A dry burning detection method and system for film heater

Abstract

The present application relates to the technical field of preventing dry burning of film heaters, and discloses a dry burning detection method and system for film heaters, including a film heater assembly and a film temperature sensor, which can adjust the heating power of the film heating plate according to the control method of the first power-on stage and the control method of the continuous operation stage, obtain the first specified duty cycle configuration parameters during the period when the first specified output power is reached after the first specified time after power-on, and synchronously obtain the coolant operation parameters; after continuing to operate for a second specified time according to the first specified duty cycle configuration parameters, obtain the real-time temperature data compared with the temperature rise data at power-on; determine the corresponding temperature rise threshold value according to the coolant operation parameters; if the temperature rise data exceeds the temperature rise threshold value, it is determined that a dry burning situation exists, otherwise it enters the continuous operation stage control method, and the dry burning of the film heating plate can be detected in sections to ensure the timeliness and stability of the accurate determination of the dry burning detection, thereby greatly reducing the risk of the film heating plate being burned out.

Description

Technical Field

[0001] The present application relates to the technical field of preventing dry burning of film heaters, and in particular to a dry burning detection method and system for film heaters. Background Art

[0002] Film heaters are mainly used in electric vehicles or PHEV hybrid vehicles. Their main function is to provide heat source for the air conditioning system in the car. Compared with traditional PTC ceramic heaters, film heaters have the advantages of fast heating and stable current.

[0003] Its main function is to adjust the power of the heater to heat the coolant based on the input of the control signal, and at the same time feedback the working status and fault information of the product.

[0004] When the film heater is working, the heating film will conduct heat outward when it is energized. The heat is conducted to the water channel through the substrate to heat the coolant. The heated coolant circulates in the system to heat the corresponding components.

[0005] The temperature of the membrane can reach over 600°C when it is heating. If the coolant cannot take away the heat in time, the membrane will be at risk of dry burning. Therefore, when designing the product, it is necessary to consider quickly shutting down the output of the heater when the membrane heating plate is dry burning to protect the membrane heating plate from damage.

[0006] Compared with the widespread application of PTC ceramic heaters in air conditioning systems in passenger cars, film heaters are still in their infancy, and there are no mature application solutions on the market. Film heaters are low-cost and heat quickly, and the resistance of the film itself will increase with the increase in temperature, but it will not change significantly, so when the voltage is stable, there is no impact current when the film heater is started, and the output current is relatively stable. However, when the temperature is very high, the film is more easily damaged, so the temperature protection of the film heating should be more sensitive and effective to effectively protect the film from being burned. Summary of the invention

[0007] In order to provide a more reliable method and system for monitoring the dry burning of a membrane heater, the present application provides a method and system for detecting the dry burning of a membrane heater.

[0008] In a first aspect, the present application provides a dry burning detection system for a film heater, which adopts the following technical solution:

[0009] A dry burning detection system for a film heater, comprising a film heater assembly and a film temperature sensor;

[0010] The film heater assembly includes a high voltage connector, a low voltage connector, an MCU controller, an upper bridge IGBT, a film heating plate and a lower bridge IGBT;

[0011] The film temperature sensor is arranged on the surface of the film heating plate, and is used to obtain real-time temperature data of the film heating plate;

[0012] The MCU controller is used to adjust the heating power of the film heating plate according to a preset dry-burning detection method; wherein the preset dry-burning detection method includes a control method for the first power-on stage and a control method for the continuous operation stage;

[0013] The first power-on stage control method comprises:

[0014] According to a preset stable power configuration method, a first specified duty cycle configuration parameter is obtained during a period in which a first specified output power is reached after a first specified time has passed after power-on, and a coolant operation parameter is simultaneously obtained;

[0015] After continuing to run for a second specified time according to the first specified duty cycle configuration parameter, obtaining the temperature rise data of the real-time temperature data compared to the temperature rise data at power-on;

[0016] Determining a corresponding temperature rise threshold value according to the coolant operating parameter;

[0017] If the temperature rise data exceeds the temperature rise threshold, it is determined that dry burning occurs, and the membrane heating plate needs to be powered off and the fault is reported after the operation is stopped;

[0018] If the temperature rise data does not exceed the temperature rise threshold, entering the continuous operation stage control method;

[0019] The first specified duty cycle configuration parameters include a first duty cycle adjustment gradient and a first duty cycle adjustment time interval.

