Controller parameters design of a fractional‐order LCL‐type grid‐connected inverter

Abstract

SummaryThe grid‐connected inverter (GCI) based on the fractional‐order LCL (FOLCL) filter can achieve good attenuation of resonant peak and simplify the control system design by omitting the capacitor current feedback as long as the orders of the inductor and capacitor are set appropriately. This paper investigates the parameter design methods of four types of controllers based on a single‐phase FOLCL‐type GCI without capacitor current feedback; the four controllers are the integer‐order proportional integral controller, fractional‐order proportional integral controller, integer‐order proportional resonance controller, and fractional‐order proportional resonance controller. Closed‐loop constraints based on steady‐state error, phase margin, and gain margin are given to design the specific parameters of each controller. The methods can accurately and quickly obtain the appropriate controller parameters to meet the system performance requirements without repeated trial and error. Simulations and hardware‐in‐the‐loop experiments verify the validity of the theoretical analyses.