Heating control method and system for car seat

Abstract

Disclosed in the present invention are a heating control method and system for a car seat. The method comprises the following steps: sampling data fed back by a temperature sensor, and calculating the sampled data to obtain an average value; if the average value is within a preset first threshold range, disabling a heating module; if the average value is within a preset second threshold range, acquiring a sampling temperature corresponding to the average value as a current sampling temperature; setting a target temperature and comparing the target temperature with the current sampling temperature, substituting the target temperature and the current sampling temperature into a PID algorithm to calculate a PID output value, and on the basis of the PID output value, calculating a PWM duty cycle value for controlling heating; and by means of a high-frequency PWM to low-frequency on-off algorithm, converting a signal corresponding to the PWM duty cycle value into a low-frequency on-off signal to control the power supply to the heating wire. The amount of data used for parameter adjustment in a seat heating calibration process is reduced, and pulse radiation caused by high-frequency PWM is avoided while adaptive temperature regulation is achieved.

Description

A method and system for controlling car seat heating Technical Field

[0001] This invention relates to the field of temperature control in heating systems, and more particularly to a method and system for controlling heating in automobile seats. Background Technology

[0002] Traditional, older car seat heating systems without temperature sensors typically achieve temperature regulation in two ways. The first is by using an electronic control unit (ECU) to preset different heating levels and output different PWM signals to control the heating power output. The second is by controlling the on / off state of a relay, adjusting the duration of each on / off cycle. This sensorless control method cannot obtain the real-time temperature of the seat, and therefore cannot precisely control the seat temperature within a specific range by adjusting the control signal in real time. Changes in ambient temperature significantly affect the temperature control effect. When the ambient temperature is too low, the seat dissipates heat too quickly and fails to heat up. When the ambient temperature is high or the seat has good insulation, heat dissipation is slow, and this heating method can cause burns to occupants. Therefore, modern mainstream car seat heating systems incorporate temperature sensors (NTCs). These systems also typically achieve temperature regulation in two ways: the first is by using an MCU to collect the real-time temperature and compare it with a preset temperature to control the relay's opening and closing; the second is by using an MCU to collect the real-time temperature and compare it with a preset temperature to control the on / off state of a high-side switch chip. The method used in this paper is the second implementation method because the high-side switch chip is smaller than the relay, the circuit is simpler and easier to integrate into the MCU circuit board, the cost is low, and the control is relatively easy. The electrical schematic diagram is shown in Figure 2.

[0003] There are generally two methods for adjusting the temperature in existing heating control systems with NTC temperature sensors and high-side switches. The first method involves the MCU comparing the NTC feedback temperature with a preset temperature. When the NTC feedback temperature is higher than the preset target temperature and exceeds a certain threshold (e.g., 2 degrees Celsius), the high-side switch is shut off. When the NTC feedback temperature is lower than the preset target temperature and exceeds a certain threshold, the high-side switch is controlled to supply power to the heating element. This causes the NTC temperature to fluctuate within the preset temperature range around a certain threshold (e.g., 2 degrees Celsius). The disadvantage of this control method is that if only one threshold (e.g., 2 degrees Celsius) is set, the temperature will fluctuate around the same threshold for different heating levels (with different preset target temperatures). Furthermore, the threshold cannot be adjusted according to the ambient temperature. This leads to a significant impact on the control effect on the seat surface temperature at different ambient temperatures. Because heat dissipation is rapid at low ambient temperatures, if the NTC sensitivity is insufficient and the fluctuation threshold is not set appropriately, the control of the seat surface temperature at different levels will be unsatisfactory, failing to achieve adaptive adjustment. To achieve adaptive adjustment, the second approach is to use the NTC temperature collected by the MCU and the preset temperature as inputs to a PID algorithm for PID calculation. The PID calculation result is then converted into a PWM output to control the on / off state of the high-side switching chip, thereby achieving very stable control of the seat surface temperature. However, high-frequency PWM (e.g., 10Hz) on / off control of high-power devices like heating wires generates pulse radiation, which fails EMC testing. Summary of the Invention

[0004] In view of the above-mentioned shortcomings in the field of temperature control of current heating systems, the present invention provides a method and system for controlling automotive seat heating, which reduces the amount of data for parameter adjustment in the seat heating calibration process, and avoids pulse radiation generated by high-frequency PWM while achieving adaptive temperature regulation.

