An AC mains isolated zero-crossing detection circuit combined with low-voltage power line carrier communication signal coupling

Abstract

The invention discloses an alternating current mains supply isolation zero crossing checking circuit combined with low-voltage power line carrier wave communication signal coupling, belonging to the field of low-voltage power line carrier wave communication and control. The circuit comprises a carrier wave signal coupling circuit, a zero crossing checking circuit and a protective circuit, wherein the carrier wave signal coupling circuit receives and sends the carrier wave signal in the carrier wave communication process in a mode of combining series resonance with a coupling transformer, and the active power consumption and the inactive power consumption of a system can be effectively lowered. in the zero crossing detection circuit, a biasing circuit is designed according to the conduction condition of a Darlington tube, the capacitance characteristics and the optocoupling working condition, so as to accurately detect the zero crossing point time of the alternating current mains supply; the carrier wave signal coupling circuit and the zero crossing detection circuit share one protective circuit to prevent impact interference, such as pulse or surge and the like; and strong current and weak current are completely isolated to guarantee system safety. In the alternating current mains supply isolation zero crossing checking circuit, a low-voltage power line carrier wave coupling circuit is combined; the characteristics of components are used for realizing the zero crossing point detection function; the coupling circuit and the detection circuit share one protective circuit, and the whole circuit is easy to realize, thereby correspondingly lowering cost, and lowering the active power consumption and the inactive power consumption of a system; and especially the zero crossing point detection accuracy required for carrier wave communication is guaranteed.

Description

technical field [0001] The invention relates to the field of low-voltage power line carrier communication and control, in particular to a detection circuit for detecting the zero-crossing moment of AC mains, in particular to an AC mains isolated zero-crossing detection circuit combined with low-voltage power line carrier communication signal coupling. Background technique [0002] AC mains zero-crossing detection refers to the detection of the moment when the AC mains waveform passes through zero potential during the conversion process of the AC mains waveform from the negative half cycle to the positive cycle, or from the positive half cycle to the negative cycle. Zero-crossing detection plays an important role in the field of low-voltage power line carrier communication and control, especially at present, a large number of field data prove that the differential time period around the zero-crossing point of AC mains has significant advantages such as low noise, stable impeda...

AI Technical Summary

Problems solved by technology

[0004] The technical problem to be solved by the present invention is to provide an AC mains zero-crossing detection circuit to solve the problem that the existing low-voltage power line carrier communication and control fields cannot obtain fast and accurate zero-crossing detection signals, and improve the effect of low-voltage power line carrier communication

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