| 摘要 |
PROBLEM TO BE SOLVED: To minimize unnecessary trip of a transducer, which is caused by β-advance control, if β-advance control is conducted in such a case as distortion is generated in the voltage waveform of an AC system. SOLUTION: If a β-advance command is inputted at time t1 , a signal '1' or a reset signal is inputted into a primary delay circuit 314 from an OR-circuit 312, so that the output of the primary delay circuit becomes zero. Therefore, a β-advance angle decreases the 120 degrees. When time T1 has past after the time t1 to become a time t2 , an on-delay circuit 316 outputs a reset cancel signal S1 and an output limit signal S2 into the primary delay circuit 314. As a result, the primary delay circuit 314 starts its operation, and the β-advance angle increases to 135 degrees. When an output of the β-advance command is cutoff to cancel the β-advance control at time t3 , the primary delay circuit 314 starts its normal operation, and the β-advance angle returns to 160 degrees with a time constant T. |
