过MATLAB仿真分析表明了该方法能够在电网电压非理想工况下准确获取电网电压的相位信息。 有源电力滤波器检测出谐波电流并运算得出谐波指令电流，此时需要控制APF实际输出的补偿电流对谐波指令电流进行跟踪。由于传统滞环电流控制方法存在跟踪性能差、开关损耗高等问题，为了降低电流跟踪误差、开关频率和提高补偿性能，利用电压空间矢量方法设计出一种空间矢量滞环电流控制方法，它利用参考电压矢量和电流跟踪误差矢量的空间分布位置选取最优的输出电压矢量。通过对两种控制方法的仿真对比研究，表明了设计的控制方法能够降低电流跟踪误差和开关频率，进而提高补偿效果。 根据上述谐波检测及锁相环技术和补偿电流控制方法，完成了并联型APF系统的软硬件设计，并分别对DSOGI-SPLL技术及 谐波检测算法和空间矢量滞环电流控制方法进行了实验，实验结果表明了设计的DSOGI-SPLL能够实时准确地获取电网电压的相位信息；利用该锁相环下的 谐波检测算法能够准确检测出谐波电流；空间矢量滞环电流控制方法也能够控制APF输出补偿电流完成谐波补偿，使电网总谐波畸变率由原来的23.68%降低至3.37%，进而改善电能质量，达到APF的设计要求。

With the widespread use of non-linear loads such as power electronic devices, the problem of harmonic pollution in the public power grid is getting more and more serious, resulting in continuous decline in power quality. Therefore, it is particularly urgent to control harmonic pollution to improve power quality. At present, the active power filter is an ideal device that can achieve dynamic compensation of harmonics, which is of great significance for reducing the total harmonic distortion rate of the power grid and improving the power quality. The premise of harmonic compensation is the need to accurately detect the harmonic current in the grid current in real time. Because active power filters mostly use harmonic detection algorithms based on the instantaneous reactive power theory, especially the harmonic detection under this theory. When the algorithm is used for harmonic current detection, the phase locked loop is required to accurately obtain grid frequency and phase information under non-ideal operating conditions of the grid voltage. For this requirement, the conventional SRF-SPLL is improved by using the second-order generalized integrator and the symmetrical component method in the αβ coordinate system. A kind of DSOGI-SPLL is designed. It can not only obtain the phase and frequency of the positive sequence component of the power grid, but also avoid the influence of the three-phase unbalanced and harmonious wave of the grid voltage. The MATLAB simulation analysis shows that this method can accurately obtain the phase information of the grid voltage under non-ideal conditions of grid voltage. The active power filter detects the harmonic current and calculates the harmonic command current. In this case, it is necessary to control the compensation current actually output by the APF to track the harmonic command current. Because the traditional hysteretic current control method has the problems of poor tracking performance and high switching loss, in order to reduce the current tracking error, switching frequency and improve the compensation performance, a space vector hysteresis current control method is designed by using the voltage space vector method. The location of the spatial distribution of the voltage vector and the current tracking error vector selects the optimal output voltage vector. Through simulation analysis of the two control methods, it is shown that the designed control method can reduce the current tracking error and switching frequency, thereby improving the compensation effect. According to the above harmonic detection and phase-locked loop technology and compensation current control method, the hardware and software design of the parallel APF system was completed, and the DSOGI-SPLL technology, the harmonic detection algorithm and space vector hysteresis current control method were respectively tested. The experimental results show that the designed DSOGI-SPLL can accurately obtain the phase information of the grid voltage in real time; the harmonic detection algorithm under the phase-locked loop can accurately detect the harmonic current; and the space vector hysteresis current control method can also control the APF. The output compensation current completes the harmonic compensation, reducing the total harmonic distortion ratio of the power grid from the original 23.68% to 3.37%, thereby improving the power quality and achieving the APF design requirements.