Car window motor thermal protection method based on car window motor thermal model

Abstract

The invention discloses a vehicle window motor thermal protection method based on a vehicle window motor thermal model, and the main design concept of the method is that the current temperature of a vehicle window motor is predicted through the current vehicle window motor operation temperature, vehicle window operation resistance, vehicle window motor operation time, vehicle window motor shutdown time and vehicle window motor stalling time; and moreover, the temperature protection interval and the temperature recovery interval are divided into different temperature control levels, the level of the temperature is estimated based on the car window motor, hierarchical control is executed, and corresponding measures are taken, for example, only a manual mode is allowed or all modes are forbidden, and the car window operation function is gradually recovered in the motor temperature recovery stage through the hierarchical measures. According to the method, the hardware thermal protection cost is saved, the influence factors of the multi-dimensional car window temperature curve are fused, more accurate motor temperature estimation is realized, and the partitioning and grading treatment is performed in a targeted manner, so that the car window motor is intelligently and finely effectively protected.

Description

Technical Field

[0001] The present invention relates to the technical field of automotive electronics, and in particular to a thermal protection method for a window motor based on a window motor thermal model. Background Art

[0002] With the advancement of electrification and intelligent vehicles, automatic window-lifting and anti-pinch features are becoming increasingly common. However, window motors generate significant heat during prolonged operation. If this heat cannot be dissipated promptly, it can affect motor performance and even cause burnout. To prevent this, the window motor thermal protection system detects that the motor temperature has reached a certain limit and stops output. It then resumes operation once the temperature returns to a controllable range, thereby reducing motor failure rates and increasing motor life.

[0003] Currently, the most commonly used thermal protection method for window motors is hardware thermal protection, which integrates a thermistor inside the motor. When the temperature reaches the set protection threshold, the motor stops moving and enters the protection state.

[0004] Hardware thermal protection technology requires additional hardware components, such as thermistors, which increases the complexity of the system and may lead to higher failure rates and maintenance costs. In addition, hardware thermal protection is also more sensitive to environmental changes. For example, under extreme conditions, the performance of the thermistor may be affected, thereby affecting the accuracy of the motor protection function. Summary of the Invention

[0005] In view of the above, the present invention aims to provide a window motor thermal protection method based on a window motor thermal model to solve the aforementioned technical problems.

[0006] The technical solution adopted in the present invention is as follows:

[0007] The present invention provides a window motor thermal protection method based on a window motor thermal model, which includes:

[0008] Calculate the window motor operating temperature rise based on the heat generated when the window is running, the window operating speed, and the ambient temperature;

[0009] Based on the heat dissipation and ambient temperature when the window is stopped, calculate the temperature drop of the window motor when it is stopped;

[0010] Calculate the window motor stall temperature rise based on the heat generated when the motor is stalled and the ambient temperature;

[0011] Obtaining the current state of the window motor and estimating the window motor temperature based on a preset window motor thermal model, wherein the window motor thermal model includes: estimated window motor temperature = window motor initial temperature + window motor operating temperature rise + window motor blocked rotor temperature rise - window motor shutdown temperature drop;

[0012] Based on the estimated temperature of the window motor and the pre-divided temperature protection intervals and temperature recovery intervals of different levels, corresponding graded thermal protection measures are implemented respectively.

[0013] In at least one possible implementation, obtaining the window motor operating temperature rise includes:

[0014] Calculate the heat generated by the window motor when it is running using the current, motor resistance, and motor running time.

[0015] Optimizing said heat in conjunction with the window operating rate;

[0016] Based on the optimized heat and the established motor heat capacity, the motor temperature rise is preliminarily calculated;

[0017] The calculated preliminary temperature rise is corrected based on the ambient temperature to obtain the final motor operating temperature rise.

[0018] In at least one possible implementation, obtaining the window motor shutdown temperature drop includes:

[0019] Calculate the heat dissipation of the window motor when it is stopped using the window motor heat dissipation coefficient, window motor heat dissipation area, current motor temperature, ambient temperature, and downtime.

[0020] Preliminary calculation of the motor temperature drop based on the heat dissipation and the established motor heat capacity;

[0021] The calculated preliminary temperature drop is corrected based on the ambient temperature to obtain the final motor shutdown temperature drop.

[0022] In at least one possible implementation, obtaining the window motor stall temperature rise includes:

[0023] Calculate the heat generated when the window motor is blocked using the current, motor internal resistance, and motor blocking time.

