Control method for controlling electronic oil pump without temperature sensor

Abstract

The invention relates to the field of control methods of electronic oil pumps, in particular to a control method for controlling an electronic oil pump without a temperature sensor. Receiving a target rotating speed; the set rotating speed of the electronic oil pump is limited to be the rotating speed value in the first data set; judging whether the device temperature meets a temperature condition or not and judging whether the rotating speed of the electronic oil pump meets a rotating speed condition or not; changing the set rotating speed of the electronic oil pump into the rotating speed value of the subsequent data set; after the set rotational speed of the electronic oil pump is changed to the rotational speed value of the Nth data group, the set rotational speed of the electronic oil pump is changed to the target rotational speed. Under the condition that no temperature sensor exists, the controller can obtain whether the current temperature of the cooling oil is higher or lower than the temperature value of the cooling oil when the current data set is established, and the negative phenomenon that the controller is damaged due to the fact that the current of the electronic oil pump is too large can be avoided; and the heat dissipation requirement on a circulation path of an electric drive axle or a gearbox and the like can be met, so that the operation reliability of the electronic oil pump is improved.

Description

Technical Field

[0001] This invention relates to the field of control methods for electronic oil pumps, specifically a control method for controlling electronic oil pumps that does not have a temperature sensor. Background Technology

[0002] An electric oil pump is used to pressurize the cooling oil, so that the pressurized cooling oil is delivered to the vehicle's electric drive axle or transmission. Taking the electric drive axle as an example, the cooling oil has two main functions: first, to lubricate the electric drive axle; and second, to control the temperature of the electric drive axle through heat exchange between the cooling oil and the electric drive axle.

[0003] In the natural environment in which a vehicle is located, the temperature of the natural environment has a significant impact on the vehicle. For the vehicle's coolant, the lower the temperature of the natural environment and the lower the temperature of the vehicle's electric drive axle, the higher the viscosity of the coolant. Conversely, the higher the temperature of the natural environment and the higher the temperature of the vehicle's electric drive axle, the lower the viscosity of the coolant.

[0004] When the temperature of the vehicle's electric drive axle is low, the viscosity of the coolant is high. This causes the current drawn by the electric oil pump when pressurizing the highly viscous coolant to be much greater than the current drawn by the electric oil pump when pressurizing the less viscous coolant. This excessive current will cause the electric oil pump to fail, resulting in the inability to pressurize the coolant and lubricate the electric drive axle. Alternatively, this excessive current may damage the controller.

[0005] Therefore, improving the operational reliability of electronic oil pumps has become a technical problem to be solved. Summary of the Invention

[0006] To address the technical problem of improving the operational reliability of electronic oil pumps, this invention provides a control method for controlling electronic oil pumps that does not have a temperature sensor.

[0007] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0008] According to one aspect of the present invention, a control method for controlling an electronic oil pump without a temperature sensor is provided, which is executed by a controller to define the temperature of the flow path of the cooling oil as the device temperature.

[0009] The steps for establishing data groups are as follows: Before starting the electronic oil pump for the first time, establish the first to the Nth data groups in sequence. Each data group includes the speed value of the electronic oil pump and the power value matched with the speed value. The speed value of the earlier data group is higher than the speed value of the later data group.

[0010] Receive target rotational speed;

[0011] For the initial startup procedure, when starting the electronic oil pump for the first time, the set speed of the electronic oil pump is limited to the speed value in the first data group;

[0012] The cyclic judgment step uses the filtered real-time data of the electronic oil pump and the current data set to determine whether the device temperature meets the temperature conditions, and uses the target speed and the speed data in the real-time data to determine whether the speed of the electronic oil pump meets the speed conditions. The real-time data is limited to speed data, current data and voltage data.

[0013] The modification procedure involves changing the set speed of the electronic oil pump to the speed value in the subsequent data set, based on meeting the device's temperature and speed requirements.

[0014] Repeat the loop judgment step and the change step;

[0015] The switching process involves changing the set speed of the electronic oil pump to the speed value of the Nth data group. If the temperature and speed conditions are met, the set speed of the electronic oil pump will then be changed to the target speed.

[0016] Furthermore, the cyclic judgment step includes:

[0017] The preliminary judgment step compares the filtered speed data with the speed value in the current data group. If the filtered speed data is equal to the speed value in the current data group, then the first judgment result is obtained; if the filtered speed data is less than the speed value in the current data group, then the second judgment result is obtained.

[0018] The temperature judgment step involves comparing the power data of the electronic oil pump with the power value in the current data set after obtaining the first judgment result. If the power data is greater than or equal to the power value, a third judgment result indicating that the temperature condition is not met is obtained. Conversely, if the power data is less than the power value, a fourth judgment result indicating that the temperature condition is met is obtained.

[0019] The speed determination step involves comparing the target speed with the filtered speed data after obtaining the first determination result. If the target speed is greater than the filtered speed data, a fifth determination result indicating that the speed condition is not met is obtained. Conversely, if the target speed is less than or equal to the filtered speed data, a sixth determination result indicating that the speed condition is met is obtained.

[0020] Furthermore, the cyclic judgment step also includes:

[0021] The sampling process involves obtaining the speed data, current data, and voltage data of the electronic oil pump before filtering, according to a preset sampling time.

[0022] The filtering step is used to remove interference data from the real-time data before filtering, and obtain the filtered speed data, filtered current data, and filtered voltage data.

[0023] The calculation steps involve obtaining the power data of the electronic oil pump using filtered current and voltage data.

[0024] Furthermore, the sampling step specifically includes:

[0025] The specific time for adoption is 1 millisecond.

[0026] The voltage data before filtering is obtained through the first formula, which is: U W =(R1+R2) / R1*U I U I The voltage obtained by the controller after voltage division, where (R1+R2) / R1 is the voltage division ratio, U W This is the voltage after line loss;

[0027] The current data before filtering is obtained through the second formula, which is specifically: I K = U K / R S / AMP, where I K U is the bus current. K R is the voltage across the sampling resistor and amplified. S The sampling resistor is the AMP amplification factor.

