Method for detecting zero crossing time, frequency and phase difference of power sinusoidal signals

Abstract

The invention discloses a method for detecting zero crossing time, frequency and phase difference of power sinusoidal signals. In the method for detecting zero crossing time, by using the fundamental principle that a sinusoidal signal close to the zero crossing can be approximately equivalent to a linear signal, after a zero crossing position of a signal is worked out by rough calculation, a voltage amplitude close to the signal zero crossing is counted by the unary linear regression theory so as to acquire the zero crossing time of the sinusoidal signal. The method for detecting a frequency of a zero crossing point of a sinusoidal signal comprises the following steps of: obtaining a period value of each zero crossing point by carrying out the cumulative mean on each zero crossing point phase different of the obtained signal, and solving the reciprocal to obtain the signal frequency value. The method for detecting phase difference comprises the following step of calculating the phase difference between different signals by means of a zero crossing point phase value of each different signal. The invention is insensitive to the relative position of the zero crossing point of the actual signal, can realize higher detection accuracy in the digital detection system, has a strong suppression function to the noise of the signal source and the interference, and finally ensures the application of the method in a high-accuracy detection field.

Description

technical field [0001] The invention relates to a detection method for a power sinusoidal signal, in particular to a detection method for the zero-crossing time, frequency and phase difference of the sinusoidal signal. Background technique [0002] Frequency is the main performance parameter of the power system and one of the electrical parameters that must be checked for each power system equipment and instrumentation. At present, through the research and development of scholars at home and abroad, many detection methods based on various principles and methods have been invented, including pulse counting method based on simple software and hardware, zero-crossing detection method, and Fourier transform based on complex algorithms. method, Kalman filter method, etc. [0003] Among many detection methods, the zero-crossing discrimination detection method is a simple, practical and widely used method for detecting the phase and frequency of power sinusoidal signals. The basi...

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Problems solved by technology

[0004] Aiming at the problems of difficulty in identifying zero-crossing points in practical applications of the prior art and insufficient phase resolution in digital signal processing, the present invention provides a method that is insensitive to signal zero-crossing detection, has strong ability to suppress noise and interference, and can effectively improve Detection method of digital sinusoidal signal frequency and phase detection accuracy for power sinusoidal signal zero-crossing time, frequency and phase difference

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