FOPID Controllers for Regulating Voltage of a Standalone SPV - Diesel Generator - Battery Bank Based Power Supply System

Standalone power supply system relies on hybrid Solar Photovoltaic (SPV) system - Diesel Generator - Battery bank is famous and established at many places for various applications. However, consumption of diesel is a key factor on the efficiency and cost of the system. Hence, a novel control methodology is developed in this manuscript to reduce consumption of diesel and also maintain energy management system irrespective of variations in the system. The proposed methodology is also helps to improve the power quality for supplying quality power at the load bus. A stable dc-bus is established by connecting SPV system, battery bank via dc/dc bidirectional converter and input terminals of the inverter. In order to obtained accurate responses, Fractional Order PID (FOPID) controllers are utilized in the proposed control methodology. Deloading action on SPV system is also implemented on proposed control methodology for effective operation under light load conditions. Additionally, an inverter with bidirectional power flow is contemplated between the point of common coupling (PCC) and the dc-bus to feed power at load bus while also facilitating battery charging from the diesel generator as needed. The new control strategies have been applied to dc and AC converters. Inverter control is utilized to ensure balanced three phase voltages at the PCC by regulating the currents produced by diesel generator when operating under unbalanced loads. Balancing the currents of diesel generators can assist in minimizing torque oscillations on the shaft, thereby enhancing the longevity of the equipment. The inverter control compensates for the demanding reactive power by loads, eliminating the need for diesel generator to provide it. This can lead to a decrease in diesel consumption. Results are presented through both MATLAB and RTDS to analyze proposed control methodology under various case studies.