Modeling and Control of Stand-alone PV System Based on Fractional-Order PID Controller

In this paper, an efficient energy management scheme for stand-alone photovoltaic microgrid system (SAPVMS) is elaborated. The proposed fractional order (FO) PID and PI based energy management scheme comprises of two control loops namely inner and outer loops to outperform a standalone PV system with satisfactory response. The main task of the inner control loop is to extract and track maximum power from SAPVMS with sufficient tracking behavior. Moreover, the outer control loop is equipped with the battery for controlling the power between the source and the load smoothly. Particle swarm optimization (PSO) is working to fine tune the proposed control loops by generating their optimal settings. The integral of the absolute error multiplied by time is utilized to define the proposed system objective function. Various scenarios include sun irradiance variations and load fluctuations are presented to demonstrate the theoretical analysis, effectiveness of the offered energy management strategy. Further validations for numerical results attained by PSO are made compared with classical controllers such as PI and PID which signify the tuned FOPID and FOPI gains. The model results of the entire SAPVMS are described given along with comprehensive simulation results that discover the feasibility of the system.