[0028] The speed data before filtering is obtained through the third formula, which is: N=10 / (P*Δt), where N is the motor speed, P is the number of motor pole pairs, and Δt is the time interval between two consecutive Hall effect transitions.

[0029] Furthermore, the filtering step specifically includes:

[0030] The real-time data before filtering is calculated using a low-pass filtering formula to obtain the real-time data after filtering.

[0031] The low-pass filter formula is specifically: Y K = Y K-1 + K*(X K -Y K-1 ); where Y K This is the real-time data after filtering; Y K-1 The previous filtered value; K is the filter coefficient; X K The data to be filtered.

[0032] Furthermore, the calculation steps are as follows:

[0033] The filtered current data and filtered voltage data are used to calculate the power data of the electronic oil pump using the power calculation formula.

[0034] The power calculation formula is as follows: P = I * U; where P is the power data; I is the filtered current data; and U is the filtered voltage data.

[0035] Furthermore, the motor of the electronic oil pump is limited to a brushless motor, and the control method of the brushless motor is limited to a sensor-based FOC control method.

[0036] Furthermore, the specific steps of the change are as follows:

[0037] Upon obtaining the third judgment result, the set speed of the electronic oil pump is maintained at the speed value of the current data set;

[0038] Upon obtaining the fourth and sixth judgment results, the set speed of the electronic oil pump is maintained at the current data set speed value, and the change step is terminated.

[0039] Upon obtaining the fourth and fifth judgment results, the set speed of the electronic oil pump is changed to the speed value in the subsequent data group.

[0040] Furthermore, the controller is used to execute a preset program;

[0041] The initial startup step also includes:

[0042] Establish a flag in the preset program;

[0043] The initialization step involves restoring the flag bit to its initial value when the controller receives the power-on signal.

[0044] If the preset program obtains the initial value of the flag bit, then the judgment result of the first start of the electronic oil pump is obtained;

[0045] After the electronic oil pump is started for the first time, the value of the flag bit is changed from the initial value to the working value.

[0046] The above technical solution has the following advantages or beneficial effects:

[0047] The present invention provides a control method for controlling an electronic oil pump without a temperature sensor. In the absence of a temperature sensor, the controller compares the speed and power data of the electronic oil pump with multiple established data sets. This allows the controller to determine whether the current temperature of the cooling oil is higher or lower than the temperature value of the cooling oil when the current data set was established. On the one hand, this avoids the negative phenomenon of excessive current from the electronic oil pump damaging the controller. On the other hand, it also meets the heat dissipation requirements of the flow path such as the electric drive bridge or gearbox, thereby improving the operational reliability of the electronic oil pump. Attached Figure Description

[0048] Figure 1 A flowchart of a control method for controlling an electronic oil pump without a temperature sensor, provided in an embodiment of the present invention;

[0049] Figure 2 A flowchart of a control method for controlling an electronic oil pump without a temperature sensor, provided in an embodiment of the present invention;

[0050] Figure 3 The electrical schematic diagram shows a control method for controlling an electronic oil pump without a temperature sensor, provided in an embodiment of the present invention. Detailed Implementation

[0051] To address the technical problem of improving the operational reliability of electronic oil pumps, the inventors have provided a technical solution that abandons the idea of ​​using temperature sensors to control the electronic oil pump. Instead, the solution aims to improve the operational reliability of the electronic oil pump by limiting its rotational speed.

[0052] The following examples illustrate this.

[0053] Example 1:

[0054] In this embodiment, a control method for controlling an electronic oil pump without a temperature sensor is provided, which is executed by a controller to define the temperature of the cooling oil flow path as the device temperature.

[0055] Step S1, Data Group Establishment Step: Before starting the electronic oil pump for the first time, establish the first to Nth data groups sequentially. Each data group includes the speed value of the electronic oil pump and the power value matched with the speed value. The speed value of the earlier data group is higher than the speed value of the later data group.

[0056] Step S2, Receive the target rotational speed;

[0057] Step S3, initial start-up step: When starting the electronic oil pump for the first time, the set speed of the electronic oil pump is limited to the speed value in the first data group;

[0058] Step S4, the cyclic judgment step, uses the filtered real-time data of the electronic oil pump and the current data group to determine whether the device temperature meets the temperature conditions, and uses the target speed and the speed data in the real-time data to determine whether the speed of the electronic oil pump meets the speed conditions. The real-time data is limited to speed data, current data and voltage data.

[0059] Step S5, Change Step: Based on meeting the device temperature and speed conditions, change the set speed of the electronic oil pump to the speed value in the subsequent data group.

[0060] Repeat the loop judgment step and the change step;

[0061] Step S6, Switching Step: After the set speed of the electronic oil pump is changed to the speed value of the Nth data group, if the temperature and speed conditions are met, then the set speed of the electronic oil pump is changed to the target speed.

[0062] Before the actual first start of the electric oil pump, multiple data sets need to be established; each data set includes the electric oil pump's speed value and the power value matched to the speed value. In addition, each data set also includes the temperature value corresponding to the establishment of the data set.

[0063] To facilitate understanding by those skilled in the art, this embodiment provides the following data sets for reference.

[0064] The first data set: speed is 500 rpm, power is 72W, and temperature is -20℃;

[0065] The second data set: speed is 1000 rpm, power is 72W, and temperature is 0℃;

[0066] The third data set: speed is 1500 rpm, power is 72W, and temperature is 20℃;

[0067] The fourth data set: speed value is 2000 rpm, power value is 72W, and temperature value is 40℃;

[0068] The fifth data set: speed is 2500 rpm, power is 96W, and temperature is 60℃.