[0020] By adopting the above technical scheme, the present invention adopts the control method of the first power-on stage and the control method of the continuous operation stage to perform segmented detection of the dry burning of the membrane heating plate, thereby minimizing the error caused by the uncertainty of the coolant heat absorption and the temperature conduction lag of the membrane temperature sensor in the dry burning detection and judgment, ensuring the timeliness and stability of the accurate judgment of the dry burning detection, and greatly reducing the risk of the membrane heating plate being burned.

[0021] Optionally, the process of acquiring the first specified duty cycle configuration parameter includes:

[0022] Obtaining the initial resistance value of the film heating plate when it is powered on and starts working;

[0023] Calculate and obtain the maximum power value according to the starting resistance value and the configuration voltage;

[0024] Configure the percentage value of the first duty cycle adjustment gradient, and calculate the unit power value corresponding to the duty cycle of each of the first duty cycle adjustment gradients;

[0025] After calculating the duty cycle required to reach the first specified output power after the first specified time period, the first duty cycle adjustment time interval required for each adjustment of the duty cycle of the first duty cycle adjustment gradient is calculated.

[0026] By adopting the above technical solution, it is achieved that even when the voltage fluctuates, the first specified output power can be stably reached after the first specified time has passed after power-on, thereby ensuring that the power heating rate of the film heater is constant during the first specified time, and subsequently reaching the first specified output power after stably running for the second specified time, so as to obtain more reliable temperature rise data.

[0027] Optionally, the continuous operation phase control method includes:

[0028] According to a preset stable power configuration method, a second specified duty cycle configuration parameter is obtained during a period in which a second specified output power is reached after a third specified time period, and a coolant operation parameter is simultaneously obtained;

[0029] The second specified duty cycle configuration parameters include a second duty cycle adjustment gradient and a second duty cycle adjustment time interval.

[0030] By adopting the above technical solution, under the condition that dry burning is not triggered, it means that the system can work normally after the first specified time period and the second specified time period. At this time, after the third specified time period, the power regulation speed is continued to be stable to ensure the power stability of the film heater.

[0031] Optionally, the process of acquiring the second specified duty cycle configuration parameter includes:

[0032] Obtaining the initial resistance value of the film heating plate when it is powered on and starts working;

[0033] Calculate and obtain the maximum power value according to the starting resistance value and the configuration voltage;

[0034] Configure the percentage value of the second duty cycle adjustment gradient, and calculate the unit power value corresponding to the duty cycle of each second duty cycle adjustment gradient;

[0035] After calculating the duty cycle required to reach the second specified output power after the third specified time period, the second duty cycle adjustment time interval required for each adjustment of the duty cycle of the second duty cycle adjustment gradient is calculated.

[0036] Optionally, after each first duty cycle adjustment time interval or the second duty cycle adjustment time interval, a threshold value is determined for the current output current of the film heating plate:

[0037] When the current output current is greater than the specified expected current, the duty cycle is adjusted according to the first duty cycle adjustment gradient or the second duty cycle adjustment gradient.

[0038] By adopting the above technical solution, since the product has entered a stable working state, its resistance value increases with the increase of temperature. According to the TCR principle, the current output current value will continue to decrease. At this time, the current output current value of the film heater is compared with the specified expected current. If the current output current > the specified expected current, it means that the temperature rise rate is too high and the duty cycle needs to be lowered.

