CN204858521U - Self-resetting overvoltage and undervoltage protection switch - Google Patents

Abstract

The utility model relates to an undervoltage protection switch is crossed from compound. The power supply circuit comprises a power supply circuit, a voltage sampling circuit, a microprocessor, a silicon controlled rectifier, an electromagnetic switch unit and a driving circuit; the microprocessor judges whether the voltage of the power grid is over-voltage or under-voltage and outputs a pull-in signal or a release signal to the driving circuit according to the judgment result; when the voltage of the power grid is in an overvoltage or undervoltage state, the microprocessor outputs a suction signal, the drive circuit controls the conduction of the silicon controlled rectifier, and the electromagnetic switch unit trips; when the voltage of the power grid is in a normal state, the microprocessor outputs a release signal, the drive circuit controls the silicon controlled rectifier to be cut off, and the electromagnetic switch unit is switched on; the microprocessor is set with a delay time T, after the electromagnetic switch unit trips, the power grid voltage recovers to a normal state, and the microprocessor outputs a release signal after the normal state maintains the time T. The utility model discloses simple structure, work is more reliable, more stable.

Description

Self-resetting overvoltage and undervoltage protection switch

technical field

The utility model relates to a switch, in particular to a self-resetting overvoltage and undervoltage protection switch.

Background technique

The protection switch is used in the circuit and can play a certain protective role. At present, in the common self-recovery overvoltage and undervoltage protection switch, it can protect the load from damage caused by overvoltage and undervoltage. However, the structure of these self-recovery overvoltage and undervoltage protection switches is relatively complex and lacks stability, especially when overvoltage or undervoltage occurs intermittently in a short period of time, the reliability and stability are poor, and the load is intermittent in a short period of time. Power off and on, easily lead to load damage.

Contents of the invention

The purpose of the utility model is to propose a self-resetting overvoltage and undervoltage protection switch with a simple structure.

The above-mentioned purpose is achieved through the following technical solutions:

A self-resetting overvoltage and undervoltage protection switch, including a power supply circuit for providing DC power, a voltage sampling circuit for collecting grid voltage, a microprocessor, a thyristor, an electromagnetic switch unit, and a drive for controlling the thyristor circuit; the input end of the power supply circuit is connected to the power grid, and its output end is connected to the microprocessor, the drive circuit and the thyristor respectively; the input end of the voltage sampling circuit is connected to the power grid, and its output end is connected to the microprocessor so that The microprocessor judges whether the grid voltage is overvoltage or undervoltage; the input end of the drive circuit is connected to the microprocessor, and its output end is connected to the thyristor; the electromagnetic switch unit is connected to the grid and the load In between, the load can be selectively connected or cut off from the grid; the microprocessor judges whether the grid voltage is overvoltage or undervoltage and outputs a pull-in signal or a release signal to the drive circuit according to the judgment result; when the grid voltage is at In the overvoltage or undervoltage state, the microprocessor outputs a pull-in signal, the drive circuit controls the thyristor to conduct, and the electromagnetic switch unit trips; when the grid voltage is in a normal state, the microprocessor outputs a release signal, and the drive circuit controls the controllable The silicon is cut off, and the electromagnetic switch unit is closed; the microprocessor is set with a delay time T. After the electromagnetic switch unit trips, the power grid voltage returns to a normal state, and the normal state is maintained for T time, and the microprocessor outputs a release signal. .

The utility model has simple structure, adopts microprocessor voltage detection and control, simple adjustment of operating voltage value and delay time, high precision, and effectively protects the load from damage caused by overvoltage and undervoltage. SCR is used as the executive element, so that it consumes almost no power in normal operation, energy saving and environmental protection. After the protection action, when the power supply returns to the normal voltage range, it will automatically turn on the power supply, ensuring the continuity of power supply and the quality of power supply. And by setting the delay time T, the self-resetting over-voltage and under-voltage protection switch can work more reliably and stably, avoiding intermittent power-off and power-on of the load in a short period of time, and more effectively protecting the load.

Above-mentioned technical scheme can adopt following measure to make further improvement:

The microprocessor includes a timing module, and the delay time T is set by the timing module. By setting the timing module, the structure is simpler and more reasonable.

The value of the delay time T is 20 seconds to 40 seconds, the design is reasonable, and the reliability and stability are improved.

The pull-in signal and the release signal are pulse signals.

The value of the delay time T is 30 seconds.