[0069] Unless otherwise stated, throughout this embodiment, the controller should be understood as a dedicated controller for controlling the electronic oil pump; throughout this embodiment, the vehicle controller is not a dedicated controller for controlling the electronic oil pump.

[0070] The aforementioned data sets are stored in the controller's internal or external memory. When the controller executes the preset program (running), the controller can read and calculate the speed and power values ​​in each data set. It should be understood that the temperature value in each data set is not the object that the controller reads and calculates.

[0071] Among the aforementioned data sets, the first data set contains the speed and power values ​​of the electric oil pump when the coolant temperature is -20℃. Specifically, the speed value in the first data set represents the electric oil pump speed tested by the experimenters, ensuring that the coolant can be pressurized by the electric oil pump at -20℃, the current from the electric oil pump will not damage the controller, and that it can lubricate and cool the electric drive axle or transmission. It also represents the set speed (starting speed) of the electric oil pump initially set by the controller. The power value in the first data set represents the power value tested by the experimenters when the coolant is pressurized by the electric oil pump at -20℃ and the electric oil pump speed reaches the speed value in the first data set.

[0072] The second set of data contains the speed and power values ​​of the electric oil pump when the coolant temperature is 0°C. The speed values ​​in this second set are the speed values ​​tested by the experimenters, provided that the coolant can be pressurized by the electric oil pump at 0°C, the current from the electric oil pump will not damage the controller, and it can lubricate and cool the electric drive axle or transmission. The power values ​​in this second set are the power values ​​tested by the experimenters when the coolant is pressurized by the electric oil pump at 0°C and the electric oil pump speed reaches the speed values ​​in the second set.

[0073] The third data set contains the speed and power values ​​of the electric oil pump when the coolant temperature is 20°C. The speed value in this third data set represents the speed of the electric oil pump tested by the experimenters, provided that the coolant is pressurized by the pump at 20°C, the pump's current does not damage the controller, it lubricates the electric drive axle or transmission, and it also cools the electric drive axle or transmission. The power value in this third data set represents the power value tested by the experimenters when the coolant is pressurized by the electric oil pump at 20°C and the pump's speed reaches the speed value in the third data set.

[0074] The fourth data set contains the speed and power values ​​of the electric oil pump when the coolant temperature is 40°C. The speed value in the fourth data set represents the speed of the electric oil pump tested by the experimenters, provided that the coolant is pressurized by the electric oil pump at 40°C, the current from the electric oil pump does not damage the controller, it lubricates the electric drive axle or transmission, and it also cools the electric drive axle or transmission. The power value in the fourth data set represents the power value tested by the experimenters when the coolant is pressurized by the electric oil pump at 40°C and the electric oil pump speed reaches the speed value in the fourth data set.

[0075] The fifth data set contains the speed and power values ​​of the electric oil pump when the coolant temperature is 60°C. The speed value in the fifth data set represents the speed of the electric oil pump tested by the experimenters, ensuring that the coolant is pressurized by the pump at 60°C, the pump's current does not damage the controller, it lubricates the electric drive axle or transmission, and it also cools the electric drive axle or transmission. The power value in the fourth data set represents the power value tested by the experimenters when the coolant is pressurized by the electric oil pump at 60°C and the pump's speed reaches the speed value in the fifth data set.

[0076] The first to fifth data groups mentioned above are not unique. Those skilled in the art can set different temperature values. For example, seven temperature values ​​can be set: -30℃, -20℃, -10℃, 0℃, 20℃, 40℃, and 60℃. Alternatively, ten temperature values ​​can be set: -30℃, -25℃, -20℃, -15℃, -10℃, -5℃, 0℃, 20℃, 40℃, and 60℃. After setting the temperature values, those skilled in the art can test the electronic oil pump at each temperature value through experimental means. The test results show that the pump can both pressurize the cooling oil to achieve a lubrication effect and prevent the current from the electronic oil pump from damaging the controller.

[0077] Before the electronic oil pump is started for the first time, the controller receives the target speed sent by the vehicle's overall controller. The target speed is received by the controller and used as one of the calculation objects. The time point at which the controller can receive the target speed sent by the vehicle controller is after the time point when the controller is powered on. The target speed is the data that the vehicle controller sets or controls so that the cooling oil can achieve the ideal heat dissipation effect for the flow path. For example, the target speed is 3000 rpm, 4000 rpm, 5000 rpm, or even higher.

[0078] When the electronic oil pump is started for the first time, according to the control method of this embodiment, the controller does not need to detect the temperature of the ambient environment and the device temperature (note that the device temperature in this embodiment is the temperature of the cooling oil flow path). Instead, the controller first determines whether the electronic oil pump is being started for the first time. If it is confirmed that it is being started for the first time, the speed value in the first data group is used as the set speed of the electronic oil pump, and the electronic oil pump is started, so that the speed of the electronic oil pump changes from "zero speed" to the set speed.

[0079] For example, if the controller determines that the electronic oil pump is being started for the first time, the controller will set the speed value of 500 rpm in the first data set as the set speed of the electronic oil pump. After the electronic oil pump is started for the first time, the speed of the electronic oil pump will change from 0 to 500 rpm until the speed of the electronic oil pump reaches 500 rpm, and will remain at 500 rpm until the controller executes the change step.

[0080] In vehicles that actually use the control method of this embodiment, since no temperature sensor is installed, the controller is unaware of the current ambient temperature, the current device temperature, and the viscosity of the current coolant. Therefore, by using the speed value in the first data set as the set speed of the electronic oil pump, the speed of the electronic oil pump during its initial startup will not cause excessive current from the electronic oil pump to damage the controller as it increases from zero speed to the set speed.

[0081] It should be understood that if the controller determines that this is not the first time the electronic oil pump has been started, then the controller can execute other control methods, and these other control methods are not the technical solutions to be protected in this embodiment. For example, if the time interval between the initial start and subsequent start of the electronic oil pump is short, or if the controller does not generate a power-on signal after a power outage, these can all be considered as "not the first time the electronic oil pump has been started".