[0005] To achieve the above objectives, the embodiments of the present invention adopt the following technical solutions:

[0006] A method for controlling heating in a car seat, comprising a heating module and a temperature sensor installed inside the car seat, wherein the temperature sensor is used to collect and feed back the temperature of the heating module, and includes the following steps:

[0007] The temperature sensor data is sampled multiple times within a preset time interval, and the average value is calculated from the sampled data.

[0008] If the average value is within a preset first threshold range, then the heating module is turned off;

[0009] If the average value is within the preset second threshold range, then the sampling temperature corresponding to the average value is obtained as the current sampling temperature.

[0010] Set a target temperature to compare with the current sampled temperature, and substitute the target temperature and the current sampled temperature into the PID algorithm to calculate and obtain the PID output value. Then, calculate and obtain the PWM duty cycle value for controlling heating based on the PID output value.

[0011] If the PWM duty cycle value is higher than the preset PWM upper limit value, the heating module accelerates the heating process.

[0012] If the PWM duty cycle value is lower than the preset PWM lower limit value, the heating module will turn off heating.

[0013] According to one aspect of the present invention, the preset first threshold range is less than 160 or greater than 3920; the preset second threshold range is between 160 and 3920.

[0014] According to one aspect of the present invention, if the average value is less than 160 or greater than 3920, the temperature sensor is set to a short-circuit or open-circuit state, the heating power supply PWM signal is set to 0, and the heating is turned off; if the average value is between 160 and 3920, the temperature sensor is set to a normal state, and the next step is performed.

[0015] According to one aspect of the present invention, the data fed back by the temperature sensor is sampled multiple times within a preset time interval, and the average value of the sampled data is calculated. If the average value is within a preset second threshold range, the sampling temperature corresponding to the average value is obtained as the current sampling temperature. If the elapsed time does not meet the preset time, the above steps are continued until the above steps have elapsed for a complete preset time.

[0016] According to one aspect of the present invention, the step of setting a target temperature to compare with the current sampled temperature, substituting the target temperature and the current sampled temperature into a PID algorithm to calculate and obtain a PID output value, and calculating and obtaining a PWM duty cycle value for controlling heating based on the PID output value, specifically involves using a high-frequency PWM to low-frequency on / off algorithm to convert the signal corresponding to the PWM duty cycle value into a low-frequency on / off signal to control the power supply of the heating module.

[0017] According to one aspect of the present invention, the preset PWM upper limit value is set to 60; the preset PWM lower limit value is set to 40.

[0018] According to one aspect of the present invention, if the PWM duty cycle value is between a preset PWM upper limit value and a preset PWM lower limit value, the power supply output state of the heating module remains unchanged, and all values ​​are cleared and reassigned after a certain period of time.

[0019] According to one aspect of the present invention, after setting a certain time to clear all values ​​and reassign them, the process returns to the step of sampling the data fed back by the temperature sensor multiple times within a preset time interval, calculating the average value of the sampled data, and repeating the subsequent steps.

[0020] According to one aspect of the present invention, the steps of the PID algorithm are as follows: start heating; execute the PID algorithm; output the power supply PWM duty cycle through the output value of the PID algorithm; switch the power supply switch state according to the PWM duty cycle; control the heating wire to heat according to the power supply switch state; the temperature sensor feeds back the temperature of the heating wire; and the feedback is returned to execute the PID algorithm and the steps are repeated.

[0021] A car seat heating control system, comprising:

[0022] The temperature sensing module is used to collect the temperature of the heating module inside the seat;

[0023] The calculation module is used to calculate the average value of the data fed back by the temperature sensing module;

[0024] The conversion module is used to convert the average value into the corresponding current sampling temperature;

[0025] The PID algorithm module sets a target temperature and compares it with the current sampled temperature. It then substitutes the target temperature and the current sampled temperature into the PID algorithm to calculate and obtain the PID output value. Finally, it calculates the corresponding power supply PWM duty cycle value based on the PID output value.

