Step-out prevention device of the synchronous machine

摘要

(57) [Abstract] [Purpose] The present invention is synchronous machine can be reliably prevented from reaching the step-out state, are intended to perform a stable operation with a sudden change of the reduction and the load of the power supply voltage. [Configuration] and a voltage detecting means for detecting the output voltage of the AC power source for operating a synchronous machine, a rotor position detecting means for detecting the position of the synchronous machine rotor, outputs a rotor position detecting means from the voltage detection means Based output and to the internal phase difference angle calculator for calculating an internal phase angle in the synchronous machine operation, the internal phase difference angle change rate arithmetic for calculating the change rate of the internal phase angle calculated by the internal phase angle calculator vessels, based on the internal phase angle calculating internal phase angle calculated by the instrument and the internal phase difference angle change rate internal phase difference angle change rate calculated by the arithmetic unit, and a control means comprising an excitation control circuit for controlling the exciter and it is characterized by comprising.