Energy saving is becoming so important since it reduces pollution and it saves economic costs as well. Since combustion engines have low efficiency( less than 30% of the energy is used) the energy from the heat of the exhaust pipe using can be reused for thermoelectric generator (TEG). It's an actuator based on the Seebeck effect : it takes thermal energy as input, it converts it to electrical energy. To use this electrical energy, the output voltage of the TEG has to be controlled with a DC-DC converter. In this application the output voltage will be used to charge the battery of the car.