正序基波提取器在光伏并网功率调节系统中的应用

摘要

The key for PV grid-connected power conditioning system to realize the uniform control of PV grid-connected and active filter is to correctly detect harmonic and reactive current and form grid-connected directive current. Considering distortion and frequency deviation of the actual grid voltage, to get the correct harmonic, reactive current and synchronous sine, the amplitude integral and selective characteristic of frequency are used to form the positive sequence fundamental extractor. The K in the positive sequence fundamental extractor is further analyzed, and then the operation expression of K is derived. If K is chosen properly, positive-sequence fundamental can be got correctly, and synchronous sine and cosine can be got without the phase lock loop. The detecting method for the harmonic, reactive power, and the sum of unsymmetrical components, as well as the grid-connected directive current composing method is analyzed to realize the active power injection, harmonic eliminating and reactive power compensation. The simulation in Matlab/Simulink verifies the correctness of the theoretical analysis. For the effect of K on the positive-sequence fundamental extracting, the miniwatt experiment is conducted to further verify the correctness of the method.%光伏并网功率调节系统实现光伏并网与有源滤波的统一控制，关键是谐波、无功电流的准确检测和并网指令电流的形成。考虑实际电网电压有畸变或频率偏差，为获得准确谐波、无功电流和同步正弦，利用幅值积分及其频率选择特性构成正序基波提取器，深入分析正序基波提取器中K参数设计方法，推导出K值的计算表达式，合理取K值，可准确提取正序基波，无需锁相环可得到同步正、余弦信号。分析了谐波、无功及不对称分量之和的检测方法和并网指令电流的合成方式，实现光伏有功注入与谐波抑制、无功补偿功能。最后进行Matlab/Simulink仿真，仿真结果验证了理论分析的正确性。针对K参数对正序基波提取的影响，完成了其小功率实验，实验结果进一步证明该方法的正确性。