An intelligent short circuit protector

Abstract

The utility model belongs to circuit technical field discloses a kind of intelligent short-circuit protector, including MOS tube Q1 and MOS tube Q2, the source electrode of MOS tube Q1 is connected with the one end of resistance R1, the source electrode of MOS tube Q2, the collector of triode Q3, the one end of resistance R2 and port VS, the gate of MOS tube Q1 is connected with the other end of resistance R1, the gate of MOS tube Q2, the emitter of triode Q3 and the negative end of diode D1, the positive end of diode D1 is connected with the base of triode Q3, the other end of resistance R2 and the emitter of photo-coupler OP1, the collector of photo-coupler OP1 is connected with port V1, and port VS and port V1 are connected with power supply.The utility model has the beneficial effect that: when output short circuit occurs, provide accurate and timely disconnection circuit, thereby protecting relay, prevent large current damage contact when short circuit, using electronic type control output circuit breaker can achieve accurate overcurrent value and time delay response.

Description

Technical Field

[0001] This utility model relates to the field of circuit technology, and in particular to an intelligent short-circuit protector. Background Technology

[0002] In mobile energy storage power supply applications, when the UPS circuit is in bypass output mode, the mains power is directly connected to the output socket through the relay without any intermediate electronic protection circuit. However, when the relay switches to inverter mode output, the inverter has complete output protection functions due to its electronic circuitry, while there is no protection in bypass output mode. In this case, a short circuit at the output terminal often leads to damage to the relay. Even if an electromagnetic circuit breaker is connected in series in the circuit for short circuit protection, the circuit breaker's response delay and peak current deviation usually cause it to exceed the relay's limit when it operates, resulting in damage to the relay contacts.

[0003] Therefore, it is necessary to provide an intelligent short-circuit protector that is connected in series with the protected relay circuit to provide a precise and timely disconnection circuit when a short circuit occurs at the output, thereby protecting the relay and preventing the large current during the short circuit from damaging the contacts. Using electronic control to disconnect the output circuit can achieve precise overcurrent value and time delay response. Utility Model Content

[0004] This utility model discloses an intelligent short-circuit protector, relating to the field of power applications requiring rapid protection, and a recoverable control device without mechanical contact, which extends service life and can effectively solve the technical problems involved in the background art.

[0005] To achieve the above objectives, the technical solution of this utility model is as follows:

[0006] A smart short-circuit protector includes MOSFETs Q1 and Q2. The source of MOSFET Q1 is connected to one end of resistor R1, the source of MOSFET Q2, the collector of transistor Q3, one end of resistor R2, and port VS. The gate of MOSFET Q1 is connected to the other end of resistor R1, the gate of MOSFET Q2, the emitter of transistor Q3, and the negative terminal of diode D1. The positive terminal of diode D1 is connected to the base of transistor Q3, the other end of resistor R2, and the emitter of optocoupler OP1. The collector of optocoupler OP1 is connected to port V1. Port VS and port V1 are connected to a power supply.

[0007] The drain of the MOSFET Q2 is connected to pins 1 and 2 of the current sensor U1. Pin 3 of the current sensor U1 is connected to pin 4 of the current sensor U1. Pin 5 of the current sensor U1 is connected to one end of the capacitor C1 and port GND. Pin 7 of the current sensor U1 is connected to one end of the resistor R4. Pin 8 of the current sensor U1 is connected to port 5V, the other end of the capacitor C1, and one end of the resistor R10. The other end of the resistor R10 is connected to one end of the resistor R11. The other end of the resistor R11 is connected to port GND.

[0008] The negative terminal of the optocoupler OP1 is connected to one end of the resistor R3, and the other end of the resistor R3 is connected to pin 1 of the controller U2. Pin 6 of the controller U2 is connected to pin 7 of the controller U2, one end of capacitor C3, one end of capacitor C2, the port 5V, and the positive terminal of the optocoupler OP1. Pin 8 of the controller U2 is connected to the other end of capacitor C3, the other end of capacitor C2, and the port GND.

