Analysis and Design of Sliding Mode Control for MPPT Based PV System with a Battery Storage

Abstract

There is a lot of demand of PV systems nowadays. It is due to the fact that they generate power without effecting the surroundings by direct conversion of sun energy into electric power. The advanced topology comprises of a Boost Converter, which boosts up the PV voltage to a value which generates the required single phase AC output voltage of 230V (RMS), 50Hz from the inverter. The output of the step-up converter is cascaded using a single-phase inverter which generates an electric energy of required magnitude and frequency. Perturb and Observe MPPT algorithm is used to obtain maximum power in a PV system. To accumulate the energy, a battery is placed between the inverter and the converter. Depending on the nature of the PV cell and its characteristics, this work designs an SMC to realize the desired inverter output voltage. The work emphasizes on analyzing system stability through a state space model and designing the Sliding Mode Controller. The performance of the controller is verified through effective tracking obtain the desired output voltage response of 230V (RMS). Stability studies are derived through frequency response characteristics. The controller is studied for both dynamic and non-linear nature of the load. The output voltage Total Harmonic Distortion (THD) is found to be consistent with the IEEE 519 standards. The proposed topology is designed for standalone applications. In PSCAD 4.6 version, simulations are performed.