Relay control method and system
By introducing dual power supply, monitoring and control modes into the relay of the power battery system, and combining the communication between the battery management unit BMU and the backup controller, the problem of abnormal disconnection of the relay is solved, and the relay is reliable operation in abnormal situations is achieved, and the power system safety of the aircraft is improved.
Patent Information
- Application Number
- CN202411978749.3
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-12-31
- Publication Date
- 2025-04-11
AI Technical Summary
In the field of aviation technology, relays in power battery systems are prone to abnormal disconnection or failure to disconnect as expected, resulting in aircraft power degradation or insufficient power, and may even affect the normal operation of other subpackets, causing catastrophic impact.
A relay control method and system is designed. By introducing two power interfaces, two voltage monitoring interfaces, two control interfaces and one grounding wire into the relay, and connecting it with the battery management unit BMU and the backup controller, the dual power supply, dual monitoring and dual control modes of the relay are realized. The system determines whether the backup controller works on the relay by determining whether the flight controller receives a thermal event signal, whether the communication function of the battery management unit BMU is intact, and other indicators, and ensures that the relay performs the action correctly in abnormal situations.
It realizes ensuring that the relay can perform the correct closing or disconnection work in different scenarios, enhances the reliability of the relay, prevents false restarts after thermal events, and improves the safety of the power system of the aircraft.
Smart Images
Figure CN119805969A_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to the field of aviation technology, and in particular to a relay control method and system. Background Art
[0002] Due to the high safety and reliability requirements in the field of aviation technology, the power battery system is generally composed of 4 to 12 sub-packs. Among them, the main positive / main negative relay arranged in the power circuit is a very critical device. The relay is driven by the drive coil, closes when the battery pack is discharged, and opens under high voltage. It is an important part of the battery function.
[0003] There are two main problems with relays: abnormal disconnection and failure to disconnect as expected. The normal closing and disconnection of the relay is not only affected by its own model and product quality, but also by the relay power supply circuit, wiring harness circuit, and battery management system. If the relay on the power circuit is abnormally disconnected, the corresponding sub-package cannot output power, which will cause the aircraft power to be degraded or insufficient. If all the relays on the main circuit are stuck (cannot be disconnected), the high voltage of the faulty package cannot be actively cut off after a thermal event occurs. Affected by the system architecture, it may affect the normal operation of other sub-packages and have a catastrophic impact on the entire machine.
[0004] In some scenarios, if the battery management system or flight controller cannot accurately know whether a power outage event or a thermal event has occurred, a complete solution is needed to ensure that the relay performs the correct action to ensure flight safety. Based on this, the present invention designs a relay control method and system to solve the above problem. Summary of the invention
[0005] In view of the above-mentioned shortcomings of the prior art, the present invention provides a relay control method and system to ensure that the relay correctly and reliably performs corresponding actions when an abnormality occurs, thereby ensuring the functional safety of the power battery and the aircraft.
[0006] To achieve the above objectives, the present invention is implemented through the following technical solutions:
[0007] A relay control system includes a relay, two power supply interfaces, two voltage monitoring interfaces, two control interfaces, a grounding wire, a battery management unit BMU and a backup controller; the two voltage monitoring interfaces are used to detect the power supply voltage of the internal coil of the relay;
[0008] Each relay is connected to two power supply interfaces, two voltage monitoring interfaces, two control interfaces and a ground wire, and the ground wire is connected to the interface of the battery management unit BMU through a wiring harness; the wiring harness of the power supply interface, voltage monitoring interface and control interface is divided into two, and one end is connected to the interface of the battery management unit BMU of the corresponding sub-pack, and the other end is connected to the interface of the backup controller; the battery management unit BMU and the backup controller are communicated with each other.
[0009] Furthermore, the backup controller is a battery management unit BMU of other sub-packs, or a battery system controller BSC.
