Low-Voltage Self-Operating MPPT Controlled Boost Converter for Thermoelectric Power Generator

This article presents the design and implementation of a low-voltage, high-power self-operating maximum power point tracking (MPPT) based boost converter for battery charging or Internet of Things (IoT) applications from thermoelectric generator (TEG). The proposed circuit consists of transformer-based oscillator (TBO) circuit that mediates low-voltage self-startup, and the flyback converter provides very low as well as a wide range of resistance matching ability with TEG. The microcontroller (μC) controlled open-circuit voltage-sensing-based MPPT technique extracts maximum power from TEG and eliminates the need of series switch and repetitive voltage sampling. The use of μC also inhibits the need of expensive sensors (current or voltage). The TBO circuit working alone self-startup at input voltage of 28
$\text{mV}$
and power of 5.8 μW and generates an output pulse of 1.1 V. The converter circuit starts MPPT operation at input voltage of 177
$\text{mV}$
(input power of 15.46
$\text{mW}$
) with an efficiency of 62% at output voltage of 4.25 V. It provides peak efficiency of 81.5% at an output voltage of 5 V with input terminal voltage 400 mV and input power of 352
$\text{mW}$
. Most of the sensors or IoT devices consume high power in discrete interval; in such a scenario, the present TEG powered discrete components based compact dc–dc boost converter-based battery charging system will be an alternative power source for remote area applications.