Copyright © 2015 IJEIR, All right reserved 668 International Journal of Engineering Innovation & Research Volume 4, Issue 4, ISSN: 2277 – 5668 Development of Micro-Controlled Multi-Powered Uninterruptible Power Supply System Ibrahim Adeyanju Department of Computer Engineering, Federal University Oye-Ekiti, Nigeria Email: ibrahim.adeyanju@fuoye.edu.ng Oluyinka Omotosho Department of Computer Science and Engineering, LAUTECH, Ogbomoso, Nigeria Email: oiomotosho@lautech.edu.ng Nathaniel Benjamen Department of Computer Science and Engineering, LAUTECH, Ogbomoso, Nigeria Elizabeth Adegbola Department of Computer Science and Engineering, LAUTECH, Ogbomoso, Nigeria Abstract – This paper discusses the design and prototype implementation of a multi-powered uninterruptible power supply system using a microcontroller. The system consisted of three basic units: the battery charging unit, the automatic switching unit and the inverter unit. The battery charging unit has components such as AC power, solar panel, a battery and the charging circuitry. The automatic switching unit includes the micro-controller and MOSFET switches to regulate the charging from multiple sources as well as switching from the power supply from AC to battery and vice versa. The inverter unit includes the transformers and other power electronic components to convert DC to AC power. Voltage and current measurement of our power supply output indicate optimal performance within expectation. Also, the battery charged faster with AC than solar power. We intend to further explore the use of miniaturized components to make the entire system smaller. Keywords – Inverter, Micro-controller, Solar energy, MOSFET switches, Electrical Power. I. INTRODUCTION The field of electrical power has witnessed tremendous development in recent years. The advent of new power controlled devices has contributed significantly to an enhanced performance of the existing power converters. The birth of innovative converter/inverter topologies has paved the way for further improvement in the overall power quality [1]. Multilevel inverter has gained much attention and became more popular now a day due its high quality output waveforms, low switching losses and high voltage capability, less EMI and reduced harmonics [13][14][16]. Using multilevel inverters specific harmonics can be eliminated in order to generate less distorted sinusoidal waveform. Multilevel inverters can be used medium voltage to high voltage range applications. It covers wide range areas including Uninterruptible Power Supplies (UPS), DC power source utilization, induction heating, high power motor drives, HVDC power transmission, electric vehicle drives, power distribution etc. The design and implementation of a multi-powered (AC and solar) uninterruptible power supply system (UPS) is explained. Section II reviews related works in the field of electrical energy generation and conversion, power electronics and inverter designs. Details of the methodology used in the UPS design and implementation are given in Section III while Section IV discusses our system evaluation. Section V concludes the paper with pointers to future work. II. RELATED WORK A designed photovoltaic (PV) module for generating electrical power by converting solar radiation into direct current electricity using semiconductors was proposed [12]. Photovoltaic power generation employs solar panels composed of a number of solar cells containing a photovoltaic material. The designed module was used in building an inverter system. Similarly, [2] [5] [8] developed an inverter with automatic voltage regulation (AVR) using switch mode square wave switching scheme. An inverter is an electrical device that converts direct current (DC) to alternating current (AC). The resulting AC can be at any required voltage and frequency with the use of appropriate transformers, switching, and control units [3] [4] A new voltage control method was proposed for single- phase full-bridge PWM inverters [6][7] The proposed voltage controller has capability to realize a zero steady- state output voltage error with fast response without complicated transformation. To control the output voltage, a voltage control based on new virtual LC resonant circuit is proposed. By using the proposed control technique, a zero steady-state error can be achieved. In order to improve the output voltage response, a virtual resistor is connected in parallel with the output filter capacitor. Experimental results showed that the output voltage of a single-phase PWM inverter can be controlled faster and accurately even under nonlinear loads. A comparison between Diode Clamped and H-Bridge Multilevel Inverter (5 to 15 odd levels) has also been previously carried out [6]. Multilevel converters are increasingly being considered for high power applications because of their ability to operate at higher output voltages while producing lower levels of harmonic components in the switched output voltages. One of the major problems in electric power quality is the harmonic contents. There are several methods of indicating the quantity of harmonic contents. The most widely used measure is the total harmonic distortion (THD) [9] [10]. The authors compared the various multilevel circuits (diode clamped and H- Bridge) with SPWM strategies. Operating principles with