The 100000 Amp DC Power Supply for a Staged Hadron Collider Superferric Magnet

A 1.5 volt 100000 A DC switcher power supply was developed for testing a superferric magnet string at Fermi National Accelerator Laboratory, FNAL. This supply was used during testing as both the ramping supply and holding supply powering a single magnet load with a total load resistance of 0.7 muOmega. The supply consists of ten paralleled switcher cells, powered by a 400 V/600 A DC power supply. Each cell consists of an IGBT H-bridge driving a step-down transformer at a switching frequency of 2 kHz. The transformer has an effective turns ratio of 224:1. The secondary consists of 32 parallel single-turn full wave rectifier windings. The rectification is done with 64 Shottky diodes. Each cell is rated at 1.5 V/10000 A. During this test each cell was operated as a constant power source without load current or field feedback. This paper will describe the design of the switcher cell and control system used during testing. We will also describe the next level of improvements to the current feedback system to improve the ramp control