[0026] The high-frequency PWM to low-frequency on / off algorithm module is used to convert the PWM duty cycle value into a low-frequency on / off signal to control the power supply of the heating wire.

[0027] The advantages of this invention are as follows: By sampling the data fed back from the temperature sensor multiple times within one second and calculating the average value of the sampled data; determining whether the average value of the sampled data is normal; if the average value is normal, obtaining the corresponding current sampled temperature based on the average value; setting a target temperature to compare with the current sampled temperature, and substituting the target temperature and the current sampled temperature into the PID algorithm to calculate and obtain the PID output value; calculating and obtaining the PWM duty cycle value for controlling heating based on the PID output value; and using a high-frequency PWM to low-frequency on / off algorithm to convert the signal corresponding to the PWM duty cycle value into a low-frequency on / off signal to control the heating wire power supply. This reduces the amount of data required for parameter adjustment during seat heating calibration and avoids pulse radiation generated by high-frequency PWM while achieving adaptive temperature regulation. Attached Figure Description

[0028] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0029] Figure 1 is a logic flowchart of a car seat heating control method and system according to the present invention.

[0030] Figure 2 is an electrical schematic diagram of the prior art of the automobile seat heating control method and system described in this invention;

[0031] Figure 3 is a comparison diagram of the high-frequency PWM control and low-frequency on / off control of the car seat heating control method and system described in this invention.

[0032] Figure 4 shows the effect of setting different upper and lower parameters of the PWM in the car seat heating control method and system of the present invention.

[0033] Figure 5 is a schematic diagram of the PID algorithm of the automobile seat heating control method and system of the present invention.

[0034] Figure 6 is a vehicle-wide NTC curve diagram of the automotive seat heating control method and system described in this invention.

[0035] Figure 7 is a curve of the actual controlled seat surface temperature of the car seat heating control method and system described in this invention. Detailed Implementation

[0036] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0037] Example 1:

[0038] As shown in Figure 1, a method for controlling heating in a car seat includes a heating module and a temperature sensor installed inside the car seat. The temperature sensor is used to collect and feed back the temperature of the heating module. The method includes the following steps:

[0039] S1: Sample the AD value of the temperature sensor feedback data 10 times within one second, and calculate the average value of the sampled data.

[0040] S2: If the average value is within the preset first threshold range, then the heating module is turned off.

[0041] In this embodiment, the preset first threshold range is less than 160 or greater than 3920. If the average value is less than 160 or greater than 3920, the temperature sensor is set to a short circuit or open circuit state, the heating power supply PWM signal is set to 0, and heating is turned off.

[0042] S3: If the average value is within the preset second threshold range, then obtain the sampling temperature corresponding to the average value as the current sampling temperature.

[0043] In this embodiment, the preset second threshold range is between 160 and 3920. If the average value is between 160 and 3920, the temperature sensor is set to normal state, and the sampling temperature corresponding to the average value is obtained as the current sampling temperature.

[0044] In step S1, the data fed back by the temperature sensor is sampled 10 times for AD value within one second, and the average value is calculated from the sampled data. In step S3, if the average value is within the preset second threshold range, the sampling temperature corresponding to the average value is obtained as the current sampling temperature. If less than one second has elapsed, the above steps continue until a full second has elapsed.

[0045] S4: Set the target temperature to compare with the current sampled temperature, and substitute the target temperature and the current sampled temperature into the PID algorithm to calculate and obtain the PID output value. Then, calculate and obtain the PWM duty cycle value for controlling heating based on the PID output value.

[0046] The steps of the PID algorithm are as follows: start heating; execute the PID algorithm; output the power supply PWM duty cycle based on the output value of the PID algorithm; switch the power supply switch state according to the PWM duty cycle; control the heating wire heating according to the power supply switch state; the temperature sensor provides feedback on the temperature of the heating wire; and the feedback is used to execute the PID algorithm and repeat the steps.

[0047] S5: A high-frequency PWM to low-frequency on / off algorithm is used to convert the signal corresponding to the PWM duty cycle value into a low-frequency on / off signal to control the power supply of the heating wire. If the PWM duty cycle value is higher than a preset PWM upper limit value, the heating module accelerates heating. In this embodiment, the preset PWM upper limit value is set to 60.

