Zero-Compensator Filter for Power Sharing Between Battery/Supercapacitor in a Grid-Connected Photovoltaic System

Abstract

This paper contributes to the energy man- agement of a Hybrid Energy Storage System (HESS), comprising a lithium-ion battery and Supercapacitors (SCs) for a grid-connected photovoltaic system. In gen- eral, an Energy Storage System (ESS) can offset the in- termittency of renewable energy. However, ESS can absorb large amounts of energy with slow dynamics, but can only absorb fast dynamics when subjected to high currents, which quickly contributes to their wear. To avoid this, SCs are added to energy storage as a supplement to batteries. There are various meth- ods for power-sharing, including the most common, which uses the Low-Pass Filter (LPF). This article proposes a new technique to distribute power between the battery and the SCs using the zero-compensator fil- ter of the battery regulator. Also, this technique is based on the compensation of the energy dissipated by the bat- tery through the SCs. Besides, the State of Charge (SoC) of the battery is kept within safe boundaries. The proposed technique is compared to the ESS and classical HESS techniques. The simulation results con- firmed the efficacy of the proposed method of rapidly restoring the DC-link voltage and improving the bat- tery lifespan. In addition, this technique is adaptable to the stand-alone site, and the AC currents showed good quality.