[0082] After the electronic oil pump is started for the first time, the controller executes a cyclic judgment step; the controller obtains real-time data from the electronic oil pump, which is obtained through the controller's internal hardware circuitry, including the voltage signal after line loss, the bus current signal, and the switching signal generated by the Hall chip; see [link to relevant documentation]. Figure 3Specifically, this is the electrical schematic diagram for controlling the electronic oil pump. The half-bridge circuit supplies power to the motor of the electronic oil pump, and the voltage of the electronic oil pump can be obtained through a voltage divider circuit (not shown in the diagram). The current acquisition circuit obtains the bus current signal by detecting the half-bridge circuit, and the Hall module is used to generate a switching signal (which is then converted into speed data). Due to the large number of electronic components in the circuit, electronic interference is inevitable. Therefore, low-pass filtering is required to obtain filtered speed, current, and voltage data. The purpose of obtaining real-time data is to enable the controller to determine the current temperature of the cooling oil.

[0083] It should be understood that, unless otherwise specified, those skilled in the art should understand the real-time data (including speed data, current data, and voltage data) described below as filtered real-time data (including filtered speed data, filtered current data, and filtered voltage data).

[0084] It should be understood that, in practice, after the electronic oil pump is started, and under the condition that the ambient temperature is lower than the temperature corresponding to when the first data set was established, the cooling oil is gradually pressurized by the electronic oil pump and absorbs heat, which is the heat generated during the operation of the device in one section of the flow path; as the cooling oil absorbs heat, the temperature of the cooling oil rises, and correspondingly, the viscosity of the cooling oil decreases; after absorbing heat, the temperature of the cooling oil is lower than the temperature corresponding to when the first data set was established due to insufficient heat absorption, and the temperature of the cooling oil is higher than or equal to the temperature corresponding to when the first data set was established due to sufficient heat absorption.

[0085] When executing the cyclic judgment step, if the controller determines that the current temperature of the cooling oil is lower than the temperature when the first data set was established, the controller maintains the current set speed of the electronic oil pump at the speed value of the first data set. This is because the viscosity of the current cooling oil is greater than the viscosity of the cooling oil when the first data set was established, and the current speed of the electronic oil pump is maintained at the speed value in the first data set. The current current of the electronic oil pump is greater than the current of the electronic oil pump when the first data set was established, so the current electronic oil pump does not have the conditions to increase the speed (i.e., the conditions to increase the current). If the speed of the electronic oil pump is forcibly increased at this time, the current of the electronic oil pump will inevitably increase, thereby increasing the risk of the controller being damaged by the current.

[0086] If the controller determines that the current temperature of the cooling oil is equal to or higher than the temperature when the first data set was established, then the controller will proceed with the subsequent speed condition determination. This is because the viscosity of the current cooling oil is less than the viscosity of the cooling oil when the first data set was established, and the current speed of the electric oil pump is maintained at the speed value in the first data set. However, the current current of the electric oil pump is less than the current of the electric oil pump when the first data set was established, thus enabling the current electric oil pump to meet the conditions for increasing its speed (i.e., increasing its current), and therefore the subsequent speed condition determination can be performed.

[0087] During the cyclic judgment step, the controller compares the current speed data of the electronic oil pump with the received target speed. If the current speed data is less than the target speed, the change step is executed. This is because the current flow rate of the cooling oil and the cooling effect of the cooling oil on the flow path have not yet met the control requirements set by the vehicle controller.

[0088] Conversely, if the current speed data is greater than or equal to the target speed, the change procedure will not be executed; this is because the current flow rate of the cooling oil and the cooling effect of the cooling oil on the flow path have already met the control requirements set by the vehicle controller.

[0089] When executing the change step, the controller changes the current set speed of the electronic oil pump to the speed value in the adjacent and subsequent data group, according to the order of the first to Nth data groups. For example, if the current set speed of the electronic oil pump is 500 rpm in the first data group, then when the controller executes the change step, it changes the set speed of the electronic oil pump to 1000 rpm in the second data group. Similarly, if the current set speed of the electronic oil pump is 1000 rpm in the second data group, then when the controller executes the change step, it changes the set speed of the electronic oil pump to 1500 rpm in the third data group.

[0090] The controller repeatedly executes the cyclic judgment and change steps until the set speed of the electronic oil pump is changed to the speed value of the last data group (i.e., the Nth data group) (e.g., after the set speed is changed to the speed value of 2500 rpm in the aforementioned fifth data group). If the controller determines that the current temperature of the cooling oil meets the temperature when the last data group was established (e.g., greater than or equal to the temperature of 60°C in the aforementioned fifth data group), then the controller changes the set speed of the electronic oil pump (the set speed of 2500 rpm in the aforementioned fifth data group) to the target speed (e.g., the aforementioned target speed of 3000 rpm or 4000 rpm), so that the electronic oil pump continues to operate at the target speed (e.g., the aforementioned target speed of 3000 rpm or 4000 rpm). This is because the current temperature of the cooling oil is very high, and the viscosity of the cooling oil is very low. Even if the operating speed of the electronic oil pump reaches the target speed, the current of the electronic oil pump will not be large, meaning the risk of the controller being damaged by the current is very small.

[0091] Furthermore, in this embodiment, the control method for controlling an electronic oil pump that does not have a temperature sensor includes the following cyclic judgment step:

[0092] Step S404, Preliminary judgment step: Compare the filtered speed data with the speed value in the current data group. If the filtered speed data is equal to the speed value in the current data group, then obtain the first judgment result; if the filtered speed data is less than the speed value in the current data group, then obtain the second judgment result.

