Improved generalised integrator for optimal dispatch of SyRG-based pico-hydro-PV system

The fluctuating outputs from renewable energy sources (RESs) and variable load power demand deteriorate the current quality, thus an improved generalised integrator with a frequency-locked loop (IGI-FLL) control strategy is used, which is not only easy but simple to attain a quick and precise fundamental extraction. IGI-FLL control method is utilised with all-pass filter and is capable to accomplish enhanced harmonics, noise and DC offset rejection ability while estimating fundamental component of the load current. In addition, the FLL structure is used to increase the frequency immunity against voltage variations. It provides improved steady-state and dynamic performances with flexibility in parameter tuning in comparison to SOGI-FLL algorithm. It also presents a cost-effective and robust genetic algorithm (GA)-based optimisation to provide optimum battery charging and discharging power while satisfying the state-of-charge (SOC) limits under RES uncertainty. In this islanded microgrid, a Synchronous Reluctance Generator for pico-hydro and photovoltaic array is used so that this hybrid system utilises maximum solar PV array power, matches the load, or else charges the battery energy storage while maintaining power balance in the microgrid. Comparative outcomes authenticate the efficacy of the algorithm to handle the issue of RES uncertainty and load unbalance in an islanded microgrid.