Compensation strategy for contactor ridthrough costs

This paper aims at developing a compensation circuit for offsetting the decreased coil voltage value due to power disturbances such as voltage sags. Through a feedforward approach to reserve a compensation voltage in the voltage reservoir in advance, once when the voltage sag occurs in the coil voltage, a triggering signal is generated based on a feedforward-based calculating algorithm so as to trigger the compensation circuit for offsetting the decreased coil voltage. For verifying the effectiveness of our proposed compensation strategy, suppose that a simulation case where voltage sags occur, and the contacts disengagement phenomenon appears as a result of the magnetic force below the springs’ tension. Through properly triggering compensation circuit, the reserved constant dc voltage is then to be super-imposed with the line voltage. Although the movable part originally has started to disengage, but finally is still successfully reengaged before the contacts disengagement.