CN115308591A - Adhesion and pressure difference detection circuit of relay - Google Patents
Adhesion and pressure difference detection circuit of relay Download PDFInfo
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- CN115308591A CN115308591A CN202211028361.8A CN202211028361A CN115308591A CN 115308591 A CN115308591 A CN 115308591A CN 202211028361 A CN202211028361 A CN 202211028361A CN 115308591 A CN115308591 A CN 115308591A
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R31/00—Arrangements for testing electric properties; Arrangements for locating electric faults; Arrangements for electrical testing characterised by what is being tested not provided for elsewhere
- G01R31/327—Testing of circuit interrupters, switches or circuit-breakers
- G01R31/3271—Testing of circuit interrupters, switches or circuit-breakers of high voltage or medium voltage devices
- G01R31/3272—Apparatus, systems or circuits therefor
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R19/00—Arrangements for measuring currents or voltages or for indicating presence or sign thereof
- G01R19/10—Measuring sum, difference or ratio
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R31/00—Arrangements for testing electric properties; Arrangements for locating electric faults; Arrangements for electrical testing characterised by what is being tested not provided for elsewhere
- G01R31/005—Testing of electric installations on transport means
- G01R31/006—Testing of electric installations on transport means on road vehicles, e.g. automobiles or trucks
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02T—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION
- Y02T10/00—Road transport of goods or passengers
- Y02T10/60—Other road transportation technologies with climate change mitigation effect
- Y02T10/70—Energy storage systems for electromobility, e.g. batteries
Abstract
The invention discloses an adhesion and differential pressure detection circuit of a relay, which comprises a vehicle-mounted high-voltage charging pack connected with a charging port, a positive relay arranged at the positive pole of the charging port, a negative relay arranged at the negative pole of the charging port, a differential detection circuit arranged between the charging port and the vehicle-mounted high-voltage charging pack, a switching circuit for switching the detection state of the differential detection circuit, and a main control unit for controlling the working state of the switching circuit, wherein the main control unit is connected with the output end of the differential detection circuit and can judge the states of the positive relay and the negative relay according to an output signal of the differential detection circuit. Compared with the prior art, the method can effectively identify the adhesion state of the relay, the adhesion detection of the relay is not influenced by external voltage, and the state of the relay can be effectively judged.
Description
Technical Field
The invention relates to the field of new energy automobile relays, in particular to an adhesion and differential pressure detection circuit of a relay.
Background
The new energy automobile has the advantages of low energy consumption, light pollution and the like which are incomparable with the traditional fuel oil automobile, can solve the problems of energy shortage, environmental pollution and the like, and obtains outstanding performance under the vigorous and continuous support of governments in recent years. The rapid development and popularization of new energy vehicles have higher and higher safety requirements on the battery charging and replacing process and the whole vehicle;
the relay on the new energy automobile mainly plays a role in controlling the on/off of a main power line so as to protect the safety of a controller and a motor, but due to the working conditions of overlarge external load current, unstable actuation voltage, large load breaking and the like, the relay is easy to have adhesion phenomena, and the problems that the existing relay adhesion detection technology and method are complex in circuit, low in detection efficiency, poor in precision, prone to be influenced by external voltage and prone to have false detection and the like, the adhesion of the high-voltage relay cannot be identified or false alarm faults are caused, so that the new energy automobile cannot be charged or devices are damaged.
Therefore, how to design an adhesion and differential pressure detection circuit of a relay can solve the defects of the prior art, and is a technical problem to be solved in the industry.
Disclosure of Invention
The invention provides a relay adhesion and differential pressure detection circuit, which aims at solving the problems of low detection efficiency and poor precision of a relay adhesion detection technology in the prior art.
The technical scheme includes that the relay adhesion and pressure difference detection circuit comprises a vehicle-mounted high-voltage charging pack connected with a charging port, a positive electrode relay arranged at the positive electrode of the charging port, a negative electrode relay arranged at the negative electrode of the charging port, a difference detection circuit arranged between the charging port and the vehicle-mounted high-voltage charging pack, a switching circuit for switching the detection state of the difference detection circuit, and a main control unit for controlling the working state of the switching circuit, wherein the main control unit is connected with the output end of the difference detection circuit and can judge the states of the positive electrode relay and the negative electrode relay according to output signals of the difference detection circuit.
Further, the differential detection circuit includes: the circuit comprises a resistor R1A, a resistor R2A, a resistor R3A, a resistor R4A, a resistor R5A, a resistor R6A, a resistor R1B, a resistor R2B, a resistor R3B, a resistor R4B, a resistor R5B, a resistor R6B and a differential amplifier U1;
the one end of resistance R3A is connected between the positive relay and the positive pole of on-vehicle high voltage battery package, other end series resistance R4A back ground connection, resistance R3B's one end is connected between the positive relay with on-vehicle high voltage battery package's positive pole, other end series resistance R4B back ground connection, resistance R5A one end is connected charge port's positive pole with between the positive relay, the other end is connected to switching circuit's first input, resistance R6A one end is connected charge port's negative pole with between the negative pole relay, the other end is connected to switching circuit's second input, resistance R1A one end is connected to switching circuit's first output, other end series resistance R2A back ground connection, resistance R5B one end is connected between the positive relay with on-vehicle high voltage battery package, the other end is connected to switching circuit's third input, resistance R6B one end is connected between the negative pole relay with on-vehicle high voltage battery package, the other end is connected to switching circuit's fourth input, resistance R1B one end is connected to switching circuit's second output, the other end is connected to switching circuit's second output, the resistor R2B is connected to between the negative pole of switching circuit's negative pole and the main control unit input, the inverting resistor R1B 2A, the inverting resistor B1B 2A is connected to the same phase of switching circuit is connected to the same phase of switching circuit.
