Relay adhesion detection circuit and method

Abstract

The invention relates to the technical field of relay fault detection, and discloses a relay adhesion detection circuit which specifically comprises a relay group which is provided with an output circuit used for being connected between a power battery and a load and a control circuit used for being connected with a relay group driving branch. The sampling circuit is connected to the output circuit and is used for sampling the output circuit to obtain sampling voltage; the BMU is used for judging whether the output circuit is adhered or not according to the voltage information of the sampling voltage and generating a fault signal when the judgment result is that the output circuit is adhered; according to the invention, adhesion fault detection of the relay set can be well realized.

Description

Technical Field

[0001] The present invention relates to the technical field of relay fault detection, and in particular to a relay adhesion detection circuit and method. Background Art

[0002] As the market share of new energy heavy-duty trucks continues to grow, their safety and reliability have become a major focus of the industry. Among them, power battery failure of new energy heavy-duty trucks is the main factor causing safety problems for new energy vehicles.

[0003] New energy heavy-duty trucks generally control the on and off of the high-voltage circuit where the power battery is located by driving high-voltage relays. If the main positive and negative relays in the high-voltage relays are stuck, the high-voltage circuit of the high-voltage relay will be unable to reduce the high voltage. When the high voltage is applied next time, the instantaneous high current generated by the high-voltage circuit will damage the relays and loads in the high-voltage circuit.

[0004] Existing relay adhesion detection control strategies usually try to detect a specific relay, and it is difficult to perform adhesion detection on relays of various circuits at the same time. For example, a fast charging relay adhesion detection circuit, method, device and vehicle with patent publication number CN 118393339 A describes a problem of adhesion detection of fast charging relays in the prior art. When an insulation detection circuit is used for insulation detection, at least one of the voltage at the fast charging port detected by the voltage sampling circuit, the voltage of the charging input positive terminal of the fast charging port to the ground, and the voltage of the charging input negative terminal of the fast charging port to the ground is obtained to determine whether the charging relay is adhered; however, this scheme does not take into account the adhesion problems of the main positive and negative relays, as well as the TMS relay, and cannot combine high voltage detection, insulation detection and relay adhesion detection. Summary of the invention

[0005] The present invention provides a relay adhesion detection circuit and method, which can overcome certain defects of the prior art.

[0006] To achieve the above objectives, the present invention proposes a relay adhesion detection circuit, which includes: A relay group having an output circuit for connecting between the power battery and the load and a control circuit for connecting to a drive branch of the relay group; A sampling circuit connected to the output circuit, which is used to sample the output circuit to obtain a sampled voltage; The battery management unit BMU is used to determine whether the output circuit is stuck according to the voltage information of the sampled voltage, and to generate a fault signal when the judgment result is sticking.

[0007] Based on the above, the adhesion fault detection of the relay group can be better achieved.

[0008] Preferably, the relay group includes a main positive relay KM1, a main negative relay KM2, a fast charging positive relay, a fast charging negative relay and a liquid cooling unit TMS relay KM7; the output circuits of the main positive relay KM1, the fast charging positive relay and the liquid cooling unit TMS relay KM7 are all connected to the positive pole of the power battery; the output circuit of the fast charging negative relay is connected to the negative pole of the power battery.

[0009] Based on the above, it is possible to better implement adhesion fault detection for multiple circuits and multiple types of relays at the same time.

[0010] Preferably, the sampling circuit includes a module unit HVB, and the input end of the module unit HVB is used to access the output circuit to obtain the sampled voltage, so that the sampling of the voltage at the output circuit can be better achieved.

[0011] Preferably, the battery management unit BMU includes a comparison circuit, which is used to compare the sampled voltage with a preset threshold voltage and to generate a fault signal when the sampled voltage is higher than the preset threshold voltage, so that the fault signal can be outputted in a timely manner when a sticking fault occurs.

[0012] Preferably, the battery management unit BMU further comprises an insulation detection circuit, which is connected to the positive electrode of the power battery and the negative electrode of the power battery respectively, so that the insulation detection of the high-voltage circuit can be better realized to ensure the stable operation of the circuit.

