An improved Single phase Locked Loop Applied to Frequency Measurement of Charging Pile

Due to the increasing number of distributed new energy sources and various types of access, the complexity of grid voltage conditions has escalated. At the same time, the increase in the number of electric vehicles and the wide use of various types of batteries also make the charging demand more complicated. In order to achieve the auxiliary frequency modulation function of charging piles, it is necessary to track the phase and frequency of the power grid more quickly and accurately. In this paper, an enhanced PLL based on a second-order generalized integrator (SOGI) is proposed. A more precise small signal approximation method is employed to improve error tracking accuracy, while suitable filters are added to enhance PLL’s anti-interference performance. The control parameters are adjusted through quantitative analysis of multiple indices, with discretization enabling the realization of the PLL, which is easy to migrate to the charging pile module. Through meticulous high-precision simulation, it has been demonstrated that the designed PLL can rapidly and accurately track power grid frequency information under diverse complex operating conditions.