CN211046453U

CN211046453U - Load overcurrent protection circuit

Info

Publication number: CN211046453U
Application number: CN201922369054.6U
Authority: CN
Inventors: 景界识; 胡应兵
Original assignee: Chengdu Saijie Technology Co ltd
Current assignee: Chengdu Saijie Technology Co ltd
Priority date: 2019-12-25
Filing date: 2019-12-25
Publication date: 2020-07-17
Anticipated expiration: 2029-12-25

Abstract

The utility model discloses a load overcurrent protection circuit, include: the transformer sampling circuit, the signal amplifying circuit, the over-current voltage comparator circuit, the microprocessor circuit and the relay control circuit; the transformer sampling circuit is connected with the signal amplifying circuit, the signal amplifying circuit is respectively connected with the over-current voltage comparator circuit and the microprocessor circuit, and the over-current voltage comparator circuit and the microprocessor circuit are mutually connected; the microprocessor circuit is also connected with the relay control circuit; the utility model discloses a divide into two tunnel transmissions with current signal, can make microprocessor circuit can judge whether appear overflowing the phenomenon according to different indexes, make overflowing the protection circuit can be more accurate monitor overflowing the phenomenon to in time handle, effectively protected the work safety of load.

Description

Load overcurrent protection circuit

Technical Field

The invention relates to the field of load current control, in particular to a load overcurrent protection circuit.

Background

With the gradual popularization of logistics systems and the gradual increase of logistics goods volume, many goods far away need to be transported by air, so that a plurality of containers for air use are needed, and most containers need to have a refrigeration function, so that goods needing to be kept fresh can be conveniently transported. In the transportation process, the power supply is a uniform power supply, and the equipment of different manufacturers has different power and control modes, so that the problem of overlarge current and damage of the equipment of a power supply system are easily caused by the simultaneous use of different equipment in the transportation process; there is therefore a need for effective monitoring and handling of over-current phenomena.

Disclosure of Invention

The invention aims to: in view of the above problems, a load over-current protection circuit is provided; the utility model provides a load appear overflowing the problem that phenomenon leads to power supply system to damage.

The technical scheme adopted by the invention is as follows:

a load overcurrent protection circuit comprising: the transformer sampling circuit, the signal amplifying circuit, the over-current voltage comparator circuit, the microprocessor circuit and the relay control circuit; the transformer sampling circuit is connected with the signal amplifying circuit, the signal amplifying circuit is respectively connected with the over-current voltage comparator circuit and the microprocessor circuit, and the over-current voltage comparator circuit and the microprocessor circuit are mutually connected; the microprocessor circuit is also connected with the relay control circuit.

Further, the transformer sampling circuit is used for collecting the working current of a load; the overcurrent voltage comparator circuit is used for judging whether the load current is overcurrent or not; the signal amplification circuit is used for amplifying and filtering the weak current; the microprocessor circuit is used for outputting control instruction information; the relay control circuit is used for controlling the work of the load.

Furthermore, the signal amplification circuit is composed of an operational amplifier, a peripheral resistor, a diode and a capacitor.

Furthermore, the signal amplification circuit comprises two circuits with the same structure, and the two circuits respectively amplify and output two current signals.

Furthermore, the over-current voltage comparator circuit is composed of an operational amplifier, a diode, a resistor and a capacitor.

Further, the operational amplifier is a 4-way operational method circuit.

Furthermore, the transformer sampling circuit comprises 2 transformer interfaces for collecting two paths of current signals.

In summary, due to the adoption of the technical scheme, the invention has the beneficial effects that:

1. the utility model discloses a divide into two tunnel transmissions with current signal, can make microprocessor circuit can judge whether appear overflowing the phenomenon according to different indexes, make overflowing the protection circuit can be more accurate monitor overflowing the phenomenon to in time handle, effectively protected the work safety of load.

Drawings

The invention will now be described, by way of example, with reference to the accompanying drawings, in which:

fig. 1 is a structural diagram of a load overcurrent protection circuit.

Fig. 2 is a schematic diagram of a load overcurrent protection circuit.

Fig. 3 is a graph of overcurrent protection action time.