[0013] Preferably, the relay group further includes a pre-charging relay KM8, and the output circuit of the main positive relay KM1 is also connected in parallel with a pre-charging circuit, which includes a pre-charging resistor R1 and an output circuit of the pre-charging relay KM8 connected in sequence. Therefore, the load can be pre-charged before the high voltage is powered on.

[0014] Preferably, the battery management unit BMU and the module unit HVB both have a CAN communication interface, so that information transmission and storage between the battery management unit BMU and the module unit HVB can be better realized.

[0015] Preferably, the control circuit of the relay group is connected to the battery management unit BMU, so that the output circuit of each relay can be driven better.

[0016] Preferably, the fast charging positive relay includes a first fast charging positive relay KM3 and a second fast charging positive relay KM4; the fast charging negative relay includes a first fast charging negative relay KM5 and a second fast charging negative relay KM6. Therefore, it is possible to further implement adhesion fault detection for relays of multiple circuits.

[0017] To achieve the above object, the present invention proposes a relay adhesion detection method based on the above relay adhesion detection circuit, comprising: using any of the above relay adhesion detection circuits to perform relay adhesion detection. Based on the above, adhesion fault detection of a relay group can be preferably achieved. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 A circuit diagram of a relay adhesion detection circuit of Example 1; Figure 2 This is a flow chart of a relay adhesion detection method according to Example 1. DETAILED DESCRIPTION

[0019] In order to further understand the content of the present invention, the present invention is described in detail in conjunction with the embodiments. It should be understood that the embodiments are only for explaining the present invention and are not intended to limit it.

[0020] Example 1 As the market share of new energy heavy trucks continues to grow, their safety and reliability performance have become a major focus of the industry. Among them, power battery failure is the main factor leading to safety problems in new energy vehicles. High-voltage relays play a very important role in controlling the on and off of high-voltage circuits in electric heavy trucks. If the main positive and negative relays are stuck, it will cause the problem of being unable to lower the high voltage; if the vehicle's charging positive relay and charging negative relay are stuck at the same time, the charging port will be energized. Therefore, a method and control strategy that can simultaneously detect the main positive and negative relays and fast charging relays is needed.

[0021] Therefore, this embodiment provides a relay adhesion detection circuit. Figure 1 As shown, it includes: A relay group composed of multiple relays, which has an output circuit for connecting between the power battery and the load and a control circuit for connecting to the drive branch of the relay group; The sampling circuit connected to the output circuit is used to sample the output circuit to obtain a sampled voltage.

[0022] The battery management unit BMU is used to determine whether the output circuit is stuck according to the voltage information of the sampled voltage, and to generate a fault signal when the judgment result is sticking.

[0023] Based on the above, the adhesion fault detection of the relay group can be better achieved.

[0024] In this embodiment, the relay group includes a main positive relay KM1, a main negative relay KM2, a fast charging positive relay 1 KM3, a fast charging positive relay 2 KM4, a fast charging negative relay 1 KM5, a fast charging negative relay 2 KM6 and a liquid cooling unit TMS relay KM7; the output circuits of the main positive relay KM1, the fast charging positive relay and the liquid cooling unit TMS relay KM7 are all connected to the positive electrode of the power battery; the output circuit of the fast charging negative relay is connected to the negative electrode of the power battery.

[0025] Furthermore, the main positive relay KM1 is connected to the load HV+, the main negative relay KM2 is connected to the load HV-, the fast charging positive relay KM3 is connected to the load CH1+, the fast charging positive relay KM4 is connected to the load CH2+, the fast charging negative relay KM5 is connected to the load CH1-, the fast charging negative relay KM6 is connected to the load CH2-, the liquid cooling unit TMS relay KM7 is connected to the load TMS, and the output circuit of the pre-charging relay KM8 is connected in parallel to the output circuit of the main positive relay KM1.

[0026] Based on the above, it is possible to better implement adhesion fault detection for multiple circuits and multiple types of relays at the same time.

[0027] The positive pole of the power battery is connected to the main positive relay KM1, and its pre-charging circuit includes pre-charging resistor R1 and pre-charging relay KM8 connected in parallel with the main positive circuit. During the high-voltage power-on process, it is necessary to pre-charge other capacitive load components of the vehicle through the power battery and the pre-charging circuit to protect the high-voltage components from damage. The negative pole of the power battery is connected to the main negative relay.

