Vehicle end relay adhesion detection circuit, negative voltage protection circuit and electric vehicle

Abstract

The utility model provides a vehicle end relay adhesion detection circuit, a negative voltage protection circuit and an electric vehicle, the negative voltage protection circuit can be applied to the vehicle end relay adhesion detection circuit, and the negative voltage protection circuit comprises a negative voltage protection voltage setting unit and a negative voltage pull-up unit connected with the negative voltage protection voltage setting unit; the negative voltage protection voltage setting unit comprises a diode, the negative voltage pull-up unit comprises a pull-up switch tube, and when the negative voltage of a negative voltage monitoring port corresponding to the vehicle end relay adhesion detection circuit is larger than the breakdown voltage of the diode, the diode and the pull-up switch tube are both switched on. The voltage of an acquisition port corresponding to an ADC analog quantity acquisition module in the vehicle-end relay adhesion detection circuit is pulled up to the reference ground, so that the problems that the ground of an existing charging pile generates a negative voltage to the vehicle-end adhesion detection circuit, and the negative voltage exceeds the voltage withstanding range of an ADC sampling chip in the vehicle-end relay adhesion detection circuit; and the ADC sampling chip is damaged.

Description

Technical Field

[0001] The present application relates to the technical field of electronic circuits, and in particular to a vehicle-end relay adhesion detection circuit, a negative pressure protection circuit and an electric vehicle. Background Art

[0002] BATTERY MANAGEMENT SYSTEM, battery management system, referred to as BMS. The controller of the BMS in electric vehicles needs to detect the sticking state of the relay of the power battery of the electric vehicle. At present, it is generally used to compare the voltage state of both ends of the relay contact by collecting analog signals after resistor voltage division, so as to realize the function of relay sticking detection.

[0003] When an electric vehicle is connected to a charging pile and is in a charging preparation state, the charging pile obtains the current total voltage of the electric vehicle through communication interaction, and outputs a voltage equal to the total voltage of the vehicle battery before the vehicle-end charging relay of the electric vehicle is closed to perform insulation detection and other functions. However, since the vehicle-end charging relay is not closed, the adhesion detection circuit of the vehicle-end charging relay is not connected to the reference ground of the charging pile, causing the ground of the charging pile to generate a negative voltage for the vehicle-end adhesion detection circuit. This negative voltage exceeds the voltage resistance range of the ADC sampling chip in the vehicle-end relay adhesion detection circuit, causing damage to the ADC sampling chip. Utility Model Content

[0004] In this regard, the present application provides a vehicle-end relay adhesion detection circuit, a negative pressure protection circuit and an electric vehicle to solve the problem that the ground of the existing charging pile will generate a negative voltage on the vehicle-end adhesion detection circuit, and the negative voltage exceeds the voltage resistance range of the ADC sampling chip in the vehicle-end relay adhesion detection circuit, causing damage to the ADC sampling chip.

[0005] To achieve the above objectives, the present application provides the following technical solutions:

[0006] In a first aspect, the present application discloses a negative voltage protection circuit, which is applied to a vehicle-end relay adhesion detection circuit, wherein the negative voltage protection circuit comprises: a negative voltage protection voltage setting unit and a negative voltage pull-up unit connected to the negative voltage protection voltage setting unit;

[0007] The negative voltage protection voltage setting unit includes a diode, and the negative voltage pull-up unit includes a pull-up switch tube. When the negative voltage of the negative pressure monitoring port corresponding to the vehicle-end relay adhesion detection circuit is greater than the breakdown voltage of the diode, the diode and the pull-up switch tube are both turned on to pull the voltage of the acquisition port corresponding to the ADC analog quantity acquisition module in the vehicle-end relay adhesion detection circuit to the reference ground.

[0008] Optionally, in the above-mentioned negative pressure protection circuit, the cathode of the diode serves as the first end of the negative pressure protection voltage setting unit, and is connected to the negative pressure monitoring port of the vehicle-end relay adhesion detection circuit; the anode of the diode serves as the second end of the negative pressure protection voltage setting unit, and is connected to the reference ground.

[0009] Optionally, in the above-mentioned negative voltage protection circuit, the diode is a Zener diode.

[0010] Optionally, in the negative voltage protection circuit described above, the negative voltage pull-up unit includes: a first resistor, a second resistor, a third resistor, a first switch tube, a second switch tube and the pull-up switch tube;

[0011] The source of the first switch tube serves as the first end of the negative voltage pull-up unit and is connected to the first end of the negative voltage protection voltage setting unit; the gate of the first switch tube serves as the second end of the negative voltage pull-up unit and is connected to the second end of the negative voltage protection voltage setting unit; the drain of the first switch tube is connected to one end of the first resistor, and the other end of the first resistor is respectively connected to one end of the second resistor and the gate of the second switch tube;

[0012] The other end of the second resistor is connected to the source of the second switch tube, and the connection point serves as the third end of the negative voltage pull-up unit and is connected to the pull-up source port of the vehicle-end relay adhesion detection circuit;

[0013] The drain of the second switch tube is respectively connected to one end of the third resistor and the gate of the pull-up switch tube, the source of the pull-up switch tube is connected to the reference ground, and the drain of the pull-up switch tube serves as the fourth end of the negative voltage pull-up unit and is connected to the acquisition port corresponding to the ADC analog quantity acquisition module.

