| 摘要 |
PURPOSE:To reduce the adverse influence of correction associated with the fluctuation of a DC voltage caused by accelerating or decelerating operations by finding a correction factor by selectively referring to a DC voltage detecting means and DC voltage storage means which stores the output of the DC voltage detecting means at the moment when the statues of a frequency comparing means changes in accordance with the statue of a timer which measures a prescribed period of time. CONSTITUTION:A frequency comparing means 8 which compares a set frequency which is the output of a frequency setting means 6 with an output frequency which is the output of acceleration/deceleration controlling means 7 and a DC voltage storage means 11 which stores the output of a DC voltage detecting means 10 at the moment when the status of the means 8 changes are provided and the outputs of the means 8 and 11 are inputted to a correction factor setting means 13. In addition, a timer 9 which is actuated when the means 8 detects a constant-speed state is provided and the output of the timer 9 is inputted to the means 13 together with the output of the means 8. In other words, when an abrupt fluctuation of a DC voltage is expected, the adverse influence of correction is reduced by calculating the correction factor by referring to the output of the DC voltage storage means which stores the DC voltage immediately before the fluctuation, stopping the correction, and so on. |