Further, the differential detection circuit also comprises a bias voltage setting circuit connected with the differential detection circuit, wherein the bias voltage setting circuit comprises a resistor R7A and a resistor R7B;
one end of the resistor R7A is connected with a bias power supply, the other end of the resistor R7A is connected with the resistor R7B in series and then is grounded, the voltage between the resistor R7A and the resistor R7B is used as bias voltage, and the non-inverting input end of the differential amplifier U1 is further connected between the resistor R7A and the resistor R7B to obtain the bias voltage.
Further, the resistance of the resistor R7A is the same as that of the resistor R7B.
Further, the switching circuit includes a relay RLY1, a relay RLY2A, a relay RLY2B;
a first movable end of the relay RLY2A is connected with the differential detection circuit as a first input end of the switching circuit, a second movable end is connected with the differential detection circuit as a second input end of the switching circuit, a stationary end is connected to the first end of the relay RLY1, a second end of the relay RLY1 is connected with the differential detection circuit as a first output end of the switching circuit, a first movable end of the relay RLY2B is connected with the differential detection circuit as a third input end of the switching circuit, a second movable end is connected with the differential detection circuit as a fourth input end of the switching circuit, and a stationary end is connected with the differential detection circuit as a second output end of the switching circuit.
The power supply circuit comprises an auxiliary source conversion circuit and a voltage conversion circuit, and the power supply circuit supplies power to a differential amplifier U1 in the differential detection circuit when receiving a wake-up signal sent by the main control unit.
Furthermore, the main control unit is also connected to a battery management system of the vehicle-mounted system, and can adjust the conduction states of the positive relay, the negative relay and the switching circuit according to a control instruction sent by the battery management system.
Further, when the relay RLY1 is disconnected, the main control unit controls the power supply circuit to be in a sleep state, and the differential detection circuit works in a default state;
when the relay RLY1 is closed, the immovable end of the relay RLY2A is connected to the first movable end of the relay RLY1, and the immovable end of the relay RLY2B is connected to the first movable end of the relay RLY2B, the main control unit controls the power supply circuit to be in an awakening state, and the differential detection circuit works in a positive relay adhesion detection state;
when the relay RLY1 is closed, the immovable end of the relay RLY2A is connected to the second movable end of the relay RLY2A, and the immovable end of the relay RLY2B is connected to the second movable end of the relay RLY2B, the main control unit controls the power supply circuit to be in an awakening state, and the differential detection circuit works in a negative relay adhesion detection state.
Further, when the relay RLY1 and the negative relay are closed, the positive relay is opened, the immobile end of the relay RLY2A is connected to the first mobile end of the relay RLY2A, and the immobile end of the relay RLY2B is connected to the first mobile end of the relay RLY2B, the main control unit controls the power supply circuit to be in an awakening state, and the differential detection circuit works in a differential pressure detection state.
Further, when the differential detection circuit works in a positive relay adhesion detection state and the voltage of an output signal of the differential detection circuit is equal to a bias given voltage, the positive relay is adhered;
when the differential detection circuit works in a negative relay adhesion detection state and the voltage of an output signal of the differential detection circuit is equal to a bias given voltage, the negative relay is adhered;
when the differential detection circuit works in a differential pressure detection state, the difference between the voltage of the output signal of the differential detection circuit and the bias given voltage is converted into the differential pressure between the charging port and the vehicle-mounted high-voltage battery pack through a certain numerical value.
Compared with the prior art, the invention has at least the following beneficial effects:
1. the invention adopts a circuit form that a group of associated action relays, associated sampling resistors and operational amplifiers form a Wheatstone bridge, thereby increasing the detection precision and efficiency of the circuit, and the tiny pressure difference change can be identified and judged;
2. when the relay adhesion and the pressure difference detection are not carried out, the device is in a default non-detection state, and the pressure difference detection circuit is in a dormant state, so that the static current loss of the new energy automobile can be effectively reduced;
3. when the relay is adhered and the voltage difference is detected, the relay is not influenced by residual voltage of a charging pile or voltage on a vehicle-mounted high-voltage charging pack, the influence of external voltage on the state judgment of the relay can be effectively avoided, the state of the relay can be effectively identified under various voltage regulation, and the relay and a motor are effectively protected from being damaged;
4. the differential pressure detection circuit adopts a group of associated action relays, when one relay breaks down, the judgment of the other relay is not influenced, and the state judgment of the two relays is independent and not influenced;
5. according to the invention, the pressure difference between the two ends of the relay is detected before the relay is closed, and when the pressure difference between the two ends of the relay is lower than a certain threshold value, the high-voltage relay is closed, so that the impact current generated at the moment of closing the high-voltage relay can be effectively reduced, and the controller and the motor are protected from being damaged.
Drawings
In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings needed to be used in the embodiments or the prior art descriptions will be briefly described below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and it is obvious for those skilled in the art to obtain other drawings based on these drawings without inventive exercise.
FIG. 1 is a schematic diagram of the operation of the present invention;
FIG. 2 is a schematic diagram of the connection of the present invention operating in a default state;
FIG. 3 is a schematic diagram of the connection of the present invention in a negative relay adhesion detection state;
FIG. 4 is a schematic diagram of the connection of the present invention operating in a positive relay adhesion detection state;
FIG. 5 is a schematic view of the connection of the present invention operating in a differential pressure sensing state;
FIG. 6 is a graph showing the output results of the present invention when different impedances of the cathode relay are simulated;
FIG. 7 is a graph showing the output results of the present invention when different impedances of the positive relay are simulated;
FIG. 8 is a graph showing the output results of the present invention when different voltage differences exist between the charging port and the on-board high voltage battery;
fig. 9 is a control flowchart of the overall invention.
