CN115520019A - Method and system for high-voltage power down of electric automobile in limping mode - Google Patents
Method and system for high-voltage power down of electric automobile in limping mode Download PDFInfo
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- CN115520019A CN115520019A CN202210986502.0A CN202210986502A CN115520019A CN 115520019 A CN115520019 A CN 115520019A CN 202210986502 A CN202210986502 A CN 202210986502A CN 115520019 A CN115520019 A CN 115520019A
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- B60—VEHICLES IN GENERAL
- B60L—PROPULSION OF ELECTRICALLY-PROPELLED VEHICLES; SUPPLYING ELECTRIC POWER FOR AUXILIARY EQUIPMENT OF ELECTRICALLY-PROPELLED VEHICLES; ELECTRODYNAMIC BRAKE SYSTEMS FOR VEHICLES IN GENERAL; MAGNETIC SUSPENSION OR LEVITATION FOR VEHICLES; MONITORING OPERATING VARIABLES OF ELECTRICALLY-PROPELLED VEHICLES; ELECTRIC SAFETY DEVICES FOR ELECTRICALLY-PROPELLED VEHICLES
- B60L3/00—Electric devices on electrically-propelled vehicles for safety purposes; Monitoring operating variables, e.g. speed, deceleration or energy consumption
- B60L3/0023—Detecting, eliminating, remedying or compensating for drive train abnormalities, e.g. failures within the drive train
- B60L3/0084—Detecting, eliminating, remedying or compensating for drive train abnormalities, e.g. failures within the drive train relating to control modules
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Abstract
The utility model relates to the technical field of electric automobiles, and provides a high-voltage power-down method and a high-voltage power-down system for an electric automobile in a limp mode, wherein a special limp mode circuit is used for controlling the power-down function which is crucial to the safe operation of the electric automobile, so that an MCU with high use cost is avoided, and the difficulty of software design is simplified; the circuit has strong adaptability, and can be used for controlling the limp-home mode switching-off of other key relays or contactors; the form of an analog circuit and delay control is adopted, enough time is reserved for a user to confirm the power-off operation, and the potential safety hazard that the conductance actuating force is lost under the condition of false triggering is avoided.
Description
Technical Field
The disclosure relates to the technical field of electric automobiles, in particular to a method and a system for realizing high-voltage power reduction of an electric automobile in a limping mode.
Background
The statements in this section merely provide background information related to the present disclosure and may not necessarily constitute prior art.
In an electric vehicle, a Vehicle Control Unit (VCU) generally controls on/off of a main positive relay and a main negative relay of a high-voltage loop, so as to realize power on/off of a high-voltage electrical system. When a main controller chip (MCU) of the VCU normally operates, the high-voltage loop relay is controlled according to set logic, but when the MCU fails, the power-off function cannot be executed according to the normal control logic, and great hidden danger is brought to the safe operation of the electric automobile.
The industry generally adopts a method of designing a redundant circuit to solve the problem of MCU failure, i.e. two MCUs are used, and when one of the MCUs fails, the other MCU takes over the key control task. However, this approach is not only costly, but also increases the difficulty of software design. Aiming at the specific problem that the key relay cannot be turned off due to the fact that the MCU fails, the second solution is to monitor the running state of the MCU by using a watchdog monitoring chip and design a special relay turn-off circuit. The existing automobile limp home control circuit monitors the running of an MCU (micro control unit) by using a system base chip SBC with a watchdog monitoring function, when the MCU cannot feed a dog, the SBC outputs a low-level effective limp enabling signal, enables the limp home control circuit, and controls two limp output signals through two input signals.
The inventor finds that the existing automobile limp home control method has the following defects: firstly, the input signal of the limp home control circuit is a digital signal, and is easily interfered under severe working conditions and complex electromagnetic environments of automobiles. Secondly, the limp home control logic is too simple, and the digital input signal is effective to trigger limp output, so that misoperation is easily caused. Under the condition that the MCU is invalid, if the high-voltage power-off operation is triggered by mistake, the electric automobile can directly lose power, and great potential safety hazard is brought.
