Title :
Multiple-bridge PWM current-regulated power amplifier for magnetic resonance imaging system and its feasible digital control implementation
Author :
Takano, H. ; Watanabe, S. ; Nakaoka, M.
Author_Institution :
R&D Center, Hitachi Med. Corp., Chiba, Japan
Abstract :
This paper presents a four-paralleled full-bridge-type PWM current controlled power amplifier using IGBTs in order to generate high speed gradient magnetic fields for magnetic resonance imaging system (MRI) and its unique parallel processing digital control scheme based on a phase-lead compensator by a reference delay and a load model feedforward in addition to a dead time compensator. The maximum output voltage of the current controlled power amplifier is 600 VDC and its maximum current is 400 A for inductive loads. The observed waveforms in its experiment are illustrated to demonstrate the effectiveness of the four-paralleled full-bridge power amplifier topology and its unique control scheme
Keywords :
PWM power convertors; bridge circuits; insulated gate bipolar transistors; magnetic resonance imaging; power amplifiers; power bipolar transistors; power semiconductor switches; power supplies to apparatus; switching circuits; 400 A; 600 V; circuit topology; dead time compensator; digital control implementation; inductive loads; load model feedforward; magnetic resonance imaging system; multiple-bridge PWM current-regulated power amplifier; phase-lead compensator; power IGBT switches; reference delay; Delay effects; Digital control; High power amplifiers; Insulated gate bipolar transistors; Magnetic fields; Magnetic resonance imaging; Parallel processing; Power amplifiers; Power generation; Pulse width modulation;
Conference_Titel :
Industrial Electronics Society, 1999. IECON '99 Proceedings. The 25th Annual Conference of the IEEE
Conference_Location :
San Jose, CA
Print_ISBN :
0-7803-5735-3
DOI :
10.1109/IECON.1999.816500