Detailed Description
In order to make the technical problems, technical solutions and advantageous effects to be solved by the present invention more clearly apparent, the present invention is further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and do not limit the invention.
Thus, a feature indicated in this specification will serve to explain one of the features of one embodiment of the invention, and does not imply that every embodiment of the invention must have the stated feature. Further, it should be noted that this specification describes many features. Although some features may be combined to show a possible system design, these features may also be used in other combinations not explicitly described. Thus, the combinations illustrated are not intended to be limiting unless otherwise specified.
The principles and structures of the present invention are described in detail below with reference to the drawings and the embodiments.
The problems that in the existing relay adhesion detection technology, a circuit is complex, detection efficiency is low, precision is poor, false detection occurs due to the fact that the relay adhesion is easily affected by external voltage, and the like, can not be recognized or faults are reported in a wrong mode, and therefore a new energy automobile can not be charged or devices are damaged. The invention relates to an adhesion and differential pressure detection circuit of a relay, which adopts a circuit form that a group of associated action relays, associated sampling circuits and operational amplifiers form a Wheatstone bridge, increases the detection precision and efficiency of the circuit and reduces the occurrence of false detection.
The invention provides an adhesion and differential pressure detection circuit of a relay, which comprises a vehicle-mounted high-voltage charging pack connected with a charging port, a positive relay arranged at the positive pole of the charging port and a negative relay arranged at the negative pole of the charging port.
In order to detect whether the positive relay and the negative relay are adhered or not, a differential detection circuit, a switching circuit for switching the detection state of the differential detection circuit and a main control unit for controlling the working state of the switching circuit are arranged between a charging port and a vehicle-mounted high-voltage charging pack.
The differential detection circuit can output different voltage signals to the main control unit under different states of the positive relay and the negative relay, and the main control unit can determine whether the positive relay and the negative relay are adhered according to the voltage signals. In addition, according to the use requirements under different conditions, the differential detection circuit can be in a default state, detection is not carried out, the differential detection circuit is in a dormant state, and the static current loss is reduced;
the adhesion detection state of the positive relay is detected, and whether the adhesion problem occurs to the positive relay is judged through the output voltage of the differential detection circuit;
the adhesion detection state of the negative relay is realized, and whether the adhesion problem occurs to the negative relay is judged through the output voltage of the differential detection circuit;
and the differential pressure detection state judges the differential pressure at two ends of the positive relay or the negative relay through the output voltage of the differential detection circuit, so that the impact current generated in the moment of closing the relay is avoided, and the controller and the motor are protected from being damaged.
The switching among various states is realized through the switching circuit, and the switching circuit is controlled by the main control unit, namely, the working state of the differential detection circuit can be switched under the control of the main control unit, so that various detection requirements are met.
Referring to fig. 1, the differential detection circuit includes: the circuit comprises a resistor R1A, a resistor R2A, a resistor R3A, a resistor R4A, a resistor R5A, a resistor R6A, a resistor R1B, a resistor R2B, a resistor R3B, a resistor R4B, a resistor R5B, a resistor R6B and a differential amplifier U1;
one end of a resistor R3A is connected between a positive pole relay and the positive pole of the vehicle-mounted high-voltage battery pack, the other end of the resistor R3A is connected with a resistor R4A in series and then is grounded, one end of a resistor R3B is connected between the positive pole relay and the positive pole of the vehicle-mounted high-voltage battery pack, the other end of the resistor R4B in series and then is grounded, one end of a resistor R5A is connected between the positive pole of the charging port and the positive pole relay, the other end of the resistor R6A is connected with the second input end of the switching circuit, one end of a resistor R1A is connected to the first output end of the switching circuit, the other end of the resistor R2A in series and then is grounded, one end of a resistor R5B is connected between the positive pole relay and the positive pole of the vehicle-mounted high-voltage battery pack, the other end of the resistor R6B is connected between the negative pole relay and the negative pole of the vehicle-mounted high-voltage battery pack, the other end of the resistor R1A is connected to the fourth input end of the switching circuit, one end of the resistor R1B is connected to the second output end of the switching circuit, the other end of the switching circuit is grounded after being connected with a resistor R2B in series, the same phase input end of the differential amplifier U1B, the same-phase input end of the differential amplifier U1B is connected with the reverse resistor R2A 2B, and the reverse-phase resistor R2A, and the main control unit, and the output end of the main control unit.
The switching circuit comprises a relay RLY1, a relay RLY2A and a relay RLY2B;
the first movable end of the relay RLY2A is used as a first input end of the switching circuit and connected with the differential detection circuit, the second movable end is used as a second input end of the switching circuit and connected with the differential detection circuit, the immobile end of the relay RLY2A is connected with the first end of the relay RLY1, the second end of the relay RLY1 is used as a first output end of the switching circuit and connected with the differential detection circuit, the first movable end of the relay RLY2B is used as a third input end of the switching circuit and connected with the differential detection circuit, the second movable end is used as a fourth input end of the switching circuit and connected with the differential detection circuit, and the immobile end is used as a second output end of the switching circuit and connected with the differential detection circuit.
Referring to fig. 1, the vehicle-mounted high-voltage charging pack is Battery, the positive relay is relay RLY _ QC +, the negative relay is relay RLY _ QC-, QC + is used as the positive pole of the charging port, and QC-is used as the negative pole of the charging port.
