| 摘要 |
The circuitry for generating filter excitation signals from a multi-phase alternating current input is provided with the following circuitry for each phase of the multi-phase alternating current input. A current transformer connected to a respective phase of the multiphase alternating current input is connected to a bridge rectifier having one node connected to a neutral conductor and including a resistor of equal resistance value connected in each parallel branch of the bridge rectifier between the neutral conductor and the input of the current transformer. An operational amplifier having inputs respectively responsive to the voltage across each of the respective resistors in the bridge rectifier generates an output for one phase of the excitation signal to the filter. The filter excitation circuitry has application to two-phase and three-phase systems wherein the excitation circuitry is identical for each phase. |
