Analytical Method for Nonlinear Vibration of PLL-type Grid-connected Converter

Abstract

In recent years, large-scale renewable energy equipment has promoted the development of grid-connected converters. Among the existing grid-connected converters, PLL-type grid-connected converters are in an unshakable position in the business. As a key device, PLL also plays an irreplaceable role. However, due to the nonlinear characteristics of PLL itself, traditional linear methods cannot be used for more in-depth research, and the existing methods do not systematically obtain the approximate analytical solution of this kind of nonlinear model. Therefore, based on the PLL-type grid-connected converter model, this paper introduces the nonlinear vibration theory to obtain the approximate analytical solution of the model. Specifically, the dynamic model of a PLL-type grid-connected converter system is obtained through the inherent characteristics of the components. Then the normal perturbation and the averaging method are introduced to derive the approximate analytical solution of the model. Finally, the correctness of approximate analytical solutions is verified through experiments, and the application scenarios of the method are summarized.