Temperature protection method and system for oil-cooled electric drive device

Abstract

The present invention discloses a temperature protection method and system for an oil-cooled electric drive device, relating to the field of new energy vehicles. The method comprises: obtaining the state of the drive motor of the oil-cooled electric drive device, determining whether the lubricating oil temperature is abnormal when the motor is overheated; determining whether the cooling system has failed based on the oil temperature and coolant flow rate; determining whether the temperature detection system of the drive motor and motor controller has failed when the cooling system is normal; and determining whether the cooling accessories are normal; and selecting different vehicle operation modes according to different fault states. By collecting the temperature of the oil-cooled electric drive device, the present invention can self-diagnose temperature faults of the electric drive device and the vehicle cooling system when the vehicle cooling system fails, and can also perform fault protection to ensure safe driving of the vehicle.

Description

Technical Field

[0001] The present invention relates to the field of new energy vehicles, and in particular to a temperature protection method and system for an oil-cooled electric drive device. Background Art

[0002] Currently, existing oil-cooled electric drive systems have a relatively simple temperature acquisition signal, typically consisting of a single motor temperature sensor. Furthermore, there is no temperature monitoring of the cooling oil, and no consideration is given to the coordinated protection between the electric drive system and the cooling system. When a temperature fault occurs in an oil-cooled electric drive system, the vehicle typically shuts off power without any proper analysis or handling of the fault. Consequently, no safe and effective driving strategy is employed to ensure the safety of the electric drive system, the vehicle, and its occupants.

[0003] For example: CN113978223A discloses an electric drive system and its heat control method, which controls the speed of the water pump to the required water pump speed according to the temperature of the motor controller; obtains the operating parameters of the motor, and obtains the heat generated by the motor according to the operating parameters; obtains the target lubricating oil amount according to the heat generated by the motor, the temperature of the lubricating oil in the oil pan of the reducer, and the temperature of the water-cooling liquid in the radiator; and controls the speed of the oil pump to the required oil pump speed according to the target lubricating oil amount.

[0004] Although the above scheme involves the acquisition of parameters such as lubricating oil temperature, water coolant temperature, and heat generated by the motor, it is still a one-way temperature detection for the motor; and the data obtained can only achieve the purpose of heat control and cannot change the vehicle operating status in response to fault conditions. Summary of the Invention

[0005] In view of the shortcomings of the existing technology, the purpose of the present invention is to provide a temperature protection method and system for an oil-cooled electric drive device. By collecting the temperature of the oil-cooled electric drive device, when the cooling system of the entire vehicle fails, the electric drive device and the entire vehicle cooling system can be self-diagnosed for temperature faults, and fault protection can be performed to ensure safe driving of the entire vehicle.

[0006] In order to achieve the above object, the present invention is implemented through the following technical solutions:

[0007] In a first aspect, an embodiment of the present invention provides a temperature protection method for an oil-cooled electric drive device, comprising:

[0008] Obtain the status of the drive motor of the oil-cooled electric drive device and determine whether the lubricating oil temperature is abnormal when the motor is overheated;

[0009] Determine whether the cooling system is faulty based on the oil temperature and coolant flow rate; if the cooling system is normal, determine whether the temperature detection system of the drive motor and motor controller itself is faulty; and determine whether the cooling accessories are normal;

[0010] Select different vehicle operation modes according to different fault conditions.

[0011] As a further implementation method, the winding temperature or stator slot temperature of the oil-cooled electric drive device is obtained. When the winding temperature or stator slot temperature is less than a set threshold value of the motor, the vehicle operates normally;

[0012] When the winding temperature or the stator slot temperature is greater than or equal to the motor setting threshold, it is determined whether the lubricating oil temperature is greater than the oil temperature setting threshold.

[0013] As a further implementation method, when the lubricating oil temperature is greater than or equal to a set threshold, it is detected whether the coolant flow rate of the vehicle cooling system is normal.

[0014] As a further implementation, when the coolant flow rate is abnormal, it is determined whether the water pump is faulty;

[0015] In the event of a water pump failure, the vehicle operates in mode three;

[0016] If the water pump is normal, the vehicle will also operate in mode 3 and the coolant capacity will be tested at the same time;

[0017] Among them, the mode three is the setting ratio continuous external characteristic operation.

[0018] As a further implementation, when the coolant flow is normal, the oil pump fault state is detected;

[0019] When the oil pump fails, the vehicle operates in Mode 2, which is continuous operation within the external characteristics.

[0020] When the oil pump has no faults, perform internal oil circuit inspection on the entire oil-cooled drive unit.

