Research On Power Electronics Technology In Thermoelectric Generator System Application

With the increasing requirement for energy efficiency, thermoelectric generation (TEG) hasattracted more and more attention. Power electronic converter with MPPT control can both improvethermoelectric conversion efficiency and output power quality of TEG system. Hence, researches intopower electronic technology in TEG application is very necessary. In this paper, both high step-upDC-DC converter and differential power processing architecture in TEG application are developed.Firstly, the theoretical fundamentals of thermoelectricity are introduced. And an electrothermalcoupled model is established by theoretical inference, which points out the importance of powerelectric converters in TEG application. Experiment results proved that the output voltage of TEGsystem is low and highly dependent on the temperature difference. Also, TEG system has a fastdynamic response. Hence, a high step-up DC-DC converter with wide input voltage range and highefficiency is required for TEG power conditioning.Then, two different types of high step-up DC-DC converters, which are cascade Boost converterand interleaved Boost converter with auxiliary transformer, are introduced. A general comparisonbased on the output electrical characteristics of TEG system has been made in details. Two220Wprototypes of these topologies have been made, and experimental results verify the high step-upcapability and high efficiency of the interleaved Boost converter with auxiliary transformer.Finally, a current mismatch problem among thermoelectric modules (TEMs) in series in TEGsystem is pointed out, which will lead to power losses. To solving this problem, a differential powerprocessing architecture with high output power and high operating efficiency has been proposed inthis paper. By this architecture, each TEM’s power is maximized, and all the output power only needonce power conversion. A minimum differential power tracking control with distributed controlleralso has been introduced, which will optimize efficiency of the whole system. A simulation platformhas been established, and a50W experimental platform has been built up. The high efficiency of theproposed architecture has been proved high both by simulation and experimental results.