[0009] Pin 12 of controller U2 is connected to one end of capacitor C4, pin 16 of controller U2 and the other end of resistor R4. Pin 13 of controller U2 is connected to one end of capacitor C5, one end of resistor R7 and one end of resistor R8. The other end of resistor R7 is connected to the negative ends of diode D2 and diode D4. The positive end of diode D2 is connected to the negative end of diode D3 and pin 3 of current sensor U1. The positive end of diode D4 is connected to the negative end of diode D5. The positive end of diode D5 is connected to the positive end of diode D3, the other end of resistor R8, the other end of capacitor C5, the other end of capacitor C4 and port GND. Pin 15 of controller U2 is connected to the other end of resistor R10.

[0010] This technology aims to achieve the goal of controllably disconnecting the AC mains circuit of a mobile energy storage power supply at any time by simulating a switch using a MOSFET, protecting all circuits through which the mains power passes, especially easily damaged relay contacts, improving response speed and accurate overcurrent action peak, ensuring both the load-carrying capacity of the power supply and extending its service life.

[0011] As a preferred improvement of this utility model: the drain of the MOS transistor Q1 is connected to pin 1 of the relay, pin 2 of the relay is connected to port L_IN, pin 3 of the current sensor U1 is connected to port L_OUT, and the positive terminal of the diode D4 is connected to ports N_IN and N_OUT.

[0012] As a preferred improvement of this utility model: the drain of the MOS transistor Q1 is connected to one end of the resistor R9, and the other end of the resistor R9 is connected to the drain of the MOS transistor Q2.

[0013] As a preferred improvement of this utility model, the current sensor U1 is model CC6900.

[0014] As a preferred improvement of this utility model, the controller U2 model is STC8H1K08.

[0015] As a preferred improvement of this utility model: the other end of the resistor R7 is connected to the negative terminal of the diode D2 and the negative terminal of the diode D4 through resistors R6 and R5 connected in series.

[0016] As a preferred improvement of this utility model: pin 9 of the controller U2 is connected to the communication port RX.

[0017] As a preferred improvement of this utility model: pin 10 of the controller U2 is connected to the communication port TX.

[0018] As a preferred improvement of this utility model: pin 1 of the relay is connected to pin 1 of transformer T1, port N_IN is connected to pin 2 of transformer T1, pin 3 of transformer T1 is connected to one end of capacitor C7 and port GND, pin 4 of transformer T1 is connected to the positive terminal of diode D7, the negative terminal of diode D7 is connected to the other end of capacitor C7 and port 5V, pin 5 of transformer T1 is connected to one end of capacitor C6 and port VS, pin 6 of transformer T1 is connected to the positive terminal of diode D6, and the negative terminal of diode D6 is connected to the other end of capacitor C6 and port V1.

[0019] As a preferred improvement of this utility model: pin 1 and pin 2 of transformer T1 share a common coil, pin 3 and pin 4 of transformer T1 share a common coil, and pin 5 and pin 6 of transformer T1 share a common coil.

[0020] The beneficial effects of this utility model are as follows:

[0021] The electromagnetic circuit breaker is replaced with a MOSFET electronic switch, which is non-mechanical and does not generate sparks during disconnection; the response speed is improved, and the circuit lines and devices are protected; a current sensor is used to accurately sample the current value, ensuring that it does not exceed the limit allowed by the protected circuit. Attached Figure Description

[0022] To more clearly illustrate the technical solutions in the embodiments of this utility model, the drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort, wherein:

[0023] Figure 1 This is a schematic diagram of the principle of this utility model;

[0024] Figure 2 This is an isolated power supply for the circuit system of this utility model;

[0025] Figure 3 This is the circuit schematic. Detailed Implementation

[0026] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0027] It should be noted that all directional indications (such as up, down, left, right, front, back, etc.) in the embodiments of the present invention are only used to explain the relative positional relationship and movement of each component in a certain specific posture (as shown in the figure). If the specific posture changes, the directional indication will also change accordingly.

[0028] Furthermore, in this invention, descriptions involving "first," "second," etc., are for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this invention, "a plurality of" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0029] In this invention, unless otherwise explicitly specified and limited, the terms "connection," "fixed," etc., should be interpreted broadly. For example, "fixed" can mean a fixed connection, a detachable connection, or an integral part; it can mean a mechanical connection or an electrical connection; it can mean a direct connection or an indirect connection through an intermediate medium; it can mean the internal communication of two components or the interaction between two components, unless otherwise explicitly limited. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0030] Furthermore, the technical solutions of the various embodiments of the present invention can be combined with each other, but only if they are feasible for those skilled in the art. If the combination of technical solutions is contradictory or cannot be implemented, it should be considered that such combination of technical solutions does not exist and is not within the scope of protection claimed by the present invention.