[0093] Step S405, temperature judgment step: Under the condition of obtaining the first judgment result, compare the power data of the electronic oil pump with the power value in the current data group. If the power data is greater than or equal to the power value, then obtain the third judgment result that the temperature condition is not met; otherwise, if the power data is less than the power value, then obtain the fourth judgment result that the temperature condition is met.

[0094] Step S406, speed judgment step: Under the condition of obtaining the first judgment result, compare the target speed with the filtered speed data. If the target speed is greater than the filtered speed data, then obtain the fifth judgment result that does not meet the speed condition. Conversely, if the target speed is less than or equal to the filtered speed data, then obtain the sixth judgment result that meets the speed condition.

[0095] From the perspective of cooling oil and electric oil pump, the lower the temperature of the cooling oil, the greater its viscosity, and vice versa. Correspondingly, when the electric oil pump drives cooling oil with different viscosities at the same speed, the current of the electric oil pump is different. The greater the viscosity of the cooling oil, the greater the current of the electric oil pump, and vice versa.

[0096] The purpose of the controller's actual execution of the pre-judgment and temperature judgment steps is to convert the viscosity of the cooling oil into the current of the electronic oil pump. By comparing the power data of the electronic oil pump (power data is the product of voltage and current) with the power value of the current data set, the controller can determine whether the current temperature of the cooling oil is higher than, equal to, or lower than the temperature when the current data set was established. For example, if the power value of the current data set is 72W (the power value of the first data set mentioned above), and the controller obtains an electronic oil pump power data of 78W, then the current viscosity of the cooling oil is greater than the viscosity of the cooling oil when the first data set was established, and the current temperature of the cooling oil is lower than the temperature value of -20℃ when the first data set was established. Alternatively, if the controller obtains an electronic oil pump power data of 71W, then the current viscosity of the cooling oil is less than the viscosity of the cooling oil when the first data set was established, and the current temperature of the cooling oil is higher than the temperature value of -20℃ when the first data set was established.

[0097] During the actual process of the controller judging the temperature of the cooling oil, the speed of the electronic oil pump changes, resulting in a dynamic electronic oil pump speed. The dynamic electronic oil pump speed also makes the power data of the electronic oil pump dynamic. This is not conducive to the controller comparing the power data with the power value in the current data set. In other words, the controller's comparison of "dynamic power data with the power value in the current data set" is inaccurate.

[0098] The controller compares "dynamic power data with the power value in the current data set." For example, during the process of changing the set speed of the electric oil pump from the speed value in the first data set to the speed value in the second data set, the speed data of the electric oil pump acquired by the controller is 750 rpm. 750 rpm is different from the speed value of 1000 rpm in the second data set. If we compare the power value in the second data set with the current power data of the electric oil pump at 750 rpm, it is obvious that the power data of the electric oil pump at 750 rpm is lower than the power value in the second data set. This comparison result is obtained after the set speed has changed to the second data set, and before the speed of the electric oil pump has reached the speed value in the second data set. Therefore, this comparison leads the controller to obtain the negative result that "the current temperature of the cooling oil is higher than the temperature value of 0°C when the second data set was established," causing the controller to "misjudge." More seriously, in the case of misjudgment, the controller may perform the speed change operation again, causing the electric oil pump speed to be too high, resulting in excessive current in the electric oil pump and damage to the controller.

[0099] When the speed of the electronic oil pump remains unchanged (either reaching the set speed before the change or reaching the set speed after the change), the speed of the electronic oil pump can be considered static. The static speed of the electronic oil pump makes the power data of the electronic oil pump static as well. This is beneficial for the controller to compare the power data with the power value in the current data set. In other words, the controller's comparison of "static power data with the power value in the current data set" is relatively more accurate.

[0100] The controller compares the "static power data with the power value in the current data group". For example, when the set speed of the electronic oil pump changes from the speed value in the first data group to the speed value in the second data group, the speed of the electronic oil pump has reached the speed value of 1000 rpm in the second data group. At this time, the controller can compare the power value of the electronic oil pump in the second data group with the current power data of the electronic oil pump at 1000 rpm. This comparison will not cause the controller to obtain the "negative result" mentioned above, and thus will not cause the controller to "misjudge".

[0101] If the controller obtains the second judgment result when it actually performs the pre-judgment step, it means that the current speed of the electronic oil pump is dynamic and that the current electronic oil pump is in the process of changing its speed. Therefore, when the second judgment result is obtained, the controller does not need to perform the subsequent temperature judgment step. In this case, even if the subsequent temperature judgment step is performed, the result will be inaccurate.

[0102] If the controller obtains the first judgment result when it actually performs the pre-judgment step, it means that the current speed of the electronic oil pump is static, and that the current electronic oil pump is at the set speed before or after the change. Therefore, when the first judgment result is obtained, the controller can perform the subsequent temperature judgment step.

[0103] When the controller performs the temperature judgment step, if the controller obtains the third judgment result, it means that the current temperature of the cooling oil is less than or equal to the temperature of the cooling oil when the current data group was established. In other words, the current viscosity of the cooling oil is greater than or equal to the viscosity of the cooling oil when the current data group was established.

[0104] When the controller performs the temperature judgment step, if the controller obtains the fourth judgment result, it means that the current temperature of the cooling oil is greater than the temperature of the cooling oil when the current data group was established. In other words, the viscosity of the current cooling oil is less than the viscosity of the cooling oil when the current data group was established.

[0105] When the speed determination step is executed by the controller, if the controller obtains the fifth determination result, it means that the current cooling effect of the cooling oil on the flow path has not met the control requirements set by the vehicle controller, and it is necessary to continue to increase the speed of the electronic oil pump. In other words, the controller has the conditions to execute the speed change step.

[0106] When the speed determination step is executed by the controller, if the controller obtains the sixth determination result, it means that the current cooling effect of the cooling oil on the flow path has reached the control requirements set by the vehicle controller. There is no need to continue to increase the speed of the electronic oil pump, nor is it necessary to change the set speed of the electronic oil pump to the target speed. In other words, the controller should terminate the execution of the speed change step.

