Title: Model predictive current control with duty ratio optimisation for a three-phase grid-tied inverter based on Runge-Kutta approximation

Authors: Shahrouz Ebrahimpanah; Qihong Chen; Liyan Zhang

Addresses: School of Automation, Wuhan University of Technology, Wuhan, China ' School of Automation, Wuhan University of Technology, Wuhan, China ' School of Automation, Wuhan University of Technology, Wuhan, China

Abstract: This paper proposes a model predictive current control for a three-phase inverter connected to the grid by using a duty cycle optimisation based on Runge-Kutta approximation. In this method, each of the seven possible switching states is checked to find one that minimises the cost function. It is a fact that the current ripples cannot decrease to a minimum value because there is only one voltage vector during one control period, thus the sampling frequency should be selected high for a sufficient performance. In order to find a solution to this problem, a duty ratio optimisation technique based on Runge-Kutta approximation is introduced by using a non-zero and a zero voltage vector. Moreover, the duration of the two voltage vectors are selected according to the current error minimisation. Simulation and experimental results verify that the proposed method obtains reduced current ripples and lower total harmonic distortions compared to the conventional method.

Keywords: model predictive current control; MPCC; cost function; three-phase grid tied inverter; total harmonic distortions; THD.

DOI: 10.1504/IJPELEC.2021.117066

International Journal of Power Electronics, 2021 Vol.14 No.2, pp.216 - 238

Received: 01 Jan 2019
Accepted: 09 Mar 2019

Published online: 13 Jul 2021 *

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