The self-resetting overvoltage and undervoltage protection switch also includes a working state indicating circuit, and the working state indicating circuit is connected with a microprocessor, which is convenient for human use and operation.

The working state indicating circuit includes a normal state indicator light and an overvoltage or undervoltage state indicator light; when the grid voltage is in an overvoltage or undervoltage state, the normal state indicator light is off, and the overvoltage or undervoltage state indicator light is on; When the grid voltage is in a normal state, the normal state indicator light is on, and the overvoltage or undervoltage state indicator light is off.

The microprocessor includes a judging module for judging whether the grid voltage is overvoltage or undervoltage, and the configuration of the judging module makes the structure simpler and more reasonable.

The utility model has simple structure, adopts microprocessor voltage detection and control, simple adjustment of operating voltage value and delay time, high precision, and effectively protects the load from damage caused by overvoltage and undervoltage. SCR is used as the executive element, so that it consumes almost no power in normal operation, energy saving and environmental protection. After the protection action, when the power supply returns to the normal voltage range, it will automatically turn on the power supply, ensuring the continuity of power supply and the quality of power supply. And by setting the delay time T, the self-resetting over-voltage and under-voltage protection switch can work more reliably and stably, avoiding intermittent power-off and power-on of the load in a short period of time, and more effectively protecting the load.

Description of drawings

Fig. 1 has shown the circuit block diagram of the present utility model;

Fig. 2 shows the circuit diagram of the utility model.

Detailed ways:

As shown in Figures 1 and 2, a self-resetting overvoltage and undervoltage protection switch includes a power supply circuit 1 for providing DC power, a voltage sampling circuit 2 for collecting grid voltage, a microprocessor 3, and a thyristor 4 , an electromagnetic switch unit 5 and a drive circuit 6 for controlling the thyristor 4;

The input end of the power supply circuit 6 is connected to the power grid, and its output end is connected to the microprocessor 3, the driving circuit 6 and the thyristor 4 respectively;

The input terminal of the voltage sampling circuit 2 is connected to the grid, and its output terminal is connected to the microprocessor 3 so that the microprocessor can judge whether the grid voltage is overvoltage or undervoltage;

The input terminal of the drive circuit 6 is connected with the microprocessor 3, and its output terminal is connected with the thyristor 4;

The electromagnetic switch unit 5 is connected between the grid and the load to selectively enable the load to connect or cut off the grid;

The microprocessor judges whether the grid voltage is overvoltage or undervoltage, and outputs a pull-in signal or a release signal to the drive circuit according to the judgment result;

When the grid voltage is in an overvoltage or undervoltage state, the microprocessor outputs a pull-in signal, the drive circuit controls the thyristor to conduct, and the electromagnetic switch unit trips;

When the grid voltage is in a normal state, the microprocessor outputs a release signal, the drive circuit controls the thyristor to cut off, and the electromagnetic switch unit closes;

The microprocessor is set with a delay time T. After the electromagnetic switch unit trips, the power grid voltage returns to a normal state, and after the normal state is maintained for T time, the microprocessor outputs a release signal, and the electromagnetic switch unit switches from tripping to closing. brake. If the grid voltage appears over-voltage or under-voltage again within T time, it is necessary to wait until the microprocessor detects that the grid voltage returns to a normal state again and delay the time T again.

In this embodiment, the power supply circuit can provide a DC 5V power supply, and the driving circuit drives the thyristor to provide instantaneous action energy.

The microprocessor includes a timing module 31, and the delay time T is set by the timing module. The timing module 31 can be a hardware or a software program.

The value of the delay time T is 20 seconds to 40 seconds. In particular, the delay time T is 30 seconds.

The pull-in signal and the release signal are pulse signals.

The self-resetting overvoltage and undervoltage protection switch also includes a working state indicating circuit 7, and the working state indicating circuit is connected with the microprocessor.

The working status indicating circuit includes a normal status indicator and an overvoltage or undervoltage status indicator;

When the grid voltage is in an overvoltage or undervoltage state, the normal state indicator light is off, while the overvoltage or undervoltage state indicator light is on;

When the grid voltage is in a normal state, the normal state indicator light is on, and the overvoltage or undervoltage state indicator light is off.

The microprocessor includes a judging module 32 for judging whether the grid voltage is overvoltage or undervoltage. The judging module can set a threshold with a certain voltage range for comparing the grid voltage with the threshold to judge whether the grid voltage is overvoltage or undervoltage. The judging module 32 can be a hardware or a software program.

