| 摘要 |
PURPOSE:To detect a speed even at the time of low speed rotation by dividing the change quantity of the phase difference between the exciting signal of a resolver and the output of secondary winding by the time required in the change of phase difference. CONSTITUTION:Rising detection circuits 20, 21 respectively grasp the risings of waveform signals S1, S2 to output pulse signals Sa, Sb. A counter 22 starts counting by the signal Sa and counting is continued on the basis of the clock signal CK of a counting transmitter 8 until the next signal Sa is inputted. Next, latch circuits 23, 24 latches the count value of the counter 22, that is, the position data Dp at each point of time of the secondary winding 3 of a resolver on the basis of the signal Sb. A CPU 25 counts the output clock CK2 of an oscillator 27 during a time when the position of the winding 3 is changed by an internal counter to measure a time. The position data Dp is taken in from the circuit 24 at the point of time of the input of the signal Sb and a rotational speed (v) is calculated on the basis of a positional change and time difference. By this method, the magnitude of the rotational speed becomes regardless of speed detection accuracy and a rotational speed at a low speed can be measured. |
