CN221633420U

CN221633420U - Switching circuit based on relay

Info

Publication number: CN221633420U
Application number: CN202420074993.6U
Authority: CN
Inventors: 陈志领; 程武; 张斗金; 章日千
Original assignee: Suzhou Ulan Zhiyuan Technology Co ltd
Current assignee: Suzhou Ulan Zhiyuan Technology Co ltd
Priority date: 2024-01-12
Filing date: 2024-01-12
Publication date: 2024-08-30
Anticipated expiration: 2034-01-12

Abstract

The utility model discloses a switching circuit based on a relay, which belongs to the technical field of relay fault detection and specifically comprises the following components: the relay, the fault detection circuit and the switching device are arranged at the load part; the relay is provided with an output circuit used for being connected between a power supply and a load and a control circuit used for being connected with a relay driving loop; the fault detection circuit is used for generating a fault signal when the driving circuit has an open circuit fault; the switching device is used for disconnecting the load from the output circuit when receiving the fault signal; the utility model uses the fault detection circuit to judge whether the relay driving loop is open or not, and the switching device acts when the open fault occurs to disconnect the power supply and the load, thereby avoiding the generation of arc when the relay contacts are disconnected under the condition of high current.

Description

Switching circuit based on relay

Technical Field

The utility model relates to the technical field of relay fault detection, in particular to a switching circuit based on a relay.

Background

When the existing control relay works under the conditions of high load and high current, the output loop of the control relay is connected with the main loop with the high current, and the driving loop of the control relay controls the closing or opening of the contacts in the output loop by receiving the control signal with the low current so as to achieve the purpose of controlling the power on and off of the main loop.

In the actual working process of the control relay, the driving circuit can have open-circuit faults, and the open-circuit of the driving circuit can lead to the disconnection of contacts in the output circuit. At this time, a normal large current still flows on the contact, and when the contact is disconnected, a large arc is easily initiated at the contact, which is unfavorable for related circuit devices and surrounding environment safety and causes a certain potential safety hazard.

Disclosure of utility model

The present utility model provides a relay-based switching circuit that overcomes some or some of the shortcomings of the prior art.

In order to achieve the above object, the present utility model is achieved by the following technical scheme, which includes:

A relay-based switching circuit comprising:

Relay RLY1, relay RLY1 has output circuit used for switching in between power and load and control circuit used for switching in the drive circuit of the relay;

The fault detection circuit is used for generating a fault signal when the driving circuit has an open circuit fault; and

And the switching device is arranged at the load and is used for disconnecting the load from the output circuit when a fault signal is generated.

In the utility model, a fault detection circuit for detecting open-circuit faults and a switching device connected with and responding to the fault detection circuit are added in a relay driving loop, and the abnormal condition can be detected when the open-circuit faults occur and the connection between a power supply and a load is disconnected in response to the switching device.

Preferably, the fault detection circuit includes a sampling circuit, an amplifying circuit, and a comparing circuit;

The sampling circuit is used for sampling the control circuit to obtain a sampling voltage Vi, and the amplifying circuit is used for amplifying the sampling voltage Vi to obtain an amplified voltage Vo; the comparison circuit is used for comparing the amplified voltage Vo with a reference voltage Vref and outputting a fault signal when the amplified voltage Vo is smaller than the reference voltage Vref.

Preferably, the sampling circuit comprises a sampling resistor for series connection to the control circuit.

According to the utility model, a sampling resistor is connected in series in a driving loop, the voltage drop at two ends of the resistor is collected, the voltage drop is amplified by an amplifying circuit, and finally the amplified voltage drop is compared with a preset reference voltage by a comparison circuit to judge whether an open circuit fault occurs. Through the cooperation of the sampling circuit, the amplifying circuit and the comparing circuit, when the driving circuit has an open circuit fault, the current flowing through the sampling resistor becomes zero immediately, so that the voltage drop at two ends of the resistor and the amplified voltage drop become zero, the output of the comparing circuit is turned from high level to low level, the output is a fault output mark, and the detection of the open circuit fault in the driving circuit is realized.

Preferably, the amplifying circuit includes a first operational amplifier U1A.

Preferably, the comparison circuit comprises a comparator.

Preferably, the fault signal and the original driving signal of the switching device are processed by the logic circuit and then used as the driving signal of the switching device.

In the utility model, the switching device is used for being matched with the fault detection circuit, and when a fault signal is generated, the switching device acts to disconnect the power supply and the load.

Preferably, the logic circuit is an or gate circuit or an and gate circuit.

Preferably, the two ends of the output circuit are connected in parallel with a current-limiting branch, and a current-limiting resistor R1 is arranged at the current-limiting branch.

Preferably, a diode D1 is arranged in series with a current limiting resistor R1 at the current limiting branch.

Preferably, a bus capacitor C1 connected in parallel with the load is arranged between the output circuit and the load, a detection circuit is arranged at the current-limiting resistor R1, the detection circuit is used for generating a relay driving signal when the voltage drop at two ends of the current-limiting resistor R1 is lower than a set value, and the relay driving signal is used for realizing the conduction of the control circuit.

In the utility model, the current limiting resistor is used for limiting the surge current at the moment of power-on, the diode is used for preventing the reverse connection of the battery, and the bus capacitor is charged before the relay conducts the connection between the battery and the load. The cooperation of the current limiting resistor, the diode and the bus capacitor is used for the pre-charging process before the relay output loop is conducted.

