Design of a 135 MW Power Supply for a 50 T Pulsed Magnet

Abstract

At the Wuhan National High Magnetic Field Center (WHMFC) a 50 T/100 ms flat-top long-pulse magnet consisting of two coaxially nested coils is designed. The power and energy to operate the magnet is provided by a 100 MVA/185 MJ inertial energy storage motor-generator set. To accommodate the needs of this and future magnets, two 67.5 MW power supply modules based on 12-pulse converters are designed to convert the ac-power produced by the generator into controlled dc-power. The modules can operate independently as well as in parallel or in series. Each module consists of a combined input disconnect/grounding switch, two rectifier transformers, two parallel-connected 6-pulse rectifiers, a crowbar circuit, and a reversing switch. Two different transformer tap settings allow the module to provide no-load voltages of 3.2 kV and 2.7 kV and full-load voltages of 2.7 kV and 2.25 kV at the rated current of 25 kA for a 2 second pulse once every half hour. All components of the power supply modules are now under construction, with complete delivery and installation expected in early 2012. The design of the power supply components is described in detail. Digital simulation results of the power supply driving the 50 T/100 ms magnet are presented.Index Terms-Flat top, high magnetic field, pulsed generator, pulse rectifier.

Concept analysis of a distributed thrust system, a novel induction propulsion method using high energy pulse solenoids in satellite swarms for reusable interorbital freight transport.

“…The cargo could take 2 orbits, 1374 days, or 3.76 years with the applied acceleration time of half a second though a quarter second pulse time and 4th orbit ~ 7.5y arrival time is more likely. Numerical modelling is necessary to determine the pulsed electromagnetic eld range, application time and force output [20] required to validate successful next orbit arrival. For rst pass calculations and concept analysis, a 4th orbit arrival and 0.25s acceleration window is accepted for now.…”

“…These repetitively pulsed magnets were rst built in a solenoid con guration [8] [22] [48] for reliability and the same design is still in use today. Pioneering design research is conducted by many high magnetic eld centres [13][17] [20][37] [54][63] around the world which are achieving > 100T strength elds and striving for second long pulse lengths but all still use solenoidal con gurations.…”

“…As the optimisation of any multicoil design is strongly related to the available energy supplies for the sub-coils [20][53][54] the power storage system is the nal component for inspection. Satellite power systems initially used Nickel Cadmium (Ni-Cd) and despite the low speci c energy of 30 Wh/kg these batteries are still used in speci c low earth orbit and geostationary platforms today [11].…”

“…At WHMFC, a wide range of power systems and pro les were used to achieve increasing eld strengths and pulse times. In 2010 the rated current peak was 20kA [18], this was expanded in 2012 [20] with a battery bank of 82x 12 V, 200 Ah lead acid batteries that were installed to provide an initial energy of 12.2 GJ and 1048 V at 30 kA. This system acts in conjunction with the 27.6 MJ capacitor system containing 26x 1 MJ 3.2 mF / 25 kV modules and 2x 0.8 MJ 2.56 mF, 25 kV modules [22].…”

“…Several key areas of variance in the literature and analysis results will be highlighted to show the challenges in concept and design development. These variances must be investigated in further research using industry standard numerical modelling tools such as Matlab/Simulink [20]. This literature review presents a brief summary of research to date and the following design and analysis is intended to stimulate researchers to explore distributed propulsion system designs.…”