A short circuit protection circuit of a charging pile charging module

Abstract

The utility model relates to short -circuit protection circuit technical field, concretely is a kind of short -circuit protection circuit of charging pile charging module, including electrically connected charging pile and battery, there is current transformer L between electrically connected charging pile and battery, there is short -circuit protection circuit between charging pile and current transformer L, there is operational amplifier and photocoupler U between current transformer L and battery electrically connected;Short -circuit protection circuit includes diode connection transistor Q1 and PNP transistor Q2.The utility model current transformer L, short -circuit protection circuit and photocoupler U can build simple voltage stabilizing circuit or bias circuit, when circuit short -circuit, overload and other faults occur, current will sharply increase, current transformer L converts fault current into secondary side signal, input relay protection device, provide stable voltage or current for subsequent circuit.

Description

Technical Field

[0001] This utility model relates to a short-circuit protection circuit, and more particularly to a short-circuit protection circuit for a charging module of a charging pile, belonging to the technical field of short-circuit protection circuits. Background Technology

[0002] New energy vehicles have obvious advantages, such as low travel costs, green and low-carbon travel, low noise, good driving experience, high driving efficiency, no worries about traffic restrictions, low maintenance costs, less car smell, large discounts, and low maintenance costs. Therefore, with the development of technology, new energy electric vehicles have entered thousands of households due to their advantages.

[0003] However, the existing charging module circuit has the following drawbacks: if the electrical system of the charging pile is not designed properly or the components are aging, it is easy to cause short circuits, leakage, or even electrical fires. For example, aging of the circuit can cause damage to the insulation layer, which may cause current leakage and endanger personal safety. Overload issue: Multiple charging stations operating simultaneously or excessive use by users may cause power lines to overload, resulting in overheating and further increasing the risk of fire.

[0004] Therefore, it is urgent to improve the short-circuit protection circuit of the charging module to solve the above-mentioned problems. Utility Model Content

[0005] The purpose of this utility model is to provide a short-circuit protection circuit for a charging module of a charging pile. The current transformer L, the short-circuit protection circuit, and the optocoupler U can form a simple voltage regulation circuit or bias circuit. When a short circuit, overload, or other fault occurs in the circuit, the current will increase sharply. The current transformer L converts the fault current into a secondary side signal and inputs it to the relay protection device to provide a stable voltage or current for the subsequent circuit.

[0006] To achieve the above objectives, the main technical solutions adopted by this utility model include: A short-circuit protection circuit for a charging module of a charging pile includes a charging pile and a battery that are electrically connected. A current transformer L is electrically connected between the charging pile and the battery. A short-circuit protection circuit is electrically connected between the charging pile and the current transformer L. An operational amplifier and an optocoupler U are electrically connected between the current transformer L and the battery. The short-circuit protection circuit includes a diode-connected transistor Q1 and a PNP transistor Q2. The PNP transistor Q2 is electrically connected to resistors R2 and R3, with the end of resistor R3 away from the PNP transistor Q2 grounded.

[0007] Preferably, the base and collector of the diode-connected transistor Q1 are short-circuited.

[0008] Preferably, the PNP transistor Q2 is of model number 9015, and the resistor R3 is electrically connected to the emitter of the PNP transistor Q2.

[0009] Preferably, an A / D converter is connected to one side of the operational amplifier, and a feedback resistor R1 is connected in parallel between the operational amplifier and the A / D converter. One end of the feedback resistor R1 is connected to the second output terminal of the secondary side of the current transformer L, and the other end is connected to the output terminal of the operational amplifier. The output terminal of the operational amplifier is connected to the input terminal of the A / D converter.

[0010] Preferably, a discharge switch S1 is electrically connected between the optocoupler U and the battery.

[0011] Preferably, pin 3 of the optocoupler U is connected to the control terminal of the discharge switch S1, and pins 1 and 4 of the optocoupler U are respectively connected to the DC regulated power supply VCC with current limiting resistor R4 and current limiting resistor R5.

[0012] Preferably, the AC charging pile short-circuit protection test circuit further includes: a switching power supply, the input terminal of which is connected to an external 220V AC power supply, and the output terminal provides ±5V operating power.

