High-efficiency step-down converter for on-board thermoelectric generators on heavy duty vehicles

Today´s combustion engines have low efficiency and a large amount of useful energy converts to heat as waste in different type of vehicles. Improving the dynamics of the car body, injection system, the shape of the internal engine components and manipulating the fuel compositions have had influence on fuel economy, but still less than 50% of energy in the fuel is converted to useful mechanical power. Since the lost energy escapes through the exhaust system as heat, taking advantage of thermoelectricity, part of that energy can be converted to useful electrical energy, improving the overall efficiency. However, the output voltage from a thermoelectric generator is a function of hot and cold side temperature and since, the electrical system of the vehicle operates with constant voltage, the use of a power converter is necessary. In this paper, simulation and experimental results of such a high-efficiency converter(94-96%), designed for thermoelectric generators on heavy duty vehicles is presented and discussed.