Zero-cross detection system

Abstract

The invention discloses a zero-cross detection system. The system comprises a zero-cross signal sampling module, a power module and a direct current filtration module, wherein the zero-cross signal sampling module comprises a thunder-proof surge interference circuit and an inductor, the thunder-proof surge interference circuit is connected with an alternating current fire line input end, an alternating current zero line input end and a primary winding of the inductor and at least comprises a safety capacitor, the primary winding of the inductor and the safety capacitor constitute a first filtration circuit, and the primary winding of the inductor is connected to an alternating current grid in series; the power module comprises a bridge rectifier, a clamping circuit, a booster transformer and a primary side feedback system, the clamping circuit is connected with a second auxiliary winding of the booster transformer, a first auxiliary winding of the booster transformer is connected withthe primary side feedback system, and a buffer circuit is arranged on a secondary side winding of the booster transformer and a direct current voltage output end. The problems of delay of the samplingcircuit, poor sampling consistency and high loss can be solved.

Description

technical field [0001] The invention relates to the technical field of electronic circuits, in particular to a zero-crossing detection system. Background technique [0002] With the development of power line carrier communication, people have higher and higher requirements for the synchronization of carrier data, so the requirements for the accuracy of zero-point detection of AC grid voltage are also continuously improved. At present, the commonly used zero-crossing detection circuit uses a current-limiting resistor at the input end to limit the current flowing through the photocoupler. Zero-crossing detection is used in many electronic devices. [0003] The existing zero-crossing detection circuit is simple in principle, and usually adopts resistance voltage division to obtain high-voltage signals, or adopts resistance-capacitance step-down and resistance division to sample AC input signals. In addition, there are some LC oscillation circuits, non-isolated Sampling circuit...

AI Technical Summary

Problems solved by technology

[0004] For this reason, the purpose of the present invention is to propose a zero-crossing detection system to solve the problems of sampling circuit delay, poor sampling consistency, and large loss

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