A Design Algorithm for Multivariable Linear Quadratic Integral Controllers in Voltage-Source Converters

This paper presents a voltage control design algorithm for a three-phase voltage source converter (VSC) connected to a linear load using a passive LCL filter. The controller is based on an optimal regulator, combined with the integral of the voltage error, which is called LQI that achieves null tracking of the error. The main objective of this paper is to present an algorithm to design a voltage controller through frequency analysis of the singular values of the system, the weight of the states involved in the system, the movement of the closed poles and their respective step response to evaluate performance and robustness against load changes. The simulation results show a satisfactory operation of the voltage controller with fast recovery after a resistive load change.