[0024] Based on the heat obtained and the established motor heat capacity, the motor temperature rise is preliminarily calculated;

[0025] The calculated preliminary temperature rise is corrected based on the ambient temperature to obtain the final motor stall temperature rise.

[0026] In at least one possible implementation, the respectively executing corresponding graded thermal protection measures specifically includes:

[0027] When the estimated value is higher than the preset first-level protection temperature threshold, the automatic window lifting function is disabled and only manual lifting is allowed;

[0028] When the estimated value is higher than the preset secondary protection temperature threshold, all window actions are prohibited;

[0029] When the estimated value drops to the preset first-level recovery temperature, the manual lifting function of the window is restored first;

[0030] When the estimated value drops to a preset secondary recovery temperature, all functions of the vehicle windows are restored.

[0031] In at least one possible implementation manner, the ambient temperature is obtained by jointly calibrating the cabin internal and external temperatures.

[0032] Compared with existing technologies, the main design concept of this invention is to predict the current window motor temperature by analyzing the current window motor operating temperature, window operating resistance, window motor operating time, window motor downtime, and window motor stall time. Furthermore, the temperature protection and recovery intervals are divided into different temperature control levels. Based on the estimated window motor temperature level, hierarchical control is implemented and corresponding measures are taken, such as only allowing manual mode or disabling all modes. Similarly, during the motor temperature recovery phase, graded measures are also used to gradually restore window operation. This invention not only saves hardware thermal protection costs but also integrates the influencing factors of the multi-dimensional window temperature curve to achieve more accurate motor temperature estimation and targeted zoning and grading processing, thereby providing intelligent and detailed protection for the window motor. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] In order to make the purpose, technical solutions and advantages of the present invention more clear, the present invention will be further described below with reference to the accompanying drawings, in which:

[0034] Figure 1 A schematic diagram of a window motor thermal protection method based on a window motor thermal model provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0035] The following describes embodiments of the present invention in detail. Examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are intended only to explain the present invention and are not to be construed as limiting the present invention.

[0036] From the above technical background, it can be seen that hardware thermal protection for window motors lacks cost advantages. Therefore, attempts have been made to adopt software thermal protection, which mainly predicts the current window temperature and performs thermal protection through a single time dimension. However, practice has found that this control method involves fewer influencing factors, resulting in a relatively rough prediction model that also fails to meet industry expectations.

[0037] Based on this, the present invention proposes an embodiment of a window motor thermal protection method based on a window motor thermal model. Specifically, Figure 1 shown, including:

[0038] Step S1, calculating the window motor operating temperature rise based on the heat generated during window operation, the window operating speed, and the ambient temperature;

[0039] To expand on this, first calculate the heat generated when the window motor is running: Q = I²Rt, where I is the window motor operating current, R is the motor resistance, and t is the motor operating time;

[0040] Furthermore, considering the effect of window operating speed on heat accumulation, the heat calculation can be adjusted: Qrun=Q×f(v), where v is the window operating speed and f(v) is the function of the window operating speed on heat accumulation;

[0041] Then, the optimized heat calculation results are used to preliminarily calculate the motor temperature rise: ΔT=Qrun÷C, where ΔT is the motor temperature rise and C is the motor thermal capacity;

[0042] Furthermore, considering the influence of ambient temperature on the temperature rise of the motor, it can be corrected, that is, the final operating temperature rise: ΔTrun=ΔT×g1(Temperature), where Temperature is the ambient temperature and g1(Temperature) is the correction function of the ambient temperature to the temperature rise.

[0043] Step S2, calculating the temperature drop of the window motor when it is stopped based on the heat dissipated by the window motor and the ambient temperature when the window motor is stopped;

[0044] In the present invention, the window motor temperature drop model can be simplified to a basic convective heat transfer model, where the heat transfer rate is proportional to the heat transfer area, temperature difference, and heat transfer coefficient. Therefore, the motor heat dissipation is first calculated: Qstop = h × A × (Tcurrent - temperature) × t, where h is the motor heat dissipation coefficient, A is the motor heat dissipation area, Tcurrent is the current motor temperature, Temperature is the ambient temperature, and t is the motor downtime. Next, a preliminary calculation of the motor temperature drop is performed: ΔT = Qstop ÷ C, where ΔT is the motor temperature drop and C is the motor heat capacity. Therefore, the shutdown temperature drop ΔTstop = ΔT × g²(Temperature), where Temperature is the ambient temperature and g²(Temperature) is the correction function for the ambient temperature to the temperature drop.