[0031] Please see Figure 1 As shown, this utility model provides an intelligent short-circuit protector. The "MOS power switch" in the figure is the protection device for the main circuit, composed of back-to-back MOS transistors, which can control the switching of AC or DC power. The "current sensor" is a Hall current sensor that samples the circuit current. The "voltage sensor" is the output voltage sampling circuit used to detect whether the output is successfully controlled. The "isolated power supply" section provides isolated power to the MCU main control circuit and the MOS switch control circuit respectively. Their connection relationship is as follows: the input phase line is connected to the MOS power switch, then to the current sensor, and finally to the output. The voltage sensor is connected between the L and N terminals of the output. Their working principle is as follows: the current sensor circuit sends the output current value to the MCU main control circuit for monitoring. When the output current suddenly increases to exceed the rated value, the MCU controls the MOS power switch to turn off, thereby realizing output overcurrent and short-circuit protection. The voltage sensor circuit monitors the output status, realizing a recovery mechanism after fault elimination.

[0032] Please see Figure 3As shown, the circuit includes MOSFETs Q1 and Q2. The source of MOSFET Q1 is connected to one end of resistor R1, the source of MOSFET Q2, the collector of transistor Q3, one end of resistor R2, and port VS. The gate of MOSFET Q1 is connected to the other end of resistor R1, the gate of MOSFET Q2, the emitter of transistor Q3, and the negative terminal of diode D1. The positive terminal of diode D1 is connected to the base of transistor Q3, the other end of resistor R2, and the emitter of optocoupler OP1. The collector of optocoupler OP1 is connected to port V1, and port VS... The power supply is connected to port V1; the drain of the MOSFET Q2 is connected to pins 1 and 2 of the current sensor U1; pin 3 of the current sensor U1 is connected to pin 4 of the current sensor U1; pin 5 of the current sensor U1 is connected to one end of capacitor C1 and port GND; pin 7 of the current sensor U1 is connected to one end of resistor R4; pin 8 of the current sensor U1 is connected to port 5V, the other end of capacitor C1, and one end of resistor R10; the other end of resistor R10 is connected to one end of resistor R11; and the other end of resistor R11 is connected to port GN. D; The negative terminal of the optocoupler OP1 is connected to one end of resistor R3, and the other end of resistor R3 is connected to pin 1 of controller U2. Pin 6 of controller U2 is connected to pin 7 of controller U2, one end of capacitor C3, one end of capacitor C2, the 5V port, and the positive terminal of optocoupler OP1. Pin 8 of controller U2 is connected to the other end of capacitor C3, the other end of capacitor C2, and the GND port. Pin 12 of controller U2 is connected to one end of capacitor C4, pin 16 of controller U2, and the other end of resistor R4. Connect one end of capacitor C5, one end of resistor R7, and one end of resistor R8. The other end of resistor R7 is connected to the negative terminals of diodes D2 and D4. The positive terminal of diode D2 is connected to the negative terminal of diode D3 and pin 3 of current sensor U1. The positive terminal of diode D4 is connected to the negative terminal of diode D5. The positive terminal of diode D5 is connected to the positive terminal of diode D3, the other end of resistor R8, the other end of capacitor C5, the other end of capacitor C4, and port GND. Pin 15 of controller U2 is connected to the other end of resistor R10. 5V forms a power supply loop with GND; V1 and VS form another isolated power supply.

[0033] In one implementation, the drain of the MOSFET Q1 is connected to pin 1 of the relay, pin 2 of the relay is connected to port L_IN, pin 3 of the current sensor U1 is connected to port L_OUT, and the positive terminal of the diode D4 is connected to ports N_IN and N_OUT. The drain of the MOSFET Q1 is connected to one end of resistor R9, and the other end of resistor R9 is connected to the drain of the MOSFET Q2. The current sensor U1 is a CC6900, and the controller U2 is an STC8H1K08. The other end of resistor R7 is connected to the negative terminals of diodes D2 and D4 through resistors R6 and R5 connected in series. Pin 9 of the controller U2 is connected to communication port RX, and pin 10 of the controller U2 is connected to communication port TX, used for outputting protection status and setting protection parameters.

