A power conditioning system for thermoelectric generator based on interleaved Boost converter with MPPT control

Abstract

The thermoelectric generation (TEG) system has its special charactristics of high stablility, low voltage and high current output, which is different from PV modules. The power conditioning system and control schemes used in PV applications cannot be directly applied to TEG applications. A power conditioning system for TEG based on interleaved Boost converter with maximum power point tracking (MPPT) control is investigated in this paper. Since an internal resistance exists inside TEG modules, an improved perturbation and observation (P&O) MPPT control scheme with power limit is proposed to extract maximum power from TEG by matching the load with internal resistance. Since the battery is usually employed as the load for TEG systems, the interleaved Boost converter operates in two different modes for battery charging: before the battery is fully charged, the system outputs the maximum power (MPPT mode); after that, the system outputs constant voltage for floating charge (constant voltage mode). A mode transfer method is proposed to ensure smooth switching between the two above operating modes. A 200W experimental prototype has been built, and the experimental results verify the feasibility and effectiveness of the developed power conditioning system with the proposed control schemes.