International Journal of Power Electronics and Drive Systems (IJPEDS) Vol. 14, No. 1, March 2023, pp. 41~450 ISSN: 2088-8694, DOI: 10.11591/ijpeds.v14.i1.pp41-50  41 Journal homepage: http://ijpeds.iaescore.com Voltage regulation of DC micro grid system using PV and battery coupled SEPIC converter Rajaboyana Narendra Rao 1 , Meda Sreenivasulu 2 , Busharaju Ramakrishna 3 1 Department of Electrical Engineering, JNTUA College of Engineering, Andhra Pradesh, India 2 Department of Electrical & Electronics Engineering, Vasavi College of Engineering, Hyderabad, India 3 Department of Electrical and Electronic Engineering, Maturi Venkata Subba Rao (MVSR) Engineering College, Hyderabad, India Article Info ABSTRACT Article history: Received May 29, 2022 Revised Aug 28, 2022 Accepted Sep 7, 2022 This paper deals with the voltage regulation of DC micro grid system using photovoltaic and battery coupled single-ended primary-inductor converter (SEPIC) converter. SEPIC converter is a DC-to-DC boost converter, it can produce non pulsating DC current with less ripples when compared to buck and buck boost converters. Non pulsating DC current is the demanding condition required in maximum power point tracking (MPPT) applications and battery charging. This paper presents the simulation of the converters for both open and closed loop systems. Firstly, the proposed PV coupled SEPIC converter and the battery coupled buck boost converters are integrated to regulate the voltage in micro grid, and it is compared with the conventional methods in terms of output voltage, ripple voltage and power. The ripple voltage has been reduced to 0.1 V from 0.3 V in the proposed method. Secondly, PI and PID controllers are employed individually to SEPIC and buck boost converter for the voltage regulation of the DC micro grid system. The performance of the closed loop analysis is done in terms of time domain specifications, and it reveals that PID controller has the better response. The proposed system is simulated using MATLAB/Simulink and the prototype has been developed to verify the simulated results. Keywords: Buck boost converter DC micro grid Photovoltaic PID controller SEPIC converter This is an open access article under the CC BY-SA license. Corresponding Author: Rajaboyana Narendra Rao Department of Electrical Engineering, JNTUA College of Engineering Pulivendula 4th UAD Campus, Muddanur Rd, Pulivendula, Andhra Pradesh 516390, India Email: rnrao.jntueee@gmail.com 1. INTRODUCTION Nowadays, grid connected photovoltaic systems are very popular due to constant demand of energy. Many countries are encouraging PV fed power generation systems by funding it. The efficiency of the PV panels to convert electrical power from sunlight is always less than 20%, and even less efficiency in case of load conditions and panel temperature. In order to improve efficiency, maximum power point tracking (MPPT) technique with power point tracker is employed to improve the efficiency. PV coupled single-ended primary-inductor converter (SEPIC) converter can able to generate or track more power from the solar panels using PWM controlled DC-DC converter [1]–[3]. The extraction of maximum power from PV panel without using microcontroller is given in [4]. The maximum power can be extracted from PV panels under all atmospheric conditions and the efficiency can be improved with controlled PWM technique [5]. The power range of low power and residential applications using grid connected single phase inverter are 10 KW and less than that. More switching losses, interference level and acoustic noise are due to high switching at three level inverters [6]. P-V and V-I characteristics of PV due to non-uniform insolation with partial shading was proposed in [7]. PV panels, interfacing circuits with load can extract maximum power from the PV