| 摘要 |
<p>PURPOSE:To suppress abrupt voltage change upon interruption of an AC excited synchronous machine from an AC system by providing a second phase generating means for generating a sine wave having predetermined frequency, a phase switching means, and a command value switching means for holding a quadrature current component command value at a predetermined level, and operating means for performing switching between a phase signal and a command value simultaneously. CONSTITUTION:Upon closing of contact X26, a slip phase operating unit 25 holds the slip phase output to start DC excited operation. Upon closing of contact 28, a quadrature current command switch 27 brings the quadrature current command to zero which is then fed to an exciting current controller 14. Upon closing of contact Y31, a slip phase switch 30 connects the output from a two- phase oscillator 29 to the exciting current controller 14. Consequently, an AC excited synchronous machine 5 enters into synchronous operation mode upon opening/closing of the contacts X26 and Y31 while enters into a mode for controlling only the direct axis current upon closing of contact Z. By such arrangement, abrupt voltage change can be suppressed upon interruption of the synchronous machine from an AC system.</p> |
