Voltage Synchronization Scheme and Control Strategy for 50 T Flat-Top Pulsed Magnetic Field Power System

• Published in: IEEE transactions on applied superconductivity Vol. 24; no. 3; pp. 1 - 5
• Main Authors: Xu, Yun, Yuan, Yang, Ding, Hongfa, Li, Liang, Guo, Ming, Tao, Hongliang, Sun, Mao
• Format: Journal Article Conference Proceeding
• Language: English
• Published: New York, NY IEEE 01.06.2014; Institute of Electrical and Electronics Engineers; The Institute of Electrical and Electronics Engineers, Inc. (IEEE)
• Subjects: Applied sciences; Band-pass filter; Band-pass filters; Bandpass filters; Circuit properties; Coils; Control systems; Electric potential; Electric, optical and optoelectronic circuits; Electrical engineering. Electrical power engineering; Electrical machines; Electrical power engineering; Electronic circuits; Electronics; Exact sciences and technology; Firing; Generators; Magnetic fields; Magnetic separation; Miscellaneous; Power electronics, power supplies; Power networks and lines; Regulation and control; Signal convertors; Strategy; subharmonic voltages; Superconducting magnets; Synchronism; Synchronization; Voltage; voltage synchronization; zero-crossing detection; Power converter; Flat top; zero-crossing detection; Band-pass filter; Magnet; Control system; System design; Zero crossing; Power electronics; Phase locking; Mutual inductance; Synchronization; Inductor; voltage synchronization; Subharmonic; Electrical network; Thermal resistance; Pulsed field; High field; Band pass filter; Feasibility; Magnetic field; Signal distortion; subharmonic voltages
• ISSN: 1051-8223; 1558-2515
• DOI: 10.1109/TASC.2013.2295682

At the Wuhan National High Magnetic Field Center (WHMFC), a 100 MJ/100 MVA pulsed generator is used to energize two 12-pulse power converter modules for 50 T flat-top pulsed magnetic field. In this paper, to get a high stability of the magnetic field, a voltage synchronization scheme and a specific control strategy for the power system are designed. Three prime factors which influence the precision of voltage synchronization are analyzed. By using a band-pass filter to smooth out the synchronized line-voltage, a fast response phase locking technique based on zero-crossing detection is adopted to reduce the effects of the above three factors. Then, considering the load characteristics of the 50 T dual-coil magnet about the mutual inductance of two coils and the dramatic increase of the thermal resistance, a no-flat control strategy which could decrease the variation of the firing angle and lower the voltage distortion is employed. By this means, 50 T pulsed field of 100 ms flat-top duration with a ripple of less than 0.5% had been produced, which verified the feasibility of the voltage Synchronization scheme and the control strategy.