[0107] The control method for controlling an electronic oil pump in this embodiment, which does not have a temperature sensor, further includes the following cyclic judgment step:

[0108] Step S401, sampling step: according to the preset sampling time, obtain the speed data, current data and voltage data of the electronic oil pump before filtering.

[0109] Step S402, filtering step, is used to remove interference data from the real-time data before filtering, and obtain the filtered speed data, filtered current data and filtered voltage data.

[0110] Step S403, calculation step: obtain the power data of the electronic oil pump by using the filtered current data and filtered voltage data.

[0111] When the controller performs the sampling step, the preset sampling time can be determined based on the sensitivity of the electronic components or the calculation speed of the controller. For example, the sampling time is 1 millisecond. The controller obtains the speed data, current data, and voltage data of the electronic oil pump before filtering based on the preset sampling time. These three data before filtering need to be filtered through subsequent filtering steps to remove interference data caused by electronic interference.

[0112] When the controller performs the filtering step, the following first formula, second formula and third formula are used to collect the speed data, current data and voltage data before filtering.

[0113] The sampling step S401 specifically includes:

[0114] The specific time for adoption is 1 millisecond;

[0115] The voltage data before filtering is obtained through the first formula, which is: U W =(R1+R2) / R1*U I U I The voltage obtained by the controller after voltage division, where (R1+R2) / R1 is the voltage division ratio, U W U is the voltage after line loss; W The voltage is acquired through a voltage divider circuit inside the controller. This voltage divider circuit is common knowledge to those skilled in the art and will not be described in detail here. R1 is the resistance value of the first resistor in the voltage divider circuit, R2 is the resistance value of the second resistor in the voltage divider circuit, and U... I This is the input voltage of the voltage divider circuit.

[0116] The current data before filtering is obtained through the second formula, which is specifically: I K = U K / R S / AMP, where I K U is the bus current. K R is the voltage across the sampling resistor and amplified. S The sampling resistor is the AMP amplification factor.

[0117] The speed data before filtering is obtained through the third formula, which is: N=10 / (P*Δt), where N is the motor speed, P is the number of motor pole pairs, and Δt is the time interval between two consecutive Hall effect transitions.

[0118] When the controller performs the sampling step, after obtaining the speed data, current data, and voltage data before filtering, the following low-pass filtering formula is used to calculate and obtain the speed data, current data, and voltage data after filtering.

[0119] The filtering step S402 specifically involves:

[0120] The real-time data before filtering is calculated using a low-pass filtering formula to obtain the real-time data after filtering.

[0121] The low-pass filter formula is specifically: Y K = Y K-1 + K*(X K -Y K-1 ); where Y K This is the real-time data after filtering; Y K-1 The previous filtered value; K is the filter coefficient; X K The data to be filtered.

[0122] Specifically, the rotational speed data before filtering is substituted into the low-pass filter formula above to obtain the rotational speed data after filtering. Similarly, the current data and voltage data before filtering are substituted into the low-pass filter formula above to obtain the current data and voltage data after filtering, respectively. The purpose of this step is to eliminate interference data in the rotational speed data, the current data, and the voltage data before filtering, thereby ensuring the accuracy of the subsequent power data and power value comparison.

[0123] When the controller performs the calculation step, power data is obtained through the power calculation formula; specifically, the calculation step S403 is as follows:

[0124] The filtered current data and filtered voltage data are used to calculate the power data of the electronic oil pump using the power calculation formula.

[0125] The power calculation formula is as follows: P = I * U; where P is the power data; I is the filtered current data; and U is the filtered voltage data.

[0126] In this embodiment, in order to ensure that the speed of the electronic oil pump is precisely controlled to the set speed, preferably, the motor of the electronic oil pump is limited to a brushless motor, and the control method of the brushless motor is limited to a sensor-based FOC control method.

[0127] The specific structure of a brushless motor is common knowledge known to those skilled in the art, and will not be described in detail here.

[0128] The sensor-guided FOC control method (literally translated as field-oriented control) is common knowledge known to those skilled in the art, and will not be elaborated here.

[0129] Sensitive FOC control of brushless motor speed adjustment is primarily achieved by altering the current. FOC regulates speed by controlling the direction and magnitude of the motor's magnetic field, with the core mechanism being the adjustment of the motor's three-phase current (i.e., the excitation component and the torque component). This control method allows for precise control of torque and speed, ensuring stable operation of the oil pump. When sensitive FOC control is combined with the brushless electronics of the electronic oil pump, the pump's speed can be precisely adjusted to the set speed, improving the accuracy of the controller's comparison between the "current electronic oil pump power data" and the "current data set power value."

[0130] Furthermore, in the control method for controlling the electronic oil pump of this embodiment that does not have a temperature sensor, the modification step S5 specifically includes:

[0131] Upon obtaining the third judgment result, the set speed of the electronic oil pump is maintained at the speed value of the current data set;

[0132] The significance of this step is as follows: The third judgment result corresponds to the current cooling oil temperature being less than or equal to the cooling oil temperature when the current data set was established. This indicates that the current cooling oil viscosity is greater than or equal to the cooling oil viscosity when the current data set was established. It also indicates that the current electronic oil pump current data is greater than or equal to the electronic oil pump current data when the current data set was established. Therefore, when the third judgment result is obtained, subsequent change steps cannot be executed. In other words, the controller should limit the electronic oil pump speed to the speed value of the current data set to avoid further increase in the current data of the current electronic oil pump, or the actual current of the electronic oil pump, thereby avoiding the phenomenon of the electronic oil pump current damaging the controller.

[0133] Upon obtaining the fourth and sixth judgment results, the set speed of the electronic oil pump is maintained at the current data set speed value, and the change step is terminated.

