Prevent Underload and Maximize PV Power in the Diesel-PV-Battery Hybrid System Due to Minimum Diesel Generation

Several islands in Indonesia use diesel generators as the main generators of the electrical system due to the ease and reliability of operation. However, the operating cost is high so it needs to be combined with a photovoltaic (PV) system. To reduce the intermittent effects of the PV system while controlling the power balancing of the microgrid system, a battery is used so that it becomes a PV-Battery-Diesel microgrid system. In the microgrid system, there are interrelated limitations, namely a minimum diesel generator (Pmin) of 4280 W and a maximum battery state of charge (SOC) of 80%. When the system only uses the Maximum Power Point Tracking (MPPT) method, underload or even reverse power can occur from the diesel generator. Therefore, the control system will work with two methods, namely MPPT for maximum power and Reduce Power Mode (RPM) for PV power reduction. The control system will use both methods and the reference current (Iref) setting on the three-phase inverter to minimize the generation of diesel generators (PDiesel) but still above the Pmin value. The control system was tested with changes in irradiation, load, and SOC. The results obtained that PDiesel is minimized and still returns above the value of Pmin. The average value of PDiesel is 4.4 kW and the efficiency of the MPPT method is 97%.