Advanced digital control scheme of two-paralleled bridge type current tracking power conversion amplifier for magnetic resonance imaging

Author

Watanabe, Shuji ; Takano, Hiroshi ; Boyagoda, P. ; Nakaoka, Mutsuo

Author_Institution

Dept. of Electr. & Electron. Eng., Yamaguchi Univ., Japan

Volume

1

fYear

1997

fDate

26-29 May 1997

Firstpage

513

Abstract

This paper presents a two parallel bridge PWM power conversion circuit for the switch-mode gradient power current tracking amplifiers for the gradient coil in the magnetic resonance imaging (MRI) systems. This power amplifying processor is connected in parallel with the conventional 4-switch type full-bridge power circuits using IGBTs at their inputs/outputs in order to realize further high-power density. A unique digital control scheme for PWM power conversion, which requires minimized ripple and improved rise/fall response characteristics of the current in the gradient coils (GCs), is proposed and described here. This power processor as an overall system is completely suited to the power amplifier for advanced MRI applications because the output current waves are not restricted to ramped-square waves and can assume any arbitrary waveform. It is expected that the proposed techniques will highly enlarge the diagnostic target and improve the image quality of MRI

Keywords

PWM power convertors; biomedical NMR; biomedical electronics; bipolar transistor switches; bridge circuits; coils; harmonic distortion; insulated gate bipolar transistors; power amplifiers; power bipolar transistors; power semiconductor switches; power supplies to apparatus; power system harmonics; switched mode power supplies; switching circuits; tracking; advanced digital control scheme; gradient coils; magnetic resonance imaging; output current waveform; power IGBT switches; ripple minimisation; switch-mode gradient power current tracking amplifiers; two parallel bridge PWM power conversion circuit; Bridge circuits; Coils; Digital control; Magnetic circuits; Magnetic resonance imaging; Power amplifiers; Power conversion; Pulse width modulation; RLC circuits; Switching circuits;

fLanguage

English

Publisher

ieee

Conference_Titel

Power Electronics and Drive Systems, 1997. Proceedings., 1997 International Conference on

Print_ISBN

0-7803-3773-5

Type

conf

DOI

10.1109/PEDS.1997.618756

Filename

618756