[0039] Optionally, the process of obtaining the temperature rise threshold includes:

[0040]

[0041]

[0042] in, is the temperature rise threshold, is the temperature rise data of the film temperature sensor when the first specified time and the second specified time have passed and the corresponding average flow rate of the coolant is 0, is the average flow rate of the coolant after the first specified time and the second specified time. The temperature rise data of the film temperature sensor at is the actual average coolant flow rate corresponding to the first specified time and the second specified time, and are the corresponding coefficients, and , The average flow rate of the coolant is The corresponding initial value.

[0043] By adopting the above technical solution, the temperature rise threshold is configured using a variable coefficient algorithm. When the actual average flow rate of the coolant is lower than the average flow rate of the coolant calibrated in advance by experiments When the temperature rise threshold is adjusted dynamically, the reliability of dry burning detection is guaranteed.

[0044] Optionally, it also includes a high-voltage battery, a high-voltage relay, a low-voltage battery, a low-voltage fuse and an air-conditioning controller connected to the film heater assembly; the high-voltage relay is connected to the high-voltage connector, and the low-voltage fuse and the air-conditioning controller are connected to the low-voltage connector.

[0045] Optionally, the film heating plate comprises a substrate, a dielectric layer, an electrode layer, a resistance layer and a protective layer which are connected in sequence; and the film temperature sensor is arranged on the protective layer.

[0046] In a second aspect, the present application provides a dry-burn detection method for a film heater, which is applied to a dry-burn detection system for a film heater.

[0047] In summary, the present application includes at least one of the following beneficial technical effects:

[0048] 1. The present invention adopts the control method of the first power-on stage and the control method of the continuous operation stage to perform segmented detection of the dry burning of the membrane heating plate, so as to minimize the error caused by the uncertainty of the heat absorption of the coolant and the temperature conduction hysteresis of the membrane temperature sensor to the dry burning detection and judgment, ensure the timeliness and stability of the accurate judgment of the dry burning detection, and greatly reduce the risk of the membrane heating plate being burned.

[0049] 2. The present invention adopts a variable coefficient algorithm to configure the temperature rise threshold. When the actual average flow rate of the coolant is lower than the average flow rate of the coolant calibrated in advance through experiments, the temperature rise threshold needs to be dynamically adjusted accordingly to eliminate the influence of factors such as different voltages, different flows, and different temperatures, so as to ensure the reliability of dry burning detection. BRIEF DESCRIPTION OF THE DRAWINGS

[0050] Figure 1 It is a schematic diagram of the connection principle of the film heater assembly and the peripheral modules in the present invention;

[0051] Figure 2 It is a flow chart of an example of the dry burning detection method of the film heater in the present invention. DETAILED DESCRIPTION

[0052] Embodiments of the present application are described in detail below, examples of which are shown in the accompanying drawings.

[0053] In the description of this specification, the description with reference to the terms "certain embodiments", "one embodiment", "some embodiments", "illustrative embodiments", "examples", "specific examples", or "some examples" means that the specific features, structures, materials, or characteristics described in conjunction with the embodiments or examples are included in at least one embodiment or example of the present application. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described may be combined in any one or more embodiments or examples in a suitable manner.

[0054] The present application embodiment discloses a dry burning detection system for a film heater, referring to Figure 1 , including a film heater assembly and a film temperature sensor;

[0055] In the actual environment of this embodiment, the periphery of the film heater assembly is configured with a high-voltage battery, a high-voltage relay, a low-voltage battery, a low-voltage fuse and an air-conditioning controller connected to the film heater assembly; the high-voltage relay is connected to the high-voltage connector, and the low-voltage fuse and the air-conditioning controller are connected to the low-voltage connector.

[0056] The film heater assembly includes a high voltage connector, a low voltage connector, an MCU controller, an upper bridge IGBT, a film heating plate and a lower bridge IGBT;

[0057] The film temperature sensor is arranged on the surface of the film heating plate, and is used to obtain real-time temperature data of the film heating plate;

[0058] The MCU controller is used to adjust the heating power of the film heating plate according to a preset dry-burning detection method; wherein the preset dry-burning detection method includes a control method for the first power-on stage and a control method for the continuous operation stage;

[0059] In the prior art, since the resistance of the film heater increases with the increase of its temperature, the current mainstream dry burning detection will be evaluated based on the resistance of the film heater. The resistance of the film heater is calculated based on the TCR effect by collecting the bus voltage, average current value and duty cycle.

