A novel ride-through system for adjustable-speed drives using common-mode voltage

This paper proposes a new ride-through system for adjustable-speed drives (ASDs) using common-mode voltage. In the proposed ride-through system, the common-mode voltage inherent in a pulsewidth-modulation boost rectifier-inverter system is used for charging the energy storage device at normal conditions of the source power. That is, controlling the common-mode voltage with a small reactor while driving motors can regulate charging current. Using simple additional circuits and the existing rectifier, at the whole range of voltage disturbances from balanced or unbalanced shallow voltage sag to full outage, ride-through is successively available with the proposed system. Various energy storage devices can be selected according to the applications and two kinds of charging topology-using inverter-side or rectifier-side common-mode voltage-are also available in the proposed system.