As shown in fig. 3, when the relay RLY1 is closed, and the immobile ends of the relay RLY2A and the relay RLY2B are connected to the second mobile end thereof, the inverting input end of the differential amplifier U1 gets electricity through the resistor R1A and the resistor R2A, the voltage of the negative electrode of the charging port is accessed, the non-inverting input end gets electricity through the resistor R1B and the resistor R2B, the voltage of the negative electrode relay facing the negative electrode side of the vehicle-mounted high-voltage battery pack is accessed, if the negative electrode relay has the adhesion problem, the voltages at the two ends of the negative electrode relay are the same, and under this condition, by detecting the output voltage of the differential amplifier U1, it can be determined whether the adhesion problem occurs to the negative electrode relay;
as in fig. 4, when relay RLY1 is closed, relay RLY2A and relay RLY 2B's motionless end is connected to its first movable end, differential amplifier U1's inverting input end gets the electricity through resistance R1A and resistance R2A, what insert is the anodal voltage of charging port, the homophase input end gets the electricity through resistance R1B and resistance R2B, what insert is that anodal relay is towards the anodal voltage of on-vehicle high voltage battery package positive pole one side, if anodal relay takes place the adhesion problem, the voltage at its anodal relay both ends is the same, under this condition, through the output voltage who detects differential amplifier U1, can determine whether the adhesion problem takes place for the negative pole relay.
As shown in fig. 5, when the relay RY1, the relay RLY _ QC-are closed, and the stationary ends of the relay RLY2A and the relay RLY2B are connected to the first movable end thereof, the inverting input end of the differential amplifier U1 gets power through the resistor R1A and the resistor R2A, the voltage of the positive electrode relay toward the positive electrode of the charging port is accessed, the voltage of the non-inverting input end gets power through the resistor R1B and the resistor R2B, and the voltage of the positive electrode relay toward the positive electrode side of the vehicle-mounted high-voltage battery pack, that is, the access voltages of the non-inverting input end and the inverting input end of the differential amplifier U1 are respectively the voltages across the positive electrode relay, in this case, the voltage difference across the positive electrode relay can be determined by detecting the output voltage of the differential amplifier U1.
In other words, the adhesion and the differential pressure detection of the positive relay and the negative relay can be realized through the arrangement of the differential detection circuit and the switching circuit.
In order to facilitate the judgment of the states of the positive relay and the negative relay, the invention is also provided with a bias voltage setting circuit which consists of a resistor R7A and a resistor R7B, wherein one end of the resistor R7A is connected with a bias power supply, the other end of the resistor R7A is connected with the resistor R7B in series and then is grounded, the voltage between the resistor R7A and the resistor R7B is used as bias voltage, and the non-inverting input end of the differential amplifier U1 is connected between the resistor R7A and the resistor R7B to obtain the bias voltage.
Through this setting mode, can give a bias voltage for differential amplifier U1's in-phase input end, if adhesion problem appears in anodal relay or negative pole relay during the detection, the voltage that differential amplifier U1's in-phase input end and inverting input end obtained through differential detection circuit under this condition is the same, if not add a bias voltage, will unable to detect behind the differential amplifier U1 voltage output. According to the invention, through the arrangement of the bias voltage setting circuit, a bias voltage is additionally added to the in-phase input end of the differential amplifier U1, namely, whether the adhesion problem of the positive relay or the negative relay occurs can be determined according to whether the final output voltage of the differential amplifier U1 is equal to the bias voltage, and the overall detection is more visual and convenient.
Further, in order to determine the magnitude of the bias voltage more accurately, the resistance value of the resistor R7A and the resistance value of the resistor R7B are set to be the same, and under the condition, the magnitude of the bias voltage can be determined to be half of that of the bias power supply, so that the determination is easier.
Since the resistor R7A and the resistor R7B are in a series relationship, according to the series voltage division, the voltage between the resistor R7A and the resistor R7B should be (VREF × R7B)/(R7A + R7B), and in other embodiments of the present invention, the ratio of the resistor R7A to the resistor R7B may also be adjusted to adjust different bias voltages to the differential amplifier U1.
According to the invention, a power supply circuit is arranged between the differential detection circuit and the main control circuit, the power supply circuit comprises an auxiliary source conversion circuit and a voltage conversion circuit, and the power supply circuit can trigger and supply power to the differential amplifier U1 only when receiving a wake-up signal sent by the main control unit.
As shown in fig. 1, the auxiliary source converting circuit is an auxiliary source (U3), the voltage converting circuit is an LDO (U4), the main control unit is an MCU, the auxiliary source converting circuit is woken up by a signal S1 sent by the main control unit, and after the auxiliary source converting circuit is woken up, the auxiliary source converting circuit controls the voltage converting circuit to work and supplies power to the voltage converting circuit, so as to ensure the normal operation of the differential detection circuit.
The main control unit is also connected to a battery management system of the vehicle-mounted system, the battery management system can send out corresponding control instructions according to the requirements of the battery management system, so that the differential detection circuit works in a sleep mode, a positive relay adhesion detection mode, a negative relay adhesion detection mode and a differential pressure detection mode, and the main control unit is also respectively connected to the relay RLY1, the relay RLY2A and the relay RLY2B and used for controlling the states of the relay RLY1, the relay RLY2A and the relay RLY 2B.
