Thermoelectric Generator Power Converter System Configurations: A Review

In a Thermoelectric Generator (TEG) system, the Thermoelectric (TE) modules can be connected in series, parallel or a combination of both. Independent of the module connection, the power production of the TEG changes with the temperature gradient applied at its input. In consequence, the system requires a power conditioning circuit to deliver a stable and maximized output to the load. The solution is to integrate a DC-DC converter between the TEG and the load. Furthermore, a suitable control strategy is necessary to make the TEG operate at its maximum power point (MPP). The maximum power point tracking (MPPT) technique is widely used for TEG systems. The aim of this paper is to create a survey over the existing state-of-the-art TEG system configurations for TE energy harvesting. Depending on the application specifications, a suitable TEG system topology can be designed with the purpose of improving the power production of the overall system. The overall TEG system configurations are presented step by step. First, the possible connections of the TE modules in a TEG system are analyzed. Afterwards, the typical converter configurations used in TEG systems are discussed and options are addressed with the purpose of improving the efficiency. A discussion about the role and benefits of the MPPT depending on the TE modules connection is given. Finally, the potential of the possible TEG system configurations classified by their TEG connection are discussed and compared. The study highlights that a complete system design approach is necessary to obtain high efficiency of the TEG system.