Analysis and Design of the Control Sequence for an Ultrahigh Magnetic Field System

To meet the requirements of scientific research, a multi-coil ultrahigh magnetic field system (MUMS) has been developed at the Wuhan National Pulsed High Magnetic Field Centre (WHMFC) for generating a 100 T magnetic field. The MUMS is composed of outer, middle and inner coils with three pulsed power supplies, and the field waveforms generated by three coils are superimposed at the highest point to obtain an ultrahigh magnetic field. Due to the complex structure of the MUMS, to ensure reliable and efficient operation, first, the whole operation process of the MUMS is decomposed into a series of timing actions. On this basis, considering the constraint relationship between all timing actions, a general analysis and visual planning method based on the design structure matrix (DSM) and directed graph is proposed to design the control sequence, which can be directly described and executed sequentially in the control system. Moreover, to realize the design control sequence, the operation process of magnetic field systems is described by a state transition process in the state space, and a precise timing signal generator has been developed in the control system with a resolution of 5 ns. Finally, MUMS has been tested in experiments, and an 80 T magnetic field has been achieved. The results verify the validity of the designed control sequence, and the design method can be applied to various magnetic field systems.