Output Characteristics Analysis of Energy Harvesting Current Transformer

It is a common power supply method in the power distribution system that energy extracted from the bus current supplies power to the intelligent monitoring devices. The ability to extract energy is directly related with the dimension of the core and the parameters design of the energy harvester. The present literatures only consider the case where the core works on unsaturated region, which rarely consider the case where the core works on saturated region. In this paper, the effects of the core saturation, the voltage ripple of the load, voltage drop of the rectifier diode, winding resistance and the number of turns are fully considered, and the output voltage theoretical model of energy harvester is established. The validity and accuracy of the output voltage theoretical model analysis is verified by experiment and simulation. To maximize the output characteristics of the energy harvester, the capacitance compensation circuit is proposed. When the core is not saturated, the capacitor plays a role of resonance. When the core is saturated, the capacitor provides some negative volt-second product to lift the output voltage. The output voltage theoretical model provides a more complete and effective approach for the optimal design of the energy harvesting current transformer parameters.