| 摘要 |
<p>A zero-cross detecting unit (30) monitors an AC voltage detected by a voltage sensor (32), generates a zero-cross point signal when the AC voltage strides across zero volt, and sends the signal to a controller (7). A rotational speed setting unit (12) of the controller (7) sets a command for a rotational speed that will become the target of a synchronous motor (1). A rotational speed correction factor data table (17) has stored therein correction factor data for target rotational speeds. A correction factor data extracting unit (16) extracts correction factor data corresponding to the elapsed time of the zero-cross point signal that was generated from the rotational speed correction factor data table by the zero-cross detecting unit (30), and outputs the correction factor data to a correction rotational speed generating unit (18). The correction rotational speed generating unit (18) corrects the rotational speed set by the rotational speed setting unit (12), according to the extracted correction factor data, and outputs the corrected rotational speed to a sine wave data creating unit (14).</p> |
