High Order Harmonic Error Compensation Strategy of Voltage Based on Phase-Locked Loop

Because distributed new energy and diversified loads are widely connected to the power grid, the traditional phase locked loop (SRF-PLL) structure based on single synchronous rotating coordinate system cannot accurately track the phase, frequency and other parameters of the power grid under complex working conditions. Therefore, this paper proposes an improved PLL to solve the problem that the output frequency and phase of the traditional SRF-PLL will have large fluctuations in the case of three-phase voltage sampling error, which eliminates the high frequency harmonics in three-phase voltage sampling. The improved PLL module is mainly composed of Clark transform, orthogonal signal generator, positive and negative sequence calculation. The PI controller and integrator are also included with the SRF-PLL.