Disclosure of Invention
In order to solve the problems, the invention provides a high-voltage power-down method and system for an electric automobile in a limp mode, a special limp mode circuit is used for controlling a power-down function which is crucial to the safe operation of the electric automobile, an MCU with high use cost is avoided, and the difficulty of software design is simplified; the circuit has strong adaptability, and can be used for controlling the limp-home mode switching-off of other key relays or contactors; the analog circuit and the time delay control mode are adopted, enough time is reserved for a user to confirm the power-off operation, and the potential safety hazard that the conductance actuating force is lost under the condition of false triggering is avoided.
In order to achieve the purpose, the following technical scheme is adopted in the disclosure:
one or more embodiments provide a high-voltage reduction method of an electric automobile in a limp home mode, which includes the following steps:
monitoring the running state of a main control chip MCU of the whole vehicle controller and the state of a vehicle start-stop switch;
when the MCU normally runs, the on-off of the controlled component is controlled by the vehicle MCU and the normal mode high-voltage relay control circuit according to the state of the vehicle start-stop switch;
when the MCU fails, the control of the MCU on the high-voltage loop relay is disconnected through the limp mode pin of the SBC, and the high-voltage main positive relay is controlled to be turned off by the limp mode high-voltage low-voltage confirmation circuit and the limp mode high-voltage relay control circuit, so that the controlled component is turned off after the set time of a turn-off signal of the start-stop switch is received.
One or more embodiments provide an electric vehicle high-voltage power down system in a limp mode, which comprises a start-stop switch tri-state detection circuit I, a limp mode high-voltage power down confirmation circuit II, a normal mode high-voltage relay control circuit III, a limp mode high-voltage relay control circuit IV and an internal power supply enabling control circuit V;
the start-stop switch three-state detection circuit I is used for detecting the working state of the start-stop switch;
when the MCU normally operates, the vehicle internal power supply enabling control circuit V enables the power supply of the normal mode high-voltage relay control circuit III, disables the power supply of the limp mode high-voltage lower voltage confirmation circuit II, and controls the on-off of the high-voltage main positive relay through the MCU and the normal mode high-voltage relay control circuit III;
when the MCU fails, the internal power supply enabling control circuit V enables the power supply of the limp mode high-voltage lower voltage confirmation circuit II, disables the power supply of the normal mode high-voltage relay control circuit III, and controls the turn-off of the high-voltage main positive relay through the limp mode high-voltage lower voltage confirmation circuit II and the limp mode high-voltage relay control circuit IV, so that the high-voltage main positive relay is turned off after the start-stop switch is pressed for a set time.
Compared with the prior art, the beneficial effect of this disclosure is:
according to the limp mode high-voltage power-down confirming circuit and the limp mode high-voltage relay control circuit, the power-down function which is crucial to safe operation of an electric automobile is achieved, an MCU with high use cost is avoided, and the difficulty of software design is simplified. The time delay control is adopted to reserve enough time for the user to confirm the power-off operation, so that the potential safety hazard that the conductance actuating force is lost under the condition of false triggering is avoided.
Advantages of the present disclosure, as well as advantages of additional aspects, will be described in detail in the following detailed description of specific embodiments.
Drawings
The accompanying drawings, which are included to provide a further understanding of the disclosure, illustrate embodiments of the disclosure and together with the description serve to explain the disclosure and not to limit the disclosure.
FIG. 1 is an overall method flow diagram of an embodiment of the present disclosure;
FIG. 2 is a circuit diagram of a start-stop switch tri-state detection circuit according to an embodiment of the disclosure;
fig. 3 is a limp mode high voltage low voltage validation circuit diagram of an embodiment of the present disclosure;
FIG. 4 is a voltage U at C2 in FIG. 3 under a first setting parameter according to an embodiment of the disclosure c The variation curve of (2);
FIG. 5 is a unit step response curve of the transfer function of the RC network of FIG. 3 with the parameters set according to an embodiment of the present disclosure
FIG. 6 is a high voltage loop relay control circuit diagram of an embodiment of the present disclosure;
fig. 7 is an internal power enable control circuit of an embodiment of the disclosure.
Detailed Description
The present disclosure is further described with reference to the following drawings and examples.
