Method for determining zero crossing point of alternating current signal and system for determining zero crossing point of alternating current signal

Abstract

The invention provides a method for determining a zero crossing point of an alternating current signal and a system for determining the zero crossing point of the alternating current signal. The method for determining the zero crossing point of the alternating current signal comprises the following steps: recording lasting time of the output zero crossing point of the alternating current signal, which is detected last time; calculating according to the lasting time and determining reference time of a next-time zero crossing point moment of the alternating current signal; and when a zero crossing signal is detected next time, determining the moment of the next-time zero crossing point moment of the alternating current signal according to the moment of the zero crossing signal detected next time and the reference time. According to the technical scheme, the detection precision of the zero crossing point is effectively improved under the precondition that hardware cost is not increased.

Description

technical field [0001] The invention relates to the technical field of zero-crossing detection, in particular to a method for determining the zero-crossing point of an AC signal and a system for determining the zero-crossing point of an AC signal. Background technique [0002] In an AC circuit, the moment when the detection voltage waveform passes through the zero position from the positive half axis to the negative half axis (or from the negative half axis to the positive half axis) is called zero-crossing detection; when the voltage waveform passes through the zero position, the output voltage signal, it is called a zero-crossing signal. The zero-crossing detection is mainly used for the frequency detection of the power supply, and it can also be used as a synchronous signal in the chopper voltage regulation circuit. [0003] However, due to voltage fluctuations, different voltage standards used in different regions, or the impact of device accuracy, there are also differ...

AI Technical Summary

Problems solved by technology

[0005] However, the scheme of using a fixed delay to judge the zero-crossing point cannot automatically adapt to the change of the voltage. The delay time needs to be determined after testing according to different input voltages, and when the resistance error is large, it will lead to inaccurate judgment of the zero-crossing point.

Although the scheme of using hardware to improve the accuracy of zero-crossing signals can improve the accuracy of judging zero-crossing points, it will increase the production cost of the product due to the need for additional devices, and will reduce the reliability and anti-interference performance of the system.

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