A current transformer for energy conversion in a super-conductive energy storage system utilizes a two-stage boost-chopper to fulfill boost control for discharge process in super-conductive energy storage magnets. The first stage of the chopper circuit adopts a plurality of metal oxide semi-conductor field-effect transistors in parallel connection, so that the voltage on both ends of a super-conductive magnet can be limited in a rather low voltage level to meet the insulation requirements of the super-conductive magnet. The second stage of the chopper circuit increases the voltage to a higherlevel, and utilizes IGBTs as switch components to regulate subsequent output voltage through adjusting the switch duty cycle of the IGBTs through a PWM control mode, so as to fulfill the adjustable target for subsequent output voltage and the controllable target of the super-conductive magnet discharge voltage. The invention can realize energy output in the super-conductive energy storage magnet in a constant-voltage and DC mode, in order to meet the requirements for subsequent voltage-type loads. Meanwhile, the output voltage of the current transformer is not limited by insulating strength ofmagnets, but can fulfill flexible regulation according to subsequent load, and meanwhile, avoid the large volume problems with transformers or the multiple circuit topology structure.