It should be noted that the following detailed description is exemplary and is intended to provide further explanation of the disclosure. Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure belongs.
It is noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of example embodiments according to the present disclosure. As used herein, the singular forms "a", "an", and "the" are intended to include the plural forms as well, and it should be understood that when the terms "comprises" and/or "comprising" are used in this specification, they specify the presence of stated features, steps, operations, devices, components, and/or combinations thereof, unless the context clearly indicates otherwise. It should be noted that, in the case of no conflict, the embodiments and features in the embodiments in the present disclosure may be combined with each other. The embodiments will be described in detail below with reference to the accompanying drawings.
Example 1
In one or more embodiments, as shown in fig. 1, a method for high-voltage power reduction of an electric vehicle in a limp home mode includes the following steps:
and 3, when the MCU fails, the control of the MCU on the high-voltage loop relay is disconnected through a limp mode pin of the SBC, and the high-voltage main relay is controlled to be turned off by the limp mode high-voltage low-voltage confirmation circuit and the limp mode high-voltage relay control circuit, so that the controlled component is turned off after the set time of a turn-off signal of the start-stop switch is received.
The controlled component can be a high-voltage main positive relay of the vehicle, a key relay or a contactor on the vehicle, and limp-home mode turn-off control of other key relays or contactors on the vehicle can be realized.
In the embodiment, the limp mode high-voltage lower voltage confirmation circuit and the limp mode high-voltage relay control circuit are adopted, so that the power-off function which is crucial to the safe operation of the electric automobile is achieved, the MCU with high use cost is avoided, and the difficulty of software design is simplified. The time delay control is adopted to reserve enough time for the user to confirm the power-off operation, so that the potential safety hazard that the conductance actuating force is lost under the condition of false triggering is avoided.
The steps can be realized by designing a circuit, and in the step 1, the operation of the MCU is monitored by using the SBC with the watchdog monitoring function, so that the start-stop switch is used as an input control signal of the high-voltage power-down function in the limp mode. The embodiment provides an electric vehicle high-voltage power-down system in a limp home mode, and as shown in fig. 2-7, a designed circuit may include: the power supply control circuit comprises a start-stop switch tri-state detection circuit I, a limp mode high-voltage lower voltage confirmation circuit II, a normal mode high-voltage relay control circuit III, a limp mode high-voltage relay control circuit IV and an internal power supply enabling control circuit V.
In the step 2, when the MCU normally operates, the vehicle internal power supply enabling control circuit V enables the power supply of the normal mode high-voltage relay control circuit III, disables the power supply of the limp mode high-voltage lower voltage confirmation circuit II, and controls the on-off of the high-voltage main positive relay through the MCU and the normal mode high-voltage relay control circuit III;
in step 3, when the MCU fails, the internal power supply enabling control circuit V enables the power supply of the limp mode high-voltage lower voltage confirmation circuit II, disables the power supply of the normal mode high-voltage relay control circuit III, and controls the turn-off of the high-voltage main positive relay through the limp mode high-voltage lower voltage confirmation circuit II and the limp mode high-voltage relay control circuit IV, so that the high-voltage main positive relay is turned off after the start-stop switch is pressed for a set time.
The set time may be about 4 seconds.
In some embodiments, the start-stop switch three-state detection circuit i comprises a start-stop switch circuit and a voltage division current limiting circuit, and the circuit diagram is shown in fig. 2.
The start-stop switch circuit and the entity switch button of the vehicle are integrated in the start-stop switch module and are connected with the VCU through the SSBin interface. The signal line of the VCU connected with the start-stop switch is SSBin. The entity switch button of the vehicle is specifically a start-stop switch of the whole vehicle and a start-stop switch for controlling the electrification of the whole vehicle.
Optionally, the start-stop switch circuit includes two resistors R4 and R5 connected in series, after the two resistors are connected in series, one end of the start-stop switch circuit is grounded and connected to the VCU, and the other end of the start-stop switch circuit is grounded and connected to two ends of one of the resistors in parallel.
The voltage division current-limiting circuit can be arranged in the VCU, and after the output signal of the SSBin interface is subjected to voltage division and current limitation, the output signal is connected to an ADC pin of the MCU through ADin, and three states of the start-stop switch are judged through the MCU.
