Analysis on a PWM power conversion amplifier with IGBT macro model to generate gradient magnetic fields in MRI systems

This paper presents a two-paralleled PWM amplifier using switch-mode power current tracking technique in order to generate a gradient magnetic field in the magnetic resonance imaging (MRI) system. This circuit has 8-IGBTs at their inputs/outputs so as to realize further high-power density. A digital control scheme can minimize the current ripple and improve its control response in the gradient coils (GCs). It is proved that the proposed technique will highly enlarge the diagnostic target and improve the image quality of MRI.