[0034] Please see Figure 2 As shown, pin 1 of the relay is connected to pin 1 of transformer T1; port N_IN is connected to pin 2 of transformer T1; pin 3 of transformer T1 is connected to one end of capacitor C7 and port GND; pin 4 of transformer T1 is connected to the positive terminal of diode D7; the negative terminal of diode D7 is connected to the other end of capacitor C7 and port 5V; pin 5 of transformer T1 is connected to one end of capacitor C6 and port VS; pin 6 of transformer T1 is connected to the positive terminal of diode D6; the negative terminal of diode D6 is connected to the other end of capacitor C6 and port V1. Pins 1 and 2 of transformer T1 share a common coil; pins 3 and 4 of transformer T1 share a common coil; and pins 5 and 6 of transformer T1 share a common coil. It should be further noted that any other components used to achieve the above effects should fall within the inventive concept of this utility model and should be protected within the scope of this utility model.

[0035] Working principle:

[0036] Q1 and Q2 are N-channel MOSFETs connected back-to-back, with their sources (S) connected together as the common terminal for the control voltage of both transistors. VS is the negative terminal of the power supply for the MOSFET control section, V1 is the positive 12V power supply for the MOSFET control section, and R1 is the gate charge discharge resistor for both MOSFETs, ensuring reliable shutdown of the MOSFET switch when idle and protecting the MOSFETs from accidental triggering. OP1, R2, D1, and Q3 form the drive circuit for the MOSFET switch. When optocoupler OP1 is on, the V1 voltage is applied to the gate-source (GS) terminals of the MOSFET switch after passing through the optocoupler and diode D1, turning on both MOSFETs and ensuring normal output circuitry. When optocoupler OP1 is off, resistor R2 pulls the control circuit low, diode D1 prevents transistor Q3 from conducting, and rapid discharge between the gate and source terminals of the MOSFETs is achieved, thus turning off the MOSFET switch.

[0037] U1 is a Hall current sensor that shares the same power supply (and ground) as the MCU. The output current flows through the Hall current sensor, and the signal it acquires is sent to pins P3.7 (pin 16) and P3.3 (pin 12) of the MCU. Pin P3.7 is the non-inverting input of the MCU's internal analog comparator, and pin P3.6 (pin 15) is the inverting input. Adjusting the values ​​of R10 and R11 changes the comparison value, thus setting the output short-circuit current. If a short circuit occurs at the output, the comparator triggers an MCU interrupt, and the MCU controls the optocoupler's level to flip, quickly turning off the MOSFET. P3.3 is the MCU's ADC input pin. When the output voltage does not exceed the comparator's set value, the ADC samples the current value for data acquisition and monitoring of the output circuit. TX and RX are serial communication pins used for outputting protection status and setting protection parameters. Other unconnected pins are idle.

[0038] D2, D3, D4, D5, R5, R6, R7, and R8 form the output voltage sensor circuit. D2-D4 form a full-bridge rectifier circuit, and R5-R8 form a voltage divider circuit. The sampled voltage is sent to P3.4 of the MCU for ADC conversion to monitor the output voltage. When the output is short-circuited, the sampled voltage is close to 0. When the output short-circuit fault is cleared, resistor R9 provides a test current to the output, pulling the output voltage up to a certain value. At this point, it can be determined that the output short-circuit fault has been cleared, and the MOS switching circuit can resume operation.

[0039] Although the embodiments of this utility model have been disclosed above, they are not limited to the applications listed in the specification and embodiments. They can be applied to various fields suitable for this utility model. For those skilled in the art, other modifications can be easily made. Therefore, without departing from the general concept defined by the claims and their equivalents, this utility model is not limited to the specific details and the illustrations shown and described herein.

