Miniaturized Pulsed Power Supply for Magnetic Resonance Imaging (MRI) Application

Pulsed power supplies are employed in various nuclear magnetic resonance (NMR) applications, such as fluid analysis in downhole formations, radar systems, and magnetic resonance imaging (MRI). Conventionally, huge capacitors are required to supply the peak loads. This project proposes a two-stage MRI power supply that reduces the capacitance requirement and system rating. The first stage is a phase-shifted full-bridge converter (PSFB), which supplies the average power of the pulsed load. To decrease the size of the energy storage capacitor that compensates for the power difference between the two stages, a variable midpoint voltage is employed. The second stage is a buck converter which supplies the peak power requirement of the pulsed load. To verify the overall system, a full-scale pulsed load (1 kHz and 15% duty cycle) with an average power of 300 W and a peak power of 2 kW is applied to this MRI power supply, and tested via simulation as well as preliminary experimental results. The proposed system can be employed to develop compact and even por table MRI machines.