Wherein, 1-mutual inductor sampling circuit; 2-a signal amplification circuit; 3-an over-current voltage comparator circuit; 4-a microprocessor circuit; 5-relay control circuit.

Detailed Description

All of the features disclosed in this specification, or all of the steps in any method or process so disclosed, may be combined in any combination, except combinations of features and/or steps that are mutually exclusive.

Any feature disclosed in this specification (including any accompanying claims, abstract) may be replaced by alternative features serving equivalent or similar purposes, unless expressly stated otherwise. That is, unless expressly stated otherwise, each feature is only an example of a generic series of equivalent or similar features.

Example 1

A load overcurrent protection circuit, as shown in fig. 1 and 2, comprising: the transformer sampling circuit 1, the signal amplifying circuit 2, the over-current voltage comparator circuit 3, the microprocessor circuit 4 and the relay control circuit 5; the transformer sampling circuit 1 is connected with the signal amplifying circuit 2, the signal amplifying circuit 2 is respectively connected with the over-current voltage comparator circuit 3 and the microprocessor circuit 4, and the over-current voltage comparator circuit 3 and the microprocessor circuit 4 are mutually connected; the microprocessor circuit 4 is also connected with a relay control circuit 5.

The transformer sampling circuit 1 is used for collecting the working current of a load; the transformer sampling circuit 1 comprises 2 transformer interfaces, and can simultaneously collect 2 paths of current signals and transmit the current signals to the signal amplification circuit 2.

The signal amplification circuit is used for amplifying and filtering the weak current; the signal amplification circuit 2 is composed of an operational amplifier, a peripheral resistor, a diode and a capacitor, and can convert an alternating current signal into stable direct current voltage after finishing amplification, rectification and filtering of a weak current sampling signal; in this embodiment, the signal amplifying circuit 2 includes 2 identical circuit structures, and is correspondingly connected to the 2 transformer interfaces, and is configured to collect and output two paths of current signals.

The overcurrent voltage comparator circuit 3 is used for judging whether the load current is overcurrent or not; the over-current voltage comparator circuit 3 is composed of an operational amplifier, a diode, a resistor and a capacitor, a current signal entering the over-current voltage comparator enters the operational amplifier after being subjected to voltage division, whether an over-current phenomenon occurs or not is judged by judging whether the operational amplifier outputs a low level, if the over-current phenomenon occurs, the output low level is transmitted to the microprocessor circuit, and the microprocessor circuit controls a load.

The microprocessor circuit 4 is used for outputting instruction information; the microprocessor circuit 4 can receive the current information from the signal amplifying circuit 2 and the overcurrent voltage comparator circuit 3, and after receiving the current information sent by the two circuit modules, the microprocessor circuit performs analog-to-digital conversion on the received information, converts the input analog signal into a digital signal, performs logic operation according to the digital signal, outputs command information according to an operation result, and sends the command information to the relay control circuit 5 to control the load to work.

The relay control circuit 5 is used for controlling the load to work, the relay control circuit 5 can receive instruction information sent by the microprocessor circuit 4 and control whether the load stops working or not according to the instruction information, when the microprocessor circuit 4 monitors that the circuit is over-current, the instruction information for stopping working is sent, and the relay control circuit 5 can control the load to stop working.

In this embodiment, the operational amplifier is a 4-way operational amplifier L M224.

In this embodiment, after the signal amplification circuit 2 completes the amplification rectification and filtering of the weak current sampling signal and converts the alternating current signal into a stable direct current voltage, the input current signal is divided into 2 paths, one path is input to the microprocessor circuit 4, a 10-bit analog-to-digital converter inside the microprocessor circuit 4 can convert the analog input signal into a 10-bit binary digit representing the signal, then the acquired current digital signal is subjected to logic operation in the microprocessor circuit 4, and instruction information is output according to an overcurrent protection action time curve, so as to control the relay control circuit 5 to turn off the power supply to the load, thereby achieving the overcurrent protection function.