Claims

1. An intelligent short-circuit protector, characterized in that: The device includes MOSFETs Q1 and Q2. The source of MOSFET Q1 is connected to one end of resistor R1, the source of MOSFET Q2, the collector of transistor Q3, one end of resistor R2, and port VS. The gate of MOSFET Q1 is connected to the other end of resistor R1, the gate of MOSFET Q2, the emitter of transistor Q3, and the negative terminal of diode D1. The positive terminal of diode D1 is connected to the base of transistor Q3, the other end of resistor R2, and the emitter of optocoupler OP1. The collector of optocoupler OP1 is connected to port V1. Port VS and port V1 are connected to a power supply. The drain of the MOSFET Q2 is connected to pins 1 and 2 of the current sensor U1. Pin 3 of the current sensor U1 is connected to pin 4 of the current sensor U1. Pin 5 of the current sensor U1 is connected to one end of the capacitor C1 and port GND. Pin 7 of the current sensor U1 is connected to one end of the resistor R4. Pin 8 of the current sensor U1 is connected to port 5V, the other end of the capacitor C1, and one end of the resistor R10. The other end of the resistor R10 is connected to one end of the resistor R11. The other end of the resistor R11 is connected to port GND. The negative terminal of the optocoupler OP1 is connected to one end of the resistor R3, and the other end of the resistor R3 is connected to pin 1 of the controller U2. Pin 6 of the controller U2 is connected to pin 7 of the controller U2, one end of capacitor C3, one end of capacitor C2, the port 5V, and the positive terminal of the optocoupler OP1. Pin 8 of the controller U2 is connected to the other end of capacitor C3, the other end of capacitor C2, and the port GND. Pin 12 of controller U2 is connected to one end of capacitor C4, pin 16 of controller U2 and the other end of resistor R4. Pin 13 of controller U2 is connected to one end of capacitor C5, one end of resistor R7 and one end of resistor R8. The other end of resistor R7 is connected to the negative ends of diode D2 and diode D4. The positive end of diode D2 is connected to the negative end of diode D3 and pin 3 of current sensor U1. The positive end of diode D4 is connected to the negative end of diode D5. The positive end of diode D5 is connected to the positive end of diode D3, the other end of resistor R8, the other end of capacitor C5, the other end of capacitor C4 and port GND. Pin 15 of controller U2 is connected to the other end of resistor R10.

2. The intelligent short-circuit protector according to claim 1, characterized in that: The drain of the MOSFET Q1 is connected to pin 1 of the relay, pin 2 of the relay is connected to port L_IN, pin 3 of the current sensor U1 is connected to port L_OUT, and the positive terminal of the diode D4 is connected to ports N_IN and N_OUT.

3. The intelligent short-circuit protector according to claim 1, characterized in that: The drain of the MOS transistor Q1 is connected to one end of the resistor R9, and the other end of the resistor R9 is connected to the drain of the MOS transistor Q2.

4. The intelligent short-circuit protector according to claim 1, characterized in that: The current sensor U1 is model CC6900.

5. The intelligent short-circuit protector according to claim 1, characterized in that: The controller U2 model is STC8H1K08.

6. The intelligent short-circuit protector according to claim 1, characterized in that: The other end of the resistor R7 is connected to the negative terminals of the diode D2 and the diode D4 through resistors R6 and R5 connected in series.

7. The intelligent short-circuit protector according to claim 1, characterized in that: Pin 9 of the controller U2 is connected to the communication port RX.

8. The intelligent short-circuit protector according to claim 1, characterized in that: Pin 10 of the controller U2 is connected to the communication port TX.

9. The intelligent short-circuit protector according to claim 2, characterized in that: Pin 1 of the relay is connected to pin 1 of transformer T1. The port N_IN is connected to pin 2 of transformer T1. Pin 3 of transformer T1 is connected to one end of capacitor C7 and port GND. Pin 4 of transformer T1 is connected to the positive terminal of diode D7. The negative terminal of diode D7 is connected to the other end of capacitor C7 and port 5V. Pin 5 of transformer T1 is connected to one end of capacitor C6 and port VS. Pin 6 of transformer T1 is connected to the positive terminal of diode D6. The negative terminal of diode D6 is connected to the other end of capacitor C6 and port V1.

10. The intelligent short-circuit protector according to claim 9, characterized in that: The transformer T1 has a shared coil for pin 1 and pin 2, a shared coil for pin 3 and pin 4, and a shared coil for pin 5 and pin 6.

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