[0060] Generally speaking, the calculation process of the resistance of the film heater is: the resistance of the film heater = bus voltage * duty cycle / average current (duty cycle: 0-1). Since the resistance of the film heater has a TCR effect, TCR (Temperature Coefficient of Resistance) is a parameter that measures the rate of change of resistance under temperature changes, indicating the relative change of resistance value per unit temperature change. In electronics, the TCR effect usually refers to the impact of the change of the resistance value of the resistor at different temperatures on the performance of the circuit. TCR is measured in ppm / °C, which reflects the change of resistance value within a temperature range. When the temperature rises, the resistance increases, which is a positive TCR, while when the temperature rises, the resistance decreases, which is a negative TCR.

[0061] Generally, the TCR of the membrane in the membrane heater is: 1500 ppm / ℃ (25℃-175℃). By obtaining the current resistance value of the membrane heater at the start of operation, the theoretical temperature protection resistance value at high temperature can be calculated. Then, when it is detected that the current resistance value is greater than the theoretical temperature protection resistance value, temperature protection is performed, power output is cut off, and dry burning protection is achieved;

[0062] However, in actual application, the resistance change caused by the TCR effect of the membrane heater is very small. For example, a 10 ohm resistor at 25°C will become 12.25 ohms at 175°C, a change of only 2.25 ohms. In addition, due to the deviation of hardware devices and acquisition circuits, there will be a certain amount of error in the acquisition of bus voltage and current values. These errors will cause the calculated resistance value to deviate, and this deviation value may even be greater than the resistance change caused by the TCR effect. Therefore, the strategy of determining whether the temperature is too high by calculating the resistance value based solely on the TCR effect cannot be guaranteed to be stable and effective.

[0063] Moreover, even if the temperature sensor is directly used to detect the film heater, it may not be completely reliable. The film heating plate includes a substrate, a dielectric layer, an electrode layer, a resistor layer and a protective layer connected in sequence; the film temperature sensor is arranged on the protective layer, which is on the surface of the film heating plate. Its temperature acquisition has a certain hysteresis, and the film heater needs to contact heat the coolant pipeline. When the coolant flow rate decreases, the temperature rise rate of the film heating plate will also increase. Therefore, in actual use, the film heater is more likely to dry burn during the startup phase (the coolant may not start to circulate or the flow rate has not reached the specified flow rate).

[0064] Therefore, in this embodiment of the present invention, the dry burning of the membrane heating plate is detected in sections by adopting the control method of the first power-on stage and the control method of the continuous operation stage, so as to minimize the error caused by the uncertainty of the coolant heat absorption and the temperature conduction lag of the membrane temperature sensor in the dry burning detection and judgment, ensure the timeliness and stability of the accurate judgment of the dry burning detection, and greatly reduce the risk of burning the membrane heating plate.

[0065] In the present invention, the first power-on stage control method includes:

[0066] According to a preset stable power configuration method, a first specified duty cycle configuration parameter is obtained during a period in which a first specified output power is reached after a first specified time has passed after power-on, and a coolant operation parameter is simultaneously obtained;

[0067] After continuing to run for a second specified time according to the first specified duty cycle configuration parameter, obtaining the temperature rise data of the real-time temperature data compared to the temperature rise data at power-on;

[0068] Determining a corresponding temperature rise threshold value according to the coolant operating parameter;

[0069] If the temperature rise data exceeds the temperature rise threshold, it is determined that dry burning occurs, and the membrane heating plate needs to be powered off and the fault is reported after the operation is stopped;

[0070] If the temperature rise data does not exceed the temperature rise threshold, entering the continuous operation stage control method;

[0071] The first specified duty cycle configuration parameters include a first duty cycle adjustment gradient and a first duty cycle adjustment time interval.

