Abstract—The world energy consumption is increasing very fast but unfortunately the global conventional fuels in reserves are running out. All scientists agreed that solar energy is one of the best solutions for energy supply in many parts of the world. In accordance with the need, the main objective of this paper is to design an effective Photovoltaic (PV) System that would charge lead acid battery efficiently in the variable environmental condition. So in order to maximise the PV output power irrespective of the temperature and irradiation conditions, Maximum Power Point Tracking (MPPT) technique is adapted. A PV system has been implemented using a boost type DC to DC converter, which is controlled through the Programmable System on Chip (PSoC) microcontroller by adjusting a duty cycle from Pulse Width Modulator. A single PSoC microcontroller can handle both analog and digital circuits, and reduces the need for additional circuit elements. It is programmed with a simple and reliable MPPT technique i.e., the Constant Voltage Maximum Power Point Tracking (VMPPT). By applying MPPT control, solar energy is charged to a lead acid battery to adjust changes in the environmental condition. Keywords— MPP (Maximum Power Point), MPPT (Maximum Power Point Tracking), PSoC (Programmable System on Chip), PV (Photovoltaic) panel. I. INTRODUCTION A photovoltaic system is a one that uses the PV panel as a source of electrical power supply. Every photovoltaic (PV) panel has an optimum operating point, called as the maximum power point. It is having a nonlinear voltage current (V-I) characteristic with a distinct maximum power point (MPP), which depends on the environmental factors such as temperature and irradiation [1]. In order to continuously harvest maximum power from the solar panels, it is necessary to control optimal impedance between the storage device and PV cell, so that the system can be operated at their Maximum power point, despite the inevitable changes in the environment. One useful impedance control method is called Maximum Power Point Tracking (MPPT) [2]. A PV system can adapt a constant voltage Maximum Power Point Tracking technique in order to charge the battery efficiently. The MPPT control is a real time detecting panel output power to make the system operate under the optimum work state. The design of a PV system consist of a PV panel, DC to DC boost converter (also known as step up converter) and a controlling section that uses the PSoC microcontroller. Solar panel voltage and current are continuously monitored by a PSoC microcontroller, and the duty cycles of the DC to DC boost converter are continuously adjusted to extract maximum power. The control section obtain the information from the PV panel through microcontroller‟s Analog to Digital Converter (ADC) ports and based on this digital information, controller can perform the pulse width modulation (PWM) to the boost converter. II. CHARACTERISTICS OF THE PHOTOVOLTAIC CELL The characteristics of the PV cell vary with different irradiation levels and ambient temperatures. A simple equivalent circuit in Fig. 1 can facilitate the investigation of the nonlinear behaviors of the PV module. The equivalent circuit consists of a current source I L which suggests the light generated current, a diode D 1 which emulates the PN junction of a real PV cell, a series resistor R S and a shunt resistor R SH which symbolize the parasitic series resistance and parallel resistance on the PV module. The voltage generated at terminals ‘V’ is the voltage of the PV module, which can be multiplied through series connected PV modules. Moreover, the current outflow from terminals ‘I’ is the current of the PV module [1]. The relationship between ‘I’ and „V” can be shown in the following equations                               Sh S th S L R R I V V n R I V I I I 1 exp 0 (1) Where; I 0 PV module reversal saturation current n Ideality factors V th Thermal voltage of a cell Fig. 2 shows the P-V curves plotted under different irradiation levels. The available electric power from the PV cell varies depending on the P-V curve, which is determined by the characteristics of the PV cell. Since this characteristic is a convex curve, a maximum power point P MAX exists, which changes with the intensity of solar irradiation. Under different irradiation levels, maximum power point increases nonlinearly as solar irradiation increases. Therefore, in order to maintain Design and Implementation of PSoC Microcontroller Based Photovoltaic System Pawan D. Kale Asst. Prof., Electronics and Telecommunication SSGMCE, Shegaon, India. Asst. Prof., Electronics and Telecommunication P. R. Patil College of Engineering, Gauravkumar N. Raut pawankale1989@yahoo.in Amravati, India nilesh5074@gmail.com Nilesh R. Patel Asst. Prof., Electronics and Telecommunication Rahul B. Lanjewar Asst. Prof., Electronics and Telecommunication JDIET, Yavatmal, India. SSGMCE, Shegaon, India 2014 International Conference on Circuit, Power and Computing Technologies [ICCPCT] 1257 978-1-4799-2395-3/14/$31.00 ©2014 IEEE