Design of PV-DC mini grid using PI-based fuzzy MPPT control considering load demand

Electrical energy supply in isolated areas is still a challenging issue faced now. Electrical energy sources such as solar, hydro, and wind are energy that can be developed to be alternative energy sources in remote areas, especially in rural areas. Photovoltaic (PV) is one source of energy that can be used to supply energy needs in rural areas. PV has the maximum point of power affected by temperature and irradiance values. To get the maximum power, Maximum Power Point Tracking (MPPT) is used. Generally, MPPT is only aimed to get PV maximum power value. However, in a mini grid system, the system can possibly need only a part of the power generated by PV, not all energy produced by PV. If PV still generates at the maximum power at a full battery condition, the over voltage may occur. Therefore, PV in the mini grid should be controlled by a PI-based fuzzy controller to manage the PV power generation. The proposed controller suppresses PV power output when there is excess power in the system. The system design is started by composing formulated load models based on survey data. It will be continued by determining the optimum PV value and battery storage capacity. Then, a PI-based fuzzy controller for the modified MPPT control is designed to control power produced by PV. Battery SOC, PV voltage and PV output current are used as fuzzy inputs. The results show that the proposed controller has better performance with no overshoot and fast response time compared to a conventional fuzzy MPPT.