Supercapacitor Assisted Hybrid PV System for Efficient Solar Energy Harnessing

Abstract

In photovoltaic (PV) systems, maximum power point (MPP) is tracked by matching the load impedance to the internal impedance of the PV array by adjusting the duty cycle of the associated DC-DC converter. Scientists are trying to improve the efficiency of these converters by improving the performance of the power stage, while limited attention is given to finding alternative methods. This article describes a novel supercapacitor (SC) assisted technique to enhance the efficiency of a PV system without modifying the power stage of the charge controller. The proposed system is an SC—battery hybrid PV system where an SC bank is coupled in series with a PV array to enhance the overall system efficiency. Developed prototype of the proposed system with SC assisted loss circumvention embedded with a DC microgrid application detailed in the article showed that the average efficiency of the PV system is increased by 8%. This article further describes the theoretical and experimental investigation of the impedance matching technique for the proposed PV system, explaining how to adapt typical impedance matching for maximum power transfer.

Maximum Power Point Tracking of an Off-Grid Photovoltaic System Consisting of a Series Connected Supercapacitor with a Step-Down Converter

“…The SC-battery hybrid off-grid PV system is a novel application of the SCALoM theory developed and introduced recently (13). As presented in the literature (13), this system can enhance the average conversion efficiency of an off-grid PV system by 8% compared with typical systems. However, the feasibility of maximum power point tracking (MPPT) for this system is yet to be validated.…”

“…As a result, all the system loads will be connected to the battery bank, similar to typical systems. According to the literature (13), this system has reached 98% average conversion efficiency. This is an 8% efficiency enhancement compared with typical off-grid PV systems.…”

“…An LED lamp load is introduced to the system through a DC micro-grid as a useful way to utilize the energy stored in the SC bank. Based on the position of each switch, the system is designed to have three operational modes, as detailed in the text below (13). Neutral Mode.…”

“…That is the SC bank's state of charge (SoC). As per the theory presented in the literature (13), expressions for the input resistance of the system, 𝑅 in each operating mode can be derived as follows.…”