| 摘要 |
PURPOSE:To prevent a low frequency vibration and to feed water under suitable pressure by calculating a rotating speed command to become a set pressure, and outputting a discharge valve opening/closing command for avoiding a beat phenomenon. CONSTITUTION:A rotating speed command MV1 is output by a feedback control PID1 with a set value SV and a present value PV. When the command MV1 is in a range of the vicinity of 1/3 or 1/6 of a slip S of a motor, i.e., a-b or a'-b' in which a beat phenomenon occurs, the command MV1 is forcibly set to a rotating speed N or N', and when it is out of the range, it is output as it is. A discharge valve command MV2 is calculated by a feedback control PID2 at the set value SV and the present value PV. When the command MV1 is in a range of a-b or a'-b', the command MV2 is output as it is, and when it is out of the range, the command MV2 is output as a totally open command. |
