Comparative Analysis of the Effects of Integral Action and Disturbance Feedforward on Current Control of Voltage-Source Converters

Abstract

This paper presents a comparison between integral action and disturbance feedforward in current control of grid converters. The current controllers are designed directly in the discrete-time domain with the objective of similar reference-tracking and disturbance-rejection performance under nominal conditions. Partial compensation of time delays is included in the controller designs. The analytically and experimentally compared properties, in addition to reference tracking and disturbance rejection, are noise sensitivity and robustness to grid impedance variations. The controllers are found to have comparable dynamic performance, although the realized disturbance-rejection performance of the integrator-based controller is slightly better. The disturbance-feedforward-based controller is found to be less susceptible to current measurement noise at the cost of having an additional entry point for noise through the voltage measurement. The integrator-based controller is found more robust to grid impedance variations.