[0072] Calculate and obtain the maximum power value according to the starting resistance value and the configuration voltage;

[0073] Configure the percentage value of the first duty cycle adjustment gradient, and calculate the unit power value corresponding to the duty cycle of each of the first duty cycle adjustment gradients;

[0074] After calculating the duty cycle required to reach the first specified output power after the first specified time period, the first duty cycle adjustment time interval required for each adjustment of the duty cycle of the first duty cycle adjustment gradient is calculated.

[0075] By adopting the above technical solution, it is achieved that even when the voltage fluctuates, the first specified output power can be stably reached after the first specified time has passed after power-on, thereby ensuring that the power heating rate of the film heater is constant during the first specified time, and subsequently reaching the first specified output power after stably running for the second specified time, so as to obtain more reliable temperature rise data.

[0076] Optionally, the continuous operation phase control method includes:

[0077] According to a preset stable power configuration method, a second specified duty cycle configuration parameter is obtained during a period in which a second specified output power is reached after a third specified time period, and a coolant operation parameter is simultaneously obtained;

[0078] The second specified duty cycle configuration parameters include a second duty cycle adjustment gradient and a second duty cycle adjustment time interval.

[0079] By adopting the above technical solution, under the condition that dry burning is not triggered, it means that the system can work normally after the first specified time period and the second specified time period. At this time, after the third specified time period, the power regulation speed is continued to be stable to ensure the power stability of the film heater.

[0080] Optionally, the process of acquiring the second specified duty cycle configuration parameter includes:

[0081] Obtaining the initial resistance value of the film heating plate when it is powered on and starts working;

[0082] Calculate and obtain the maximum power value according to the starting resistance value and the configuration voltage;

[0083] Configure the percentage value of the second duty cycle adjustment gradient, and calculate the unit power value corresponding to the duty cycle of each second duty cycle adjustment gradient;

[0084] After calculating the duty cycle required to reach the second specified output power after the third specified time period, the second duty cycle adjustment time interval required for each adjustment of the duty cycle of the second duty cycle adjustment gradient is calculated.

[0085] Specifically, take the configuration of a membrane heater with a first designated duration of 2s, a second designated duration of 8s, a third designated duration of 35s, a first designated output power of 1000W, a second designated output power of 7000W, a maximum operating voltage of 500V, a minimum coolant flow rate of 3L / min, a first duty cycle adjustment gradient and a second duty cycle adjustment gradient of 1%, and a maximum rated power of 7000W as an example.

[0086] like Figure 2 As shown, after confirming that the film heating plate is the first output after power-on, the power-on stage control method is entered, otherwise the continuous operation stage control method is entered:

[0087] The control method of the power-on stage is:

[0088] Record the current film temperature sensor temperature;

[0089] Determine whether the timing after power-on has reached 10 seconds. If the timing after power-on has not reached 10 seconds, calculate the maximum power value, the power corresponding to the 1% duty cycle, the duty cycle required to output 1000W, the interval time required for each 1% duty cycle adjustment required to reach 1000W in 2 seconds, and the specified expected current according to the preset stable power configuration method, and then determine whether the required interval time has passed. If not, re-determine whether the timing after power-on has reached 10 seconds. If it exceeds the required interval time, enter the step of threshold judgment of the current output current of the membrane heating plate; and if the timing after power-on has reached 10 seconds, enter the dry burning judgment step. If it is determined that there is no dry burning, enter the continuous operation stage control method;

[0090] The control method for the continuous operation stage is:

[0091] After calculating the maximum power value, the power corresponding to 1% duty cycle, the duty cycle required for outputting 7000W, the interval time required for adjusting the duty cycle by 1% to reach 7000W in 35 seconds, and the specified expected current according to the preset stable power configuration method, it is determined whether the required interval time has passed. If not, the preset stable power configuration method is re-executed. If the required interval time has passed, the step of performing a threshold value judgment on the current output current of the film heating plate is entered;