[0048] S6: A high-frequency PWM to low-frequency on / off algorithm is used to convert the signal corresponding to the PWM duty cycle value into a low-frequency on / off signal to control the power supply of the heating wire. If the PWM duty cycle value is lower than a preset PWM lower limit value, the heating module turns off heating. In this embodiment, the preset PWM lower limit value is set to 40.

[0049] If the PWM duty cycle value is between the preset PWM upper limit and the preset PWM lower limit, the power supply output state of the heating module remains unchanged. A one-second interval is set to clear all values ​​and reassign them. Then, returning to step S1, the data fed back from the temperature sensor is sampled multiple times within a preset time interval, and the average value is calculated from the sampled data. This process is repeated for subsequent steps.

[0050] The advantages of this invention are as follows: By sampling the data fed back from the temperature sensor multiple times within one second and calculating the average value of the sampled data; determining whether the average value of the sampled data is normal; if the average value is normal, obtaining the corresponding current sampled temperature based on the average value; setting a target temperature to compare with the current sampled temperature, and substituting the target temperature and the current sampled temperature into the PID algorithm to calculate and obtain the PID output value; calculating and obtaining the PWM duty cycle value for controlling heating based on the PID output value; and using a high-frequency PWM to low-frequency on / off algorithm to convert the signal corresponding to the PWM duty cycle value into a low-frequency on / off signal to control the heating wire power supply. This reduces the amount of data required for parameter adjustment during seat heating calibration and avoids pulse radiation generated by high-frequency PWM while achieving adaptive temperature regulation.

[0051] Example 2:

[0052] As shown in Figure 1, a car seat heating control system, based on the car seat heating control method described in Embodiment 1, includes:

[0053] The temperature sensing module is used to collect the temperature of the heating module inside the seat and convert the collected analog signal into a digital signal to provide feedback data.

[0054] The calculation module is used to sample the data fed back by the temperature sensor multiple times within a preset time interval and calculate the average value of the sampled data.

[0055] The average value determination module is used to determine the calculated average value. If the average value is within a preset first threshold range, the heating module is turned off. If the average value is within a preset second threshold range, the sampling temperature corresponding to the average value is obtained as the current sampling temperature.

[0056] The PID algorithm module sets a target temperature and compares it with the current sampled temperature. It then substitutes the target temperature and the current sampled temperature into the PID algorithm to calculate and obtain the PID output value. Finally, it calculates the corresponding power supply PWM duty cycle value based on the PID output value.

[0057] The high-frequency PWM to low-frequency on / off algorithm module is used to convert the PWM duty cycle value into a low-frequency on / off signal to control the power supply of the heating wire. If the PWM duty cycle value is higher than the preset PWM upper limit value, the heating module accelerates heating; if the PWM duty cycle value is lower than the preset PWM lower limit value, the heating module turns off heating.

[0058] Preferably, the calculation module further includes: determining whether the average value of the sampled data is normal.

[0059] By modifying some structures in the embodiments, the new embodiments can achieve the same technical functions and effects. The advantages of this invention are as follows: Multiple samples of data from the temperature sensor are taken within one second, and the average value of the sampled data is calculated; it is determined whether the average value of the sampled data is normal; if the average value is normal, the corresponding current sampled temperature is obtained based on the average value; a target temperature is set and compared with the current sampled temperature, and the target temperature and the current sampled temperature are substituted into the PID algorithm to calculate and obtain the PID output value; the PWM duty cycle value for controlling heating is calculated and obtained based on the PID output value; through a high-frequency PWM to low-frequency on / off algorithm, the signal corresponding to the PWM duty cycle value is converted into a low-frequency on / off signal to control the heating wire power supply. This reduces the amount of data for parameter adjustment during the seat heating calibration process and avoids pulse radiation generated by high-frequency PWM while achieving adaptive temperature regulation.

