PWM rectifier with low DC voltage ripple for magnet supply

PWM (pulsewidth-modulated) bridge rectifiers with GTO switches are considered for application to particle acceleration magnet power supplies, where two-quadrant operation and extremely low DC current ripple are required. Different control strategies, with both preprogrammed and variable switching patterns, are examined and compared in view of optimization of the system performance. In particular, optimum digital PWM, multilevel delta modulation, and hybrid PWM/delta techniques are analyzed. The validity of the control methods is verified by simulation and experimental tests on a 60 kW prototype.<
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