| Authors |
Hyung-Beom Park ; Sang-Pil Mun ; Han-Seok Park ; Kyung-IL Woo |
| Keywords |
Two-Paralleled Four Quadrant DC Chopper ; Gradient Coils(GCs) ; High Speed Current Tracking Control ; Magnetic Resonance Imaging(MRI) |
| Abstract |
This paper presents a two-paralleled four quadrant DC chopper type PWM power conversion circuit in order to generate a gradient magnetic field in the Magnetic Resonance Imaging (MRI) system. This circuit has 8-IGBTs at their inputs/outputs to realize further high-power density, high speed current tracking control, and to get a low switching ripple amplitude in a controlled current in the Gradient Coils (GCs). Moreover, the power conversion circuit has to realize quick rise/fall response characteristics in proportion to various target currents in GCs. It is proposed in this paper that a unique control scheme can achieve the above objective DSP-based control system realize a high control facility and accuracy. It is proved that the new control system will greatly enlarge the diagnostic target and improve the image quality of MRI. |