[0021] As a further implementation, when the lubricating oil temperature is less than the oil temperature threshold, the motor controller checks whether the change rates of the winding temperature and the stator slot temperature are both abnormal.

[0022] As a further implementation method, when the rates of change of the winding temperature and the stator slot temperature are not abnormal at the same time, the vehicle still operates in mode 1; wherein mode 1 operates within the peak external characteristics;

[0023] When the rates of change of the winding temperature and the stator slot temperature are both abnormal, the vehicle operates in mode three and the motor controller is tested at the same time.

[0024] In a second aspect, an embodiment of the present invention further provides a temperature protection system for an oil-cooled electric drive device, comprising a three-in-one electric drive system, wherein the three-in-one electric drive system is equipped with a temperature acquisition system, wherein the temperature acquisition system comprises a winding temperature sensor for collecting the temperature of the motor stator winding, a stator slot temperature sensor for collecting the temperature of the motor stator slot, and an oil temperature sensor for collecting the temperature of the lubricating oil.

[0025] As a further implementation, the three-in-one electric drive system is connected to a cooling system, and a flow rate sensor is provided in the cooling system.

[0026] As a further implementation, the winding temperature sensor is installed at the end of the motor stator winding, the stator slot temperature sensor is installed in the middle of the motor stator slot, and the oil temperature sensor is installed in the reducer cavity.

[0027] The beneficial effects of the present invention are as follows:

[0028] (1) The present invention determines whether the lubricating oil temperature is abnormal when the drive motor is overheated, and determines whether the cooling system has failed based on whether the oil temperature and coolant flow rate are abnormal; when the cooling system is normal, it detects and determines whether the temperature detection system of the drive motor and the motor controller itself has failed, and finally determines whether the cooling accessories such as the coolant capacity are normal; based on the fault status of the above-mentioned components, the entire vehicle is promptly operated in different safe and effective driving modes, thereby protecting the safety of the oil-cooled electric drive device, the cooling system and the entire vehicle.

[0029] (2) The present invention sets three operating modes, namely, operation within the peak external characteristics, operation within the continuous external characteristics, and operation with a set proportion of continuous external characteristics. By judging different fault forms, the whole vehicle is operated according to the corresponding mode to ensure the safety of the whole vehicle.

[0030] (3) The driving motor in the oil-cooled electric drive device of the present invention includes two temperature sensors, which perform redundant monitoring of the motor temperature. At the same time, a flow rate sensor is provided in the cooling system to monitor the coolant flow rate, and a temperature sensor is provided in the reducer cavity to monitor the lubricating oil temperature, thereby realizing the identification of various faults and improving the accuracy of temperature fault judgment of electric vehicles with oil-cooled electric drive devices. It enables the entire vehicle to select different modes of operation and improves operational safety. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] The accompanying drawings, which constitute a part of the present invention, are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute improper limitations on the present invention.

[0032] Figure 1 is a schematic diagram of a three-in-one oil cooling system according to one or more embodiments of the present invention;

[0033] Figure 2 is a schematic diagram of a temperature acquisition system according to one or more embodiments of the present invention;

[0034] Figure 3 is a flow chart according to one or more embodiments of the present invention;

[0035] Figure 4 It is a schematic diagram of the working mode of the present invention according to one or more embodiments.

[0036] Among them, 1. Three-in-one electric drive system, 2. Cooling system, 3. Motor controller, 4. Drive motor, 5. Reducer, 6. Oil pump, 7. Expansion tank, 8. Radiator, 9. High-voltage accessories, 10. Water pump, 11. Stator slot temperature sensor, 12. Winding temperature sensor, 13. Oil temperature sensor, 14. Flow rate sensor. DETAILED DESCRIPTION

[0037] Example 1:

[0038] This embodiment provides a temperature protection method for an oil-cooled electric drive device, which is used in new energy vehicles, including:

[0039] Obtain the status of the drive motor of the oil-cooled electric drive device and determine whether the lubricating oil temperature is abnormal when the motor is overheated;

[0040] Determine whether the cooling system is faulty based on the oil temperature and coolant flow rate; if the cooling system is normal, determine whether the temperature detection system of the drive motor and motor controller itself is faulty; and determine whether the cooling accessories are normal;

[0041] Select different vehicle operation modes according to different fault conditions.

[0042] Specifically, such as Figure 3 As shown, when the vehicle self-test has no faults and operates normally, the winding temperature T of the oil-cooled electric drive device is detected. 绕组 Or the stator slot temperature T 槽 , T 绕组 or T 槽 The temperature is lower than the motor setting threshold T MAX阈 When , the vehicle operates normally according to mode 1; if Figure 4 As shown, mode 1 is: operating within the peak external characteristics.