[0014] Optionally, in the above-mentioned negative voltage protection circuit, the first switch tube and the pull-up switch tube are NMOS tubes, and the second switch tube is a PMOS tube.

[0015] The second aspect of the present application discloses a vehicle-end relay adhesion detection circuit, comprising: a charging pile power supply positive relay voltage sampling unit, a charging pile power supply negative relay voltage sampling unit, a pull-up voltage generating unit, an ADC analog quantity acquisition module and a controller;

[0016] The charging pile power supply positive relay voltage sampling unit is connected to the charging pile power supply negative relay voltage sampling unit, and the connection point is connected to the pull-up voltage generating unit;

[0017] The ADC analog quantity acquisition module includes a plurality of acquisition ports, each of which is respectively connected to the charging pile power supply positive relay voltage sampling unit and the charging pile power supply negative relay voltage sampling unit, and the output end of the ADC analog quantity acquisition module is connected to the controller;

[0018] The first end of the pull-up voltage generating unit serves as a pull-up source port of the vehicle-end relay adhesion detection circuit;

[0019] A negative pressure protection circuit as described in any one of the items disclosed in the first aspect is respectively arranged between the positive relay voltage sampling unit of the charging pile power supply and the sampling port corresponding to the ADC analog quantity acquisition module, and / or between the negative relay voltage sampling unit of the charging pile power supply and the sampling port corresponding to the ADC analog quantity acquisition module.

[0020] Optionally, in the above-mentioned vehicle-end relay adhesion detection circuit, the charging pile power supply positive relay voltage sampling unit includes: a first sampling resistor, a second sampling resistor and a third sampling resistor;

[0021] One end of the first sampling resistor is used as the first end of the charging pile power positive relay voltage sampling unit and is connected to the charging pile power positive relay;

[0022] The other end of the first sampling resistor is connected to one end of the second sampling resistor, and the connection point serves as a negative pressure monitoring port of the vehicle-end relay adhesion detection circuit;

[0023] The other end of the second sampling resistor is connected to one end of the third sampling resistor, and the connection point serves as the second end of the charging pile power positive relay voltage sampling unit, which is connected to the acquisition port corresponding to the ADC analog acquisition module;

[0024] The other end of the third sampling resistor serves as the third port of the charging pile power positive relay voltage sampling unit and is connected to the first end of the pull-up voltage generating unit.

[0025] Optionally, in the above-mentioned vehicle-end relay adhesion detection circuit, the charging pile power supply negative relay voltage sampling unit includes: a fourth sampling resistor, a fifth sampling resistor and a sixth sampling resistor;

[0026] One end of the fourth sampling resistor is used as the first end of the charging pile power supply negative relay voltage sampling unit and is connected to the charging pile power supply negative relay;

[0027] The other end of the fourth sampling resistor is connected to one end of the fifth sampling resistor, and the connection point serves as a negative pressure monitoring port of another vehicle-end relay adhesion detection circuit;

[0028] The other end of the fifth sampling resistor is connected to one end of the sixth sampling resistor, and the connection point serves as the second end of the charging pile power supply negative relay voltage sampling unit, which is connected to the acquisition port corresponding to the ADC analog quantity acquisition module;

[0029] The other end of the sixth sampling resistor serves as the third port of the charging pile power supply negative relay voltage sampling unit and is connected to the first end of the pull-up voltage generating unit.

[0030] Optionally, in the above-mentioned vehicle-end relay adhesion detection circuit, the pull-up voltage generating unit includes: a battery, the positive electrode of the battery serves as the first end of the pull-up voltage generating unit, and the negative electrode of the battery is connected to the reference ground.

[0031] The third aspect of the present application discloses an electric vehicle, comprising: a vehicle-end relay adhesion detection circuit as described in any one of the items disclosed in the second aspect.

[0032] The negative pressure protection circuit provided in the present application can be applied to a vehicle-end relay adhesion detection circuit. The negative pressure protection circuit may include: a negative pressure protection voltage setting unit and a negative pressure pull-up unit connected to the negative pressure protection voltage setting unit; the negative pressure protection voltage setting unit includes a diode, and the negative pressure pull-up unit includes a pull-up switch tube. When the negative pressure of the negative pressure monitoring port corresponding to the vehicle-end relay adhesion detection circuit is greater than the breakdown voltage of the diode, the diode and the pull-up switch tube are both turned on, so that the voltage of the acquisition port corresponding to the ADC analog quantity acquisition module in the vehicle-end relay adhesion detection circuit is pulled up to the reference ground, which solves the problem that the ground of the existing charging pile will generate a negative voltage for the vehicle-end adhesion detection circuit, and the negative voltage exceeds the voltage resistance range of the ADC sampling chip in the vehicle-end relay adhesion detection circuit, causing damage to the ADC sampling chip. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on the provided drawings without paying any creative work.