[0134] The significance of this step is as follows: the fourth judgment result corresponds to the fact that the current cooling oil temperature is greater than the cooling oil temperature when the current data set was established, indicating that the current cooling oil viscosity is less than the cooling oil viscosity when the current data set was established, and also indicating that the current current data of the electronic oil pump is less than the current current data of the electronic oil pump when the current data set was established; therefore, upon obtaining the fourth judgment result, the controller already has the basis to execute the change step; however, the fourth judgment result is only one of the necessary conditions for executing the speed change step, not a sufficient condition.

[0135] If the sixth judgment result is obtained based on the fourth judgment result, it means that the current speed of the electronic oil pump has reached or exceeded the target speed received by the controller. Therefore, there is no need to perform subsequent change steps. The controller only needs to keep the set speed of the electronic oil pump at the speed value of the current data set to meet the design requirements of lubrication and heat dissipation of the electric drive axle or gearbox.

[0136] Upon obtaining the fourth and fifth judgment results, the set speed of the electronic oil pump will be changed to the speed value of the subsequent data group;

[0137] The significance of this step is as follows: The fourth judgment result corresponds to the current cooling oil temperature being greater than the cooling oil temperature when the current data set was established, indicating that the current cooling oil viscosity is less than the cooling oil viscosity when the current data set was established, and also indicating that the current current data of the electric oil pump is less than the current current data of the electric oil pump when the current data set was established. Therefore, upon obtaining the fourth judgment result, the controller already has the basis to execute the change step. At the same time, if the fifth judgment result is obtained, it indicates that the current electric oil pump speed has not yet reached the target speed received by the controller. Therefore, the controller changes the set speed of the electric oil pump from the speed value in the current data set to the speed value in a subsequent data set (specifically, the speed value in a subsequent and adjacent data set). Thus, the controller has completed the change step, and the electric oil pump changes from the speed value in the current data set to the speed value in a subsequent data set, causing the speed of the electric oil pump to gradually increase until the speed data of the electric oil pump is completely changed to the speed value in a subsequent data set, and the controller executes the cyclic judgment step again.

[0138] Furthermore, in this embodiment, the control method for controlling an electronic oil pump that does not have a temperature sensor includes a controller for executing a preset program.

[0139] The initial startup step S3 also includes:

[0140] Establish a flag in the preset program;

[0141] The initialization step involves restoring the flag bit to its initial value when the controller receives the power-on signal.

[0142] If the preset program obtains the initial value of the flag bit, then the judgment result of the first start of the electronic oil pump is obtained;

[0143] After the electronic oil pump is started for the first time, the value of the flag bit is changed from the initial value to the working value.

[0144] In all the aforementioned technical solutions, since no temperature sensor is installed, the controller is unaware of the current ambient temperature and the device temperature. Therefore, for the first start-up of the electronic oil pump, the controller controls the electronic oil pump entirely based on the current device temperature being low (refer to the first to fifth data groups mentioned above, where -20°C in the first data group is considered the low temperature).

[0145] The vehicle has both a driving state and a stationary state. When the vehicle is in a driving state, the controller (which controls the electronic fuel pump) and the vehicle controller will not experience power outages (power outages due to malfunctions will not be discussed here). When the vehicle is stationary, it is under the driver's control, and the controller (which controls the electronic fuel pump) and the vehicle controller may experience power outages or remain powered on. Therefore, it is only necessary to confirm whether the controller is powered on when the vehicle is stationary.

[0146] Each time the controller is powered on, it loads and executes a preset program, forming the initialization program described above. The controller can obtain a power-on signal when it is powered on. The power-on signal can be displayed in the preset program executed by the controller, which is common knowledge known to those skilled in the art.

[0147] In the preset program executed by the controller, the flag bit is restored to its initial value using the power-on signal. This is because, in some registers, the data is not lost after the register is powered off. Therefore, restoring the flag bit to its initial value using the power-on signal can eliminate the data stored in the flag bit in the register.

[0148] The flag is assigned an initial value, for example, "1". When the preset program is executed later, the flag is changed from the initial value to the working value. For example, the speed is changed as a control command, or the speed of the electronic oil pump reaches the target speed as a control command, so that the flag is changed from the initial value "1" to "0".

[0149] When the flag is set to its initial value, the controller determines that the electronic oil pump is starting for the first time; conversely, when the flag is set to "working", the controller determines that the electronic oil pump is not starting for the first time.

[0150] This embodiment provides a control method for controlling an electronic oil pump without a temperature sensor. When the controller determines that the electronic oil pump is starting for the first time, it sets the speed value in the first data group of multiple data groups as the set speed of the electronic oil pump. After the electronic oil pump starts, the controller compares the speed and power data of the electronic oil pump with the speed and power values ​​in the current data group to obtain whether the current temperature of the cooling oil is higher or lower than the temperature value when the current data group was established. If the cooling oil temperature is higher than the temperature value when the current data group was established, the controller compares the target speed with the current speed data of the electronic oil pump to obtain whether the target speed is lower or higher than the current speed data of the electronic oil pump. If the target speed is higher than the current speed data of the electronic oil pump, the controller changes the set speed of the electronic oil pump to the speed value in a later data group and repeats the cyclic judgment step and the speed change step until the set speed of the electronic oil pump is changed to the target speed, or the speed data of the electronic oil pump is higher than the target speed.

[0151] The control method for controlling an electronic oil pump without a temperature sensor provided in this embodiment compares multiple established data sets with the speed and power data of the electronic oil pump. This allows the controller to determine whether the current temperature of the cooling oil is higher or lower than the temperature value of the cooling oil when the current data set was established. On the one hand, this avoids the negative phenomenon of excessive current from the electronic oil pump damaging the controller. On the other hand, it also meets the heat dissipation requirements of the flow path such as the electric drive bridge or gearbox, thereby improving the operational reliability of the electronic oil pump.