As shown in fig. 1, the battery management system is a BMS, which can send a control command K1 to a main control unit according to a requirement, the main control unit can send control signals of relays according to the control command K1, a signal S2 is used as an RLY1 control signal for controlling the on-off state of the relay RLY1, a signal S3 is used as an RLY2 control signal for respectively controlling the inactive ends of the relay RLY2A and the relay RLY2B to be connected to a first active end or a second active end, a signal S4 is used as an RLY _ QC-control signal for controlling the on-off state of the relay RLY _ QC-, a signal S5 is used as an RLY _ QC + control signal for controlling the state of the relay RLY _ QC-, and the main control unit sends different control signals according to the control command K1 sent by the battery on-off management system, which can be used for realizing the adhesion and differential pressure detection functions of an anode relay or a cathode relay.
Wherein, relay RLY1 can set up to normally open relay, when the main control unit received the control command K1 that battery management system sent, the main control unit sent a high level signal to relay RLY1, and then closed relay RLY1, relay RLY2A and relay RLY2B can set up to normally closed relay, and the end that does not move under the normally closed state is connected with the second end that moves, when the main control unit received the control command that battery management system sent, the main control unit sends high level signal to relay RLY2A, relay RLY2B, make relay RLY2A, relay RLY 2B's end that does not move is connected to first end that moves, thereby realize the control of above-mentioned each detection state.
Referring to fig. 2, when the relay RLY1 is turned off, the main control unit controls the power supply circuit to be in a sleep state, and the differential detection circuit operates in a default state.
In the state, the main control unit does not receive a control command K1 sent by the battery management system, signals S2, S3, S4 and S5 sent by the main control unit are all in a low level state, at the moment, the relay RLY1, the relay RLY _ QC-, and the relay RLY _ QC + are disconnected, the relay RLY2A and the relay RLY2B are in a default state, the main control unit controls the auxiliary source conversion circuit to sleep through the S1 signal, at the moment, the voltage conversion circuit stops supplying power, the whole detection system is in a sleep state, and static current loss of the system is reduced as much as possible;
referring to fig. 3, when the relay RLY1 is closed, the inactive terminal of the relay RLY2A is connected to the second active terminal thereof, and the inactive terminal of the relay RLY2B is connected to the second active terminal thereof, the main control unit controls the power supply circuit to be in the wake-up state, and the differential detection circuit works in the negative relay adhesion detection state.
In the state, the main control unit receives a control instruction K1 for detecting the adhesion of the relay RLY _ QC-sent by a battery management system of the whole vehicle, the main control unit firstly wakes up the auxiliary source conversion circuit through an S1 signal so as to enable the voltage conversion circuit to start power supply, meanwhile, the relay RLY1 is in a closed state through a signal S2 and a signal S3, the fixed ends of the relay RLY2A and the relay RLY2B are connected to the second movable end of the relay RLY2A, and the system enters a relay RLY _ QC-adhesion detection state.
If the relay RLY _ QC-is in an adhesion state, the impedance of the relay RLY _ QC-is very small, the relay RLY _ QC-is in an approximate short-circuit state at the moment, the voltages at two ends of the relay RLY _ QC-are the same, the voltage acquired by the in-phase input end of the differential amplifier U1 from the resistor R1A and the resistor R2A is equal to the voltage acquired by the reverse-phase input end of the differential amplifier U1 from the resistor R1B and the resistor R2B, and as the in-phase input end of the differential amplifier U1 is additionally connected with a bias voltage, the bias power supply is 5V, the resistances of the resistor R7A and the resistor R7B are the same, and the bias voltage is 2.5V, so that the differential amplifier U1 can output 2.5V voltage, namely bias given voltage, in the adhesion state of the relay RLY _ QC-QC;
on the contrary, when the relay RLY _ QC-is in a non-adhesion state, the impedance of the relay RLY _ QC-is large, the relay RLY _ QC-is approximate to an open circuit state at the moment, a certain difference value exists between the voltage acquired by the reverse phase input end of the differential amplifier U1 through the resistor R1A and the resistor R2A and the voltage acquired by the non-phase input end of the differential amplifier U1 through the resistor R1B and the resistor R2B, and the output voltage of the differential amplifier circuit is equal to the given bias voltage plus the differential amplification voltage at the moment, so that the voltage output by the differential amplifier is higher than the bias voltage by 2.5V under the condition.
Namely, in the negative relay adhesion detection state, if the voltage of the output signal of the differential amplifier U1 is equal to the bias given voltage, the relay RLY _ QC-adhesion is determined, and if the voltage of the output signal of the differential amplifier U1 is greater than the bias given voltage, the relay RLY _ QC-adhesion is determined.
Referring to fig. 6, the vehicle-mounted high-voltage charging packets are typically 250V, 300V, and 500V, when the relay RLY _ QC-is in the adhesion state, the voltage of the output signal of the differential amplifier U1 is the bias voltage 2.5V, and when the relay RLY _ QC-is in the non-adhesion state, the voltage of the output signal of the differential amplifier U1 is much larger than the bias voltage 2.5V, and it can be known from the result that the voltage of the vehicle-mounted high-voltage charging packet does not affect the adhesion detection of the relay RLY _ QC-.
Referring to fig. 4, when the relay RLY1 is closed, the immobile end of the relay RLY2A is connected to the first mobile end thereof, and the immobile end of the relay RLY2B is connected to the first mobile end thereof, the main control unit controls the power supply circuit to be in the wake-up state, and the differential detection circuit works in the positive relay adhesion detection state;
in the state, the main control unit receives a control instruction K1 for detecting the adhesion of the relay RLY _ QC + sent by a battery management system of the whole vehicle, the main control unit firstly wakes up the auxiliary source conversion circuit through an S1 signal so as to enable the voltage conversion circuit to start power supply, meanwhile, the relay RLY1 is in a closed state through a signal S2 and a signal S3, the fixed ends of the relay RLY2A and the relay RLY2B are connected to the first movable end of the relay RLY2A, and the system enters a relay RLY _ QC + adhesion detection state.