[0010] In order to better achieve the purpose of the present invention, the present invention also provides a relay control method, comprising the following steps:
[0011] Step 1: If the relay on the main circuit of a sub-package is in the disconnected state, first determine whether the flight controller has received the thermal event signal uploaded by the battery management unit BMU; if so, it means that a thermal event has occurred, and the backup controller does not work on the relay; if not, proceed to step 2;
[0012] Step 2: Determine whether the current battery management unit BMU communication function is intact, which is achieved by determining whether the battery management unit BMU communication function continues to work. If so, it indicates that the relay disconnection is a typical power interruption event, and the backup controller controls the relay to restart; if not, proceed to step 3;
[0013] Step 3: Determine whether any of the following indicators are met within P seconds before the battery management unit BMU communication is lost:
[0014] 1) The battery cell temperature exceeds the maximum safety application limit specified by the manufacturer for L seconds;
[0015] 2) The cell temperature rises by 1°C / s for N seconds;
[0016] 3) Cell voltage <1.5V, last for M seconds;
[0017] 4) System insulation failure occurs;
[0018] 5) The sampling line is disconnected;
[0019] If yes, it means that the battery has a high probability of a thermal event, and the backup controller will not work on the relay;
[0020] If not, the backup controller controls the relay to restart.
[0021] Furthermore, if any of the following situations occurs, the relay is judged to be in the disconnected state:
[0022] A. |Relay coil voltage|<|Relay minimum operating voltage|;
[0023] B. |The absolute value of the voltage at one end of the relay - the absolute value of the voltage at the other end of the relay|>max(10%*the maximum working voltage of the battery, 10V).
[0024] Furthermore, in step A, the relay coil voltage = the relative voltage between the voltage monitoring interface A and the voltage monitoring interface B.
[0025] Furthermore, in step B, the absolute value of the voltage at one end of the relay minus the absolute value of the voltage at the other end of the relay=the absolute value of the relative voltage between U1 and U3 minus the absolute value of the relative voltage between U2 and U3.
[0026] Furthermore, in step 3, P takes the value of 30.
[0027] Furthermore, in step three, L, N, and M are all 3.
[0028] Compared with the prior art, the present invention has the following beneficial effects: the present invention can determine whether the backup controller works on the relay in different scenarios for the abnormal disconnection of the relay, and prevent the backup controller from mistakenly restarting the relay after the battery management unit BMU cuts off the relay after a thermal event occurs. The relay can reliably perform the correct closing or disconnection work in various scenarios, thereby enhancing reliability. BRIEF DESCRIPTION OF THE DRAWINGS
[0029] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the prior art descriptions. Obviously, the drawings described below are only some embodiments of the present invention, and for ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.
[0030] Figure 1 This is a schematic diagram of the connection results of the relay control system;
[0031] Figure 2 is a flow chart of a relay control method in an emergency;
[0032] Figure 3 It is the method of collecting the voltage at the relay terminal. Figure 3 In the diagram, the module is a series-parallel combination of battery cells. It is the energy source of the battery sub-pack and is only a part of the battery sub-pack. Module + BMS (battery management system) + wiring harness + BDU (battery pack disconnect unit) + structural parts, etc. = battery sub-pack. DETAILED DESCRIPTION
[0033] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.
[0034] Embodiment 1: In some embodiments, please refer to the drawings of the specification Figure 1 A relay control system includes a relay, two power supply interfaces (power supply interface A, power supply interface B), two voltage monitoring interfaces (voltage monitoring interface A, voltage monitoring interface B, used to detect the power supply voltage of the internal coil of the relay (i.e., 12V or 24V voltage)), two control interfaces (control interface A, control interface B), a ground wire, a battery management unit BMU (Battery Management Unit) and a standby controller; the two voltage monitoring interfaces are used to detect the power supply voltage of the internal coil of the relay;
[0035] Each relay of the main power circuit is connected to two power supply interfaces, two voltage monitoring interfaces, two control interfaces and a ground wire to realize the dual-way power supply, dual-way monitoring and dual-way control mode of the relay; the ground wire is connected to the interface of the battery management unit BMU (Battery Management Unit) through the wiring harness; the low-voltage wiring harness of the power supply interface, voltage monitoring interface and control interface is split into two, and one end is connected to the interface of the battery management unit BMU of the corresponding sub-pack, and the other end is connected to the interface of the standby controller;
[0036] The standby controller may be a battery management unit BMU of other sub-packs, or a battery system controller BSC (Battery System Controller, responsible for coordinating and aggregating information of various battery management units BMU).
