| 摘要 |
PURPOSE:To detect a frequency high accurately at a high speed by a rough sampling period similar to the control period of a controller. CONSTITUTION:From each phase voltage (ea, eb, ec) and current (ia, ib, ic) of a synchronous machine, a signal (ea'', eb'', ec'') in proportion to a number of interlinkage magnetic fluxes is detected, and by a value of the signal as an input, a sum of products of a value at time (t) and a signal before 1 sampling period, obtained through delay circuits 11, to 13, is detected by multipliers 14 to 22 and adders 23 to 25, to detect a frequency (f) from these values. Thus in no relation to operation and external conditions of the synchronous machine, a frequency can be realized by a rough sampling period high accurately at a high speed. |