[0034] Figure 1 An original topological structure of a relay in an existing electric vehicle and a related vehicle-end relay adhesion detection circuit part provided in an embodiment of the present application;

[0035] Figure 2 A topological structure of an existing negative voltage protection circuit provided in an embodiment of the present application;

[0036] Figure 3 and Figure 4Specific structural schematic diagrams of two negative pressure protection circuits provided in the embodiments of the present application;

[0037] Figure 5 A schematic diagram of the specific structure of a vehicle-end relay adhesion detection circuit provided in an embodiment of the present application. DETAILED DESCRIPTION

[0038] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0039] The embodiments of the present application provide a vehicle-end relay adhesion detection circuit, a negative pressure protection circuit and an electric vehicle to solve the problem that the ground of the existing charging pile will generate a negative voltage on the vehicle-end adhesion detection circuit, and the negative voltage exceeds the voltage resistance range of the ADC sampling chip in the vehicle-end relay adhesion detection circuit, causing damage to the ADC sampling chip.

[0040] The original topology of the relay and its related vehicle-end relay adhesion detection circuit in an electric vehicle can be as follows: Figure 1 As shown in the figure. The figure mainly shows: ADC analog quantity acquisition module, charging pile power supply, relay module, power battery, battery load and other parts. Among them, the relay module includes: main positive relay, main negative relay, pre-charge relay, charging pile power supply positive relay (CHA+ relay in the figure), and charging pile power supply negative relay (CHA- relay in the figure).

[0041] In practical applications, the vehicle-end relay adhesion detection circuit is mainly composed of the voltage sampling circuit of each relay, the ADC analog quantity acquisition module and the controller; the voltage sampling circuit usually samples the resistor voltage division sampling method, and after sampling by the ADC sampling chip of the ADC analog quantity acquisition module, the voltage state of the two ends of the relay contact is compared in the controller to determine whether the relay is stuck.

[0042] by Figure 1 Taking the charging pile as an example, the principle of negative pressure generated by charging at point V1 in the original topology is as follows: when the charging pile power supply does not output voltage, the ADC analog quantity acquisition module normally performs voltage analog quantity acquisition in the relay unclosed mode; when the charging pile power supply outputs high voltage, negative pressure will appear on the acquisition port corresponding to the ACD analog quantity acquisition module.

[0043] It should be noted that the power battery is the power source for driving the power motor. In the present application, it can be considered that the power battery is always present and can provide a stable power supply; the power battery generally has a voltage level of hundreds of volts, which can drive the power motor in the electric vehicle. For the convenience of explanation, this application takes the power battery voltage of 400V as an example. The charging pile power supply can output a voltage equivalent to the power battery of the electric vehicle for charging the power battery. During the charging of the power battery, all relays are in the disconnected state. Specifically, in practice, after completing the insulation test, that is, the adhesion test, the charging pile power positive relay (CHA+ relay in the figure) and the charging pile power negative relay (CHA- relay in the figure) in the electric vehicle can be closed to enter the charging state.

[0044] Taking point V1 as an example, by using battery E1 as a pull-up source, the supply voltage of battery E1 can be 5V, and the voltage collected at V1 is 5V. Due to the precision error of resistors in actual applications, the resistors R3 / R4 cannot be too small, otherwise R4 / (R3+R4) will approach 1 and the disconnection and closing states of the relay cannot be distinguished. The same is true for resistors R1 and R2. When the charging pile power supply outputs the voltage Vout and the charging relay is disconnected, the voltage at V1 is 5V-Vout(R4 / (R1+R2+R3+R4)), and the voltage at I is 5V-Vout((R3+R4) / (R1+R2+R3+R4)). Since R1 cannot be too small, it will cause a negative voltage ranging from tens to hundreds of volts at V1. The negative voltage protection circuit provided in this application only works in this state, and the negative voltage is placed diagonally to the ground to achieve the purpose of protecting the acquisition port of the ADC analog acquisition module.

[0045] The inventor has found that an existing negative voltage protection circuit uses a ground Schottky diode to protect negative voltage, such as Figure 2 As shown, taking point V1 as an example, when a voltage greater than 0V appears, the Schottky diode (D1 in the figure) is reversely cut off and does not affect normal voltage acquisition; when a negative voltage appears, the negative voltage on the acquisition port of the ADC sampling chip is forward-conducted through the Schottky diode and the voltage is clamped, so that the negative voltage of V1 is protected within the range of 0V to the conduction voltage of the Schottky diode; however, in this negative voltage protection method, the conduction voltage drop of the Schottky diode is greatly affected by the current and temperature, and the conduction voltage drop of the Schottky diode may be greater than the negative voltage withstand voltage of the ADC sampling chip, and the negative voltage protection of the ADC sampling chip cannot be achieved within the full temperature range.

