Development of digital optimum predictive control implementation for gradient magnetic field current controller in MRI system

This paper presents a digital control scheme for a four-quadrant high frequency PWM chopper type power conversion amplifier. It is the gradient magnetic field current pattern generator which is designed for medical use MRI. The main research objective of this paper is to propose the current control implementation in gradient magnetic coil (GC), which is driven by a high frequency PWM DC-DC converter system with a four-quadrant output scheme. The current pattern required for GC should follow up in accordance with any desired current pattern. In this current amplifier system, the current servo controller employs the optimum type-1 predictive control strategy, which has the advantages for the multiple input voltage and output current. The dynamic and steady state performances of the current PWM amplifier are described and evaluated on the basis of simulation analysis.