[0013] This utility model has at least the following beneficial effects: 1. A current transformer L, a short-circuit protection circuit, and an optocoupler U can form a simple voltage regulator circuit or bias circuit. When a short circuit or overload occurs in the circuit, the current will increase sharply. The current transformer L converts the fault current into a secondary signal and inputs it to the relay protection device to provide a stable voltage or current for the subsequent circuit.

[0014] 2. The primary winding of the current transformer L is connected in series in the circuit under test, and the secondary winding is connected to the measuring instrument. According to the law of electromagnetic induction, a large current on the primary side generates magnetic flux in the iron core, and the secondary winding induces a small current proportional to the primary current. The current value of the high voltage or high current circuit is directly measured without direct contact with the high voltage or high current, ensuring the safety of personnel and equipment. When a short circuit, overload or other fault occurs in the circuit, the current will increase sharply. The current transformer L converts the fault current into a secondary side signal and inputs it into the relay protection device. By comparing the actual current with the set threshold, the fault type can be quickly identified.

[0015] 3. When Vin is low relative to GND, the base voltage of PNP transistor Q2 decreases, causing PNP transistor Q2 to conduct, and current flows from the emitter to the collector, thereby generating a relatively high voltage at Vout terminal. When Vin is high relative to GND, the base voltage of PNP transistor Q2 increases, PNP transistor Q2 tends to turn off, and the voltage at Vout terminal will approach the voltage value set by resistor R3 and PNP transistor Q2. Attached Figure Description

[0016] The accompanying drawings, which are included to provide a further understanding of this application and form part of this application, illustrate exemplary embodiments and are used to explain this application, but do not constitute an undue limitation of this application. In the drawings: Figure 1 This is the circuit diagram of this utility model.

[0017] In the diagram, 1 is the short-circuit protection circuit; 2 is the operational amplifier; and 3 is the optocoupler U. Detailed Implementation

[0018] The following will describe in detail the implementation of this application with reference to the accompanying drawings and embodiments, so that the implementation process of how this application uses technical means to solve technical problems and achieve technical effects can be fully understood and implemented accordingly.

[0019] like Figure 1 As shown, the short-circuit protection circuit of the charging module provided in this embodiment includes a charging pile and a battery electrically connected. A current transformer L is electrically connected between the charging pile and the battery. The primary winding of the current transformer L is connected in series in the circuit under test, and the secondary winding is connected to a measuring instrument. According to the law of electromagnetic induction, a large current on the primary side generates magnetic flux in the iron core, and a small current proportional to the primary current is induced in the secondary winding. The current value of the high-voltage or high-current circuit is directly measured without direct contact with the high voltage or high current, ensuring the safety of personnel and equipment. When a short circuit, overload, or other fault occurs in the circuit, the current will increase sharply. The current transformer L converts the fault current into a secondary signal and inputs it to the relay protection device. By comparing the actual current with a set threshold, the fault type is quickly identified. The charging pile and the current transformer L are electrically connected. The circuit includes a short-circuit protection circuit 1. An operational amplifier 2 and an optocoupler U3 are electrically connected between the current transformer L and the battery. The short-circuit protection circuit 1 is used for level conversion or simple signal amplification / buffering. For example, it adjusts the input signal Vin to a certain extent and outputs it to Vout. At the same time, it uses the stable voltage reference provided by the PNP transistor Q2 to ensure the stability of the output. It is used to build a simple voltage regulator circuit or bias circuit to provide a stable voltage or current for the subsequent circuit. Therefore, the current transformer L, the short-circuit protection circuit 1, and the optocoupler U3 can build a simple voltage regulator circuit or bias circuit. When a short circuit, overload, or other fault occurs in the circuit, the current will increase sharply. The current transformer L converts the fault current into a secondary side signal and inputs it to the relay protection device to provide a stable voltage or current for the subsequent circuit. The short-circuit protection circuit 1 includes a diode-connected transistor Q1 and a PNP transistor Q2. The base and collector of the diode-connected transistor Q1 are shorted, and this stable voltage drop can provide a reference voltage for the circuit. The PNP transistor Q2 is electrically connected to resistors R2 and R3. The end of resistor R3 away from the PNP transistor Q2 is grounded. When Vin is low relative to GND, the base voltage of the PNP transistor Q2 decreases, causing the PNP transistor Q2 to conduct. Current flows from the emitter to the collector, thereby generating a relatively high voltage at the Vout terminal. When Vin is high relative to GND, the base voltage of PNP transistor Q2 increases. The type of PNP transistor Q2 is 9015. Resistor R3 is electrically connected to the emitter of PNP transistor Q2. PNP transistor Q2 tends to be cut off, and the voltage at Vout terminal will approach the voltage value set by resistor R3 and PNP transistor Q2.