[0046] In this regard, based on the above, the negative voltage protection circuit provided in the embodiment of the present application uses MOSFET and Zener diode, which is extremely less affected by temperature and can achieve negative voltage protection for the ADC sampling chip in a wider temperature range. Figure 3 or Figure 4The negative pressure protection circuit can be applied to the vehicle-end relay adhesion detection circuit, including: a negative pressure protection voltage setting unit (101 in the figure) and a negative pressure pull-up unit (102 in the figure) connected to the negative pressure protection voltage setting unit.

[0047] The negative voltage protection voltage setting unit includes a diode (Z2 in the figure), and the negative voltage pull-up unit includes a pull-up switch tube (Q3 in the figure). When the negative voltage of the negative pressure monitoring port corresponding to the vehicle-end relay adhesion detection circuit is greater than the breakdown voltage of the diode, the diode and the pull-up switch tube are both turned on, so that the voltage of the acquisition port corresponding to the ADC analog acquisition module in the vehicle-end relay adhesion detection circuit is pulled up to the reference ground.

[0048] In some embodiments, Figure 3 or Figure 4 As shown, the cathode of the diode serves as the first end of the negative voltage protection voltage setting unit, connected to the negative voltage monitoring port of the vehicle-end relay adhesion detection circuit; the anode of the diode serves as the second end of the negative voltage protection voltage setting unit, connected to the reference ground.

[0049] In practical applications, the specific type of the diode may be a Zener diode; of course, it is not limited thereto, and may also be other existing types of diodes, which are not limited in this application and are within the protection scope of this application.

[0050] In some embodiments, Figure 3 or Figure 4 As shown, the negative voltage pull-up unit may include: a first resistor (R6 in the figure), a second resistor (R5 in the figure), a third resistor (R7 in the figure), a first switch tube (Q1 in the figure), a second switch tube (Q2 in the figure) and a pull-up switch tube.

[0051] The source of the first switch tube is connected to the first end of the negative voltage pull-up unit as the first end of the negative voltage protection voltage setting unit; the gate of the first switch tube is connected to the second end of the negative voltage protection voltage setting unit as the second end of the negative voltage pull-up unit; the drain of the first switch tube is connected to one end of the first resistor, and the other end of the first resistor is respectively connected to one end of the second resistor and the gate of the second switch tube;

[0052] The other end of the second resistor is connected to the source of the second switch tube, and the connection point is used as the third end of the negative voltage pull-up unit and connected to the pull-up source port of the vehicle-end relay adhesion detection circuit;

[0053] The drain of the second switch tube is respectively connected to one end of the third resistor and the gate of the pull-up switch tube, the source of the pull-up switch tube is connected to the reference ground, and the drain of the pull-up switch tube serves as the fourth end of the negative voltage pull-up unit and is connected to the acquisition port corresponding to the ADC analog acquisition module.

[0054] In actual applications, the first switch tube and the pull-up switch tube can be NMOS tubes, and the second switch tube can be PMOS tube; further, the specific type of the two can be MOSDFET; the first resistor, the second resistor and the third resistor mainly function to set the static point voltage for the first switch tube, the pull-up switch tube and the second switch tube to ensure that when the negative pressure of the negative pressure monitoring port corresponding to the vehicle-end relay adhesion detection circuit is greater than the breakdown voltage of the diode, the pull-up switch tube is turned on to pull up the voltage of the acquisition port corresponding to the ADC analog acquisition module in the vehicle-end relay adhesion detection circuit to the reference ground.

[0055] The vehicle-side relay adhesion detection circuit may include multiple negative pressure monitoring ports, such as Figure 3 , Figure 4 or Figure 5 As shown, the negative pressure detection port can be point A and point B in the figure; taking point A as an example, the main working process of the negative pressure protection circuit is as follows:

[0056] When negative voltage appears between the negative relay of the charging pile power supply in the electric vehicle and the connection point of the charging pile power supply (point I in the figure), the battery supply voltage is 5V, and the input voltage at point I is 5V-Vout((R3+R4) / (R1+R2+R3+R4)). Without the protection of the diode, the GS inter-electrode voltage of the first switch tube will exceed the withstand voltage. Therefore, the diode enters the breakdown mode at this time to protect the GS inter-electrode withstand voltage of the first switch tube. Due to the current limiting effect of the first sampling resistor (R4_1 in the figure), the power demand of the diode is reduced, and the GS inter-electrode voltage of the first switch tube is equal to the breakdown voltage V_Z2 of the diode. At this time, the first switch tube is turned on, and the GS inter-electrode voltage of the second switch tube is: (5V+V_Z2)*R5 / (R5+R6). Through the voltage division of the second resistor R5 and the first resistor R6, this voltage meets the conduction condition of the second switch tube. 5V is applied to the G pole of the pull-up switch tube, so that the pull-up switch tube is turned on to pull the voltage of the acquisition port (V1 in the figure) corresponding to the ADC analog acquisition module in the vehicle-end relay adhesion detection circuit to close to the reference ground (HV_GND in the figure). Due to the current limiting effect of the first sampling resistor and the second sampling resistor (R4_2 in the figure), the current that needs to be placed obliquely is extremely small, so the on-resistance requirement of the pull-up switch tube is relatively low. If there is a high requirement for negative voltage, the negative voltage can also be reduced by reducing the on-resistance of the pull-up switch tube.

