Improving Regulation in the Fermilab Main Ring Magnet Power Supply System

In the past two years a number of changes have been made to the Main Ring Magnet Power Supply System to improve current regulation and long term drift. Some of the modifications discussed include new computers, new passive filters, direct analog feedback, a voltage-to-frequency converter for bend bus regulation, and a "smart" Nuclear Magnetic Resonance probe. Among the improvements to be described are the attenuation of power supply ripple by a factor of five and the reduction of long term flattop drift by an order of magnitude.