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US 2009/0154203 A1Published application
AC to DC power supply having zero low frequency harmonic contents in 3-phase power-factor-corrected output ripple
AssigneeSwitching Power, Inc.
InventorDavid Kravitz
Life of this patent
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Abstract
An AC-DC power supply circuit utilizing an output stage configuration designed to achieve no output ripple at the power line frequency. To eliminate the ripple formed, each separate processing output stage corresponding to a respective ac voltage source phase which provides a 120 Hz ripple, is stacked, in a series connection, and due to their respective ripple phase shifts of 120° degrees, achieves ripple cancellation at the output.
Claims9
An AC-DC power supply comprising:
- a 3-phase AC voltage source providing balanced 120° phase-shifted input voltage signals;
- an active power-factor corrected (PFC) circuit associated with each phase, each PFC circuit receiving a respective AC input voltage signal of a respective phase and providing respective DC signal carrying a ripple voltage of a respective phase;
- an output filter circuit for attenuating said ripple voltage of said respective phase;
- an isolation circuit coupling said PFC output DC voltage to each respective output filter and ripple voltage of said respective phase;
- said output filters of each phase forming a stacked series connection, wherein each isolated DC output voltage being added together to form said output DC signal and each ripple of each respective phase are added together and cancelled such that said ripple voltage at the power line frequency is eliminated.
2 more elements
Dependencies are inferred from the claim text.