[0092] Maximum power value = voltage * voltage / resistance;

[0093] The power corresponding to 1% duty cycle = maximum power value / 100;

[0094] The duty cycle required to output 1000W = the power value corresponding to 1000 / 1% duty cycle = the power value corresponding to 100000 / 100% duty cycle;

[0095] The duty cycle required to output 7000W = 7000 / 1% duty cycle corresponding to the power value = 700000 / 100% duty cycle corresponding to the power value;

[0096] The interval time required to adjust the duty cycle by 1% to reach 1000W in 2 seconds = 3*maximum power value / 100000;

[0097] The interval time required to adjust the duty cycle by 1% to reach 7000W in 35 seconds = 35*maximum power value / 100000;

[0098] Specified expected current = specified output power / voltage;

[0099] The process of the step of performing a threshold judgment on the current output current of the film heating plate is as follows:

[0100] When the current output current is greater than the specified expected current, the duty cycle is reduced by 1%;

[0101] When the current output current is ≤ the specified expected current, if it is in the power-on stage control method stage, return to the step of determining whether the timing after power-on has reached 10 seconds; if it is in the continuous operation stage control method, return to the step of calculating the maximum power value.

[0102] With this design, at the 10th second of timing, the film heater runs at a stable power of 1000W for 8 seconds. If the coolant is not flowing or there is no coolant, the temperature of the film temperature sensor will rise more than the film temperature sensor temperature recorded at the start of work. If the coolant is flowing, the heat is taken away and the temperature rise of the film temperature sensor is smaller.

[0103] Therefore, the temperature rise protection value needs to be calibrated on different products. In this embodiment, a 7KW film heater is selected. Under different voltages, the calibration results are:

[0104] ①: Dry burning without coolant flow, the temperature rise of the film temperature sensor at the 10th second of the first power-on output is 19°C.

[0105] ②: The coolant can flow, the flow rate is 3L / min, and the temperature rise of the film temperature sensor is 13℃ at the 10th second after the first power-on output.

[0106] In this way, since the detection logic limits the power output within the 10-second detection period, the temperature rise in the 10th second is basically fixed during dry burning. In this case, the dry burning judgment step is: determine whether the temperature value collected by the current film temperature sensor satisfies (the film temperature sensor temperature value recorded at startup + 16°C, 16°C is the middle value of 19°C and 13°C). If it is satisfied, it is determined that dry burning exists, and an over-temperature fault is reported, and the film heater stops outputting, otherwise it enters the continuous operation stage control method. Under the condition of the maximum operating voltage of 500V and the minimum coolant flow rate of 3L / min, a temperature rise of 13°C will not mistakenly trigger the dry burning protection, so the protection measures are stable and effective.

[0107] The protection can be triggered in the 10th second after the product starts working, which is very timely. During this period, the power output is only 1000W. Even if the product really has a dry burning situation, the 1000W output power will not cause the film temperature to be very high, further protecting the product from working at extremely high temperatures. The most important part of this implementation is the logic of this dry burning detection method. Within the detection time of 10 seconds, the power startup rate and output power are guaranteed to be consistent, which also ensures the consistency of the heat generated, and also ensures the consistency of the temperature rise of the film temperature sensor.

[0108] The second is the control of the duty cycle adjustment rate. The software control method can achieve consistency in the time to reach the set power under different voltages. This is very important for the heating stability of the product and is also convenient for the control of the entire vehicle.

[0109] However, the coolant flow rate is still lower than 3L / min. In this case, the process of obtaining the temperature rise threshold includes:

[0110]

[0111]

[0112] in, is the temperature rise threshold, is the temperature rise data of the film temperature sensor when the first specified time and the second specified time have passed and the corresponding average flow rate of the coolant is 0 or there is no coolant, is the average flow rate of the coolant after the first specified time and the second specified time. The temperature rise data of the film temperature sensor at is the actual average coolant flow rate corresponding to the first specified time and the second specified time, and are the corresponding coefficients, and , The average flow rate of the coolant is The corresponding initial value can be set to 0.5.