The working principle of the utility model is as follows:

When the power grid is powered on, the microprocessor continuously detects the grid voltage through the voltage sampling circuit. When it detects that the grid voltage is within the normal range, it outputs two sets of signals. The pull-in signal is output to the drive circuit, the drive circuit controls the thyristor to cut off, the electromagnetic switch unit closes, the main circuit is connected, and the power grid supplies power to the load normally. When the grid voltage is overvoltage or undervoltage, the microprocessor detects that the grid voltage is in an overvoltage or undervoltage state through the voltage sampling circuit, and outputs two sets of signals, one set is output to the working status indicating circuit, and the overvoltage or undervoltage status indication When the light is on, the other output release signal is sent to the drive circuit. The drive circuit controls the conduction of the thyristor, the electromagnetic switch unit trips, cuts off the main circuit, and cuts off the load to achieve the purpose of overvoltage and undervoltage protection.

When the grid voltage returns to normal, the microprocessor detects that the grid voltage returns to normal through the voltage sampling circuit, and the normal signal is output to the working status indicating circuit. Time timing (T time can be 20 seconds, 30 seconds or 40 seconds, etc.), when the grid voltage is normal within T time, the microprocessor will output the pull-in signal to the drive circuit, and the drive circuit will control the thyristor to cut off. The electromagnetic switch unit is closed, the main circuit is connected, and the power grid restores power to the load to achieve the purpose of self-recovery.

Claims (8)

1. A self-resetting overvoltage and undervoltage protection switch, characterized in that: It includes a power supply circuit for providing DC power, a voltage sampling circuit for collecting grid voltage, a microprocessor, a thyristor, an electromagnetic switch unit and a drive circuit for controlling the thyristor; The input end of the power supply circuit is connected to the power grid, and the output end is respectively connected to the microprocessor, the drive circuit and the thyristor; The input end of the voltage sampling circuit is connected to the grid, and its output end is connected to the microprocessor so that the microprocessor can judge whether the grid voltage is overvoltage or undervoltage; The input end of the drive circuit is connected with the microprocessor, and the output end is connected with the thyristor; The electromagnetic switch unit is connected between the power grid and the load to selectively enable the load to connect or cut off the power grid; The microprocessor judges whether the grid voltage is overvoltage or undervoltage, and outputs a pull-in signal or a release signal to the drive circuit according to the judgment result; When the grid voltage is in an overvoltage or undervoltage state, the microprocessor outputs a pull-in signal, the drive circuit controls the thyristor to conduct, and the electromagnetic switch unit trips; When the grid voltage is in a normal state, the microprocessor outputs a release signal, the drive circuit controls the thyristor to cut off, and the electromagnetic switch unit closes; The microprocessor is set with a delay time T. After the electromagnetic switch unit trips, the power grid voltage returns to a normal state and the normal state is maintained for T time before the microprocessor outputs a release signal. 2. The self-resetting overvoltage and undervoltage protection switch according to claim 1, characterized in that: The microprocessor includes a timing module, and the delay time T is set by the timing module. 3. The self-resetting overvoltage and undervoltage protection switch according to claim 1 or 2, characterized in that: The value of the delay time T is 20 seconds to 40 seconds. 4. The self-resetting overvoltage and undervoltage protection switch according to claim 1 or 2, wherein the delay time T is 30 seconds. 5. The self-resetting overvoltage and undervoltage protection switch according to claim 1 or 2, characterized in that: the pull-in signal and the release signal are pulse signals. 6. The self-resetting overvoltage and undervoltage protection switch according to claim 1 or 2, characterized in that the self-resetting overvoltage and undervoltage protection switch further comprises a working state indicating circuit connected to a microprocessor. 7. The self-resetting overvoltage and undervoltage protection switch according to claim 6, characterized in that: The working status indicating circuit includes a normal status indicator and an overvoltage or undervoltage status indicator; When the grid voltage is in an overvoltage or undervoltage state, the normal state indicator light is off, while the overvoltage or undervoltage state indicator light is on; When the grid voltage is in a normal state, the normal state indicator light is on, and the overvoltage or undervoltage state indicator light is off. 8. The self-resetting overvoltage and undervoltage protection switch according to claim 1, wherein the microprocessor includes a judging module for judging whether the grid voltage is overvoltage or undervoltage.