| 摘要 |
PURPOSE:To make the highly accurate speed sensing possible by sampling the voltage across the coil terminals of a linear motor at a specified cycle, and preventing the flow of the driving current through the coil during the sampling period. CONSTITUTION:The terminal voltage across a linear motor coil is applied to a differential amplifier 2, thereby a counter electromotive force is detected. The output of the differential amplifier 2 is supplied to a control circuit 5 together with a reference speed Vref, and the control output CONi is intermittently supplied to a holding circuit 6 by a sampling signal SMP, and the output of the holding circuit 6 is given to a linear motor coil 1 by a signal N/FD which is formed by inverting the sampling signal. During the sampling period, the driving current is not flowed through the coil. Therefore, only a speed component is included in the terminal voltage of the coil, and the accuracy in speed sensing can be enhanced. |
