Adaptive control of a boost-buck converter for thermoelectric generators

Abstract

Abstract-Thermoelectric generators (TEGs) are used to recover waste heat of the exhaust gas and convert it into electric energy in automotive applications. The temperature of the waste heat influences the voltage and internal resistor of a TEG. For the electric linking of TEGs to the on-board power supply, a DC-DC converter may be used. The control of the DC-DC converter must be robust against dynamic changes and additionally has to track the maximum power point (MPP) of the TEG. This paper presents a digital cascade controller for a boost-buck converter to charge a vehicle battery and to supply the load. To track the MPP, a hill climbing (HC) algorithm is implemented, which is also used for photovoltaics. The conversion time of the HC is minimized with an adaptive step size. Width variations of electric parameters of TEG influence the dynamic and stability of the controllers. With a closed loop identification, the parameter variation is estimated, and the control parameters can be redesigned. An experimental result show the efficiency of the adaptive control.

Electrical Power Conditioning System for Thermoelectric Waste Heat Recovery in Commercial Vehicles

“…N. A. Zarkadis et al performed a study on the electrical system of a TEG for marine applications, where a high-ratio step-up converter was proposed and simulated [22]. In [23] and [24] extensive studies have been conducted on the control system of a converter connected to an emulated TEG. Moreover, Zhang et al conducted a study where a prototype of a thermoelectric-photovoltaic hybrid system and its power conditioning system were designed.…”