[0057] Similarly, taking point B as an example, the main working process of the negative pressure protection circuit is as follows:

[0058] When negative voltage appears at the connection point between the positive relay of the charging pile power supply and the charging pile power supply (point E in the figure) in the electric vehicle, the battery supply voltage is 5V, and the input voltage at point E is 5V-Vout((R1+R2) / (R1+R2+R3+R4)). Without the protection of the diode, the GS inter-electrode voltage of the first switch tube will exceed the withstand voltage. Therefore, the diode enters the breakdown mode at this time to protect the GS inter-electrode withstand voltage of the first switch tube. Due to the current limiting effect of the first sampling resistor (R1_1 in the figure), the power demand of the diode is reduced, and the GS inter-electrode voltage of the first switch tube is equal to the breakdown voltage V_Z2 of the diode. At this time, the first switch tube is turned on, and the GS inter-electrode voltage of the second switch tube is: (5V+V_Z2)*R5 / (R5+R6). Through the voltage division of the second resistor R5 and the first resistor R6, this voltage meets the conduction condition of the second switch tube. 5V is applied to the G pole of the pull-up switch tube, so that the pull-up switch tube is turned on to pull the voltage of the acquisition port (V2 in the figure) corresponding to the ADC analog acquisition module in the vehicle-end relay adhesion detection circuit to close to the reference ground (HV_GND in the figure). Due to the current limiting effect of the first sampling resistor and the second sampling resistor (R1_2 in the figure), the current that needs to be placed obliquely is extremely small, so the on-resistance requirement for the pull-up switch tube is relatively low. If there is a high requirement for negative voltage, the negative voltage can also be reduced by reducing the on-resistance of the pull-up switch tube.

[0059] In the present application, although the on-resistance of the pull-up switch tube is affected by temperature, compared with directly using a Schottky diode for negative voltage protection, the temperature variation range of the present application is controllable, and calculation can ensure that the ADC negative withstand voltage requirements are met in a wider temperature range.

[0060] When there is no negative voltage between the negative relay of the charging pile power supply in the electric vehicle and the connection point of the charging pile power supply (point I in the figure), that is, when the input voltage at point I is greater than 0V, the diode cannot be turned on, the Vgs of the first switch tube is 0V, the first switch tube is turned off, and then the second switch tube and the pull-up switch tube are turned off. At this time, the corresponding topology can be restored to Figure 1 As shown, the vehicle-end relay adhesion detection circuit can perform normal collection and judgment by only using the sampling resistor R1 and the sampling resistor R2 for voltage division.

[0061] It should be noted that Figure 3 The resistors R3_1 and R3_2 in Figure 1 The sampling resistor R3 in the circuit has the following relationship: the sum of the resistance values ​​of the resistors R3_1 and R3_2 is equal to the resistance value of the sampling resistor R3, that is, Figure 3 The resistors R3_1 and R3_2 are Figure 1 The deformation of the sampling resistor R3. Figure 4 The resistors R1_1 and R1_2 in Figure 1The sampling resistor R1 in the circuit has the following relationship: the sum of the resistance values ​​of the resistors R1_1 and R1_2 is equal to the resistance value of the sampling resistor R1, that is, Figure 4 The resistors R1_1 and R1_2 are Figure 1 Deformation of the sampling resistor R1.

[0062] Based on the above principles, the negative pressure protection circuit provided in this embodiment can be applied to the vehicle-end relay adhesion detection circuit. The negative pressure protection circuit may include: a negative pressure protection voltage setting unit and a negative voltage pull-up unit connected to the negative pressure protection voltage setting unit; the negative pressure protection voltage setting unit includes a diode, and the negative pressure pull-up unit includes a pull-up switch tube. When the negative voltage of the negative pressure monitoring port corresponding to the vehicle-end relay adhesion detection circuit is greater than the breakdown voltage of the diode, the diode and the pull-up switch tube are both turned on, so that the voltage of the acquisition port corresponding to the ADC analog quantity acquisition module in the vehicle-end relay adhesion detection circuit is pulled up to the reference ground, which solves the problem that the ground of the existing charging pile will generate a negative voltage for the vehicle-end adhesion detection circuit, and the negative voltage exceeds the voltage resistance range of the ADC sampling chip in the BMS, causing damage to the ADC sampling chip.

