Control signal method based on solid-state relay

Abstract

The invention provides a circuit design scheme for controlling flicker of a signal lamp of feeder automation terminal equipment. According to the circuit, the isolation control effect of a solid-staterelay is mainly utilized, a photoelectric coupling device and the solid-state relay are added between an MCU and a large-current voltage load for isolation protection, so the purposes of controllingan external circuit through small-current voltage, controlling a high-voltage current loop or controlling on-off of a large-load circuit are achieved. According to the control signal method based on the solid-state relay, when the MCU receives a normal operation or fault alarm signal, an IO port of the MCU generates a 1s square wave signal to control the on and off of a photoelectric coupler so asto control the on and off of the solid-state relay to achieve the purpose of flickering of a signal lamp; the photoelectric coupler is additionally arranged between the MCU and the solid-state relayto carry out conversion isolation of different voltage levels, so multi-level isolation among the different voltage levels is realized, and a guarantee is provided for stable and reliable operation ofthe circuit.

Description

technical field [0001] The invention relates to the field of electric power technology, in particular to a control signal technology based on a solid state relay. Background technique [0002] The standard of the feeder terminal equipment has the following requirements: the bottom of the feeder terminal has an externally visible running indicator light and a line fault indicator light: the running indicator light is green and flashes when it is running normally. The line fault indicator light is red, flashes in the fault state, is always on when the lock is closed, and goes out in the non-fault and non-block state. [0003] In response to this requirement, it was decided to use 220V AC LED lights as the indicator lights of the equipment after comprehensive analysis of various aspects. When designing the automatic flashing control circuit of the indicator light, considering that the IO port level of the MCU is only 3.3V, the current it can sink or output is relatively limite...

AI Technical Summary

Problems solved by technology

Its shortcomings basically focus on its working method: the switch on-off time is too slow, and it has relatively high control current noise! Arcing or sparks may occur between contacts during switching Sensitive to environmental factors (such as vibration, humidity, etc.)

In addition, the flickering of the indicator light requires the continuous opening and closing of the mechanical contacts of the relay, which greatly shortens the service life of the mechanical relay

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