The utility model provides a relay-based switching circuit, which has the following beneficial effects: a fault detection circuit and a switching device connected with and responding to the fault detection circuit are added in the driving circuit, when the relay driving circuit has open-circuit fault, the fault detection circuit can react in microsecond time, compared with the prior art, the utility model can effectively inhibit the generation of electric arcs when the relay drive loop has open-circuit faults under the conditions of high load and high current when the relay works in the prior art.

Drawings

Fig. 1 is a circuit diagram of embodiment 1 of the present utility model.

Detailed Description

For a further understanding of the present utility model, the present utility model will be described in detail with reference to examples. It is to be understood that the examples are illustrative of the present utility model and are not intended to be limiting.

Example 1

As shown in fig. 1, a relay-based switching circuit includes: the relay is provided with an output circuit used for being connected between a power supply and a load and a control circuit used for being connected with a relay driving loop; the fault detection circuit is used for generating a fault signal when the driving circuit has an open circuit fault; and a switching device provided at the load, the switching device being configured to realize disconnection of the load from the output circuit when a fault signal is generated; the fault detection circuit comprises a sampling circuit, an amplifying circuit and a comparison circuit; the sampling circuit is used for sampling the control circuit to obtain a sampling voltage Vi, and the amplifying circuit is used for amplifying the sampling voltage Vi to obtain an amplified voltage Vo; the comparison circuit is used for comparing the amplified voltage Vo with a reference voltage Vref and outputting a fault signal when the amplified voltage Vo is smaller than the reference voltage Vref; the sampling circuit comprises a sampling resistor R4 used for being connected in series with the control circuit; the amplifying circuit comprises a first operational amplifier U1A; the comparison circuit comprises a comparator implemented based on a second operational amplifier U2A; the fault signal and the original driving signal of the switching device are processed through a logic circuit and then used as the driving signal of the switching device; the logic circuit is an OR gate circuit or an AND gate circuit; the two ends of the control circuit are connected in parallel with a current-limiting branch, and a current-limiting resistor R1 is arranged at the current-limiting branch; a diode D1 connected in series with a current limiting resistor R1 is arranged at the current limiting branch; the output circuit is provided with a bus capacitor C1 connected with the load in parallel, the current limiting resistor R1 is provided with a detection circuit, and the detection circuit is used for generating a relay driving signal when the voltage drop at two ends of the current limiting resistor R1 is lower than a set value, and the relay driving signal is used for realizing the conduction of the control circuit.

The utility model adds a fault detection circuit in the existing circuit, and the specific working process is as follows:

The system is electrified, the relay driving signal is in a low level, the corresponding relay RLY1 is not conducted by the switching tube Q1, and the contact (normally open) of the relay RLY1 is not operated and is in an off state; the battery is powered on to output, and the bus capacitor C1 is charged through the diode D1 and the resistor R1, so that the process is a precharge process; when the detection circuit detects that the C1 is charged, a control signal of the switching tube Q1 is set to be high level, the switching tube Q1 is conducted, and then the relay RLY1 works for a plurality of milliseconds and then is attracted;

In the operation process after the relay RLY1 is attracted, when the relay driving circuit has an open-circuit fault, the fault detection circuit can react in microsecond time and drive the switching device to disconnect the load from the power supply before the relay contacts are disconnected.

In this embodiment, the load may be, for example, a boost circuit, the switching device may be a thyristor disposed at the boost circuit, and the fault signal may be logically processed with a driving signal of the thyristor by an or gate circuit or an and gate circuit and then sent to the thyristor, so that when the control circuit of the relay generates an open fault, the switching-off of the boost circuit may be controlled in time.

It is to be understood that, based on one or several embodiments provided in the present application, those skilled in the art may combine, split, reorganize, etc. the embodiments of the present application to obtain other embodiments, which do not exceed the protection scope of the present application.

The utility model and its embodiments have been described above by way of illustration and not limitation, and the examples are merely illustrative of embodiments of the utility model and the actual construction is not limited thereto. Therefore, if one of ordinary skill in the art is informed by this disclosure, the structural mode and the embodiments similar to the technical scheme are not creatively designed without departing from the gist of the present utility model.

Claims

1. A relay-based switching circuit, comprising:

2. The relay-based switching circuit according to claim 1, wherein the fault detection circuit comprises a sampling circuit, an amplifying circuit, and a comparing circuit;

3. A relay-based switching circuit according to claim 2, wherein: the sampling circuit comprises a sampling resistor R4 for series connection to the control circuit.

4. A relay-based switching circuit according to claim 3, wherein: the amplifying circuit includes a first operational amplifier U1A.

5. A relay-based switching circuit according to claim 4, wherein: the comparison circuit includes a comparator.

6. A relay-based switching circuit according to claim 1, wherein: the fault signal and the original driving signal of the switching device are processed through the logic circuit and then serve as the driving signal of the switching device.

7. A relay-based switching circuit according to claim 6, wherein: the logic circuit is an OR gate circuit or an AND gate circuit.

8. A relay-based switching circuit according to claim 1, wherein: the two ends of the output circuit are connected in parallel with a current-limiting branch, and a current-limiting resistor R1 is arranged at the current-limiting branch.

9. A relay-based switching circuit according to claim 8, wherein: a diode D1 connected in series with a current limiting resistor R1 is arranged at the current limiting branch.

10. A relay-based switching circuit according to claim 8, wherein: a bus capacitor C1 connected in parallel with the load is arranged between the output circuit and the load, a detection circuit is arranged at the current limiting resistor R1 and used for generating a relay driving signal when the voltage drop at two ends of the current limiting resistor R1 is lower than a set value, and the relay driving signal is used for realizing the conduction of the control circuit.