[0043] T 绕组 or T 槽 The temperature is greater than or equal to the set threshold T MAX阈 When the lubricating oil temperature T 油 Is it greater than the oil temperature setting threshold T 油阈 When T 油 Greater than or equal to T 油阈When the vehicle is in a faulty state, the coolant in the cooling system of the vehicle is detected to see if it is normal (the coolant flow rate is detected to see if it is normal). In the event of a cooling fault, the water pump is detected to see if it is faulty. In the event of a water pump fault, the vehicle will operate in mode three, which means that the vehicle can operate in mode three without external cooling, and at the same time remind the vehicle to replace the water pump.

[0044] Among them, such as Figure 4 As shown, mode three is: XX% continuous external characteristic operation; the MCU temperature rise changes quickly, so the external characteristics of mode three are lower than those of mode two; XX% is set according to the specific oil-cooled electric drive device.

[0045] When the water pump has no faults, the vehicle also operates in mode three, while checking whether there is any abnormality in the coolant capacity of the cooling system.

[0046] When the coolant flow rate is normal, it is necessary to detect the oil pump fault status. If the oil pump fails, the vehicle will operate in mode 2 and it is recommended to replace the oil pump. Figure 4 As shown, mode 2 is: continuous operation within external characteristics.

[0047] When the oil pump has no faults, it is necessary to perform an internal oil circuit inspection on the entire oil-cooled drive unit.

[0048] When the lubricating oil temperature does not reach the oil temperature threshold, the MCU needs to check the winding temperature T 绕组 , stator slot temperature T 槽 Whether the change rate is abnormal at the same time; if the temperatures reported by the two temperature sensors are not abnormal at the same time, it is determined that one of the temperature sensors (winding temperature sensor or stator slot temperature sensor) is abnormal, and the vehicle still operates in mode 1.

[0049] If the temperatures reported by the two temperature sensors are abnormal at the same time, it is considered that there is an internal fault in the MCU. At this time, the entire vehicle operates in mode 3 and the MCU is tested at the same time.

[0050] The drive motor in the oil-cooled electric drive device of this embodiment includes two temperature sensors. One temperature sensor is set at the end of the motor stator winding, which usually generates the highest heat. The other temperature sensor is set in the middle of the motor stator slot. The purpose is to perform dual temperature collection and redundant monitoring of the motor temperature.

[0051] The temperature sensors at the winding ends are easily damaged during stator production, resulting in a high failure rate and significant after-sales costs for the vehicle. Water pumps also have a high failure rate and are not diagnosed promptly. For example, if the water pump experiences intermittent stalling or idling, the fault is not reported promptly, preventing the vehicle from taking timely action to protect the vehicle, leading to failure or even burnout of the oil cooling components. Therefore, flow rate sensors are embedded in the cooling system hoses to monitor the coolant flow rate, while temperature sensors are also embedded in the reducer cavity to monitor the lubricating oil temperature.

[0052] This embodiment takes into account the linkage protection between the electric drive device and the cooling system. By collecting the temperature of the oil-cooled electric drive device, when the vehicle cooling system fails, the electric drive device and the vehicle cooling system can self-diagnose temperature faults and perform fault protection to ensure safe driving of the vehicle.

[0053] Example 2:

[0054] This embodiment provides a temperature protection system for an oil-cooled electric drive device, such as Figure 1 As shown, it includes a three-in-one electric drive system 1, which integrates electronic control, motor and reducer into one, including a cooling system 2, a motor controller (MCU) 3 connected to the cooling system 2, and the cooling system 2 is connected to the drive motor (MOT) 4, the reducer (REDU) 5, and the oil pump 6.

[0055] The three-in-one electric drive system 1 is connected to the water pump 10 through a three-way valve, the water pump 10 is connected to the radiator 8, the radiator 8 is connected to the high-pressure accessory 9 through the three-way valve, and an expansion tank 7 is connected between the radiator 8 and the three-way valve; the high-pressure accessory 9 is connected to the motor controller 3.

[0056] The three-in-one electric drive system is equipped with a temperature acquisition system, such as Figure 2 As shown, the temperature acquisition system includes a stator slot temperature sensor 11, a winding temperature sensor 12, and an oil temperature sensor 13. The stator slot temperature sensor 11 is used to collect the stator slot temperature, the winding temperature sensor 12 is used to collect the motor stator winding temperature, and the oil temperature sensor 13 is used to collect the lubricating oil temperature. The above sensors are functional names and do not limit the structure of the temperature sensors.