[0028] In this embodiment, the fast charging positive relay includes a first fast charging positive relay KM3 and a second fast charging positive relay KM4; the fast charging negative relay includes a first fast charging negative relay KM5 and a second fast charging negative relay KM6. Therefore, it is possible to further implement adhesion fault detection for relays of multiple circuits.

[0029] In this embodiment, the sampling circuit includes a module unit HVB, and the input end of the module unit HVB is used to access the output circuit to obtain the sampling voltage. Specifically, Figure 1The module unit HVB samples the voltage of the main positive relay KM1 and the main negative relay KM2 through loops 11 and 15; samples the voltage of the TMS liquid cooling unit relay KM7 through loop 12; samples the voltage of the fast charging positive relay KM3, the fast charging positive relay KM4, the fast charging negative relay KM5 and the fast charging negative relay 2KM6 through loops 13, 14, 16 and 17 respectively. The input end of the module unit HVB is connected to the main positive relay KM1, the main negative relay KM2, the first fast charging positive relay KM3; the second fast charging positive relay KM4, the first fast charging negative relay KM5, the second fast charging negative relay KM6 and the No. 2 position of the contact of the liquid cooling unit TMS relay KM7, respectively, and can sample the voltage of the No. 2 position of the contact in the output circuit corresponding to each relay. Therefore, the sampling of the voltage at the output circuit can be better achieved.

[0030] In this embodiment, the battery management unit BMU receives the relay voltage information read by the module unit HVB to determine whether the relay is stuck and send a fault signal. The specific judgment method is based on the comparison circuit in the battery management unit BMU. The comparison circuit can compare the sampled voltage with the preset threshold voltage. The comparison circuit can also generate a fault signal when the sampled voltage is higher than the preset threshold voltage. Therefore, it is better to output the fault signal in time when a sticking fault occurs.

[0031] In this embodiment, the battery management unit BMU may also include an insulation detection circuit, which is connected to the positive electrode of the power battery and the negative electrode of the power battery respectively, and can be used as a trigger source to detect whether the fast charging relay, the main positive and negative relays, and the liquid cooling unit relay are sticking. Therefore, the insulation detection of the high-voltage circuit can be better realized to ensure the stable operation of the circuit.

[0032] During the high-voltage power-on process, it is necessary to pre-charge other capacitive load components of the vehicle through the power battery and the pre-charging circuit to protect the high-voltage components from damage. Therefore, in this embodiment, the relay group may also include a pre-charging relay KM8, and the output circuit of the main positive relay KM1 may also be connected in parallel with a pre-charging circuit, which includes a pre-charging resistor R1 and an output circuit of the pre-charging relay KM8 connected in sequence. Therefore, it is possible to preferably pre-charge the load before the high-voltage power-on.

[0033] In this embodiment, the battery management unit BMU and the module unit HVB both have a CAN communication interface, and the battery management unit BMU performs system insulation detection, and the battery management unit BMU receives the relay voltage information read by the HVB module unit to determine whether the relay is stuck and issue a fault information alarm. Based on the above, information transmission and storage between the battery management unit BMU and the module unit HVB can be better realized.

[0034] In this embodiment, the control circuits of the relay group, namely the main positive relay KM1, the main negative relay KM2, the fast charge positive relay, the fast charge negative relay, the liquid cooling unit TMS relay KM7 and the pre-charge relay KM8, are all connected to the battery management unit BMU. Therefore, the output circuits of each relay can be driven preferably.

[0035] To achieve the above objectives, combined Figure 2 The present embodiment further proposes a relay adhesion detection method based on the aforementioned relay adhesion detection circuit, and the specific steps of the method are as follows: Step 101: Detect the system insulation through the battery management unit BMU; Step 102: If the system insulation fails, the module unit HVB samples the sampled voltage of each circuit of the relay group, and sends the sampled voltage to the battery management unit BMU through the CAN communication interface; Step 103: Analyze the sampled voltage through the software judgment logic of the battery management unit BMU, and judge the relay that has adhesion in the relay group.

