Abstract: To ensure the stable energy supply of monitoring device under the wide range fluctuation of transmission line current, three optimization energy harvesting models were proposed, which were compound cores with single winding, double windings and three windings. By analyzing the energy harvesting principle of the structure of compound cores, the equivalent models based on various winding connections were established. In addition, the formulas between the power and the parameters of three energy harvesters were also derived. Compared with the single material core, the simulation results show that the energy harvesting topologies of compound cores with single winding and double windings perform better in the stability of energy scavenging, when the transmission line current fluctuates at wide range. Furthermore, based on the combination of characteristics of three energy harvesting topologies, the strategy of power control was proposed to extend the energy harvester working current range, and output curve distortion was relieved at a large current. Finally, the experimental results verify the feasibility of the methods of optimization design for energy harvester.