The Lock-On Mechanism MPPT algorithm as applied to the hybrid photovoltaic cell and thermoelectric generator system

Abstract

The thermoelectric generator (TEG) is a clean and noiseless renewable electrical power source that requires no moving parts. In the meantime, the hybrid photovoltaic cell and thermoelectric generator (PV/TEG) system is also popularly considered in research because of its potential improved power conversion efficiency over its monolithic counterparts. This paper continues the work on several previous publications from the authors where the focus here is to perform maximum power point tracking (MPPT) on the hybrid PV/TEG system. It reuses the Lock-On Mechanism (LOM) MPPT algorithm which was previously used by the authors in two separate publications on the solar panel and TEG alone. In comparison to conventional fixed step based MPPT algorithms, the LOM algorithm improves the MPP tracking performance by adaptively scaling the DC-DC converter duty cycle whenever the MPP is located. In doing so, the steady state oscillations become negligibly small thus be considered eliminated and a smooth steady state MPP response is achieved. The simulation and experiment in this paper are conducted using a double SEPIC converter where each input source is treated independently with the proposed algorithm. Results prove that the proposed algorithm is fast and stable in comparison to the conventional fixed step hill climbing algorithm.