Design and implementation of PV system for a constant voltage operation

Renewable energy source based distributed power generation systems are gaining popularity because of fast depletion of conventional sources of energy and also the environmental threats they are causing. Interfacing of renewable energy sources with the utility grid is achieved using power electronic converters. Among all the Renewable sources, solar power is the most effective because of the advances in the Photovoltaic industry. Since the solar power is mainly depending on environmental conditions, the large-scale integration of solar PV has a large impact on the system stability issues. In this paper scheme for stabilising the voltage at a constant level in PV connected system. Photovoltaic system to the gird for constant voltage operation is explained. The solar PV system consists of two-stages of conversion. The two stages are, boost converter and inverter. In first stage, controller is built across the boost converter which ensures a constant voltage to the DC-link capacitor. The algorithm is implemented using PIC16F877A microcontroller. Controller reads both input and DC-link voltages to minimise the error so as to maintain a constant output voltage. The second stage involves an inverter which is capable of providing a constant voltage across the load due to the constant DC-link voltage. An IRAM 136-1061a inverter is used and the gating pulses for the inverter is generated using PWM switching operation. The full system including the boost converter, the controller and inverter is tested various irradiances conditions and it has been observed that the system is able to provide constant voltage across the inverter output terminals for all these conditions. In this paper, a system to the integration of the Photovoltaic system to the grid is designed and implemented for a constant voltage operation.