[0063] It can be understood that the present application scheme can realize negative pressure protection of the vehicle-end relay adhesion detection circuit. When the positive relay of the charging pile power supply or the negative relay of the charging pile power supply in the electric vehicle is disconnected, the conduction characteristics of the MOS MOSFET and the breakdown characteristics of the Zener diode are utilized, and the negative voltage of the charging pile power supply can be discharged through the low on-resistance of the pull-up switch tube, thereby protecting the normal operation of the ADC analog quantity acquisition module in the vehicle-end relay adhesion detection circuit from damage; in addition, the negative pressure protection circuit can be triggered automatically without occupying IO control resources; in addition, the current limiting resistor (resistor R2_1 and resistor R2_2 in the figure) can be configured to reduce the power demand of the diode, and the negative pressure amplitude can be controlled, and different negative pressure ranges can be configured according to the voltage resistance requirements of the ADC analog quantity acquisition module in the vehicle-end relay adhesion detection circuit.

[0064] It is worth noting that compared with the existing acquisition by using a differential ADC sampling chip with stronger negative pressure tolerance, the application cost of this application is lower.

[0065] On the basis of the above, this application also provides a vehicle-end relay adhesion detection circuit, see Figure 5 , which can mainly include: a charging pile power supply positive relay voltage sampling unit (201 in the figure), a charging pile power supply negative relay voltage sampling unit (202 in the figure), a pull-up voltage generating unit (203 in the figure), an ADC analog quantity acquisition module and a controller (not shown in the figure).

[0066] The charging pile power supply positive relay voltage sampling unit is connected to the charging pile power supply negative relay voltage sampling unit, and the connection point is connected to the pull-up voltage generating unit.

[0067] The ADC analog quantity acquisition module includes multiple acquisition ports, each of which is respectively connected to the charging pile power supply positive relay voltage sampling unit and the charging pile power supply negative relay voltage sampling unit, and the output end of the ADC analog quantity acquisition module is connected to the controller; the first end of the pull-up voltage generating unit serves as the pull-up source port of the vehicle-end relay adhesion detection circuit;

[0068] A negative pressure protection circuit as described in any of the above embodiments is respectively arranged between the positive relay voltage sampling unit of the charging pile power supply and the sampling port corresponding to the ADC analog quantity acquisition module, and / or between the negative relay voltage sampling unit of the charging pile power supply and the sampling port corresponding to the ADC analog quantity acquisition module.

[0069] In some embodiments, Figure 5 As shown, the charging pile power positive relay voltage sampling unit may include: a first sampling resistor (R1_1 in the figure), a second sampling resistor (R1_2 in the figure) and a third sampling resistor (R2 in the figure).

[0070] One end of the first sampling resistor serves as the first end of the charging pile power positive relay voltage sampling unit and is connected to the charging pile power positive relay (CHA+ relay in the figure); the other end of the first sampling resistor is connected to one end of the second sampling resistor, and the connection point serves as the negative pressure monitoring port of a vehicle-end relay adhesion detection circuit (point B in the figure); the other end of the second sampling resistor is connected to one end of the third sampling resistor, and the connection point serves as the second end of the charging pile power positive relay voltage sampling unit and is connected to the acquisition port corresponding to the ADC analog quantity acquisition module; the other end of the third sampling resistor serves as the third port of the charging pile power positive relay voltage sampling unit and is connected to the first end of the pull-up voltage generating unit.

[0071] It should be noted that setting the number of sampling resistors in the positive relay voltage sampling unit of the charging pile power supply to 3 can more conveniently realize negative pressure monitoring; specifically, Figure 1 Compared with the original topology shown, the resistors in the positive relay voltage sampling unit of the charging pile power supply have the following relationship: R1_1+R1_2=R1, R2=R2.

[0072] In some embodiments, Figure 5 As shown, the charging pile power negative relay voltage sampling unit may include: a fourth sampling resistor (R4_1 in the figure), a fifth sampling resistor (R4_2 in the figure) and a sixth sampling resistor (R3 in the figure).

[0073] One end of the fourth sampling resistor serves as the first end of the charging pile power negative relay voltage sampling unit and is connected to the charging pile power negative relay (CHA-relay in the figure); the other end of the fourth sampling resistor is connected to one end of the fifth sampling resistor, and the connection point serves as the negative pressure monitoring port of another vehicle-end relay adhesion detection circuit (point A in the figure); the other end of the fifth sampling resistor is connected to one end of the sixth sampling resistor, and the connection point serves as the second end of the charging pile power negative relay voltage sampling unit and is connected to the acquisition port corresponding to the ADC analog acquisition module; the other end of the sixth sampling resistor serves as the third port of the charging pile power negative relay voltage sampling unit and is connected to the first end of the pull-up voltage generating unit.

[0074] It should be noted that setting the number of sampling resistors in the negative relay voltage sampling unit of the charging pile power supply to 3 can more conveniently realize negative pressure monitoring; specifically, Figure 1 Compared with the original topology shown, the resistors in the negative relay voltage sampling unit of the charging pile power supply have the following relationship: R3=R3, R4_1+R4_2=R4.