Optionally, the voltage-dividing current-limiting circuit includes a first resistor R1 and a second resistor R2 connected in series, and further includes a first capacitor C1 and a third resistor R3, a connection point of the first resistor R1 and the second resistor R2 is connected to the VCU through an SSBin interface, the first capacitor C1 and the third resistor R3 are connected to both ends of the second resistor R2 after connected in series, a connection point of the first capacitor C1 and the third resistor R3 is grounded, and a connection point of the third resistor R3 and the second resistor R2 is an output terminal ADin of the voltage-dividing current-limiting circuit.
When the start-stop switch is in the states of input open circuit, pressing and bouncing, the nominal voltage value of the SSBin is respectively marked as V open 、V press 、V release The values of the resistors R1, R2, R3, R4 and R5 are reasonably selected, so that V is obtained open 、V press 、V release The following relationship is satisfied:
V press ·(1±0.2)<V release ·(1±0.2)<V open ·(1±0.2)(1)
r1, R2, R3, R4 and R5 adopt common resistors with the precision of +/-5%, and the resistance values are respectively recorded as R 1 、R 2 、R 3 、R 4 、R 5 The nominal voltage value is the voltage value of SSBin when R1, R2, R3, R4, R5 take the nominal resistance value.
Let the ADin voltage value be V ssb_mcu The value of the SSBin voltage is denoted as V ssb The two satisfy the following relation:
and the MCU judges three states of the start-stop switch according to the magnitude relation of the input open circuit, pressing and bouncing states of the start-stop switch through the analog-to-digital conversion result of the ADin. The switch signal is passed to the VCU via a wiring harness, which may be broken, i.e., an input open circuit condition.
In some embodiments, the limp home mode high voltage down enable confirmation circuit ii comprises a start-stop switch down confirmation circuit and a high voltage down power down countdown circuit connected in sequence, and the circuit form is as shown in fig. 3.
Optionally, the start-stop switch pressing confirmation circuit includes a first series resistor voltage-dividing circuit, a comparator U1, and a triode Q1, output ends of the first series resistor R6 and R7 voltage-dividing circuits are connected to a negative input end of the comparator U1, and a positive input end of the comparator U1 is connected to an SSBin interface of the VCU; the output end of the comparator U1 is connected to the base electrode of the triode Q1, and the state of the start-stop switch is judged by conducting or stopping the triode Q1.
The input of the start-stop switch pressing confirmation circuit is SSBin, the SSBin is connected to the positive input end of the analog comparator U1, and the voltage obtained by dividing Vcc through the resistors R6 and R7 is connected to the negative input end of the U1. By reasonably selecting the resistance values of R6 and R7, after the start-stop switch is pressed down, the positive input end voltage is lower than the negative input end voltage, U1 outputs low level, the triode Q1 is conducted, and the collector is high level. When the start-stop switch is in an input open circuit or bounce state, the voltage of the positive input end of the U1 is higher than that of the negative input end, the U1 outputs high level, and the Q1 is cut off.
In the embodiment, the starting and stopping switch circuit and the starting and stopping switch pressing confirmation circuit are arranged, so that the accuracy of state detection of the starting and stopping switch can be improved, the accuracy of vehicle limp down control is improved, misoperation of the system is reduced, and the safety of vehicle running is improved.
Optionally, the high-voltage power-off countdown circuit may adopt a timer circuit, and may also adopt a circuit structure as shown in fig. 3, and includes a resistance-capacitance network, a comparator U2, and a second series resistance voltage division circuit, an input end of the resistance-capacitance network is connected to an output end of the start-stop switch press confirmation circuit, that is, an emitter of the triode Q1, the second series resistance voltage division circuit and the resistance-capacitance network are respectively connected to an input end of the comparator U2, and an output end of the comparator U2 is connected to the limp mode high-voltage relay control circuit iv.
The second series resistance voltage division circuit comprises two resistors R12 and R13 which are connected in series.
