A Robust Control for Solar and SyRG Based Hydro Generation Microgrid With Grid Synchronization

Abstract

The control of a microgrid is quite challenging thus this work implements a robust and fast control technique based on an enhanced second-order generalized integrator with a modified frequency locked loop (ESOGI-MFLL) for switching operation between an islanded and the grid-connected mode. For phase angle estimation, a circular limited cycle oscillator frequency locked loop with an inner loop filter (CLO-FLL-WIF) is implemented instead of a conventional phase-locked loop technique to provide better synchronization performance for polluted grid voltages. This microgrid is combing a solar photovoltaic (PV) generation, a synchronous reluctance generator for pico-hydro generation, and the battery, which works in both standalone and grid-connected modes while feeding local loads uninterruptedly. The output power conversion of a PV array is influenced by irradiation of the solar PV array; therefore, a maximum power point tracking namely an incremental conductance method is used. The implemented control techniques are used for fundamental extraction of load components of voltage and currents for assessment of reference currents with their respective phases of synchronization while maintaining the required IEEE power quality standard-519. In addition, the comparative results validate the faster response of ESOGI-MFLL control algorithm to the existing control algorithm. Simulated and test results of a microgrid for islanded, switching mode, and grid-connected mode demonstrate its performance under load unbalance and generation perturbation.