一种基于双定频SOGI与交叉补偿的三相锁相环设计方法

基于频率自适应二阶广义积分器(second-order generalized integrator, SOGI)的锁相技术因其具有良好的滤波性能，常与滑模观测器(sliding mode observer, SMO)相结合来解决电网电压存在的直流偏置、频率偏移以及相位跳变等问题。针对常规的频率自适应SOGI锁相环(phase-locked loop, PLL)的前级SOGI与后级PLL之间存在频率耦合导致锁相环的动态性能较差的问题，提出了一种基于双定频SOGI与交叉补偿的锁相环设计方法。所提方法采用定频SOGI代替频率自适应SOGI，消除了前级SOGI与后级PLL之间的频率耦合。同时设计了一种电网电压交叉补偿的方法，该方法能够精准地对电网电压相位和幅值进行同时补偿，改善了传统的补偿方法需将幅值和相位单独补偿的缺点。并详细推导了常规的基于频率自适应SOGI锁相环和所提基于定频SOGI的锁相环的小信号模型，并证明了所提出的PLL稳定性更高。最后，在不同电网电压工况下，通过对比实验研究验证了所提方法的有效性。

A three-phase phase-locked loop design method based on improved frequency-fixed DSOGI and cross-compensation

Phase-locked loop technology based on a frequency adaptive second-order generalized integrator (SOGI) is often combined with a sliding mode observer (SMO) because of its good filtering performance to solve the problems of DC offset, frequency deviation, and phase jump of power grid voltage. For conventional frequency-adaptive SOGI phase-locked loop (PLL), there is frequency coupling between the front-end SOGI block and the back-end PLL block, resulting in poor dynamic performance of the PLL. The proposed method uses frequency-fixed SOGI instead of frequency-adaptive SOGI, eliminating the frequency coupling between the front-end SOGI block and the back-end PLL block. At the same time, a method for cross-compensation of grid voltage is designed. This can accurately compensate for both the phase and amplitude of grid voltage simultaneously, improving the disadvantage of traditional compensation methods that require separate compensation for amplitude and phase. The conventional frequency-adaptive SOGI based PLL and the small-signal model of the proposed frequency-fixed SOGI based PLL is derived in detail, and comparative analysis proves that the proposed PLL is more stable. Finally, the effectiveness of the proposed method is verified through comparative experimental research in different grid voltage conditions.