[0060] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A method for controlling heating in a car seat, wherein a heating module and a temperature sensor are installed inside the car seat, the temperature sensor being used to collect and feed back the temperature of the heating module, characterized in that... Includes the following steps: The temperature sensor data is sampled multiple times within a preset time interval, and the average value is calculated from the sampled data. If the average value is within a preset first threshold range, then the heating module is turned off; If the average value is within the preset second threshold range, then the sampling temperature corresponding to the average value is obtained as the current sampling temperature. Set a target temperature to compare with the current sampled temperature, and substitute the target temperature and the current sampled temperature into the PID algorithm to calculate and obtain the PID output value. Then, calculate and obtain the PWM duty cycle value for controlling heating based on the PID output value. If the PWM duty cycle value is higher than the preset PWM upper limit value, the heating module accelerates the heating process. If the PWM duty cycle value is lower than the preset PWM lower limit value, the heating module will turn off heating.

2. The method for controlling heating a car seat according to claim 1, characterized in that, The preset first threshold range is less than 160 or greater than 3920; the preset second threshold range is between 160 and 3920.

3. The method for controlling heating of a car seat according to claim 2, characterized in that, If the average value is less than 160 or greater than 3920, the temperature sensor is set to short-circuit or open-circuit state, the heating power supply PWM signal is set to 0, and heating is turned off; if the average value is between 160 and 3920, the temperature sensor is set to normal state, and the next step is performed.

4. The method for controlling heating a car seat according to claim 1, characterized in that, The process involves sampling the data fed back by the temperature sensor multiple times within a preset time interval and calculating the average value of the sampled data. If the average value is within a preset second threshold range, the sampling temperature corresponding to the average value is obtained as the current sampling temperature. If the elapsed time does not meet the preset time, the above steps continue until the above steps have elapsed for a complete preset time.

5. A method for controlling heating of a car seat according to any one of claims 1 to 4, characterized in that, The target temperature is set and compared with the current sampled temperature. The target temperature and the current sampled temperature are then substituted into the PID algorithm to calculate and obtain the PID output value. The PWM duty cycle value for controlling heating is calculated based on the PID output value. Specifically, a high-frequency PWM to low-frequency on / off algorithm is used to convert the signal corresponding to the PWM duty cycle value into a low-frequency on / off signal to control the power supply of the heating module.

6. The method for controlling heating a car seat according to claim 5, characterized in that, The preset PWM upper limit is set to 60; the preset PWM lower limit is set to 40.

7. The method for controlling heating of a car seat according to claim 1, characterized in that, If the PWM duty cycle value is between the preset PWM upper limit value and the preset PWM lower limit value, the power supply output state of the heating module remains unchanged, and all values ​​are cleared and reassigned after a certain period of time.

8. The method for controlling heating of a car seat according to claim 7, characterized in that, After setting a certain time interval to clear all values ​​and reassign them, the process returns to the step of sampling the data fed back by the temperature sensor multiple times within a preset time interval, calculating the average value of the sampled data, and repeating the subsequent steps.

9. A method for controlling heating a car seat according to claim 1, characterized in that, The steps of the PID algorithm are as follows: start heating; execute the PID algorithm; output the power supply PWM duty cycle through the output value of the PID algorithm; switch the power supply switch state according to the PWM duty cycle; control the heating wire heating according to the power supply switch state; and the temperature sensor provides feedback on the temperature of the heating wire. Feedback is given back to execute the PID algorithm and the steps are repeated.

10. A car seat heating control system, characterized in that, include: The temperature sensing module is used to collect the temperature of the heating module inside the seat; The calculation module is used to sample the data fed back by the temperature sensor multiple times within a preset time interval and calculate the average value of the sampled data. The average value determination module is used to determine the calculated average value. If the average value is within a preset first threshold range, the heating module is turned off. If the average value is within the preset second threshold range, then the sampling temperature corresponding to the average value is obtained as the current sampling temperature. The PID algorithm module sets a target temperature and compares it with the current sampled temperature. It then substitutes the target temperature and the current sampled temperature into the PID algorithm to calculate and obtain the PID output value. Finally, it calculates the corresponding power supply PWM duty cycle value based on the PID output value. The high-frequency PWM to low-frequency on / off algorithm module is used to convert the PWM duty cycle value into a low-frequency on / off signal to control the power supply of the heating wire. If the PWM duty cycle value is higher than the preset PWM upper limit value, the heating module accelerates heating; if the PWM duty cycle value is lower than the preset PWM lower limit value, the heating module turns off heating.

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