[0075] In some embodiments, Figure 5 As shown, the pull-up voltage generating unit may include: a battery (E1 in the figure), the positive electrode of the battery serves as the first end of the pull-up voltage generating unit, and the negative electrode of the battery is connected to the reference ground.

[0076] In practical applications, resistors can be connected in parallel at both ends of the battery based on the actual application situation to meet different usage requirements.

[0077] It should be noted that the controller may be a controller in a BMS, and the adhesion state of the relay may be detected according to the analog signal collected by the ADC analog acquisition module; the ADC analog acquisition module has an ADC sampling chip built in it.

[0078] In this embodiment, a negative pressure protection circuit as described in any of the above embodiments is respectively provided between the charging pile power positive relay voltage sampling unit and the sampling port corresponding to the ADC analog quantity acquisition module in the vehicle-end relay adhesion detection circuit, and / or between the charging pile power negative relay voltage sampling unit and the sampling port corresponding to the ADC analog quantity acquisition module. When the charging pile power positive relay and the charging pile power negative relay are closed, the charging pile power supply can generate a negative pressure on the vehicle-end relay adhesion detection circuit. The voltage of the sampling port corresponding to the ADC analog quantity sampling module can be pulled up to a safe voltage range by means of voltage pull-up, thereby realizing the function that the high voltage input of the charging pile power supply does not affect the ADC sampling chip.

[0079] It is worth noting that the control method of the negative pressure protection circuit in the vehicle-end relay adhesion detection circuit provided in the present application is passive control. Through this negative pressure protection circuit, when the charging pile power supply outputs high voltage, the negative voltage of the sampling port corresponding to the ADC analog sampling module is controlled within the withstand voltage range, and is extremely less affected by temperature.

[0080] It should be noted that in addition to detecting the adhesion of the charging pile power positive relay and the charging pile power negative relay, the vehicle-end relay adhesion detection circuit can also use the same detection method to detect the adhesion of other relays in the electric vehicle, such as the main positive relay, pre-charging relay, main negative relay, etc.

[0081] It should also be noted that, for the relevant description of the negative pressure protection circuit, please refer to the corresponding embodiment above, and for the relevant description of the vehicle-end relay adhesion detection circuit, please refer to the prior art, which will not be repeated here.

[0082] On the basis of the above, the present application also provides an electric vehicle, which includes a vehicle-end relay adhesion detection circuit as described in any of the above embodiments.

[0083] It should be noted that, for the description of the vehicle-end relay adhesion detection circuit, please refer to the above corresponding embodiment, and for the relevant description of the electric vehicle, please refer to the prior art, which will not be repeated here.

[0084] The features recorded in the various embodiments in this specification can be replaced or combined with each other, and the same and similar parts between the various embodiments can refer to each other, and each embodiment focuses on the differences from other embodiments. In particular, for the system or system embodiment, since it is basically similar to the method embodiment, the description is relatively simple, and the relevant parts can refer to the partial description of the method embodiment. The system and system embodiments described above are only schematic, wherein the units described as separate components may or may not be physically separated, and the components displayed as units may or may not be physical units, that is, they may be located in one place, or they may be distributed on multiple network units. Some or all of the modules can be selected according to actual needs to achieve the purpose of the scheme of this embodiment. Ordinary technicians in this field can understand and implement it without paying creative work.

[0085] Professionals may further appreciate that the units and algorithm steps of each example described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, computer software, or a combination of the two. In order to clearly illustrate the interchangeability of hardware and software, the composition and steps of each example have been generally described in the above description according to function. Whether these functions are performed in hardware or software depends on the specific application and design constraints of the technical solution. Professionals and technicians may use different methods to implement the described functions for each specific application, but such implementation should not be considered to be beyond the scope of this application.

[0086] The above description of the disclosed embodiments enables those skilled in the art to implement or use the present application. Various modifications to these embodiments will be apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present application. Therefore, the present application will not be limited to the embodiments shown herein, but will conform to the widest scope consistent with the principles and novel features disclosed herein.

[0087] It should also be noted that, in this article, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, the elements defined by the sentence "comprise a ..." do not exclude the presence of other identical elements in the process, method, article or device including the elements.

Claims

1. A negative voltage protection circuit, characterized in that: Applied to the vehicle-end relay adhesion detection circuit, the negative pressure protection circuit comprises: a negative pressure protection voltage setting unit and a negative pressure pull-up unit connected to the negative pressure protection voltage setting unit; The negative voltage protection voltage setting unit includes a diode, and the negative voltage pull-up unit includes a pull-up switch tube. When the negative voltage of the negative pressure monitoring port corresponding to the vehicle-end relay adhesion detection circuit is greater than the breakdown voltage of the diode, the diode and the pull-up switch tube are both turned on to pull the voltage of the acquisition port corresponding to the ADC analog quantity acquisition module in the vehicle-end relay adhesion detection circuit to the reference ground.

