Simplified type alternating-current zero-crossing detecting and amplitude value sampling unit

Abstract

The invention relates to a simplified alternating-current zero-crossing detecting and amplitude value sampling unit which comprises a microprocessor, a current transformer, and a voltage amplitude value sampling component and a current zero-crossing detecting component which are connected with the current transformer, wherein the voltage amplitude value sampling component comprises a rectifying bridge, a voltage-stabilizing tube D18 and a first filter circuit which are sequentially connected, and the current value obtained by sampling of the current transformer sequentially flows the rectifying bridge, the voltage-stabilizing tube D18 and the first filter circuit, and a direct-current voltage signal is output to the AD (analog / digital) conversion port of the microprocessor for processing by the microprocessor; and the current zero crossing detecting component comprises a second filter circuit, a differential comparator, and a schmitt trigger which are sequentially connected, and the current value obtained by sampling of the current transformer flows through the second filter circuit, the differential comparator and the schmitt trigger and then is transmitted to the microprocessor for generating interrupt. The simplified alternating-current zero-crossing detecting and amplitude value sampling unit has the advantages of simple and compact structure, low cost, wide application range, capability of greatly improving the working stability and reliability and the like.

Description

technical field [0001] The invention mainly relates to the fields of motor driving and thyristor control, in particular to an alternating current zero-crossing detection and amplitude sampling device. Background technique [0002] In the prior art, most of the current sampling circuits are too complicated and use too many components, thus greatly increasing the hardware cost. Most of the usual current sampling processing requires high-performance DSP and extremely high-speed AD conversion chips. There is no unique circuit structure for occasions with low real-time performance requirements and strict cost control. In a general conventional circuit, if the current amplitude sampling and the current zero-crossing detection are realized at the same time, the circuit will be extremely redundant, the design will be complicated, and the cost will be further increased. [0003] At present, conventional current sampling circuits such as figure 1 As shown, all adopt high-precision c...

AI Technical Summary

Problems solved by technology

For the voltage translation circuit, it takes a lot of debugging time to achieve more accurate voltage translation and convert bipolar to unipolar

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