[0045] Step S3, calculating the window motor stall temperature rise based on the heat generated when the motor is stalled and the ambient temperature;

[0046] Specifically, the heat generated when the motor is stalled is calculated: Qstall = Istall²Rt, where Istall is the motor's stall current, R is the motor's internal resistance, and t is the motor's stall time, typically around 500ms. The stalled-rotor temperature rise is then preliminarily calculated as ΔT = Qstall ÷ C, where ΔT is the motor's stalled-rotor temperature rise and C is the motor's thermal capacity. Then, combined with correction and compensation, the final stalled-rotor temperature rise is calculated as ΔTstall = ΔT × g³(Temperature), where Temperature is the ambient temperature and g³(Temperature) is the correction function for the ambient temperature's effect on the stalled-rotor temperature rise.

[0047] It should be noted that, first, the motor heat dissipation coefficient h, motor heat dissipation area A, and motor internal resistance R are all motor properties and can be pre-set or read from stored information. Second, regarding the operating rate and influence function, the window operating rate v can be calculated by calculating the window travel distance L by the number of ripples generated by the ripple motor over a period of time t. The rate v = L ÷ t. Therefore, by varying the window resistance at a normal temperature of 25°C, experiments can be conducted to derive window heat accumulation curves at different window operating rates. Using a set standard rate as a benchmark, the f(v) factor can be corrected for other window operating rates. Third, the window motor is generally installed inside the vehicle door, and electric vehicles are generally equipped with both an in-cabin temperature sensor and an out-cabin temperature sensor. Therefore, the aforementioned ambient temperature, Temperature, can be obtained by calibrating the cabin's internal and external temperatures. Fourth, the aforementioned g1 (Temperature), g2 (Temperature), and g3 (Temperature) can be calibrated using experimental data, specifically in a thermostat for different temperatures. For example, taking the temperature rise and drop curve at 25°C as a benchmark, the temperature rise and drop curves of the window motor at other different temperatures are collected to determine three correction functions g1 (Temperature), g2 (Temperature), and g3 (Temperature) for the aforementioned correction of the temperature curve.

[0048] Continuing from the above, step S4, the current state of the window motor is obtained, and the window motor temperature is estimated in combination with a preset window motor thermal model, wherein the window motor thermal model includes:

[0049] Tpredict = Tinitial + ΔTrun - ΔTstop + ΔTstall. That is, the estimated window motor temperature Tpredict is: the initial motor temperature Tinitial plus the temperature rise during operation, plus the temperature rise when stalled, minus the temperature drop when stopped. The initial motor temperature Tinitial is the ambient temperature Temperature a certain period of time (for example, 20 minutes) after the window stops operating.

[0050] Step S5: Execute corresponding graded thermal protection measures according to the estimated value of the window motor temperature and the pre-divided temperature protection intervals and temperature recovery intervals of different levels.

[0051] Regarding the above-mentioned graded thermal protection measures, the specific reference is as follows: the window motor temperature can be estimated in real time through the window motor thermal model. When the window motor temperature is higher than the preset first-level protection temperature threshold (the window motor burn-in temperature can be -40°C), the automatic window raising and lowering functions are prohibited, that is, only manual lifting and lowering are allowed; when the window motor temperature is higher than the preset second-level protection temperature threshold (the window motor burn-in temperature can be -20°C), all window movements are prohibited; when the window motor temperature drops to the preset first-level recovery temperature (the window motor burn-in temperature can be -20°C), the manual window raising and lowering functions of the window are restored first, that is, automatic lifting and lowering are temporarily prohibited; and when the window motor temperature drops to the preset second-level recovery temperature (the window motor burn-in temperature can be -40°C), all window functions are restored, that is, manual and electric lifting and lowering are allowed.

[0052] In summary, the main design concept of the present invention is to predict the current window motor temperature by analyzing the current window motor operating temperature, window operating resistance, window motor operating time, window motor downtime, and window motor stall time. Furthermore, the temperature protection and recovery intervals are divided into different temperature control levels. Based on the estimated window motor temperature level, hierarchical control is implemented and corresponding measures are taken, such as allowing only manual mode or prohibiting all modes. Similarly, during the motor temperature recovery phase, hierarchical measures are also used to gradually restore window operation. This present invention not only saves hardware thermal protection costs but also integrates the influencing factors of the multi-dimensional window temperature curve to achieve more accurate motor temperature estimation and perform targeted zoning and grading processing, thereby providing intelligent and detailed protection for the window motor.