[0152] The above description is merely a preferred embodiment of the present invention and does not limit the patent scope of the present invention. Any equivalent structural transformations made based on the description and drawings of the present invention, or direct or indirect applications in other related technical fields, are similarly included within the patent protection scope of the present invention.

Claims

1. A control method for controlling an electronic oil pump that does not have a temperature sensor, for execution by a controller, characterized in that, The temperature along the flow path of the cooling oil is defined as the device temperature; The steps for establishing data groups are as follows: Before starting the electronic oil pump for the first time, establish the first to the Nth data groups in sequence. Each data group includes the speed value of the electronic oil pump and the power value matched with the speed value. The speed value of the earlier data group is higher than the speed value of the later data group. Receive target rotational speed; For the initial startup procedure, when starting the electronic oil pump for the first time, the set speed of the electronic oil pump is limited to the speed value in the first data group; The cyclic judgment step uses the filtered real-time data of the electronic oil pump and the current data set to determine whether the device temperature meets the temperature conditions, and uses the target speed and the speed data in the real-time data to determine whether the speed of the electronic oil pump meets the speed conditions. The real-time data is limited to speed data, current data and voltage data. The modification procedure involves changing the set speed of the electronic oil pump to the speed value in the subsequent data set, based on meeting the device's temperature and speed requirements. Repeat the loop judgment step and the change step; The switching process involves changing the set speed of the electronic oil pump to the speed value of the Nth data group. If the temperature and speed conditions are met, the set speed of the electronic oil pump will then be changed to the target speed.

2. The control method for controlling an electronic oil pump according to claim 1, which does not have a temperature sensor, is characterized in that, The cyclic judgment step includes: The preliminary judgment step compares the filtered speed data with the speed value in the current data group. If the filtered speed data is equal to the speed value in the current data group, then the first judgment result is obtained; if the filtered speed data is less than the speed value in the current data group, then the second judgment result is obtained. The temperature judgment step involves comparing the power data of the electronic oil pump with the power value in the current data set after obtaining the first judgment result. If the power data is greater than or equal to the power value, a third judgment result indicating that the temperature condition is not met is obtained. Conversely, if the power data is less than the power value, a fourth judgment result indicating that the temperature condition is met is obtained. The speed determination step involves comparing the target speed with the filtered speed data after obtaining the first determination result. If the target speed is greater than the filtered speed data, a fifth determination result indicating that the speed condition is not met is obtained. Conversely, if the target speed is less than or equal to the filtered speed data, a sixth determination result indicating that the speed condition is met is obtained.

3. The control method for controlling an electronic oil pump without a temperature sensor according to claim 2, characterized in that, The cyclic judgment step also includes: The sampling process involves obtaining the speed data, current data, and voltage data of the electronic oil pump before filtering, according to a preset sampling time. The filtering step is used to remove interference data from the real-time data before filtering, and obtain the filtered speed data, filtered current data, and filtered voltage data. The calculation steps involve obtaining the power data of the electronic oil pump using filtered current and voltage data.

4. The control method for controlling an electronic oil pump according to claim 3, which does not have a temperature sensor, is characterized in that... The sampling steps are as follows: The specific time for adoption is 1 millisecond. The voltage data before filtering is obtained through the first formula, which is: U W =(R1+R2) / R1*U I U I The voltage obtained by the controller after voltage division, where (R1+R2) / R1 is the voltage division ratio, U W This is the voltage after line loss; The current data before filtering is obtained through the second formula, which is specifically: I K = U K / R S / AMP, where I K U is the bus current. K R is the voltage across the sampling resistor and amplified. S The sampling resistor is the AMP amplification factor. The speed data before filtering is obtained through the third formula, which is: N=10 / (P*Δt), where N is the motor speed, P is the number of motor pole pairs, and Δt is the time interval between two consecutive Hall effect transitions.

5. The control method for controlling an electronic oil pump according to claim 3, which does not have a temperature sensor, is characterized in that, The filtering steps are as follows: The real-time data before filtering is calculated using a low-pass filtering formula to obtain the real-time data after filtering. The low-pass filter formula is specifically: Y K = Y K-1 + K*(X K -Y K-1 ); where Y K This is the real-time data after filtering; Y K-1 The previous filtered value; K is the filter coefficient; X K The data to be filtered.

6. The control method for controlling an electronic oil pump according to claim 3, which does not have a temperature sensor, is characterized in that, The calculation steps are as follows: The filtered current data and filtered voltage data are used to calculate the power data of the electronic oil pump using the power calculation formula. The power calculation formula is as follows: P = I * U; where P is the power data; I is the filtered current data; and U is the filtered voltage data.

7. The control method for controlling an electronic oil pump according to claim 1, which does not have a temperature sensor, is characterized in that, The motor of the electronic oil pump is limited to a brushless motor, and the control method of the brushless motor is limited to a sensor-based FOC control method.

8. The control method for controlling an electronic oil pump according to claim 2, which does not have a temperature sensor, is characterized in that, The specific steps for making the change are as follows: Upon obtaining the third judgment result, the set speed of the electronic oil pump is maintained at the speed value of the current data set; Upon obtaining the fourth and sixth judgment results, the set speed of the electronic oil pump is maintained at the current data set speed value, and the change step is terminated. Upon obtaining the fourth and fifth judgment results, the set speed of the electronic oil pump is changed to the speed value in the subsequent data group.

9. The control method for controlling an electronic oil pump according to claim 1, which does not have a temperature sensor, is characterized in that, The controller is used to execute a preset program; The initial startup step also includes: Establish a flag in the preset program; The initialization step involves restoring the flag bit to its initial value when the controller receives the power-on signal. If the preset program obtains the initial value of the flag bit, then the judgment result of the first start of the electronic oil pump is obtained; After the electronic oil pump is started for the first time, the value of the flag bit is changed from the initial value to the working value.

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