Performance Optimization and Verification of the Transformer-rectifier Flux Pump for HTS Magnet Charging

In order to charge the superconducting magnets, the means of current leads has been utilized widely. Nevertheless, due to the losses in high-temperature superconducting (HTS) magnets, the need for compensating the current decay periodically promotes the development of HTS flux pumps. Among them, transformer-rectifier type flux pump grabs attention owing to the simple rectifying component. However, it is the principle of bridge rectifying that may lead to an unavoidable induced direct current which self-evidently would make a negative impact on the charging speed. To this regard, this paper proposed the means of combining the current-controlled transformer-rectifier type flux pump with a secondary resistor to achieve an improved charging performance. With a verification experiment carried out, it was confirmed that the proposed method is viable. And there exists an optimal resistance -0.9 mΩ, which is essential to speed the charging progress up.