A Hybrid Power Supply Based on Capacitor and Battery for Accurate Regulation of the Pulsed High Current for Inductive Load

Generating steep, pulsed heavy currents with a high stability flat-top on a highly inductive load is a challenging task. This is due to the voltage of the current rising tens of times higher than that of the stable current, and the load resistance undergoing nonlinear changes caused by Joule heat. Hence a hybrid power supply, which includes the cooperative discharge of capacitor - battery and a novel flat-top regulation bypass circuit, is proposed in this paper. The high voltage of capacitor source makes the magnet current rise fast. The stable output of battery voltage can maintain high current output and the bypass circuit with IGBTs operating in the active region (IGBTs-AR) regulates the magnet current accurately during the flat-top. A unit of RC with semiconductor switch is in series with the IGBTs-AR to suppress the power dissipation of IGBTs-AR. An isolation valve set of 28 kV/ 22 kA and a bypass circuit of 4 kA/ 100 ms are developed to implement isolation and automatic commutation between the battery source and capacitor source, and to regulate the magnet current, respectively. Finally, the detailed tests are performed and the magnetic fields of 20.058 T/10 ms/ 200 ppm and 10.747 T/ 45 ms/ 450 ppm are realized.