Electrical Power Conditioning System for Thermoelectric Waste Heat Recovery in Commercial Vehicles

A considerable part of the fuel energy in vehicles never reaches the wheels and entirely converts to waste heat. In a heavy duty vehicle (HDV), the heat power that escapes from the exhaust system may reach 170 kW. The waste heat can be converted into useful electrical power using a thermoelectric generator (TEG). During the last decades, many studies on the electrical power conditioning system of TEGs have been conducted. However, there is a lack of studies evaluating the electrical instrumentation, the impact of the converter efficiency, and the TEG arrangement on a real large-scale TEG on-board a drivable vehicle. In this paper, the most important parameters for designing electrical power conditioning systems for two TEGs, developed for a real-scale HDV as well as experimental results demonstrating the recovered electrical power, are presented. Eight synchronous interleaved step-down converters with 98% efficiency with a perturb and observe maximum power point tracker was developed and tested for this purpose. The power conditioning system was communicating with the on-board computers through the controller area network and reported the status of the TEGs and the recovered electrical power. The maximum recovered electrical power from the TEGs reached 1 kW which was transmitted to the electrical system of the vehicle, relieving the internal combustion engine.