[0037] The communication connection between the battery management unit BMU and the backup controller is used to realize the action control of the relay and reduce the risk.
[0038] Embodiment 2: In some embodiments, Figure 2 As shown, a relay control method comprises the following steps:
[0039] Step 1: If any of the following situations occurs, the relay is judged to be in the disconnected state:
[0040] A. |Relay coil voltage| (i.e. the absolute value of the relative voltage between voltage monitoring interface A and voltage monitoring interface B) < |relay minimum operating voltage|;
[0041] B. |absolute value of voltage at one end of relay - absolute value of voltage at the other end of relay|>max(10%*maximum working voltage of battery, 10V);
[0042] For example Figure 3 , |the absolute value of the relative voltage between U1 and U3 - the absolute value of the relative voltage between U2 and U3|>max(10%*the maximum working voltage of the battery, 10V);
[0043] Step 2: If the relay on the main circuit of a sub-package is in the disconnected state, first determine whether the flight controller has received the thermal event signal uploaded by the battery management unit BMU; if so, it means that a thermal event has occurred, and the backup controller does not work on the relay; if not, proceed to step 3;
[0044] In order to identify whether the main circuit disconnection is a passive result after a thermal event (thermal runaway of series cells, disconnection of the high-voltage circuit) or an active result (the BMS actively cuts off the relay after a thermal event occurs), if the flight controller receives a thermal event signal uploaded by the battery management unit BMU, indicating that a thermal event has occurred, the backup controller will not work on the relay to prevent the scenario where it should be disconnected from being unable to disconnect; if the flight controller does not receive a thermal event signal uploaded by the battery management unit BMU, it is necessary to further determine the reason for the relay disconnection.
[0045] Step 3: Determine whether the current battery management unit BMU communication function is intact, which is achieved by determining whether the battery management unit BMU communication function continues to work. If so, it indicates that the relay disconnection is a typical power interruption event, and the backup controller controls the relay to restart; if not, proceed to step 4;
[0046] If the battery management unit BMU does not upload a thermal event signal and the communication function is intact, it indicates that the relay disconnection is a typical power interruption event, and the backup controller should restart the relay. If the battery management unit BMU does not upload a thermal event signal and the communication function is lost, it is necessary to further determine the cause of the relay disconnection.
[0047] Step 4: Determine whether any of the following indicators are met within 30 seconds before the battery management unit BMU communication is lost:
[0048] 1) The battery cell temperature (generally collected by a thermistor) exceeds the maximum safety application limit specified by the manufacturer for 3 seconds;
[0049] 2) The cell temperature rises by 1°C / s for 3s;
[0050] 3) Battery cell voltage <1.5V, special duration 3s;
[0051] 4) System insulation failure occurs;
[0052] 5) A sampling line disconnection failure occurs.
[0053] If yes, it means that the battery has a high probability of a thermal event, and the backup controller will not work on the relay;
[0054] If not, the backup controller controls the relay to restart.
