As the output power of electromagnetic energy harvester is not sufficient to drive the wireless sensor in weak power density

a power management circuit using frequency up-conversion is proposed for harvesting electromagnetic energy around power lines.Because the output power of the resonant circuit increases with the quality (Q) factor which is inversely proportional to the square root of the circuit resonant capacitor

the proposed frequency up-conversion matching circuit working at a higher resonant frequency with a smaller resonant capacitor can obtain a higher Q factor

a stronger output power and a lower energy loss.Experimental results reveal that the maximum charging power of this management circuit is 2.1 times higher than that in the traditional full-bridge rectifier circuit.A maximum charging power of 780W and a harvest efficiency of 48.75% are achieved at a line current of 1A and a frequency of 50Hz.When the electric energy accumulates to a certain level

the storage capacitor will discharge to drive the wireless sensor.