RESIDUAL CHARGE CONTROLLER FOR SWITCHED CAPACITOR INSTALLATION

摘要

16 A device is taught for controlling the residual charge on a thyristor switched capacitor. A capacitor is in series circuit relationship with at least two pairs of back-to-back thyristor switches which is then connected across an AC network. Each back-to-back thyristor combination is shunted by a non-linear clamping device which exhibits a very high resistance below a specified voltage level and a very low resistance above that voltage level. A pulse stretcher and a sequential firing circuit arrangement is utilized so as to prolong the conduction of one of the back to-back pair of thyristor switches at a time. During an overvoltage condition in the AC network the non-linear clamping device will limit the residual charge on the capacitor. A plurality of capacitor, thyristor switch, non-linear clamping device combinations may be utilized in parallel with the AC network.