[0055] When the battery management unit BMU does not upload a thermal event signal and the communication function is lost, and further diagnosis is needed to determine whether a thermal event has occurred, the devices or harnesses on the entire functional link of acquisition, diagnosis, and signal upload are affected by the thermal event. Therefore, the present invention adds diagnostic logic: determine whether any of the following indicators are met within 30 seconds before the battery management unit BMU communication is lost: 1) The battery cell temperature exceeds the maximum safety application upper limit specified by the manufacturer and lasts for 3 seconds; 2) The battery cell temperature rises by 1°C / s and lasts for 3 seconds; 3) The battery cell voltage is <1.5V, especially for 3 seconds; 4) A system insulation fault occurs; 5) A sampling line disconnection fault occurs. If any of the above indicators exists, it indicates that the battery is likely to have a thermal event, and the backup controller does not work on the relay. If none of the above indicators exist, the backup controller should restart the relay.
[0056] The present invention can determine whether the backup controller works on the relay in different scenarios for abnormal disconnection of the relay, and prevent the backup controller from restarting the relay by mistake after the battery management unit BMU cuts off the relay after a thermal event occurs. The relay can reliably perform the correct closing or disconnection work in various scenarios, thereby enhancing reliability.
[0057] The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit the same. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that the technical solutions described in the aforementioned embodiments may still be modified, or some of the technical features may be replaced by equivalents. Such modifications or replacements will not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.
Claims
1. A relay control system, characterized in that: It includes a relay, two power supply interfaces, two voltage monitoring interfaces, two control interfaces, a ground wire, a battery management unit BMU and a backup controller; the two voltage monitoring interfaces are used to detect the power supply voltage of the internal coil of the relay; Each relay is connected to two power supply interfaces, two voltage monitoring interfaces, two control interfaces and a ground wire, and the ground wire is connected to the interface of the battery management unit BMU through a wiring harness; The wiring harness of the power interface, voltage monitoring interface and control interface is divided into two, one end of which is connected to the interface of the battery management unit BMU of the corresponding sub-pack, and the other end is connected to the interface of the backup controller; the battery management unit BMU and the backup controller are communicated with each other.
2. The relay control system according to claim 1, characterized in that: The backup controller is a battery management unit BMU of other subpacks, or a battery system controller BSC.
3. A relay control method, characterized in that: The following steps are involved: Step 1: If the relay on the main circuit of a sub-package is in the disconnected state, first determine whether the flight controller has received the thermal event signal uploaded by the battery management unit BMU; if so, it means that a thermal event has occurred, and the backup controller does not work on the relay; if not, proceed to step 2; Step 2: Determine whether the current battery management unit BMU communication function is intact, which is achieved by determining whether the battery management unit BMU communication function continues to work. If so, it indicates that the relay disconnection is a typical power interruption event, and the backup controller controls the relay to restart; if not, proceed to step 3; Step 3: Determine whether any of the following indicators are met within P seconds before the battery management unit BMU communication is lost: 1) The battery cell temperature exceeds the maximum safety application limit specified by the manufacturer for L seconds; 2) The cell temperature rises by 1°C / s for N seconds; 3) Cell voltage <1.5V, last for M seconds; 4) System insulation failure occurs; 5) The sampling line is disconnected; If yes, it means that the battery has a high probability of a thermal event, and the backup controller will not work on the relay; If not, the backup controller controls the relay to restart.
4. The relay control method according to claim 3, characterized in that: If any of the following situations occurs, the relay is judged to be in the disconnected state: A. |Relay coil voltage|<|Relay minimum operating voltage|; B. |Absolute value of the voltage at one end of the relay - absolute value of the voltage at the other end of the relay|>max(10%*maximum operating voltage of the battery, 10V).
5. The relay control method according to claim 4, characterized in that: In step A, the relay coil voltage = the relative voltage between the voltage monitoring interface A and the voltage monitoring interface B.
6. The relay control method according to claim 5, characterized in that: In step B, the absolute value of the voltage at one end of the relay - the absolute value of the voltage at the other end of the relay = the absolute value of the relative voltage between U1 and U3 - the absolute value of the relative voltage between U2 and U3.
7. The relay control method according to claim 6, characterized in that: In step 3, P takes the value of 30.
8. The relay control method according to claim 7, characterized in that: In step 3, L, N, and M are set to 3.