High‐Gain Boost Converter Based Energy Harvesting Method for the Ultra‐Low Voltage Difference of HVDC Transmission Line

ABSTRACT Online monitoring sensors are crucial for ensuring the long‐term stable operation of high‐voltage direct current (HVDC) transmission systems. However, ensuring a sustainable and reliable energy supply for these sensors in the HVDC transmission line is extremely challenging. Energy harvesting is an efficient solution to meet the energy supply needs of self‐powered online monitoring sensors. This work proposes a novel method for harvesting energy from the ultra‐low voltage difference of HVDC transmission line using a high‐gain boost converter. Firstly, the structure of the energy harvesting system is proposed. Then, the mechanism by which the gain of the boost converter is easily affected by parasitic parameters of the circuit and device under ultra‐low input voltage is analyzed. A method for automatically stabilizing the output voltage of the boost converter using a post‐stage energy management circuit is proposed. This method avoids the use of closed‐loop control circuits, which would otherwise increase losses. Finally, the boost converter with high gain is designed to elevate the ultra‐low voltage difference to a higher voltage, providing sufficient power for the online monitoring sensors. The effectiveness of the proposed method has been verified through simulations and experiments, demonstrating that the energy harvesting system can extract energy from a voltage difference as low as 35 mV. Additionally, the system can produce a stable output power of up to 128 mW when the voltage difference is 100 mV.