Smooth Transition Control With Logarithmic Hyperbolic Cosine Filter for Wind–Solar–Diesel based AC/DC Microgrid At Different Operating States

Abstract

Renewable sources equipped AC/DC microgrids in rural areas need to be augmented with diesel generator (DG)-set for reliable power deliverability at prolonged grid outage scenarios. In view of this, a DG set equipped AC/DC microgrid along with the control strategy is presented in this work. Here, multiple doubly-fed induction generators (DFIGs) and multiple solar photovoltaic (SPV) arrays are employed for wind and solar power generations, respectively. In this microgrid topology, the operation of DFIGs are in no way influenced by any of the grid voltage irregularities like unbalance or distortions. Microgrid control is devised for a decentralized implementation, and it ensures disruption-free power to local loads, while, also enabling smooth transitions among different operating states. The disconnections and reconnections of DFIGs and DG-set from the microgrid effectuate these operating states. A logarithmic hyperbolic cosine filter (LHCF) is utilized in the microgrid control strategy. In a healthy grid scenario, the control strategy operates to inject a constant power into the grid even amidst intermittencies in wind, solar, or load powers. Meanwhile, at prolonged grid outage when the integration of DG-set becomes indispensable, the control strategy operates to ensure an optimal consumption of diesel fuel from the generator. The AC/DC microgrid operation and the LHCF-based control strategy are validated through simulation results.