A vehicle safety protection circuit

Abstract

A vehicle safety protection circuit claimed by the present invention uses a MOS transistor array to replace the traditional high-voltage relay, improving the response speed of the circuit. It can be turned off at a faster speed in the event of a vehicle collision or battery pack short circuit, etc., thus ensuring the safety of personnel. The pre-charge circuit function is realized by means of parasitic inductance with the help of switching transistors, reducing the use of high-voltage relays and enhancing the circuit safety.

Description

Technical Field

[0001] The present invention relates to the field of vehicle circuits, and particularly to a vehicle safety protection circuit. Background Art

[0002] With the development of the modern automotive industry, cars have become one of the most commonly used means of transportation for people. In recent years, due to people's increasing concern about environmental protection, more and more countries and regions have strengthened the control of energy conservation and emission reduction. At the same time, with the development of lithium-ion battery technology, electric vehicles, as a new type of zero-emission means of transportation, have gradually matured and entered people's lives. So far, most developed regions and large automobile manufacturers around the world have respectively announced the schedules for vehicle electrification. The development and application of electric vehicles have become an inevitable trend in the development of automobiles.

[0003] Different from traditional fuel vehicles, electric vehicles mainly use lithium-ion batteries as the energy source. Lithium-ion batteries have potential risks such as high energy density, flammability after collision and extrusion, and difficulty in quickly extinguishing fires after combustion. This has brought unprecedented challenges to automotive safety designers.

[0004] As Figure 1 shown, in the prior art, in the circuit design of electric vehicles, high-voltage relays are mainly used to control the on-off of the circuit. And fuses are used to protect the discharge circuit against short circuits. Such a circuit has the following problems: 1. When a vehicle collides, the front engine compartment will be completely crushed by the impact within 10 ms. For a traditional control circuit using a relay as a circuit breaker, the response action time of the relay is relatively slow, and it takes more than 100 mS from the signal being sent to actually disconnecting. When a short circuit or other faults occur, the relay will also have an adhesion fault when cutting off under a large current, resulting in inability to cut off. When a short circuit occurs, the fuse takes more than 1 s to blow, so it will cause a fire.

[0005] 2. The vehicle protection circuit in the prior art does not adopt different control circuits according to the driving environment to achieve the purpose of safety protection and power saving;

[0006] 3. A dedicated relay K2 needs to be set up to form a pre-charge circuit, and the service life of the relay is limited, reducing the vehicle safety factor. Summary of the Invention

[0007] The purpose of the present invention is to provide a vehicle safety protection circuit, which can provide safety protection for electric vehicles, quickly cut off the power supply in case of an accident, and reduce line loss in safe road conditions.

[0008] A vehicle safety protection circuit, the circuit comprising: a power battery, a fuse F1, parasitic inductors L1, L2, a high-voltage relay K1, parasitic capacitors C1, C2, C3, diodes D1, D2, a Hall current sensor, a processor, a MOS transistor array, a drive circuit, and a load circuit;

[0009] Wherein, the power battery is sequentially connected in series with the fuse F1, the parasitic inductor L1, the Hall current sensor H1, the MOS transistor array Q1, the parasitic inductor L2, the load circuit, and the high-voltage relay K1;

[0010] The diodes D1 and D2 are connected in reverse series and are connected in parallel with the parasitic inductor L2 and the load circuit;

[0011] One end of the capacitor C2 is connected to the parasitic inductor L1 and the Hall current sensor, and the other end is connected to the forward input terminal of the diode D1 and the reverse input terminal of the diode D2;

[0012] The processor is connected to the Hall current sensor H1 for receiving a current signal;

[0013] The processor is further connected to the drive circuit to drive the MOS transistor array through the drive circuit;

[0014] When the processor receives an abnormal current signal from the Hall current sensor, it issues an instruction to the drive circuit to drive the MOS transistor array to cut off the circuit connection; the MOS transistor array is designed as a high-voltage MOS transistor array, which can pass a large current and withstand a high voltage;

[0015] The parasitic inductors L1, L2, the capacitor C2, the capacitor C3, the diodes D1 and D2 cooperate with each other, and utilize the fast switching characteristics of the MOS transistor to form a controllable current switching power supply short circuit, thereby realizing a pre-charge function;

[0016] Advantageous effects: A vehicle safety protection circuit claimed in the present invention replaces a traditional high-voltage relay with a MOS transistor array, improving the response speed of the circuit, and can be turned off at a faster speed in the event of a vehicle collision or battery pack short circuit, etc., thereby ensuring personal safety; the pre-charge circuit function is realized by means of a parasitic inductor with the help of a switching transistor, reducing the use of high-voltage relays and improving the circuit safety. Description of the Drawings

[0017] Figure 1 Is a vehicle safety circuit in the prior art;

[0018] Figure 2 Is a simplified safety protection circuit of the present invention;

[0019] Figure 3This is Embodiment 1 of the safety protection circuit of the present invention;