The overcurrent protection action time curve mainly represents the functional relation between the action time of the protection circuit and the expected current. As shown in fig. 3, the curve is composed of different expected operating currents and corresponding circuit operation time intervals during overcurrent protection, the region between 2 lines is the interval of the protection circuit operation time under the expected current, the black dots are the operation time of the overcurrent protection circuit under the overcurrent protection, and the different overload currents and protection operation times are plotted on an icon as the curve. The curve can visually represent the action time of the protection circuit under different overload currents; the microprocessor circuit 4 converts the collected load working current signal into a digital signal corresponding to the load current through analog-to-digital conversion, the microprocessor circuit 4 matches the digital information with the overcurrent protection action time curve information, and different expected load currents correspond to different protection action times; after the digital information is matched with the curve information, the microprocessor circuit 4 automatically outputs a control instruction within corresponding time after logical operation, and drives the protection control circuit to close a working power supply of the load, so that overcurrent protection of the load is realized.

The other path of current signal is sent to an overcurrent voltage comparator circuit 3, wherein a 12 pin of an operational amplifier L M224 is a reference voltage input end and consists of R35, R41, R42 and C11, the current signal is sent to a 13 pin of L M224 after passing through a voltage division circuit consisting of D1, D7, R8 and R47, when the voltage of the 13 pin is higher than the 12 pin, a 14 pin outputs a low level (the pin outputs the low level to indicate that more than 10 times of rated working current appears), the output low level signal is input into a microprocessor circuit 4, and the microprocessor circuit 4 turns off the power output after logic operation, so that the load is powered off and stops working, and the overcurrent protection function is realized.

In practical use, when detecting that the working current of the load is overcurrent, the microprocessor circuit 4 outputs a corresponding control signal and closes the load power supply of the circuit according to an overcurrent protection action time curve. 30 seconds after the output of the path is closed, the microprocessor circuit 4 automatically starts the output of the path to supply power to the load, and when the condition that the overcurrent condition still exists is monitored, the microprocessor circuit 4 closes the output again to stop supplying power to the load. If the load is detected to be overcurrent for more than 3 times, the output of the path is closed, and alarm information is output. After the fault is removed by professional maintainers, the normal working state is recovered.

The utility model discloses a divide into two tunnel transmissions with current signal, can make microprocessor circuit 4 can judge whether appear overflowing the phenomenon according to different indexes, make overflowing the protection circuit can be more accurate monitor overflowing the phenomenon to in time handle, effectively protected the work safety of load.

The invention is not limited to the foregoing embodiments. The invention extends to any novel feature or any novel combination of features disclosed in this specification and any novel method or process steps or any novel combination of features disclosed.

Claims

1. A load overcurrent protection circuit, comprising: the transformer sampling circuit (1), the signal amplification circuit (2), the overcurrent voltage comparator circuit (3), the microprocessor circuit (4) and the relay control circuit (5); the transformer sampling circuit (1) is connected with the signal amplification circuit (2), the signal amplification circuit (2) is respectively connected with the overcurrent voltage comparator circuit (3) and the microprocessor circuit (4), and the overcurrent voltage comparator circuit (3) and the microprocessor circuit (4) are mutually connected; the microprocessor circuit (4) is also connected with the relay control circuit (5).

2. The load overcurrent protection circuit as set forth in claim 1, wherein the transformer sampling circuit (1) is configured to collect an operating current of a load; the overcurrent voltage comparator circuit (3) is used for judging whether the load current is overcurrent or not; the signal amplification circuit is used for amplifying and filtering the weak current; the microprocessor circuit (4) is used for outputting control instruction information; the relay control circuit (5) is used for controlling the work of the load.

3. The load overcurrent protection circuit according to claim 1, characterized in that the signal amplification circuit (2) is composed of an operational amplifier, a peripheral resistor, a diode, and a capacitor.

4. The load overcurrent protection circuit as set forth in claim 3, wherein the signal amplification circuit (2) comprises two circuits with the same structure, and respectively amplifies and outputs two current signals.

5. A load over-current protection circuit according to claim 1, characterized in that the over-current voltage comparator circuit (3) is composed of an operational amplifier, a diode, a resistor and a capacitor.

6. The load over-current protection circuit according to any one of claims 3 or 5, wherein the operational amplifier is a 4-way operational amplifier.

7. The load overcurrent protection circuit as claimed in claim 1, characterized in that the transformer sampling circuit (1) comprises 2 transformer interfaces for collecting two current signals.