[0053] If the expressions expressing directions are mentioned in the embodiments of the present invention, they are relative concepts based on the embodiments. In addition, "at least one" refers to one or more, and "more" refers to two or more. "And / or" describes the association relationship of the associated objects, indicating that three relationships may exist. For example, A and / or B can represent the existence of A alone, the existence of A and B at the same time, and the existence of B alone. Among them, A and B can be singular or plural. The character " / " generally indicates that the previous and next associated objects are in an "or" relationship. "At least one of the following" and similar expressions refer to any combination of these items, including any combination of single or plural items. For example, at least one of a, b and c can represent: a, b, c, a and b, a and c, b and c or a, b and c, where a, b, c can be single or multiple.

[0054] The above describes in detail the structure, features and effects of the present invention based on the embodiments shown in the drawings, but the above is only a preferred embodiment of the present invention. It should be noted that the technical features involved in the above embodiments and their preferred modes can be reasonably combined and matched into a variety of equivalent schemes by those skilled in the art without departing from or changing the design ideas and technical effects of the present invention; therefore, the scope of implementation of the present invention is not limited to what is shown in the drawings. Any changes made in accordance with the concept of the present invention, or modifications to equivalent embodiments with equivalent changes, which still do not exceed the spirit covered by the description and drawings, should be within the scope of protection of the present invention.

Claims

1. A window motor thermal protection method based on a window motor thermal model, characterized in that: include: Calculate the window motor operating temperature rise based on the heat generated when the window is running, the window operating speed, and the ambient temperature; Based on the heat dissipation and ambient temperature when the window is stopped, calculate the temperature drop of the window motor when it is stopped; Calculate the window motor stall temperature rise based on the heat generated when the motor is stalled and the ambient temperature; Obtaining the current state of the window motor and estimating the window motor temperature based on a preset window motor thermal model, wherein the window motor thermal model includes: estimated window motor temperature = window motor initial temperature + window motor operating temperature rise + window motor blocked rotor temperature rise - window motor shutdown temperature drop; Based on the estimated temperature of the window motor and the pre-divided temperature protection intervals and temperature recovery intervals of different levels, corresponding graded thermal protection measures are implemented respectively.

2. The window motor thermal protection method based on the window motor thermal model according to claim 1, characterized in that: Determining the window motor operating temperature rise includes: Calculate the heat generated by the window motor when it is running using the current, motor resistance, and motor running time. Optimizing said heat in conjunction with the window operating rate; Based on the optimized heat and the established motor heat capacity, the motor temperature rise is preliminarily calculated; The calculated preliminary temperature rise is corrected based on the ambient temperature to obtain the final motor operating temperature rise.

3. The window motor thermal protection method based on the window motor thermal model according to claim 1, characterized in that: Determining the window motor shutdown temperature drop includes: Calculate the heat dissipation of the window motor when it is stopped using the window motor heat dissipation coefficient, window motor heat dissipation area, current motor temperature, ambient temperature, and downtime. Preliminary calculation of the motor temperature drop based on the heat dissipation and the established motor heat capacity; The calculated preliminary temperature drop is corrected based on the ambient temperature to obtain the final motor shutdown temperature drop.

4. The window motor thermal protection method based on the window motor thermal model according to claim 1, characterized in that: Determining the window motor locked-rotor temperature rise includes: Calculate the heat generated when the window motor is blocked using the current, motor internal resistance, and motor blocking time. Based on the heat obtained and the established motor heat capacity, the motor temperature rise is preliminarily calculated; The calculated preliminary temperature rise is corrected based on the ambient temperature to obtain the final motor stall temperature rise.

5. The window motor thermal protection method based on the window motor thermal model according to claim 1, characterized in that: The respective execution of corresponding graded thermal protection measures specifically includes: When the estimated value is higher than the preset first-level protection temperature threshold, the automatic window lifting function is disabled and only manual lifting is allowed; When the estimated value is higher than the preset secondary protection temperature threshold, all window actions are prohibited; When the estimated value drops to the preset first-level recovery temperature, the manual lifting function of the window is restored first; When the estimated value drops to a preset secondary recovery temperature, all functions of the vehicle windows are restored.

6. The window motor thermal protection method based on the window motor thermal model according to any one of claims 1 to 5, characterized in that: The ambient temperature is obtained by jointly calibrating the cabin internal and external temperatures.

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