978-1-5386-9175-5/18/$31.00 ©2018 IEEE Arduino-based Buck Boost Converter for PV Solar System Waheb A. Jabbar 1, * , Wasan Kadhim Saad 2 , Yasir Hashim 3 , Nurshuhadah Binti Zaharudin 1 , and Mohd Firdaus Bin Zainal Abidin 1 1 Faculty of Engineering Technology, Universiti Malaysia Pahang, 26300 Gambang, Kuantan, Pahang, Malaysia 2 Al-Furat Al-Awsat Technical University, Engineering Technical College-Najaf, Iraq 3 Computer Engineering Department, Faculty of Engineering, Ishik University, Erbil-Kurdistan, Iraq *waheb@ieee.org Abstract— Recently, photovoltaic systems (PV) have gained tremendous attention as one of the most promising technology for harnessing renewable energy sources. However, the fluctuation of output voltage with time due to due irradiance variation is one of the major drawback of PV solar system. Thus, in this paper, we propose a buck-boost converter based on Arduino microcontroller to maintain the output voltage of PV system at a desired value by controlling the duty cycle of the converter using pulse width modulator (PWM). The proposed system has been tested using both simulation and prototype to prove effectiveness of our design and obtain a fixed voltage at the output of solar panel regardless of irradiation conditions. The obtained results show that the developed converter performed well and attained 12 V constant output voltage in both modes (buck and boost). Keywords— PV system; buck-boost converter; Arduino; PWM I. INTRODUCTION The concern of environmental issue nowadays causing rising in demand of renewable energy that is cheaper and sustainable with less emission. Solar energy is considered a promising technology in harnessing renewable energy that considered cheaper and sustainable [1-2]. However, the weather conditions and the fluctuation of sun irradiance are main limitations of this technology [3-5]. Photovoltaic systems (PV) is module that built in a form of array solar panel where harnessing solar energy take place. PV cell consists of multiple thin layers of silicon which is a semiconductor material that generates electrical charges when it is exposed to light. It is directly converts solar energy into DC electrical energy. The DC voltage is available at the terminals of a PV module and can directly feed various loads such as Battery, LED lighting, DC motors or it may connect to a grid via a proper power converter [6-7]. Energy consumption has become a big challenge with the emergence of Internet of Things [8-9]. Electrical power converter is one of the main components in the PV system which plays a critical role in controlling consumed energy. It serves the aim of providing the desired form of output current (DC or AC) and transferring maximum power from the solar PV module to the load [10]. In addition, it is used to regulate the output voltage of PV system before connecting to the load [11-12]. There are several types of DC/DC converters that can be utilized by PV system including buck converter, boost converter and buck-boost converter. Buck-boost converter (step-down and step-up) uses to control the output voltage and maintain it at a desired level regardless the variation in the input voltage. According to the duty cycle value, the output voltage of the buck-boost converter can be either higher or lower than the input voltage [13]. Therefore, this type of DC/DC converters can be used with PV system to achieve the desired output voltage in spite of the variation of sun radiation. If the generated voltage from the PV cell is low due to low irradiance, the converter will cork in the boost mode to step- up the output voltage. In contrast, if the generated voltage is higher than the desired voltage, the converter will switch to buck mode to step-down the output voltage, thus always maintains the voltage at the proper level. The switching of buck-boost converter between two mode of operation can be achieved by controlling the its duty cycle [14-15]. In this paper, we have designed and fabricated a buck-boos converter for PV solar system in order to regulate and maintain the output voltage of the system regardless the changing in the input voltage. An Arduino Mega microcontroller was used to control the Duty Cycle of the converter via Pulse Width Modulator (PWM) output from the Arduino to regulate the output voltage. The developed converter acts as an interface between the solar cell and the load. The main benefits of this system include the maximizing of transferring power from the PV system to the load while maintain a fixed output voltage at PV terminal for instrumentations which are sensitive to voltage variations. This study adopted the following methodology and contributions: (i) Design and fabrication of a buck boost converter for PV solar system; (ii) Implementation of Arduino-based controller for controlling the duty cycle of the developed converter to continuously adapt the mode of operation based on the variation of PV voltage; (iii) Evaluating the performance of the developed system using both simulation and prototype and analysis of the obtained results to assure the switching between the operation modes of the converter (buck and boost) according to the input voltage.