An automotive exhaust thermoelectric generator (AETEG) has a non-uniform temperature field among thermoelectric modules (TEMs), resulting in current mismatches of TEMs and lower energy output of the AETEG. In order to implement high maximum power point tracking efficiency of the AETEG, a distributed thermoelectric energy recovery system consisting of three parallel thermoelectric generators and lithium iron phosphate (LiFePO4) battery pack is proposed. In addition, a two-level energy harvesting strategy is developed to efficiently recover more automotive exhaust energy, and guarantee the safety of the proposed system under the modified Highway Fuel Economy Test (HWFET) driving cycle. The proposed strategy aims to achieve the lower power loss of DC/DC converters and keep the battery pack working at the optimal point. When the initial SOC of LiFePO4 battery pack is 10%, the charging energy has been increased by 174013J and the efficiency of DC/DC converters has been raised of 2.4% than PI control.
Keywords automotive exhaust thermoelectric generator, parallel thermoelectric generator, two-level energy harvesting strategy, power loss