A High-Efficient Power Converter for Thermoelectric Energy Harvesting

Self-power technique is a vital key for stand-alone applications whereas battery replacement may be impossible. For wearable applications, extracting energy from the ambient temperature is one of the best solutions among the other energy harvesting methods such as solar, wireless waves, and temperature. In this paper, a high-efficient power dc-dc converter with maximum power point tracking (MPPT) and zero-current switching (ZCS) based on digital counters is proposed for thermoelectric energy harvesting. The proposed technique is able to adapt to a wide range of temperature differences. The integrated ZCS module plays an essential role in reducing the loss induced by inaccurately controlling the high-side switch. Besides, the maximum power extracted from the thermal energy source is monitored with the MPPT module. The power converter was simulated using CMOS 600nm Nuvoton technology. From the simulation results, it shows that when employing a thermoelectric generator with a temperature gradient of 3 Celsius degrees, the converter is capable of providing a maximum power of 112μW with a high-efficient of 66%.