An Improved Integrator Discretization Method for Multiple Second-Order Generalized Integrators

Multiple second-order generalized integrators (MSOGI) can extract fundamental waves, harmonics and their orthogonal components in real time, which plays a vital role in power quality assessment, grid synchronization, harmonic compensation and other aspects. Different discretization methods of MSOGI determine the complexity of its implementation and the accuracy of its extraction. The discretization methods of MSOGI can be divided into three categories: the whole transfer function discretization of MSOGI, the transfer function discretization of second-order generalized integrator (SOGI) and the traditional integrator discretization. Among them, the first method is not easy to implement because of the order of transfer function. The latter two methods have some errors in phase angle and orthogonality. In order to pursue better performance, this paper proposes an improved discretization method based on MSOGI integrator discretization. This method has the advantages of small phase angle error, good output orthogonality and so on. It can better meet the discretization requirements of MSOGI with less computation, and is verified by experiments.