The resistance-capacitance network comprises a resistor R9, a resistor R10, a resistor R11 and a capacitor C2, one end of the resistor R9 is respectively connected with the resistor R10 and the resistor R11, the other end of the resistor R10 is grounded, the resistor R11 is connected with the capacitor C2, the other end of the capacitor C2 is grounded, and the voltage at the two ends of the capacitor C2 is the voltage of the output end.
The input of the high-voltage low-voltage countdown circuit is a collector of a triode Q1, the triode Q1 is connected to the positive input end of a comparator U2 through a resistance-capacitance network, and voltage obtained by dividing voltage of Vlimp through resistors R12 and R13 is connected to the negative input end of the U2. Through reasonable selection of the resistance values of R9, R10, R11, R12 and R13 and the capacitance value of the capacitor C2, the voltage of the positive input end of the U2 is higher than that of the negative input end of the U2 after the start-stop switch is pressed for a set time interval, if the time interval can be about 4 seconds, the U2 outputs a high level, and the high level is connected to the limp mode high-voltage relay control circuit through the LimpCtrl. As shown in FIG. 4 as R 9 ＝47kΩ、R 10 ＝56kΩ、R 11 ＝130kΩ、R 12 ＝47kΩ、R 13 ＝47kΩ、C 2 ＝10uF、V limp C2 terminal voltage U at 12v c The change curve of (2).
The input of the resistance-capacitance network is Q1 collector voltage, and the output is capacitor C2 terminal voltage U c The transfer function is:
wherein R is 9 、R 10 、R 11 Resistance values of the resistor R9, the resistor R10 and the resistor R11, respectively, C 2 Is the capacitance value of C2. FIG. 5 is R 9 ＝47kΩ、R 10 ＝56kΩ、R 11 ＝130kΩ、C 2 Unit step response curve of resistance-capacitance network transfer function at 10 uF.
In this embodiment, vcc is a power supply of a low-voltage system of the electric vehicle, vlimp is a power supply of a limp mode high-voltage low-voltage power-down confirmation circuit, and enabling and disabling of Vlimp is controlled by the internal power supply enable control circuit v.
In some embodiments, the high-voltage loop relay control circuit includes two parts, a normal mode high-voltage relay control circuit iii and a limp-home mode high-voltage relay control circuit iv, as shown in fig. 6.
Optionally, the normal mode high voltage relay control circuit iii includes a normal mode on control circuit and a normal mode off control circuit.
The normal mode conduction control circuit comprises a triode Q2, a triode Q3, a diode D4 and a triode Q4, wherein the base of the triode Q2 is connected with the Mcu _ on (microprogrammed control Unit) of the MCU, namely a conduction signal output end, the collector of the triode Q2 is connected with the base of the triode Q3, the collector of the triode Q3 is connected with a Vnor for power supply, when in a limp mode, the Vnor is disabled for power supply, the emitter of the triode Q3 is connected to the base of the triode Q4 through a resistor R16, and the collector of the triode Q4 is connected to a power supply Vcc; the emitter of the triode Q3 is connected to the diode D4 through the resistor R15, and the cathode of the diode D4 is the control output terminal Relay _ ctrl.
The input signal of the normal mode conduction control circuit is Mcu _ on from the MCU, the output signal is Relay _ ctrl, and the conduction of the high-voltage main positive Relay is controlled.
When the MCU normally operates, the Vnor normally supplies power, and the Mcu _ on effectively controls the conduction of the Relay _ ctrl. When the Mcu _ on is at a high level, the triodes Q2 and Q3 are conducted, the collector of the triode Q3 outputs a high level, the one-way diode D4 is conducted, the Relay _ ctrl signal outputs a high level, and the high-voltage main positive Relay is conducted. When the limp home mode is entered, the Vnor power supply is disabled, Q3 is turned off, D4 is turned off, and the turn-on control of Relay _ ctrl by Mcu _ on is disabled.
Optionally, as shown in fig. 6, the normal mode turn-off control circuit includes a transistor Q5, a transistor Q6, and a unidirectional diode D3, which are sequentially connected, a collector of the transistor Q6 is connected to Vnor for power supply, when in limp-home mode, the Vnor power supply is disabled, and a cathode of the unidirectional diode D3 is connected to the turn-off and turn-on interlock circuit.
