J Electr Eng Technol.2016; 11(?): 1921-718 http://dx.doi.org/10.5370/JEET.2016.11.1.1921 1921 Copyright ⓒ The Korean Institute of Electrical Engineers This is an Open-Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http://creativecommons.org/ licenses/by-nc/3.0/) which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited. Model Predictive Control for Shunt Active Power Filter in Synchronous Reference Frame A. K. Al-Othman † , M. E. AlSharidah*, Nabil A. Ahmed** and Bader. N. Alajmi* Abstract – This paper presents a model predictive control for shunt active power filters in synchronous reference frame using space vector pulse-width modulation (SVPWM). The three phase load currents are transformed into synchronous rotating reference frame in order to reduce the order of the control system. The proposed current controller calculates reference current command for harmonic current components in synchronous frame. The fundamental load current components are transformed into dc components revealing only the harmonics. The predictive current controller will add robustness and fast compensation to generate commands to the SVPWM which minimizes switching frequency while maintaining fast harmonic compensation. By using the model predictive control, the optimal switching state to be applied to the next sampling time is selected. The filter current contains only the harmonic components, which are the reference compensating currents. In this method the supply current will be equal to the fundamental component of load current and a part of the current at fundamental frequency for losses of the inverter. Mathematical analysis and the feasibility of the suggested approach are verified through simulation results under steady state and transient conditions for non-linear load. The effectiveness of the proposed controller is confirmed through experimental validation. Keywords: Active power filter, Model predictive control, Synchronous reference frame Harmonic compensation, dSPACE controller 1. Introduction Power electronic devices impose nonlinear loads on the ac mains, such as single-phase and three-phase diode rectifiers, thyristor converters and electronic appliances [1]. Aluminum smelter plants and large electrolysis chemical plants, in which large DC rectifiers with high power ratings, are usually used [2, 3]. They generate considerable amounts of characteristic and non-characteristic harmonics, which will be harmful for other loads connected to the same bus. In such plants, auxiliary control, protection measuring systems and kWh counters severely suffer from these harmonics [4]. Also, large DC drives used in cement factories or in electric traction application generate enormous harmonics. DC arc furnaces generate several harmonics in the feeding system [5, 6]. Electrolysis of water and wind mill generators are other examples of harmonic pollution. Many international agencies have implemented firm harmonic restrictions to electronic equipment [7, 8]. To overcome these problems, classically, passive LC filters are used to eliminate the current harmonics and to improve the power factor. However, passive LC filters are bulky, load dependent and inflexible [9, 10]. As a result, a vast number of power factor correction techniques have been developed in compliance with these regulations [11, 12]. As an alternative, parallel harmonic correction techniques, shunt active power filters (APFs), have been explored by many researchers and considered as a possible solution for reducing current harmonics and improving the power quality [13-14]. The APF is required to generate a matched reactive and harmonic current to compensate for the negative effect of nonlinear loads on the line, thus it handles only the fraction of the total power supplied to the load. Many articles have been published that focus on obtaining the current reference for three-phase or single- phase APF. Standard APFs configurations require the measurement of both load and filter currents with reference current regulators implemented by hysteresis and PWM modulators. Ozdemir et al. proposed a simplified control algorithm for shunt APF without load and filter current measurement in [15]. In [16], Chen developed a state-space model of the four-leg APF based on H controller for current tracking from the passivity point of view based on 4-leg VSI. In [17], APF is combined with thyristor switched capacitor for the purpose of reducing cost. A model predictive control (MPC) is presented where Fuzzy model predictive control [18] and neural network predictive control [19] are used in shunt APFs, but the control designs are still complicated. Mohanty evaluates † Corresponding Author: Dept. of Electrical Engineering, College of Technological Studies, Kuwait. (ak.alothman@paaet.edu.kw ) * Dept. of Electrical Engineering, College of Technological Studies, Kuwait. (malshar@gmail.com, bna01@hotmail.com ) ** Dept. of Electrical Engineering, College of Technological Studies, Kuwait. (na.ahmed@paaet.edu.kw ), on leave from Assiut University, Egypt. Received: August 15, 2015; Accepted: November 10, 2015 ISSN(Print) 1975-0102 ISSN(Online) 2093-7423