Utilizing IGBT Modules in the Active Region for a High-Precision Pulsed Current Supply of Magnets

A high-power and high-precision pulsed current supply of magnets was developed by using insulated-gate bipolar transistor (IGBT) modules in the active region. First, two basic circuit topologies including the series structure and parallel structure were compared in detail. With a wider current range, higher power efficiency, and reliability, the series structure was suitable for the application requirements. Thereafter, a new cascade feedback scheme in the IGBT driver was proposed to weaken the nonlinearity and time-varying of the system, and improve its dynamic responses. Accordingly, a fit average model was established based on the measured Bode diagrams of the quasi-linearization system. The control strategies of feedforward and feedback were both adopted to realize the high-precision and high-bandwidth current supply. Finally, the proposed current supply was experimentally verified and can meet the demands of the application with a pulsed output current of 200 A/10 ms and static precision of about 0.02 A.