Suboptimal MPPT control for power management in PV-diesel remote area power supply systems

Maximum power point tracking (MPPT) is commonly being used in solar-photovoltaic (PV) power generation systems to maximise solar energy extraction. In this paper it is proposed to operate the solar-PV system at the suboptimal MPPT to manage power balance in a remote area power supply (RAPS) system. This is performed based on three different operating modes: 1) Frequency control mode; 2) Active power control mode; 3) MPPT control mode. The operating modes are decided based on the load level and the operating mode of the diesel generator (i.e. synchronous condenser mode or generator mode). This power management strategy balances the generation and load demand that requires transition between the three operating modes without using the dummy load. The proposed strategy is capable of extending the diesel generator life time and improves the operating efficiency of the diesel generator. Simulation studies are carried out to validate the effectiveness of the suboptimal MPPT control strategy in a PV-Diesel RAPS system, and have shown that the proposed strategy can seamlessly maintain power balance in the RAPS system while maintaining the voltage and frequency within stipulated limits. Substantial cost savings can also be achieved in long run due to the life time extension and efficiency improvement of the diesel generator.