Proceedings of the OAU Faculty of Technology Conference 2017 DESIGN AND IMPLEMENTATION OF AN ARDUINO-BASED CONTROLLER FOR INTEGRATION OF PV GENERATOR WITH THE LOW VOLTAGE UTILITY GRID T.O. Olowu* 1 O.D Makinde 1 F.K. Ariyo 1 , M.O Omoigui 1 1 Department of Electronic and Electrical Department, Obafemi Awolowo University, Ile-Ife, Nigeria. *Email of Corresponding Author: olowuagain@yahoo.com ABSTRACT This paper presents the design and the implementation of an Arduino based controller for integration of the output of a solar power generation system with the utility grid and ensuring energy transfer to the grid. With the increasing need for power generation, distributed generation allows for modular power generating systems to be developed. To integrate the output of a solar power generating system with the utility grid at the distribution voltage level, certain criteria has to be met. These are equal voltage amplitude, frequency and phase angle of the two systems. This controller using ATmega 256 was designed to check for all these criteria. The AC voltage amplitude measurement was done with the conversion to a DC, an LM 741 was used for the frequency measurement module, and a PLL phase comparison unit was used for the phase comparison module. A prototype of the controller was built, performance analysis was carried out on the controller and its switching under various input conditions based on the IEEE 1547 standards The results showed that the controller only allows energy transfer between the two systems when all the required criteria for synchronization were met within the required switching time. Keywords: Grid, Controller, Arduino, Distributed generation, Photovoltaic generation, Phase locked loop. INTRODUCTION With the rising cost of energy from conventional sources and the effects of global warming, the need to develop more environmentally friendly ways of generating electricity becomes imperative [1]. The methods of electricity generation is currently moving from the centralized form to distributed generation [2]. This allows modular renewable energy forms of electricity generation to be easily integrated to the grid. The fastest developing of all renewable energy sources is the solar photovoltaic (PV) system [3]. This is due to advancement in the efficiency of the cells, reduction in cost, ease of installation and high level of reliability. In Nigeria, the use of rooftop PV generating system is increasing. The rising cost of fuel and the cost of maintenance of generating sets has forced many electricity users to opt for the use of PV powered inverter systems. With the lower power generation in Nigeria compared to the existing load, there is an obvious need to allow the possibly of owners of modular PV generating systems to become “prosumers” (both producers and consumers). This would allow for net metering where each prosumers only pays for his net power consumption. This work involves the design and implementation of a controller circuitry that ensures connection and transfer of excess energy from a Solar Power Generation System to the Utility Grid. The technical requirements for connecting and transferring energy from the solar power generation to the utility grid on a low voltage distribution network are equal voltage amplitude, frequency and phase angle of both the solar power generation system and the utility grid [4], [6]. This controller is based on the use of the ATmega 256 microcontroller for the comparison of these parameter and the consequent switching. LITERATURE REVIEW With the proliferation of the use of solar powered inverter systems in Nigeria, there is an obvious need to allow enable owners of these systems become prosumers. There are grid-tied inverters already in the international market, but presently there is none in use by thousands of inverter users in Nigeria and many developing countries. The design of a separate controller that can enable a non-grid-tie inverter system connect to the grid is therefore necessary. There isn’t many literal references till date on this problem. Paper [5] proposed and implemented a design that was based on the detection of zero crossing. This design on detects the change deviation in frequency of the output PV system by making the frequency of the grid supply a reference. The drawback of this design is the non-consideration of the constantly varying voltage output of the utility grid as well as the possible phase different between the voltage of the utility grid and the output of the solar powered inverter system. Authors of [6] proposed a system was based on the use of PIC 16F877A. Though the design was performed satisfactorily based on proteus software simulation, the design was not validated experimentally. The use on this conventional PIC reduces communication capabilities of the system with a possible smart metering system. The use of Arduino in this work mitigates this problem. Paper [7] simulated an integrated control system that controls the switching of the MOSFETs of a three phase inverter. This control would enable the output of the parameters of align to that of the grid for synchronization. This work does not 1