Specifically, the turn-off and turn-on interlock circuit comprises a triode Q7, a collector of the triode Q7 is connected to the control output end Relay _ ctrl through a resistor R6, the collector of the triode Q7 is connected to a power supply Vcc through a resistor R19, the collector of the triode Q7 is connected to a base of the triode Q7 through a diode D1 connected in series, a resistor R18, a resistor R20 and a resistor R21, the base and an emitter of the triode Q7 are directly connected through a capacitor C4, and a connecting point of the resistor R20 and the resistor R21 is connected with an output end of the normal mode turn-off control circuit.
The input signal of the normal mode off control circuit is MCU _ off from the MCU, and the output signal is Relay _ ctrl.
And controlling the high-voltage main positive relay to be turned off in a normal mode. When the MCU normally operates, the Vnor normally supplies power, when the Mcu _ off is at a high level, the triodes Q5 and Q6 are conducted, the collector of the Q6 outputs a high level, the one-way diode D3 is conducted, the triode Q7 is conducted, the collector outputs a low level, the Relay _ ctrl signal outputs a low level, and the high-voltage main positive Relay is turned off.
When the vehicle enters the limp-home mode, the Vnor power supply is disabled, the triode Q6 is cut off, the one-way diode D3 is cut off, and the turn-off control of the Relay _ ctrl by the Mcu _ off is disabled.
The limp mode high voltage Relay control circuit iv is a limp mode turn-off control circuit, as shown in fig. 6, the input signal is LimpCtrl from the limp mode high voltage low voltage confirmation circuit, and the output signal is Relay _ ctrl. The limp-home mode high voltage relay control circuit iv includes a diode D2 connected to the turn-off and turn-on interlock circuit of the normal mode high voltage relay control circuit iii.
In the limp-home mode, when the LimpCtrl is at a high level, the one-way diode D2 is turned on, the triode Q7 is turned on, the collector Q7 outputs a low level, the Relay _ ctrl signal outputs a low level, and the high-voltage loop Relay is turned off.
In a limp-home mode in which the Q7 is conducted, when the LimpCtrl is at a low level, the one-way diodes D1 and D2 are cut off, the base electrode of the Q7 is kept at a conducting voltage through the capacitor C4, the Q7 is kept in a conducting state continuously, the Relay _ ctrl signal outputs a low level, and the high-voltage loop Relay is kept in a disconnected state continuously.
Optionally, when the Relay _ ctrl outputs a high level, the Relay is turned on, and when the Relay _ ctrl outputs a low level, the Relay is turned off.
And Vnor is a power supply of the normal mode on control circuit and the normal mode off control circuit, and the enabling and disabling of Vnor is controlled by the internal power supply enabling control circuit V.
In some embodiments, internal power enable control circuit v controls the enabling and disabling of Vnor and Vlimp, as shown in fig. 7.
The internal power supply enabling control circuit V is realized through a triode on-off control circuit and comprises a triode Q8, a triode Q9, a triode Q10 and a triode Q11 which are sequentially connected, wherein the base of the triode Q8 is connected with a Limp mode pin Lipp of SBC, the collector of the triode Q8 is connected with a power supply Vcc, the collector of the triode Q8 is connected with a power supply output Vnor end through a resistor, the emitter of the triode Q8 is connected with the base of the triode Q9 through a resistor R22, and the collector of the triode Q9 is connected with the power supply output Vnor end; the emitter of the triode Q8 is connected to the base of the triode Q10, the collector of the triode Q10 is connected to the base of the triode Q11, the collector of the triode Q11 is connected with the power supply Vcc, the emitter of the triode Q10 is connected to the emitter of the triode Q11 through the capacitor C2, and the emitter of the triode Q11 is the power supply output Vlimp end
When the MCU is in a normal running state, a Limp mode pin Limp of the SBC outputs a high level, Q8, Q9, Q10 and Q11 are cut off, power supply of the Vnor is enabled, and power supply of the Vlimp is disabled; when the Limp running mode is in, limp outputs low level, Q8, Q9, Q10 and Q11 are conducted, power supply of the Vlimp is enabled, and power supply of the Vnor is disabled.
