Forming a Reliable Hybrid Microgrid Using Electric Spring Coupled With Non-Sensitive Loads and ESS

The intermittency of renewable energy sources, i.e., photovoltaic cells and wind power causes problems such as unreliability, harmonic pollution, unpredictability and inefficiency, which pose a great challenge for constructing a reliable modern microgrid. To address these problems, in this paper, we propose a novel structure of microgrid, where sensitive loads, non-sensitive loads and the concept of "load follows demand" are adopted and incorporated. Within the designed microgrid, energy storage systems (ESSs) are coupled with the non-sensitive loads to achieve the supply/demand balance. In addition, a particle swarm optimization (PSO)-based collective load control is employed in this study to create pure resistiveness and piecewise constant active power features in the microgrid, in order to resolve harmonics and unpredictability problems. The proposed microgrid experimental platform is established based on real-time (RT)-lab and dSPACE in a hardware-in-the-loop (HIL) environment, where the efficacy of the proposed microgrid structure is verified in both islanded mode and grid-connected mode, which is able to achieve nearly 100% utilization rate of the intermittent solar energy, piecewise constant power and unity power factor. The proposed microgrid structure and established testing environment also have the potential to be scaled up to multi-microgrid power systems for advanced and wider applicability.