Modeling, P&O MPPT and PI controls and performance analysis of PV/Energy storage hybrid power system

The variable nature of renewable energy sources, coupled with unpredictable changes in load, requires the simultaneous implementation of high power and high energy density storage systems. This work addresses dynamic modeling, control and performance analysis of a PV/Batteries/Ultra capacitor hybrid energy system connected to a DC load in a remote house located around the town of Rouyn Noranda (Quebec-Canada) during one day in winter period. The P&O MPPT control is used to extract the maximum power of a photovoltaic generator which is considered as the main energy source of the hybrid system. In this paper, batteries and ultra-capacitors (UC) are serving as an energy storage system (ESS) and a main source in winter period. The UC are used for facing high frequency variations of the load, such as in transient state, while the batteries are in charge of slow load/source variations. Classical control of battery current and ultra-capacitor current allows choosing the suitable storage element in order to face correctly the production/ consummation variations. Classical PI control strategy is proposed in manner to stabilize the DC bus voltage by controlling the attached DC/DC bidirectional converters. Simulations during 00 AM to 3 PM (during a snowy day) are carried out using Matlab/Simulink which confirm the good performances of the hybrid system and associated control systems.