The above description is only a preferred embodiment of the present disclosure and is not intended to limit the present disclosure, and various modifications and changes may be made to the present disclosure by those skilled in the art. Any modification, equivalent replacement, improvement and the like made within the spirit and principle of the present disclosure should be included in the protection scope of the present disclosure.
Although the present disclosure has been described with reference to specific embodiments, it should be understood that the scope of the present disclosure is not limited thereto, and those skilled in the art will appreciate that various modifications and changes can be made without departing from the spirit and scope of the present disclosure.
Claims (10)
1. A high-voltage reduction method of an electric automobile in a limp home mode is characterized by comprising the following steps:
monitoring the running state of a main control chip MCU of the whole vehicle controller and the state of a vehicle start-stop switch;
when the MCU normally runs, the on-off of the controlled component is controlled by the vehicle MCU and the normal mode high-voltage relay control circuit according to the state of the vehicle start-stop switch;
when the MCU fails, the control of the MCU on the high-voltage loop relay is disconnected through the limp mode pin of the SBC, and the high-voltage main positive relay is controlled to be turned off by the limp mode high-voltage low-voltage confirmation circuit and the limp mode high-voltage relay control circuit, so that the controlled component is turned off after the set time of a turn-off signal of the start-stop switch is received.
2. The method for high-voltage power reduction of the electric automobile in the limp home mode as claimed in claim 1, wherein: the controlled component is a high-voltage main positive relay of the vehicle, a key relay or a contactor on the vehicle.
3. The utility model provides an electric automobile high pressure system of unloading under limp mode which characterized in that: the limp-home high-voltage relay control circuit comprises a start-stop switch three-state detection circuit I, a limp-home high-voltage lower voltage confirmation circuit II, a normal-mode high-voltage relay control circuit III, a limp-home high-voltage relay control circuit IV and an internal power supply enabling control circuit V;
the start-stop switch three-state detection circuit I is used for detecting the working state of the start-stop switch;
when the MCU normally operates, the vehicle internal power supply enabling control circuit V enables the power supply of the normal mode high-voltage relay control circuit III, disables the power supply of the limp mode high-voltage lower voltage confirmation circuit II, and controls the on-off of the high-voltage main positive relay through the MCU and the normal mode high-voltage relay control circuit III;
when the MCU fails, the internal power supply enabling control circuit V enables the power supply of the limp mode high-voltage lower voltage confirmation circuit II, disables the power supply of the normal mode high-voltage relay control circuit III, and controls the turn-off of the high-voltage main positive relay through the limp mode high-voltage lower voltage confirmation circuit II and the limp mode high-voltage relay control circuit IV, so that the high-voltage main positive relay is turned off after the start-stop switch is pressed for a set time.
4. A limp home mode electric vehicle high voltage power down system as defined in claim 3 wherein: the start-stop switch three-state detection circuit I comprises a start-stop switch circuit and a voltage division current limiting circuit;
the start-stop switch circuit comprises two resistors connected in series, one end of the circuit after series connection is grounded, the other end of the circuit is connected with an SSBin interface of the VCU, and the start-stop switch is connected to two ends of one resistor in parallel;
the voltage division and current limitation circuit is arranged in the VCU and divides and limits the voltage of an output signal of the SSBin interface.
5. A limp home electric vehicle high voltage electrical discharge system as defined in claim 4 wherein: the voltage-dividing current-limiting circuit comprises a first resistor R1 and a second resistor R2 which are connected in series, and further comprises a first capacitor C1 and a third resistor R3, the connecting point of the first resistor R1 and the second resistor R2 is connected to a VCU (vertical synchronous rectifier) through an SSBin interface, the two ends of the second resistor R2 are connected after the first capacitor C1 and the third resistor R3 are connected in series, the connecting point of the first capacitor C1 and the third resistor R3 is grounded, and the connecting point of the third resistor R3 and the second resistor R2 is the output end of the voltage-dividing current-limiting circuit.
6. A limp home mode electric vehicle high voltage power down system as defined in claim 3 wherein: the detected states of the start-stop switch comprise input open circuit, press-down and bounce states.