2. The negative voltage protection circuit according to claim 1, characterized in that: The cathode of the diode serves as the first end of the negative voltage protection voltage setting unit and is connected to the negative voltage monitoring port of the vehicle-end relay adhesion detection circuit; the anode of the diode serves as the second end of the negative voltage protection voltage setting unit and is connected to the reference ground.

3. The negative voltage protection circuit according to claim 2, characterized in that: The diode is a Zener diode.

4. The negative voltage protection circuit according to claim 1, characterized in that: The negative voltage pull-up unit comprises: a first resistor, a second resistor, a third resistor, a first switch tube, a second switch tube and the pull-up switch tube; The source of the first switch tube serves as the first end of the negative voltage pull-up unit and is connected to the first end of the negative voltage protection voltage setting unit; the gate of the first switch tube serves as the second end of the negative voltage pull-up unit and is connected to the second end of the negative voltage protection voltage setting unit; the drain of the first switch tube is connected to one end of the first resistor, and the other end of the first resistor is respectively connected to one end of the second resistor and the gate of the second switch tube; The other end of the second resistor is connected to the source of the second switch tube, and the connection point serves as the third end of the negative voltage pull-up unit and is connected to the pull-up source port of the vehicle-end relay adhesion detection circuit; The drain of the second switch tube is respectively connected to one end of the third resistor and the gate of the pull-up switch tube, the source of the pull-up switch tube is connected to the reference ground, and the drain of the pull-up switch tube serves as the fourth end of the negative voltage pull-up unit and is connected to the acquisition port corresponding to the ADC analog quantity acquisition module.

5. The negative voltage protection circuit according to claim 4, characterized in that: The first switch tube and the pull-up switch tube are NMOS tubes, and the second switch tube is a PMOS tube.

6. A vehicle-end relay adhesion detection circuit, characterized in that: include: Charging pile power positive relay voltage sampling unit, charging pile power negative relay voltage sampling unit, pull-up voltage generating unit, ADC analog quantity acquisition module and controller; The charging pile power supply positive relay voltage sampling unit is connected to the charging pile power supply negative relay voltage sampling unit, and the connection point is connected to the pull-up voltage generating unit; The ADC analog quantity acquisition module includes a plurality of acquisition ports, each of which is respectively connected to the charging pile power supply positive relay voltage sampling unit and the charging pile power supply negative relay voltage sampling unit, and the output end of the ADC analog quantity acquisition module is connected to the controller; The first end of the pull-up voltage generating unit serves as a pull-up source port of the vehicle-end relay adhesion detection circuit; A negative pressure protection circuit as described in any one of claims 1 to 5 is respectively arranged between the positive relay voltage sampling unit of the charging pile power supply and the sampling port corresponding to the ADC analog quantity acquisition module, and / or between the negative relay voltage sampling unit of the charging pile power supply and the sampling port corresponding to the ADC analog quantity acquisition module.

7. The vehicle-end relay adhesion detection circuit according to claim 6, characterized in that: The charging pile power supply positive relay voltage sampling unit includes: a first sampling resistor, a second sampling resistor and a third sampling resistor; One end of the first sampling resistor is used as the first end of the charging pile power positive relay voltage sampling unit and is connected to the charging pile power positive relay; The other end of the first sampling resistor is connected to one end of the second sampling resistor, and the connection point serves as a negative pressure monitoring port of the vehicle-end relay adhesion detection circuit; The other end of the second sampling resistor is connected to one end of the third sampling resistor, and the connection point serves as the second end of the charging pile power positive relay voltage sampling unit, which is connected to the acquisition port corresponding to the ADC analog acquisition module; The other end of the third sampling resistor serves as the third port of the charging pile power positive relay voltage sampling unit and is connected to the first end of the pull-up voltage generating unit.

8. The vehicle-end relay adhesion detection circuit according to claim 6, characterized in that: The charging pile power supply negative relay voltage sampling unit includes: a fourth sampling resistor, a fifth sampling resistor and a sixth sampling resistor; One end of the fourth sampling resistor is used as the first end of the charging pile power supply negative relay voltage sampling unit and is connected to the charging pile power supply negative relay; The other end of the fourth sampling resistor is connected to one end of the fifth sampling resistor, and the connection point serves as a negative pressure monitoring port of another vehicle-end relay adhesion detection circuit; The other end of the fifth sampling resistor is connected to one end of the sixth sampling resistor, and the connection point serves as the second end of the charging pile power supply negative relay voltage sampling unit, which is connected to the acquisition port corresponding to the ADC analog quantity acquisition module; The other end of the sixth sampling resistor serves as the third port of the charging pile power supply negative relay voltage sampling unit and is connected to the first end of the pull-up voltage generating unit.

9. The vehicle-end relay adhesion detection circuit according to claim 6, characterized in that: The pull-up voltage generating unit comprises: a battery, wherein the positive electrode of the battery serves as the first end of the pull-up voltage generating unit, and the negative electrode of the battery is connected to the reference ground.

10. An electric vehicle, characterized in that: include: A vehicle-end relay adhesion detection circuit as described in any one of claims 6 to 9.

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