Controlled characteristics of a superconducting AC coil by pulse width modulated current

The authors propose the application of superconducting AC coils to superconducting magnet energy storage. The stored energy of the superconducting coil is to be supplied to the AC power line (60 Hz) via a power converter, and the pulsation of supplied power controlled in the frequency range between DC and several tens of hertz. A variable-voltage variable-frequency drive system was developed to study the possibility and characteristics of this sort of SMES system. The developed system is composed of a small superconducting AC coil and MOSFET pulse-width modulation converters. The combination of superconducting AC coil and PWM control can be utilized for SMES stabilization of a power system.