Five-level, single-phase active rectifier with extended functions

A five-level, single-phase active rectifier, which is commonly used to improve the power factor, is analyzed in order to extend its functions for voltage sag ride-through and simultaneously works as active filter. It makes use of two bidirectional switches between the rectifier A C and DC sides. The stages used to achieve the extended functions are: an output power estimator, which uses the A C mains voltage peak value calculated by using the single-phase DQ transformation to perform the voltage sag ride-through; a DC-link voltage regulator, and a harmonic current estimator. A hysteresis current controller is applied to track the reference current. Theoretical and predicted results of its analysis are verified initially through digital simulation, and confirmed by using a 1 kVA experimental prototype. Copyright C 2007 Praise Worthy Prize S.r.l. - All righ is reserved.