二阶广义积分器的三种改进结构及其锁相环应用对比分析

二阶广义积分器(SOGI)可以提取三相电网电压信号中的基波正序分量,通过锁相得到精确的电网相位信息。而SOGI本身存在对输入信号频率依赖性强的缺陷,为此提出三种改进型SOGI。对三种改进型SOGI进行详细的对比分析,并将其应用到锁相环(PLL)中。之后将三种改进型SOGI-PLL分别在电网电压不平衡、含有直流分量和含有高次谐波的情况下进行对比实验,可以证明改进Ⅲ型SOGI-PLL具有更好的电网适应性。最后,通过实验验证了理论分析的正确性和可行性,并给出了结论。

Three Improved Second Order Generalized Integrators and the Comparative Analysis in Phase Locked Loop Application

Second order generalized integrator (SOGI) can extract the fundamental positive sequence component from three-phase grid voltage signals and obtain the accurate input signal phase by phase-locked loops (PLL). The traditional SOGI has a strong dependence on the input signal frequency, so three improved SOGIs are proposed in the paper. This paper mainly focuses on the detailed comparative analysis of the three improved SOGIs and applies them to PLL. The comparative experiments of three improved SOGI-PLLs are implemented under the conditions of grid voltage imbalance, containing DC components or containing higher harmonics. It can be proved that the improved Ⅲ-type SOGI-PLL has better adaptability to the grid. The correctness and feasibility of the theoretical analysis are verified by the experimental results.