The dynamics of a superconducting inductor and a thyristor converter (I-C) unit have been studied. For the optimal control of I-C unit, the dynamics of the unit must be described. But difficulties arise in the deduction of dynamics of a superconducting magnet (SM) from the properties of conductors and the coil configurations. To avoid these difficulties, the identification of dynamics through input/output relations has been studied.
For this study, the input/output data are acquired through the following procedures. The experimental system is the I-C unit composed of a 12 phase thyristor power converter and a 100kJ superconducting magnet. The input gate-signal of random waveform is given to the thyristor coverter and the response waveforms of currents and voltages of the I-C unit are sampled and memorized to form an input/output (I/O) sequence. The I/O sequence is identified by a multi-input/multi-output discrete time system (MI/MO DTS), and the dynamics of the I-C unit is described.
The discrete time system which relates the input and output waveforms of the I-C unit is derived by being based on least square method such that the euclidean norm between the measured and simulated outputs is minimized. The simulated outputs of the derived MI/MO DTS have closely fitted to the measured waveforms.
The derived systems revealed that one of the equivalent circuits of SM was a simple connection of R-L and the parameters were estimated so that the simulated waveforms of the equivalent circuit were closely fitted to the measured ones.
