A converter for energy conversion of superconductive energy storage system

Abstract

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 higher level, 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 of magnets, but can fulfill flexible regulation according to subsequent load, and meanwhile, avoid the large volume problems with transformers or the multiple circuit topology structure.

Description

technical field [0001] The invention relates to a converter for charging and discharging a superconducting energy storage system. Background technique [0002] In recent years, with the development of power electronics technology, superconducting magnet technology and low temperature technology, with the improvement of the cost performance of superconducting materials, the ability of superconducting wires to carry current in strong magnetic fields has been greatly improved, and superconducting energy storage technology has become increasingly mature. received extensive attention. Superconducting magnets have replaced almost all bulky and power-hungry conventional magnets in high-energy physics experiments. In the field of superconducting power, micro-superconducting magnet energy storage systems have been commercialized abroad, and are widely used to improve power quality and power system stability. [0003] Superconducting magnet energy storage systems (SMES) have the adv...

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Problems solved by technology

When the switch 20 is turned off, the voltage across the magnet is equal to the output voltage, and the superconducting magnet system is limited by low-temperature insulation and other conditions, and the voltage across the magnet cannot be very high, which makes the superconducting variable current with the above structure The device cannot be directly applied to the high-voltage system, which limits the application of the superconducting energy storage system. At the same time, when the output voltage is high, this method of directly cutting the magnet current will bring a lot of switching loss and increase The AC loss of the magnet is increased, which is not conducive to the stability of the superconducting magnet system

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