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

This paper proposes a novel ride-through system for adjustable-speed drives (ASD' s) using common-mode voltage. In proposed ride-through system, common-mode voltage inherent in PWM converter-inverter system is used for charging the energy storage device at normal conditions of source power. That ist charging current can be regulated by control of common-mode voltage with small reactor while driving motors. At the whole range of voltage disturbance from balanced or unbalanced shallow voltage sag to outage, ride-through is successively available with proposed system. Various energy storage devices can be selected according to the applications and two kinds of the charging topology - using inverter side or converter side common-made voltage - are also available in the proposed system.