An 86.7%-Efficient Three-Level Boost Converter with Active Voltage Balancing for Thermoelectric Energy Harvesting

Thermoelectric energy has proved to be a dependable source for sustainable loT devices in practice. However, efficiently harvesting this energy source still remains a challenge because of system size constraints and large conversion ratios from a low input voltage (10s mV) out of a thermoelectric generator (TEG) to ~1V output levels for system circuit loads [1]–[5]. To meet this challenge, different converter topologies have been explored, including a conventional boost topology [1]–[2] and a bipolar hybrid converter [3] that combined a flyback stage with a boost converter. Unfortunately, while the former suffers from an undesirable small duty cycle, leading to low efficiency, the latter requires a bulky transformer, unwanted for loT applications. To better bridge the large voltage gap, a more power-and space-efficient DC-DC converter is desirable for this application.