A nonlinear control approach to the energy management of solar power plant with supercapacitor for grid-independent applications

A renewable energy hybrid power plant, fed by photovoltaic (PV) source with a supercapacitor (SC) storage device and suitable for distributed generation applications, is proposed herein. The PV is used as the main generator and the supercapacitor functions as an auxiliary source for supplying the deficiency power (transient and steady-state) from the PV. For high power applications, 4-phase parallel boost converters and 4-phase parallel bidirectional converters are implemented for the PV converter, and a storage device, respectively. A mathematical model (reduced-order model) of the PV, and supercapacitor converters is described for the control of the power plant. Using the nonlinear approach based on the flatness property, we propose a simple solution to the optimization, stabilization, and robustness problems in the hybrid power system. This is the key innovative contribution of this research paper. The prototype small-scale power plant studied was composed of a PV array (0.8 kW) and a supercapacitor module (100 F). Experimental results authenticate the excellent control algorithm during load cycles.