[0020] Figure 4 This is Embodiment 2 of the safety protection circuit of the present invention. Specific embodiments

[0021] Embodiment 1 provided by the present invention provides a vehicle safety protection circuit, and the circuit includes: a power battery, a fuse F1, parasitic inductors L1, L2, a high-voltage relay K1, parasitic capacitors C1, capacitors C2, C3, diodes D1, D2, a Hall current sensor, a processor, a MOS transistor array, a drive circuit, and a load circuit;

[0022] The capacitor C3 is used to protect the load circuit. Since there are parasitic inductors in the circuit, high voltage and large current generally occur at the moment when the load circuit is powered on and off. When the circuit has frequent on-off operations, it will cause premature aging of the circuit. By setting the capacitor C3, voltage spikes and large current impacts can be reduced, and the service life of the circuit can be extended.

[0023] The Hall current sensor is used to detect abnormal current in the circuit. When an electric vehicle is used under high-temperature conditions, special situations such as the insulation layer of the circuit falling off and short-circuiting, circuit aging and short-circuiting, and the vehicle being immersed in water and short-circuiting may occur. At this time, abnormal large current will appear. If the circuit connection cannot be cut off in time, fire or battery burning will occur. Using the Hall current sensor can detect abnormal large current in the circuit and cut off the power supply in time to ensure the safety of the vehicle.

[0024] Collision protection is of very important significance for electric vehicles. Due to the high voltage existing in electric vehicles, the strategies adopted when they have a collision accident are different from those of traditional fuel vehicles. The main difference is that when a serious collision accident occurs, measures must be taken in time to cut off the voltage output of the power battery. In the process of collision protection, the collision sensor plays an important role. Its specific installation position is generally inside the front fender on both sides of the vehicle body, and some are also installed under the left and right headlight brackets, which vary according to the specific vehicle model. When the collision sensor detects a collision accident of the vehicle, it sends a signal to the airbag ECU. On the one hand, the airbag ECU controls the airbag to open, and on the other hand, it sends a signal to the processor. Then, after the processor receives the sent collision signal, it controls the electronic relay (MOS transistor array) to cut off the high-voltage output of the power battery.

[0025] Among them, the power battery, the fuse F1, the parasitic inductor L1, the Hall current sensor H1, the MOS transistor array Q1, the parasitic inductor L2, the load circuit, and the high-voltage relay K1 are connected in series in sequence;

[0026] The diodes D1 and D2 are connected in reverse series and are connected in parallel with the parasitic inductor L2 and the load circuit;

[0027] One end of the capacitor C2 is connected to the parasitic inductor L1 and the Hall current sensor, and the other end is connected to the forward input terminal of the diode D1 and the reverse input terminal of the diode D2;

[0028] The processor is connected to the Hall current sensor H1 for receiving current signals;

[0029] The processor is also connected to the drive circuit to drive the MOS transistor array through the drive circuit;

[0030] When the processor receives an abnormal current signal from the Hall current sensor, it issues an instruction to the drive circuit to drive the MOS transistor array to cut off the circuit connection; in the prior art, the MOS transistors generally used in vehicles are of low power and are used in weak-current circuits, such as for powering on-board devices with relatively low power consumption. Therefore, using a single MOS transistor to work will not cause burnout and safety is guaranteed. However, for the main circuit of an electric vehicle, it has characteristics such as high voltage, large current, and unstable current. Therefore, when designing, it must be designed as a high-voltage MOS transistor array, which can not only increase the working current of the circuit but also reduce the voltage across a single MOS transistor, providing more working redundancy. When one of the MOS transistors fails, it will not cause the circuit to be instantly damaged.

[0031] The parasitic inductors L1, L2, the parasitic capacitor C1, the capacitors C2, C3, the diodes D1, D2 utilize the fast switching characteristics of the MOS transistors to form a controllable current switching power supply short circuit, thereby realizing the pre-charging function. Through this unique design, the use of pre-charging high-voltage relays can be reduced, enhancing the safety of the circuit and improving vehicle safety;

[0032] As Figure 4 shown, another embodiment provided by the present invention is: a vehicle safety protection circuit, the circuit comprising: a power battery, a fuse F1, parasitic inductors L1, L2, a high-voltage relay K1, a parasitic capacitor C1, capacitors C2, C3, diodes D1, D2, a Hall current sensor, a collision sensor, a speed sensor, a processor, a MOS transistor array, a drive circuit, and a load circuit;

[0033] Among them, the power battery is sequentially connected in series with the fuse F1, the parasitic inductor L1, the Hall current sensor H1, the MOS transistor array Q1, the parasitic inductor L2, the load circuit, and the high-voltage relay K1;

[0034] The diodes D1 and D2 are connected in reverse series and are connected in parallel with the parasitic inductor L2 and the load circuit;

[0035] One end of the capacitor C2 is connected to the parasitic inductor L1 and the Hall current sensor, and the other end is connected to the forward input terminal of the diode D1 and the reverse input terminal of the diode D2;

