| 摘要 |
<p><P>PROBLEM TO BE SOLVED: To estimate the timing, with which a circuit breaker should be turned on, with higher accuracy. <P>SOLUTION: First, the rise of a rectangular wave Wb, after a phase difference detection time Ts, corresponding to a single period of an initial unit wave Wb<SB>0</SB>, is detected. The first and next period counted values RWb<SB>0</SB>(0) and RWb<SB>1</SB>are read from a register 5, and a phase difference counted value RWg<SB>1</SB>is similarly read from a register 6. The phase differenceΔθ<SB>1</SB>of the unit wave Wg<SB>1</SB>, relative to the unit wave Wb<SB>1</SB>, is computed, and with respect to each unit wave, phase difference computation is repeated, until the phase difference computed valueΔθcorresponds to a first target thresholdΔϕ<SB>1</SB>. When the phase difference computed valueΔθcorresponds to the first target thresholdΔϕ<SB>1</SB>, a first phase difference computed valueΔθ(C<SB>1</SB>) and the first index count value RC<SB>1</SB>at that time are determined. Next, phase difference computation is similarly repeated, until the phase difference computed value corresponds to a second target threshold valueΔϕ<SB>2</SB>. Then, a second phase difference computed valueΔθ(C<SB>2</SB>) and the second index count value RC<SB>2</SB>at that time are determined. Last, a synchronization time T<SB>syn</SB>is computed, and a command is outputted so that a circuit breaker 8 starts making at a time Te earlier by a progressive time Tα. <P>COPYRIGHT: (C)2005,JPO&NCIPI</p> |
