International Journal of Power Electronics and Drive System (IJPEDS) Vol. 11, No. 2, June 2020, pp. 844~850 ISSN: 2088-8694, DOI: 10.11591/ijpeds.v11.i2.pp844-850  844 Journal homepage: http://ijpeds.iaescore.com Buck converter optimization using P&O algorithm for PV system based battery charger Zainul Abidin, Adharul Muttaqin, Eka Maulana, M. Gilang Ramadhan Department of Electrical Engineering, Universitas Brawijaya, Indonesia Article Info ABSTRACT Article history: Received Sep 13, 2019 Revised Oct 27, 2019 Accepted Jan 23, 2020 In this research, battery charger based on Photovoltaic (PV) system consists of buck converter as useful PV module interface was fabricated. Since output power of PV module changes quickly due to changing solar radiation, optimization is required. One of the easy and cheap optimization techniques is by implementing Perturb and Observe (P&O) algorithm for controlling switch of the buck converter. The P&O algorithm tracks maximum power point by generating suitable duty cycle for switching of the buck converter. The objective of this paper is to present the experimental proof of the P&O algorithm implementation in optimizing performance of the buck converter. The experimental results prove that the P&O algorithm can optimize the work of the buck converter and support shorter charging time by producing higher output voltage and power. Keywords: Battery charger Buck converter Optimization P&O algorithm Photovoltaic system This is an open access article under the CC BY-SA license. Corresponding Author: Zainul Abidin, Department of Electrical Engineering, Universitas Brawijaya, Jl. MT Haryono 167 Malang, Indonesia. Email: zainulabidin@ub.ac.id 1. INTRODUCTION Photovoltaic (PV) system requires DC-DC converter to adjust PV module output become suitable for load specifications [1,2]. Some DC-DC converter development is oriented towards IC fabrication [3,4]. A kind of DC-DC converter is buck converter. Development of the buck converter is also popular among researchers. For example, high conversion ratio quasi square wave buck converter is designed and presented in reference [5]. Synchronous buck converter for specific application (LED) is also evaluated by simulation [6]. Switch-inductor semi-quadratic buck converter is proposed and analyzed in reference [7]. Buck converter controlled by fuzzy logic is realized and reported in reference [8]. The buck converter is also very important part of battery charger. Battery charger based on PV system needs high efficiency. The more efficient the PV system, the shorter charging time required. PV system efficiency is mainly affected by three factors, i.e. inverter efficiency (95-98%) [9], PV panel efficiency which is between 8-15% (commercial PV panels) [10], and efficiency of Maximum Power Point Tracking (MPPT) algorithm which is over 98% [11]. Improving the efficiency of the inverter and the PV panel is not easy since it depends on availability of technology. Furthermore, it may require better components and can increase drastically the installation cost. Instead, improving the tracking of the Maximum Power Point (MPP) with new or simple control algorithms is easier and cheaper. It can be done even in plants which are already used by updating their control algorithms. It would also lead to an immediate increase in PV system power generation and consequently price reduction. Since PV panels have a non-linear voltage-current characteristic with power produced is maximum in a unique point, MPPT algorithms are necessary to be implemented [12]. This point depends on irradiance conditions and on temperature of the PV panels. Both conditions are different depend on the season and change during the day.