Hybrid centralized-distributed power conditioning system for thermoelectric generator with high energy efficiency

Abstract

The unbalanced temperature distribution influences the power output of thermoelectric generator (TEG) system, which leads to mismatch power among TEG modules. This mismatch power degrades the energy efficiency of TEG systems based on the series-connected TEG modules. A hybrid centralized-distributed (HCD) power conditioning system for TEG and its control strategy are proposed in this paper. The HCD power conditioning system is composed by a centralized power conversion stage and multiple distributed power conversion stages. Most of the power is processed by the centralized power conversion stage while only the mismatched power among the TEG modules is processed by the distributed power conversion stages. As a result, accurate distributed maximum power point tracking (MPPT) for each TEG module and single-stage power conversion between TEG modules and the load can be achieved by using the proposed system, which benefits for implementing high MPPT efficiency and high conversion efficiency simultaneously. A hybrid MPPT control strategy is proposed for this HCD power conditioning system. The characteristics, circuit implementation and operation principles of the proposed system are presented. Experimental tests have been carried out on a practical TEG system, which verify the feasibility and effectiveness of the proposed system.