[0036] The processor is connected to the Hall current sensor H1 and is used to receive current signals;

[0037] The processor is connected to the collision sensor and is used to receive vehicle collision signals;

[0038] The processor is connected to the speed sensor and is used to receive vehicle running speed signals;

[0039] The processor is also connected to the drive circuit and drives the MOS transistor array through the drive circuit;

[0040] When the processor receives an abnormal current signal from the Hall current sensor, it issues an instruction to the drive circuit to drive the MOS transistor array to cut off the circuit connection; the MOS transistor array is designed as a high-voltage MOS transistor array, which can pass large currents and withstand high voltages;

[0041] The parasitic inductor L1, parasitic inductor L2, capacitor C2, capacitor C3, diode D1, and diode D2 cooperate with each other, utilize the fast switching characteristics of the MOS transistor, and constitute a controllable current switching power supply short circuit, thereby realizing the pre-charge function;

[0042] Further, the circuit further includes a high-voltage relay K2. The high-voltage relay K2 is connected in parallel with the MOS transistor array and is controlled by the processor. The processor receives the signal from the speed sensor. When the vehicle speed is lower than 60 KM / h, it controls the high-voltage relay K2 to close first and then disconnect the MOS transistor array. When the vehicle speed exceeds 60 KM / h, it first controls the MOS transistor array to close and then controls the high-voltage relay K2 to disconnect.

[0043] The circuit further includes a high-voltage relay K2. The high-voltage relay K2 is connected in parallel with the MOS transistor array and is controlled by the processor; the processor is connected to the speed sensor and is used to receive vehicle running speed signals; and controls the operation of the MOS transistor array according to the speed signal;

[0044] The processor receives the signal from the speed sensor. When the vehicle speed is lower than 60 KM / h, it controls the high-voltage relay K2 to close first and then disconnect the MOS transistor array. When the vehicle speed exceeds 60 KM / h, it first controls the MOS transistor array to close and then controls the high-voltage relay K2 to disconnect. This is because when the MOS transistor array is in use, there will be a certain power loss. At the same time, when the vehicle is running at a low speed of 60 KM / h, the collision force is generally small and it is not easy to cause a short circuit. This is to use the high-voltage relay for short-circuit connection and can reduce the line loss, achieving a balance between safety and power consumption.

[0045] Further, when the vehicle speed is lower than 60 km / h and the processor receives a collision signal, the processor sends an instruction to control the high-voltage relay K2 to cut off the power supply. When the vehicle speed is higher than 60 km / h and the processor receives a collision signal, the processor sends an instruction to control the MOS transistor array to cut off the power supply.

[0046] In the various embodiments of the present invention, the technical solutions can be combined with each other, but it must be based on the fact that those of ordinary skill in the art can implement them. When the combination of technical solutions results in contradictions or cannot be implemented, it should be considered that such a combination of technical solutions does not exist and is not within the scope of protection required by the present invention.

[0047] The above are only the preferred embodiments of the present invention, and do not limit the patent scope of the present invention. Any equivalent structure or equivalent process transformation made by using the content of the specification and drawings of the present invention, or directly or indirectly applied in other related technical fields, shall be included in the patent protection scope of the present invention by the same token.

Claims

1. A vehicle safety protection circuit, characterized in that: the circuit includes: a power battery, a fuse F1, parasitic inductors L1, L2, a high-voltage relay K1, parasitic capacitors C1, C2, C3, diodes D1, D2, a Hall current sensor, a processor, a MOS transistor array, a drive circuit, and a load circuit; wherein, the power battery is sequentially connected in series with the fuse F1, the parasitic inductor L1, the Hall current sensor H1, the MOS transistor array Q1, the parasitic inductor L2, the load circuit, and the high-voltage relay K1; the diodes D1 and D2 are connected in reverse series and then connected in parallel with the parasitic inductor L2 and the load circuit; one end of the capacitor C2 is connected to the parasitic inductor L1 and the Hall current sensor, and the other end is connected to the forward input terminal of the diode D1 and the reverse input terminal of the diode D2; the processor is connected to the Hall current sensor H1 for receiving current signals; the processor is connected to the drive circuit and drives the MOS transistor array through the drive circuit.

2. The vehicle safety protection circuit according to claim 1, characterized in that: when the processor receives an abnormal current signal from the Hall current sensor, it issues an instruction to the drive circuit to drive the MOS transistor array to cut off the circuit connection.

3. The vehicle safety protection circuit according to claim 2, characterized in that: the parasitic inductors L1, L2, the capacitor C2, the capacitor C3, the diodes D1, D2 cooperate with each other, and utilize the fast switching characteristic of the MOS transistor to form a controllable current switching power supply short circuit, thereby realizing the pre-charge function.

4. The vehicle safety protection circuit according to claim 3, characterized in that: the MOS transistor array is designed as a high-voltage MOS transistor array.

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