[0020] Furthermore, such as Figure 1 As shown, an A / D converter is connected to one side of operational amplifier 2. A feedback resistor R1 is connected in parallel between operational amplifier 2 and the A / D converter. One end of the feedback resistor R1 is connected to the second output terminal of the secondary side of current transformer L, and the other end is connected to the output terminal of operational amplifier 2. The output terminal of operational amplifier 2 is connected to the input terminal of the A / D converter. One end of the feedback resistor R1 is connected to the second output terminal of the secondary side of current transformer L, and the other end is connected to the output terminal of operational amplifier 8. A preferred but non-limiting embodiment is to use a precision resistor with a temperature drift of 1ppm and an initial accuracy of 0.01% to ensure the accuracy of the measurement. The output of operational amplifier 8 is connected to the input of A / D converter. In a preferred but non-limiting embodiment, operational amplifier 8 is an OPA343 with harmonic distortion plus noise of less than 0.0007%, which ensures the accuracy of measurement.

[0021] Furthermore, such as Figure 1 As shown, a discharge switch S1 is electrically connected between optocoupler U3 and the battery. Pin 3 of optocoupler U3 is connected to the control terminal of discharge switch S1. Pins 1 and 4 of optocoupler U3 are connected to current-limiting resistors R4 and R5 respectively between them and the DC regulated power supply VCC. When a high-level input is applied to the input terminal of optocoupler U1, the LED changes from cutoff to conduction. This causes the output terminal of optocoupler U1 to conduct, thereby controlling the discharge switch S1 to turn off, thus cutting off the discharge circuit and improving the stability of the circuit.

[0022] Furthermore, such as Figure 1As shown, the AC charging pile short-circuit protection test circuit also includes: a switching power supply, whose input terminal is connected to an external 220V AC power supply, and whose output terminal provides ±5V operating power. The output is a DC voltage with two output terminals, +5V and -5V, and a ground terminal (GND) to power various electronic devices that require a stable 5V DC power supply. It provides a suitable potential reference and power supply for different parts of the circuit, converts the 220V AC mains power into a stable +5V and -5V DC power supply, and provides a suitable power supply for subsequent electronic devices or circuits.

[0023] like Figure 1 As shown, the principle of the short-circuit protection circuit of the charging pile charging module provided in this embodiment is as follows: The primary winding of current transformer L is connected in series in the circuit under test, and the secondary winding is connected to the measuring instrument. According to the law of electromagnetic induction, a large current on the primary side generates magnetic flux in the iron core, inducing a small current in the secondary winding proportional to the primary current. This allows for direct measurement of the current value in high-voltage or high-current circuits without direct contact with the high voltage or high current, ensuring the safety of personnel and equipment. When a short circuit or overload occurs, the current increases sharply. Current transformer L converts the fault current into a secondary-side signal, which is input to the relay protection device. By comparing the actual current with a set threshold, the fault type is quickly identified. Short-circuit protection circuit 1 is used for level conversion or simple signal... The current transformer L, short-circuit protection circuit 1, and optocoupler U3 can be used to construct a simple voltage regulator or bias circuit to provide stable voltage or current for subsequent circuits. For example, the current transformer L, short-circuit protection circuit 1, and optocoupler U3 can construct a simple voltage regulator or bias circuit. When the circuit experiences faults such as short circuit or overload, the current will increase sharply. The current transformer L converts the fault current into a secondary side signal and inputs it to the relay protection device to provide stable voltage or current for subsequent circuits. The short-circuit protection circuit 1 includes a diode-connected transistor Q1 and a PNP transistor Q2. The base and collector of the diode-connected transistor Q1 are shorted, and this stable voltage drop can provide a reference voltage for the circuit. The PNP transistor Q2 is electrically connected to resistors R2 and R3. The end of resistor R3 away from the PNP transistor Q2 is grounded. When Vin is low relative to GND, the base voltage of the PNP transistor Q2 decreases, causing the PNP transistor Q2 to conduct. Current flows from the emitter to the collector, thereby generating a relatively high voltage at the Vout terminal. When Vin is high relative to GND, the base voltage of PNP transistor Q2 increases, PNP transistor Q2 tends to turn off, and the voltage at Vout terminal will approach the voltage value set by resistor R3 and PNP transistor Q2.

