Maximum power point tracking for thermoelectric generators with high frequency injection

Abstract

Thermoelectric Generators (TEG) can harvest a part of the thermal energy otherwise lost in the exhaust gases of vehicles and are combined with Maximum Power Point Tracking (MPPT) schemes to maximize the power output. This paper proposes a novel TEG MPPT scheme named High Frequency Injection (HFI) method. The method injects a high frequency voltage to the TEG and yields a power with a high frequency component. This component is demodulated and yields a signal proportional to the distance from the optimal operation point. The duty cycle setpoint is adjusted with a proportional-integral (PI) controller. The method is compared to the Perturb & Observe method using a drive cycle. Both show good results in terms of dynamic tracking of the optimal operation point. However, the HFI method is shown to be significantly more robust against sensor noise.