[0036] Combination Figure 2 As shown, in this embodiment, the insulation of the entire system can be detected by the battery management unit BMU. If there is a problem with the insulation of the entire system, the voltage of each relay circuit is sampled in step 102, and the sampled voltage is sent to the battery management unit BMU through step 103. The faulty relay is determined through software / hardware logic, so rapid maintenance can be achieved.

[0037] If the relays in the relay group are stuck, the fault information will be stored in the system. Before the system goes high voltage next time, the battery management unit BMU will determine whether there is relay sticking fault information. If the fault information is stored, the high voltage operation will not be performed.

[0038] It is easy to understand that those skilled in the art can combine, split, reorganize, etc. the embodiments of the present application to obtain other embodiments based on one or several embodiments provided in the present application, and these embodiments do not exceed the protection scope of the present application.

[0039] The present invention and its implementation methods are described schematically above, and the description is not restrictive. The embodiments shown in the embodiments are only part of the implementation methods of the present invention, and the actual structure is not limited thereto. Therefore, if a person skilled in the art is inspired by the embodiments and designs a structure and an implementation method similar to the technical solution without creativity without departing from the purpose of the invention, they should all fall within the protection scope of the present invention.

Claims

1. A relay adhesion detection circuit, characterized in that: include: A relay group having an output circuit for connecting between the power battery and the load and a control circuit for connecting to a drive branch of the relay group; A sampling circuit connected to the output circuit, which is used to sample the output circuit to obtain a sampled voltage; The battery management unit BMU is used to determine whether the output circuit is stuck according to the voltage information of the sampled voltage, and to generate a fault signal when the judgment result is sticking.

2. A relay adhesion detection circuit according to claim 1, characterized in that: The relay group includes the main positive relay KM1, the main negative relay KM2, the fast charging positive relay, the fast charging negative relay and the liquid cooling unit TMS relay KM7; the output circuits of the main positive relay KM1, the fast charging positive relay and the liquid cooling unit TMS relay KM7 are all connected to the positive pole of the power battery; the output circuit of the fast charging negative relay is connected to the negative pole of the power battery.

3. A relay adhesion detection circuit according to claim 1, characterized in that: The sampling circuit comprises a module unit HVB, and an input end of the module unit HVB is used to access an output circuit to obtain a sampling voltage.

4. A relay adhesion detection circuit according to claim 3, characterized in that: The battery management unit BMU includes a comparison circuit, which is used to compare the sampled voltage with a preset threshold voltage and to generate a fault signal when the sampled voltage is higher than the preset threshold voltage.

5. A relay adhesion detection circuit according to claim 4, characterized in that: The battery management unit BMU further includes an insulation detection circuit, which is connected to the positive electrode of the power battery and the negative electrode of the power battery respectively.

6. A relay adhesion detection circuit according to claim 2, characterized in that: The relay group also includes a pre-charging relay KM8. The output circuit of the main positive relay KM1 is also connected in parallel with a pre-charging circuit. The pre-charging circuit includes a pre-charging resistor R1 and an output circuit of the pre-charging relay KM8 connected in sequence.

7. A relay adhesion detection circuit according to claim 2, characterized in that: Both the battery management unit BMU and the module unit HVB have CAN communication interfaces.

8. A relay adhesion detection circuit according to claim 6, characterized in that: The control circuit of the relay group is connected to the battery management unit BMU.

9. A relay adhesion detection circuit according to claim 2, characterized in that: The fast charging positive relay includes a first fast charging positive relay KM3 and a second fast charging positive relay KM4; the fast charging negative relay includes a first fast charging negative relay KM5 and a second fast charging negative relay KM6.

10. A relay adhesion detection method, characterized in that: A relay adhesion detection circuit according to any one of claims 1 to 9 is used to perform relay adhesion detection, and the steps of the relay adhesion detection are as follows: Step 101: Testing the system insulation through the battery management unit BMU; Step 102: If the system insulation fault by the module unit HVB sampling relay group sampling voltage of each circuit, and the sampled voltage is sent to the battery management unit BMU via the CAN communication interface; Step 103: Analyze the sampled voltage through the software judgment logic of the battery management unit BMU, and judge the relays in the relay group that are stuck.

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