| Abstract |
CERN, the European Centre for Particle Physics Research, had a requirement for a large number of converters to power corrector magnets for LEP (Large Electron Positron Collider) which is under construction at Geneva. The work was done in collaboration with GEC Transmission and Distribution Projects Limited, who designed the power converter and voltage control, following a technical specification issued by CERN. The precision current control capable of 10 ppm stability on the 5 Amp output was designed by CERN. Various design aspects are discussed, including the design of the power circuit, the PWM control, filtering and the servo control loops. Particular consideration is given to aspects of SMPS which have prevented them being used in high precision requirements until now, ie loop stability versus bandwidth, ripple filtering and RFI emission and susceptibility. |