7. A limp home mode electric vehicle high voltage power down system as defined in claim 3 wherein: the limp mode high-voltage power-down confirmation circuit II comprises a start-stop switch pressing confirmation circuit and a high-voltage power-down countdown circuit which are sequentially connected;
the start-stop switch pressing confirmation circuit comprises a first series resistance voltage division circuit, a comparator U1 and a triode Q1, wherein the output end of the first series resistance voltage division circuit is connected to the negative input end of the comparator U1, and the positive input end of the comparator U1 is connected to the SSBin interface of the VCU; the output end of the comparator U1 is connected to the base electrode of the triode Q1, and the state of the start-stop switch is judged by conducting or stopping the triode Q1.
8. A limp home mode electric vehicle high voltage power down system as defined in claim 7 wherein: the low-voltage countdown circuit adopts a timer circuit;
or the high-voltage power-off countdown circuit comprises a resistance-capacitance network, a comparator U2 and a second series resistance voltage division circuit, the input end of the resistance-capacitance network is connected with the output end of the start-stop switch pressing confirmation circuit, the second series resistance voltage division circuit and the resistance-capacitance network are respectively connected with the input end of the comparator U2, and the output end of the comparator U2 is connected to the limp-home mode high-voltage relay control circuit IV.
9. A limp home mode electric vehicle high voltage power down system as defined in claim 3 wherein: the normal mode high-voltage relay control circuit III comprises a normal mode on control circuit and a normal mode off control circuit;
the normal mode conduction control circuit comprises a triode Q2, a triode Q3, a diode D4 and a triode Q4, wherein the base of the triode Q2 is connected with a conduction signal output end Mcu _ on of an MCU (microprogrammed control Unit), the collector of the triode Q2 is connected with the base of the triode Q3, the collector of the triode Q3 is connected with a Vnor for power supply, when the circuit is in a limp mode, the Vnor is disabled for power supply, the emitter of the triode Q3 is connected to the base of the triode Q4 through a resistor R16, and the collector of the triode Q4 is connected to a power supply Vcc; the emitter of the triode Q3 is connected to the diode D4 through the resistor R15, and the cathode of the diode D4 is a control output end;
or the normal mode turn-off control circuit comprises a triode Q5, a triode Q6 and a one-way diode D3 which are sequentially connected, wherein a collector of the triode Q6 is connected with a Vnor for power supply, when the limp mode is adopted, the Vnor is disabled in power supply, and a cathode of the one-way diode D3 is connected to the turn-off and conduction interlocking circuit;
the turn-off and turn-on interlocking circuit comprises a triode Q7, a collector of the triode Q7 is connected to a control output end through a resistor R6, a collector of the triode Q7 is connected to a power supply Vcc through a resistor R19, a collector of the triode Q7 is connected to a base electrode of the triode Q7 through a diode D1, a resistor R18, a resistor R20 and a resistor R21 which are connected in series, a base electrode and an emitting electrode of the triode Q7 are directly connected through a capacitor C4, and a connecting point of the resistor R20 and the resistor R21 is connected with an output end of the normal mode turn-off control circuit;
or the limp-home mode high-voltage relay control circuit iv comprises a diode D2 connected to the turn-off and turn-on interlock circuit of the normal mode high-voltage relay control circuit iii.
10. A limp home mode electric vehicle high voltage power down system as defined in claim 3 wherein: and the internal power supply enabling control circuit V realizes enabling control of power supply output through the triode on-off control circuit.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202210986502.0A CN115520019A (en) | 2022-08-17 | 2022-08-17 | Method and system for high-voltage power down of electric automobile in limping mode |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202210986502.0A CN115520019A (en) | 2022-08-17 | 2022-08-17 | Method and system for high-voltage power down of electric automobile in limping mode |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN115520019A true CN115520019A (en) | 2022-12-27 |
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202210986502.0A Pending CN115520019A (en) | 2022-08-17 | 2022-08-17 | Method and system for high-voltage power down of electric automobile in limping mode |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN115520019A (en) |
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2022
- 2022-08-17 CN CN202210986502.0A patent/CN115520019A/en active Pending
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