[0024] If certain terms are used in the specification and claims to refer to specific components, those skilled in the art will understand that hardware manufacturers may use different names to refer to the same component. This specification and claims do not distinguish components based on differences in name, but rather on differences in function. The term "comprising" as used throughout the specification and claims is an open-ended term and should be interpreted as "comprising but not limited to." "Approximately" means that within an acceptable margin of error, those skilled in the art can solve the technical problem and substantially achieve the technical effect within a certain margin of error.

[0025] It should be noted that the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a product or system comprising a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a product or system. Without further limitation, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the product or system that includes that element.

[0026] The foregoing description illustrates and describes several preferred embodiments of the present invention. However, as previously stated, it should be understood that the present invention is not limited to the forms disclosed herein and should not be construed as excluding other embodiments. It can be used in various other combinations, modifications, and environments, and can be altered within the scope of the inventive concept described herein through the foregoing teachings or techniques or knowledge in related fields. Any modifications and variations made by those skilled in the art that do not depart from the spirit and scope of the present invention should be within the protection scope of the appended claims.

Claims

1. A short-circuit protection circuit for a charging module of a charging pile, comprising a charging pile and a battery electrically connected, characterized in that, A current transformer L is electrically connected between the charging pile and the battery. A short-circuit protection circuit (1) is electrically connected between the charging pile and the current transformer L. An operational amplifier (2) and an optocoupler U (3) are electrically connected between the current transformer L and the battery. The short-circuit protection circuit (1) includes a diode-connected transistor Q1 and a PNP transistor Q2. The PNP transistor Q2 is electrically connected to resistors R2 and R3, and the end of resistor R3 away from the PNP transistor Q2 is grounded.

2. The short-circuit protection circuit for a charging pile charging module according to claim 1, characterized in that: The base and collector of the diode-connected transistor Q1 are shorted.

3. The short-circuit protection circuit for a charging pile charging module according to claim 1, characterized in that: The PNP transistor Q2 is model number 9015, and the resistor R3 is electrically connected to the emitter of the PNP transistor Q2.

4. The short-circuit protection circuit for a charging pile charging module according to claim 1, characterized in that: An A / D converter is connected to one side of the operational amplifier (2). A feedback resistor R1 is connected in parallel between the operational amplifier (2) and the A / D converter. One end of the feedback resistor R1 is connected to the second output terminal of the secondary side of the current transformer L, and the other end is connected to the output terminal of the operational amplifier (2). The output terminal of the operational amplifier (2) is connected to the input terminal of the A / D converter.

5. The short-circuit protection circuit for a charging pile charging module according to claim 1, characterized in that: The optocoupler U(3) is electrically connected to the battery via a discharge switch S1.

6. The short-circuit protection circuit for a charging module of a charging pile according to claim 1, characterized in that: The 3rd pin of the optocoupler U (3) is connected to the control terminal of the discharge switch S1. The 1st and 4th pins of the optocoupler U (3) are respectively connected to the DC regulated power supply VCC with current limiting resistor R4 and current limiting resistor R5.

7. The short-circuit protection circuit for a charging pile charging module according to claim 1, characterized in that: Also includes: A switching power supply, wherein the input terminal of the switching power supply is connected to an external 220V AC power supply, and the output terminal provides ±5V operating power.

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