Huijun Yu1, Frank Huethe2, Sebastian Littin1, Kelvin J. Layton1, Feng Jia1, Stefan Kroboth1, and Maxim Zaitsev1
1Dept. of Radiology, Medical Physics, University Medical Center Freiburg, Freiburg, Germany, 2Dept. of Clinical Neurology and Neurophysiology, University of Freiburg, Freiburg, Germany
To address the
increased cost of high numbers of amplifiers for matrix gradient coils, a low
cost home-built 100A/100V gradient amplifier is proposed. The water cooling amplifier
consists of several parts: a controller that interfaces to a waveform generator
and provides the current control signal; an H-bridge circuit that generates
constant current to the load; and a ripple cancellation filter that reduces the
inevitable ripple current. The switching frequency and peak ripple current of
amplifier is 100 kHz and 300 mA, respectively. The amplifier can be operated
with maximum continuous current (100A) for at least 1 min.