If the relay RLY _ QC + is in an adhesion state, the impedance of the relay RLY _ QC + is small, the relay RLY _ QC + is approximate to a short-circuit state at the moment, the voltages at two ends of the relay RLY _ QC + are the same, the voltage obtained by the non-inverting input end of the differential amplifier U1 from the resistor R1A and the resistor R2A is equal to the voltage obtained by the inverting input end of the differential amplifier U1 from the resistor R1B and the resistor R2B, and the non-inverting input end of the differential amplifier U1 is additionally connected with bias voltage, so that the bias power supply is 5V, the resistance values of the resistor R7A and the resistor R7B are the same, and the bias voltage is 2.5V, and therefore, in the adhesion state of the relay RLY _ QC-, the differential amplifier can output 2.5V voltage, namely bias given voltage;
on the contrary, when the relay RLY _ QC + is in a non-adhesion state, the impedance of the relay RLY _ QC + is very large, at this time, the relay RLY _ QC + is approximately in an open circuit state, a certain difference exists between the voltage obtained by the reverse-phase input end of the differential amplifier U1 through the resistor R1A and the resistor R2A and the voltage obtained by the non-phase input end of the differential amplifier U1 through the resistor R1B and the resistor R2B, and at this time, the output voltage of the differential amplifier circuit is equal to the given offset voltage minus the differential amplification voltage, so that the voltage output by the differential amplifier U1 under this condition is lower than the offset voltage by 2.5V.
In other words, in the positive relay adhesion detection state, if the voltage of the output signal of the differential amplifier U1 is equal to the bias given voltage, it is determined that the relay RLY _ QC + is adhered, and if the voltage of the output signal of the differential amplifier U1 is less than the bias given voltage, it is determined that the relay RLY _ QC + is not adhered.
Referring to fig. 7, the voltage of the output signal of the differential amplifier U1 is typically 250V, 300V, or 500V, when the relay RLY _ QC + is in the adhesion state, the voltage of the output signal of the differential amplifier U1 is 2.5V, and when the relay RLY _ QC + is in the non-adhesion state, the voltage of the output signal of the differential amplifier U1 is much smaller than the bias voltage 2.5V.
Referring to fig. 5, when the relay RLY1 and the relay RLY _ QC-are closed, the relay RLY _ QC + is opened, the immobile end of the relay RLY2A is connected to the first mobile end thereof, and the immobile end of the relay RLY2B is connected to the first mobile end thereof, the main control unit controls the power supply circuit to be in the wake-up state, and the differential detection circuit operates in the differential pressure detection state.
In this state, the whole circuit can form two power supply loops, the non-inverting input end of the differential amplifier U1 obtains the voltage of the positive electrode of the vehicle-mounted high-voltage charging pack through the resistor R1B and the resistor R2B, and the inverting input end obtains the voltage of the positive electrode of the vehicle-mounted high-voltage charging pack through the resistor R1A and the resistor R2A, so that the voltage of the output signal of the differential amplifier U1 in this case can represent the voltage difference between the charging port and the vehicle-mounted high-voltage battery pack, namely, the voltage difference between two ends of the relay RLY _ QC +, and because the non-inverting input end of the differential amplifier U1 is connected with the bias voltage, the difference between the voltage magnitude of the output signal of the differential amplifier U1 and the bias voltage is the voltage difference between the charging port and the vehicle-mounted high-voltage battery pack through certain numerical value conversion.
Referring to fig. 8, when a certain voltage difference exists between the charging port and the vehicle-mounted high voltage battery pack, the output voltage of the differential amplifier is linearly changed, and the voltage signal read by the corresponding main control unit is also changed, so that the voltage difference between the two ends of the relay can be judged by reading the real-time voltage sampling signal, and the impulse current generated at the moment of closing the relay can be effectively reduced by setting a certain judgment range and setting the relay closing condition according to different relay parameters.
According to the invention, when the differential pressure at two ends of the relay is greater than 5V according to the specification parameters of the relay, reporting that the differential pressure fault does not close the relay RLY _ QC +, and when the differential pressure at two ends of the relay RLY _ QC + is less than 5V, normally closing the relay RLY _ QC +.
Since the impact current is emitted by the positive electrode of the charging port, the differential pressure is judged by closing the relay RLY _ QC-, under the condition that the impact current is not considered, the relay RLY _ QC + and the relay RLY1 can be closed, the fixed ends of the relay RLY2A and the relay RLY2B are connected to the second movable end to obtain the differential pressure at two ends of the relay RLY _ QC-, and the working principle of the differential pressure acquisition method is the same as that of the differential pressure at two ends of the relay RLY _ QC +, so that the differential pressure acquisition method is not repeated.
Referring to fig. 9, the overall control flow of the present invention is mainly divided into 4 stages, a triggering stage, a control and adhesion detection stage, a pressure difference detection stage, and a state reporting stage.
A triggering stage: the control instruction used for judging the relay determines whether to enter an adhesion detection state;
and (3) control and adhesion detection stages: performing corresponding adhesion detection judgment according to a control instruction of the relay, and if a closing instruction of the relay is received, directly entering adhesion state detection; if the received command is a switching-off command of the relay, firstly controlling the switching-off of the relay and then detecting the adhesion state of the relay;
a differential pressure detection stage: when the relay needs to be closed and adhesion detection is completed without failure, performing pressure difference detection, and determining whether to close the relay RLY _ QC + according to the state of the pressure difference detection;
and a state reporting stage: and reporting the relay state (open, closed and fault) according to the requested state and the detected state, and reporting the relay state (open and closed) according to the control state.
