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 (ASDs) using common-mode voltage. In the proposed ride-through system, the common-mode voltage inherent in PWM converter-inverter systems is used for charging the energy storage device at normal conditions of source power. That is, charging current can be regulated by the control of common-mode voltage with a 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-mode voltage-are also available in the proposed system