| 摘要 |
<p>The present invention relates to an electric-power frequency measurement apparatus based on zero-crossing and an electric-power frequency measurement method based on zero-crossing. According to the present invention, the electric-power frequency measurement apparatus can reduce error rate as not increasing a sampling rate, and can be driven by low power consumption with only a hardware resource, by calculating points of internal division by applying a simple formula using a coordinate of voltage data pairs and obtaining an electric-power frequency by the method of obtaining a weighted average by reflecting a weight value which is set differently according to an error of each point of internal division. The apparatus of the present invention includes: a zero-crossing detection part for detecting zero-crossing of voltage data sampled by a predetermined sampling frequency; a profile storage part which is connected to the zero-crossing detection part, and stores the coordinate of the voltage data pairs comprising first voltage data and second voltage data; a point of internal division calculation part which is connected to the profile storage part, and calculates a coordinate of points of internal division which are points of intersection between a straight line connecting the first voltage data and the second voltage data of each voltage data pair and a straight line whose voltage value is zero; a first frequency calculation part which is connected to the point of internal division calculation part, and obtains first frequencies; a weight value setting part which is connected to the profile storage part, and sets each weight value determined to be inversely proportional to the variation of a voltage difference of voltage data located just before and after each zero-crossing point; and a second frequency calculation part which is connected to the first frequency calculation part and the weight value setting part, and calculates a second frequency.</p> |