[0057] In this embodiment, the drive motor 4 includes two temperature sensors, one of which is set at the end of the motor stator winding, and the other is set in the middle of the motor stator slot. The purpose is to perform two-way temperature collection and redundant monitoring of the motor temperature.

[0058] An oil temperature sensor 13 is disposed within the cavity of the reducer 5. This embodiment also includes a flow rate sensor 14, which is disposed within the cooling system hose and is used to monitor the coolant flow rate. These sensors enable timely detection of faults, ensuring vehicle safety.

[0059] The working principle of the temperature protection system of this embodiment is:

[0060] First, when the drive motor 1 is overheated, it is determined whether the lubricating oil temperature is abnormal, and whether the cooling system 2 is faulty based on whether the oil temperature and coolant flow rate are abnormal.

[0061] Secondly, when the cooling system 2 is normal, it is detected and determined whether the temperature detection system of the drive motor (MOTOR) and the motor controller (MCU) itself has failed.

[0062] Finally, determine whether the cooling accessories such as coolant capacity are normal.

[0063] According to the fault status of the above components, the vehicle will be operated in different safe and effective driving modes in a timely manner to protect the oil-cooled electric drive device, cooling system and vehicle safety.

[0064] The above description is merely a preferred embodiment of the present application and is not intended to limit the present application. Various modifications and variations are possible for those skilled in the art. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present application shall be included within the scope of protection of the present application.

Claims

1. A temperature protection method for an oil-cooled electric drive device, characterized in that: include: Obtain the status of the drive motor of the oil-cooled electric drive device and determine whether the lubricating oil temperature is abnormal when the motor is overheated. Specifically, obtain the winding temperature or stator slot temperature of the oil-cooled electric drive device. When the winding temperature or stator slot temperature is less than the motor set threshold, the vehicle is operating normally. When the winding temperature or stator slot temperature is greater than or equal to the motor set threshold, determine whether the lubricating oil temperature is greater than the oil temperature set threshold. Determine whether the cooling system has failed based on the oil temperature and coolant flow rate; if the cooling system is normal, determine whether the temperature detection system of the drive motor and motor controller itself has failed; and determine whether the cooling accessories are normal; select different vehicle operation modes according to different fault conditions; When the lubricating oil temperature is greater than or equal to the set threshold, the coolant flow rate of the vehicle cooling system is detected to see if it is normal; if the coolant flow rate is abnormal, it is determined whether the water pump is faulty; In the event of a water pump failure, the vehicle operates in mode three; If the water pump is normal, the vehicle will also operate in mode three, and the coolant capacity will be detected at the same time; mode three is to set the proportion of continuous external characteristics; When the coolant flow is normal, detect the oil pump fault status; When the oil pump fails, the vehicle operates in Mode 2, which is continuous operation within the external characteristics. When the oil pump has no faults, perform internal oil circuit inspection on the entire oil-cooled drive unit.

2. The temperature protection method for an oil-cooled electric drive device according to claim 1, characterized in that: When the lubricating oil temperature is lower than the oil temperature threshold, the motor controller checks whether the change rates of the winding temperature and the stator slot temperature are both abnormal.

3. The temperature protection method for an oil-cooled electric drive device according to claim 2, characterized in that: When the rates of change of the winding temperature and the stator slot temperature are not abnormal at the same time, the vehicle still operates in mode 1; wherein, mode 1 operates within the peak external characteristics; When the rates of change of the winding temperature and the stator slot temperature are both abnormal, the vehicle operates in mode three and the motor controller is tested at the same time.

4. A temperature protection system for an oil-cooled electric drive device, using the temperature protection method for an oil-cooled electric drive device according to any one of claims 1 to 3, characterized in that: It includes a three-in-one electric drive system, which is equipped with a temperature acquisition system. The temperature acquisition system includes a winding temperature sensor for collecting the temperature of the motor stator winding, a stator slot temperature sensor for collecting the temperature of the motor stator slot, and an oil temperature sensor for collecting the temperature of the lubricating oil.

5. The temperature protection system for an oil-cooled electric drive device according to claim 4, characterized in that: The three-in-one electric drive system is connected to a cooling system, and a flow rate sensor is provided in the cooling system.

6. The temperature protection system for an oil-cooled electric drive device according to claim 4, characterized in that: The winding temperature sensor is installed at the end of the motor stator winding, the stator slot temperature sensor is installed at the middle part of the motor stator slot, and the oil temperature sensor is installed in the reducer cavity.

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