Compared with the prior art, the invention has at least the following beneficial effects:
1. the invention adopts a circuit form that a group of associated action relays, associated sampling resistors and operational amplifiers form a Wheatstone bridge, thereby increasing the detection precision and efficiency of the circuit, and the tiny pressure difference change can be identified and judged;
2. when the relay adhesion and the pressure difference detection are not carried out, the device is in a default non-detection state, and the pressure difference detection circuit is in a dormant state, so that the static current loss of the new energy automobile can be effectively reduced;
3. when the relay is adhered and the voltage difference is detected, the relay is not influenced by residual voltage of a charging pile or voltage on a vehicle-mounted high-voltage charging pack, the influence of external voltage on the state judgment of the relay can be effectively avoided, the state of the relay can be effectively identified under various voltage regulation, and a motor of the relay is effectively protected from being damaged;
4. the differential pressure detection circuit adopts a group of associated action relays, when one relay breaks down, the judgment of the other relay is not influenced, and the state judgment of the two relays is independent and not influenced;
5. according to the invention, the pressure difference at two ends of the relay is detected before the relay is closed, and when the pressure difference at two ends of the relay is lower than a certain threshold value, the high-voltage relay is closed, so that the impact current generated at the moment of closing the high-voltage relay can be effectively reduced, and the controller and the motor are protected from being damaged.
The above description is only for the purpose of illustrating the preferred embodiments of the present invention and is not to be construed as limiting the invention, and any modifications, equivalents and improvements made within the spirit and principle of the present invention are intended to be included within the scope of the present invention.
Claims (10)
1. The utility model provides an adhesion and pressure difference detection circuitry of relay, includes the on-vehicle high pressure package that charges that is connected with the port of charging, locates charge the positive relay of the positive pole department of port and locate charge the negative relay of the negative pole department of port, its characterized in that, still including locating charge the port with on-vehicle high pressure charge difference detection circuitry between the package, switch the switching circuit and the control of difference detection circuitry detection state the main control unit of switching circuit operating condition, the main control unit with difference detection circuitry's output is connected, and can be according to difference detection circuitry's output signal judges positive relay and the state of negative relay.
2. The stick and differential pressure detection circuit of claim 1 wherein the differential detection circuit comprises: the circuit comprises a resistor R1A, a resistor R2A, a resistor R3A, a resistor R4A, a resistor R5A, a resistor R6A, a resistor R1B, a resistor R2B, a resistor R3B, a resistor R4B, a resistor R5B, a resistor R6B and a differential amplifier U1;
the one end of resistance R3A is connected between the positive relay and the positive pole of on-vehicle high voltage battery package, other end series resistance R4A back ground connection, resistance R3B's one end is connected between the positive relay with on-vehicle high voltage battery package's positive pole, other end series resistance R4B back ground connection, resistance R5A one end is connected charge port's positive pole with between the positive relay, the other end is connected to switching circuit's first input, resistance R6A one end is connected charge port's negative pole with between the negative pole relay, the other end is connected to switching circuit's second input, resistance R1A one end is connected to switching circuit's first output, other end series resistance R2A back ground connection, resistance R5B one end is connected between the positive relay with on-vehicle high voltage battery package, the other end is connected to switching circuit's third input, resistance R6B one end is connected between the negative pole relay with on-vehicle high voltage battery package, the other end is connected to switching circuit's fourth input, resistance R1B one end is connected to switching circuit's second output, the other end is connected to switching circuit's second output, the resistor R2B is connected to between the negative pole of switching circuit's negative pole and the main control unit input, the inverting resistor R1B 2A, the inverting resistor B1B 2A is connected to the same phase of switching circuit is connected to the same phase of switching circuit.
3. The stick and differential pressure detection circuit of claim 2, further comprising a bias voltage setting circuit connected to the differential detection circuit, the bias voltage setting circuit comprising a resistor R7A, a resistor R7B;
one end of the resistor R7A is connected with a bias power supply, the other end of the resistor R7A is connected with the resistor R7B in series and then is grounded, the voltage between the resistor R7A and the resistor R7B is used as bias voltage, and the non-inverting input end of the differential amplifier U1 is further connected between the resistor R7A and the resistor R7B to obtain the bias voltage.
4. The adhesion and differential pressure detection circuit of claim 3, wherein the resistance of the resistor R7A is the same as the resistance of the resistor R7B.
5. The sticking and pressure difference detecting circuit according to claim 1, wherein the switching circuit includes a relay RLY1, a relay RLY2A, a relay RLY2B;
a first movable terminal of the relay RLY2A is connected to the differential detection circuit as a first input terminal of the switching circuit, a second movable terminal is connected to the differential detection circuit as a second input terminal of the switching circuit, a fixed terminal is connected to the first terminal of the relay RLY1, a second terminal of the relay RLY1 is connected to the differential detection circuit as a first output terminal of the switching circuit, a first movable terminal of the relay RLY2B is connected to the differential detection circuit as a third input terminal of the switching circuit, a second movable terminal is connected to the differential detection circuit as a fourth input terminal of the switching circuit, and a fixed terminal is connected to the differential detection circuit as a second output terminal of the switching circuit.
6. The adhesion and differential pressure detection circuit according to claim 5, further comprising a power supply circuit connected to the differential detection circuit and the main control unit, wherein the power supply circuit includes an auxiliary source conversion circuit and a voltage conversion circuit, and the power supply circuit supplies power to a differential amplifier U1 in the differential detection circuit when receiving the wake-up signal sent by the main control unit.
