A controller design method for 3 phase 4 wire grid connected VSI with LCL filter

Abstract

Closed loop control of a grid connected VSI requires line current control and dc bus voltage control. The closed loop system comprising PR current controller and grid connected VSI with LCL filter is a higher order system. Closed loop control gain expressions are therefore difficult to obtain directly for such systems. In this work a simplified approach has been adopted to find current and voltage controller gain expressions for a 3 phase 4 wire grid connected VSI with LCL filter. The closed loop system considered here utilises PR current controller in natural reference frame and PI controller for dc bus voltage control. Asymptotic frequency response plot and gain bandwidth requirements of the system have been used for current control and voltage controller design. A simplified lower order model, derived for closed loop current control, is used for the dc bus voltage controller design. The adopted design method has been verified through experiments by comparison of the time domain response.

Power Converter Based Impedance Emulation of Passive Loads for Anti-Islanding Tests

“…The proposed control architecture is shown in Fig. 3, where the PLEC is operated in current controlled mode using an inner current loop consisting of a proportional resonant controller (G pri (s)) operating in stationary reference frame [10] and an outer reference generator block providing the required current reference derived from the sensed grid voltage. The bode plots of loop transfer function (G pri (s).G i (s)) and closed loop transfer function of current loop are shown in Fig.…”

“…Calculation of K iri is done by assuming that a band of ± ω o rad/sec around ω o rad/sec in magnitude plot of G pri (s) always has a gain of K i [10].…”

High‐accuracy multi‐rate implementation of resonant integrator using FPGA

“…A fundamental frequency PR controller is implemented in the above-described method for a grid-connected application. Tuning of the controller gains are based on [33]. Grid voltage and current waveform for SS operation of the VSI with LCL filter as an static compensator (STATCOM) are shown in Fig.…”

Battery impedance spectroscopy using bidirectional grid connected converter

“…The inner loop controls the current by a proportional resonant controller. The outer loop controls the dc bus voltage using a PI controller [16].…”