Advanced Research in Electrical and Electronic Engineering Print ISSN: 2349-5804; Online ISSN: 2349-5812 Volume 1, Number 4 (2014) pp. 32-36 © Krishi Sanskriti Publications http://www.krishisanskriti.org/areee.html Simulink Based Performance Analysis of PID Controller for Single Phase Grid Connected Voltage Source Inverter Puneet Singla 1 , Ajai Kumar Singh 2 1,2 Electrical Engineering Deptt., D.C.R. Univ. of Sci. & Tech. , Murthal, Sonepat, India Abstract: With the increase in load demand, the Renewable Energy Sources are increasingly connected in the distribution systems which utilizes power electronic Converters/Inverters. PWM based Voltage Source inverters are mostly meant for synchronizing the utility grid to the distributed generation system. Following objectives are meant to be achieved for a grid connected PWM inverter in order to meet the growing energy demand: 1) To ensure grid stability 2) Active and reactive power control 3) Power quality improvement (i.e. harmonic elimination) etc. This paper describes a control method for single phase grid connected inverter system. The inverter performance is largely depends on the applied current control strategy. In this, for current control of the PWM-VSI, proportional integral derivative controller (PID) is employed to enhance the power quality by diminishing current error. An analysis of hysteresis controller is studied for providing control of a grid connected inverter. The hysteresis controller along with PID controller is analyzed for controlling the harmonic content in current. The studied system is modeled and simulated in the MATLAB/Simulink environment and the results obtained from PID controllers are compared with hysteresis Controller. 1. INTRODUCTION Due to rapid population growth and global industrialization, the electrical energy demand is growing exponentially. To meet the future energy crisis, DG is one of the viable options because of its environmental friendliness, lower cost and easy availability. To increase the effectiveness of the DG’s it must be synchronized with the utility grid [1]. In most of the cases current controlled PWM-VSI is used to match the characteristics of the DGs and requirement of the grid connection, including active and reactive power control through frequency and voltage control and harmonic minimization etc. [2]. To inject high quality power to the utility grid the current control scheme for the grid connected PWM-VSI plays a predominate role. Inspite of the several advantages, the main technical challenge is the synchronization of the DGs with the utility grid according to the grid code requirements [3]. In most of the cases power electronics converter, especially current controlled PWM-VSI is used for the integration of the DGs with utility grid. The main objectives of the control of grid connected PWM-VSI are: 1) to ensure grid stability 2) active and reactive power control 3) power quality improvement (i.e. harmonic elimination) etc. Distributed generation systems and their interconnection should meet certain requirements and specifications when interconnecting with existing electric power systems (EPS). For an inverter-based distributed generator, the power quality largely depends on the inverter controller’s performance. As compared with the open loop voltage PWM converters, the current controlled PWM has several advantages such as fast dynamic response, inherent peak current protection, good dc- link utilization, instantaneous current control etc. [4]. Pulse width modulation (PWM) is the most popular control technique for grid-connected inverters. Among the various PWM techniques, the hysteresis band current control is used very often because of its simplicity of implementation. Also, besides fast response current loop, the method does not need any knowledge of load parameters. There are many researches in implementation hysteresis current control, for example in [5]-[8], but many have yet to implement together with the grid. For quick current controllability, unconditioned stability, good current tracking accuracy and easy implementation, the hysteresis band current control (HBCC) technique has the highest rate among other current control methods such as sinusoidal PWM. However, the bandwidth of the hysteresis current controller determines the allowable current shaping error. By changing the bandwidth, the user can control the average switching frequency of the grid connected inverter and evaluate the performance for different values of hysteresis bandwidth [6]. Inverters in DG applications constantly experience a wide range of dc input voltage variations, where the output voltage needs to be boosted up to a level compatible with ac grid [8]. The objective of this paper is to present a conventional controller for a single phase grid connected PWM inverter. The improvement in power quality is achieved by reducing the harmonic content in the current and compared by implementing two control schemes. i) Hysteresis controller ii) PID Controller