7. The adhesion and differential pressure detection circuit according to claim 6, wherein the main control unit is further connected to a battery management system of a vehicle-mounted system, and adjusts the conduction states of the positive relay, the negative relay, and the switching circuit according to a control instruction sent by the battery management system.
8. The sticking and pressure difference detection circuit as claimed in claim 7, wherein when the relay RLY1 is turned off, the main control unit controls the power supply circuit to be in a sleep state, and the differential detection circuit operates in a default state;
when the relay RLY1 is closed, the immovable end of the relay RLY2A is connected to the first movable end of the relay RLY1, and the immovable end of the relay RLY2B is connected to the first movable end of the relay RLY2B, the main control unit controls the power supply circuit to be in an awakening state, and the differential detection circuit works in a positive relay adhesion detection state;
when the relay RLY1 is closed, the immovable end of the relay RLY2A is connected to the second movable end of the relay RLY1, and the immovable end of the relay RLY2B is connected to the second movable end of the relay RLY2B, the main control unit controls the power supply circuit to be in a wake-up state, and the differential detection circuit works in a negative relay adhesion detection state.
9. The sticking and voltage difference detection circuit according to claim 8, wherein when the relay RLY1 and the negative relay are closed, the positive relay is opened, the fixed terminal of the relay RLY2A is connected to the first movable terminal thereof, and the fixed terminal of the relay RLY2B is connected to the first movable terminal thereof, the main control unit controls the power supply circuit to be in a wake-up state, and the differential detection circuit operates in a voltage difference detection state.
10. The sticking and voltage difference detecting circuit according to claim 9, wherein when the differential detecting circuit operates in a positive relay sticking detection state and a voltage of an output signal of the differential detecting circuit is equal to a bias given voltage, the positive relay sticks;
when the differential detection circuit works in a negative relay adhesion detection state and the voltage of an output signal of the differential detection circuit is equal to a bias given voltage, the negative relay is adhered;
when the differential detection circuit works in a differential pressure detection state, the difference between the voltage of the output signal of the differential detection circuit and the bias given voltage is converted into the differential pressure between the charging port and the vehicle-mounted high-voltage battery pack through a certain numerical value.
Priority Applications (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202211028361.8A CN115308591A (en) | 2022-08-25 | 2022-08-25 | Adhesion and pressure difference detection circuit of relay |
| PCT/CN2023/096128 WO2024041059A1 (en) | 2022-08-25 | 2023-05-24 | Adhesion detection and voltage difference measurement circuit for relay |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202211028361.8A CN115308591A (en) | 2022-08-25 | 2022-08-25 | Adhesion and pressure difference detection circuit of relay |
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| Publication Number | Publication Date |
|---|---|
| CN115308591A true CN115308591A (en) | 2022-11-08 |
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Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202211028361.8A Pending CN115308591A (en) | 2022-08-25 | 2022-08-25 | Adhesion and pressure difference detection circuit of relay |
Country Status (2)
| Country | Link |
|---|---|
| CN (1) | CN115308591A (en) |
| WO (1) | WO2024041059A1 (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2024041059A1 (en) * | 2022-08-25 | 2024-02-29 | 深圳威迈斯新能源股份有限公司 | Adhesion detection and voltage difference measurement circuit for relay |
Family Cites Families (11)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| KR102204099B1 (en) * | 2014-12-30 | 2021-01-18 | 한국단자공업 주식회사 | Method of checking state of pra |
| CN205941816U (en) * | 2016-07-07 | 2017-02-08 | 河北深海电器有限公司 | Detect circuit of high -pressure contactor contact state |
| CN106427614A (en) * | 2016-08-31 | 2017-02-22 | 天津市捷威动力工业有限公司 | System and method for total voltage sampling and relay diagnosis for battery system of electric vehicle |
| KR102042756B1 (en) * | 2016-10-10 | 2019-11-08 | 주식회사 엘지화학 | Diagnostic appratus and power system including the same |
| CN113281642A (en) * | 2017-02-23 | 2021-08-20 | 宁德时代新能源科技股份有限公司 | Relay diagnosis circuit |
| CN209417199U (en) * | 2018-12-29 | 2019-09-20 | 深圳市英威腾电动汽车驱动技术有限公司 | Detection circuit |
| CN215067144U (en) * | 2021-05-21 | 2021-12-07 | 惠州市德赛电池有限公司 | Relay adhesion detection circuit |
| CN113341310A (en) * | 2021-05-26 | 2021-09-03 | 力神动力电池系统有限公司 | High limit of battery system and low limit contactor adhesion detection circuitry |
| CN216956276U (en) * | 2022-01-21 | 2022-07-12 | 武汉千帆动力技术有限公司 | Device for judging state of multi-path high-voltage fuse and contactor |
| CN115091957A (en) * | 2022-05-31 | 2022-09-23 | 中国第一汽车股份有限公司 | Device and method for diagnosing contact state of high-voltage upper and lower electric contactors and vehicle |
| CN115308591A (en) * | 2022-08-25 | 2022-11-08 | 深圳威迈斯新能源股份有限公司 | Adhesion and pressure difference detection circuit of relay |
-
2022
- 2022-08-25 CN CN202211028361.8A patent/CN115308591A/en active Pending
-
2023
- 2023-05-24 WO PCT/CN2023/096128 patent/WO2024041059A1/en unknown
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2024041059A1 (en) * | 2022-08-25 | 2024-02-29 | 深圳威迈斯新能源股份有限公司 | Adhesion detection and voltage difference measurement circuit for relay |
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| WO2024041059A1 (en) | 2024-02-29 |
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