A High-Efficiency Management Circuit Using Multiwinding Upconversion Current Transformer for Power-Line Energy Harvesting

This paper presents a high-efficiency management circuit using a multiwinding upconversion current transformer (CT) for power-line energy harvesting. Due to sharing the same loop for matching and charging in a low working frequency (50 Hz), the traditional matching circuit of the CT has a low Q value and low magnetoelectric efficiency, and it cannot be used in both a weak power-line current and a heavy load. A multiwinding CT upconversion matching circuit with a higher Q value is developed. Higher charging power (> 175%) and a larger ultimate charging voltage (> 150%) in a weak power-line current (1-100 A) can be obtained by using an independent upconversion resonant matching loop. The matching circuit can efficiently work at a wider load capacitance. In order to drive a wireless sensor with higher power consumption, an instantaneous discharging circuit that is suitable for weak energy harvesting (<; 700 μW) is developed. The instantaneous discharging circuit can accumulate weak energy from a CT transducer during a long period, and it can provide a higher power output in a very short time. The management circuit can drive a wireless sensor with an output power of 60 mW at a distance of over 40 m. The multiwinding high-efficiency upconversion management circuit can be used in many other low-frequency energy harvesters.