Estimation of Output Voltage Ripple in Phase-Staggered Series-Connected Two-Quadrant Power Converters for Electromagnets in Particle Accelerators
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1
Raja Ramanna Centre for Advanced Technology, Indore 452013, India
2
Homi Bhabha National Institute, Mumbai 400094, India
Power Electronics and Drives 2023;8 (43):174-195
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ABSTRACT
In booster synchrotron, fast-ramped power converters (FRPCs) are used for ramping up the magnetic field of electromagnets
connected in series, at a fast rate, typically 1,000s of ampere per second. In large accelerators, the number of electromagnets is
large. Therefore, during ramping, the peak value of driving voltage becomes prohibitively large considering the insulation requirement
of the magnets and cables. The power converter is therefore developed by connecting a suitable number of smaller voltage rated
modules in series. The series-connected modules are operated in phase-staggered mode to reduce the output voltage ripple or to
reduce the filtering requirement to meet the prescribed ripple voltage. Since the filter component values predominantly decide the
dynamic response, the achievable small-signal bandwidth of the control loop and hence the achievable tracking accuracy of the
ramping output current are essentially governed by the filter components. To optimise the filter design, quantification of overall
ripple voltage is crucial, that too under the most practical conditions considering non-ideal conditions. In this paper, estimation of
overall ripple voltage is performed for series-connected two-quadrant power converters (TQPCs) operating in phase-staggering
mode for ideal and non-ideal conditions. Simulation and experimental verification results are shown to be in good agreement with
the analytical results.