Preliminary Design of Power Supply for Water-Cooled Resistive Magnet Based on Three-Level Buck Converters

Water-cooled resistive high-field magnets require a high power supply with an extremely high current stability, and a low current ripple and noise. The conventional resistive magnet power supply uses thyristor rectifiers, followed by a passive filter and an active filter to reduce the voltage ripple. This Paper describes a new circuit topology design of the resistive magnet power supply, which consists of uncontrolled rectifier bridges and three-level buck converters in series instead of the conventional thyristor rectifiers. The three-level buck converters work at a higher switching frequency, which can greatly reduce the cost, volume and weight of the filter. According to simulation and analysis results, it is seen that the three-level buck converter structure provides a lower voltage and current ripple than the conventional thyristor rectifiers, reduces the voltage stress of the power electronic devices. Beside, this new design can achieve a higher power factor than the power supply based on thyristor rectifiers.