Optimalization of SOGI PLL for single-phase converter control systems: Second order generalized integrator (SOGI)

A precise and robust synchronization of a control system of single-phase converters connected to ac power grid is a key factor for proper function of these devices. This paper presents optimization of Second Order General Integrator Phase Locked Loop (SOGI PLL) and its implementation. The SOGI makes it possible to identify the position of either the power grid voltage or current vector in a stationary reference frame. The presented method is able to secure fast response on amplitude steps of input signal and hence track precisely the fundamental harmonic of the input signal.