[0113] By adopting the above technical solution, the smaller the temperature rise threshold is, the easier it is to trigger the dry burning judgment in the actual detection process. Therefore, the variable coefficient algorithm is used to configure the temperature rise threshold. Generally speaking, Compared with Smaller, so when the actual average flow rate of the coolant is lower than the average flow rate of the coolant calibrated in advance by experiment The temperature rise threshold can be dynamically adjusted accordingly to minimize the temperature rise threshold, thereby ensuring the reliability of dry-burn detection while reducing the probability of false triggering of dry-burn detection.

[0114] In a second aspect, the present application provides a dry-burn detection method for a film heater, which is applied to a dry-burn detection system for a film heater.

[0115] Although the embodiments of the present application have been shown and described above, it can be understood that the above embodiments are exemplary and cannot be understood as limitations on the present application. Ordinary technicians in this field can change, modify, replace and modify the above embodiments within the scope of the present application.

Claims

1. A dry burning detection system for a film heater, characterized in that: including a film heater assembly and a film temperature sensor; The film heater assembly includes a high voltage connector, a low voltage connector, an MCU controller, an upper bridge IGBT, a film heating plate and a lower bridge IGBT; The film temperature sensor is arranged on the surface of the film heating plate, and is used to obtain real-time temperature data of the film heating plate; The MCU controller is used to adjust the heating power of the film heating plate according to a preset dry-burning detection method; wherein the preset dry-burning detection method includes a control method for the first power-on stage and a control method for the continuous operation stage; The first power-on stage control method comprises: According to a preset stable power configuration method, a first specified duty cycle configuration parameter is obtained during a period in which a first specified output power is reached after a first specified time has passed after power-on, and a coolant operation parameter is simultaneously obtained; After continuing to run for a second specified time according to the first specified duty cycle configuration parameter, obtaining the temperature rise data of the real-time temperature data compared to the temperature rise data at power-on; Determining a corresponding temperature rise threshold value according to the coolant operating parameter; If the temperature rise data exceeds the temperature rise threshold, it is determined that dry burning occurs, and the membrane heating plate needs to be powered off and the fault is reported after the operation is stopped; If the temperature rise data does not exceed the temperature rise threshold, entering the continuous operation stage control method; Wherein, the first specified duty cycle configuration parameter includes a first duty cycle adjustment gradient and a first duty cycle adjustment time interval; The process of obtaining the first specified duty cycle configuration parameter includes: Obtaining the initial resistance value of the film heating plate when it is powered on and starts working; Calculate and obtain the maximum power value according to the starting resistance value and the configuration voltage; Configure the percentage value of the first duty cycle adjustment gradient, and calculate the unit power value corresponding to the duty cycle of each of the first duty cycle adjustment gradients; After calculating the duty cycle required to reach the first specified output power after the first specified time period, the first duty cycle adjustment time interval required for each adjustment of the duty cycle of the first duty cycle adjustment gradient is calculated.

2. The dry burning detection system for a film heater according to claim 1, characterized in that: The continuous operation stage control method comprises: According to a preset stable power configuration method, a second specified duty cycle configuration parameter is obtained during a period in which a second specified output power is reached after a third specified time period, and a coolant operation parameter is simultaneously obtained; The second specified duty cycle configuration parameters include a second duty cycle adjustment gradient and a second duty cycle adjustment time interval.

3. The dry burning detection system for a film heater according to claim 2, characterized in that: The process of obtaining the second specified duty cycle configuration parameter includes: Obtaining the initial resistance value of the film heating plate when it is powered on and starts working; Calculate and obtain the maximum power value according to the starting resistance value and the configuration voltage; Configure the percentage value of the second duty cycle adjustment gradient, and calculate the unit power value corresponding to the duty cycle of each second duty cycle adjustment gradient; After calculating the duty cycle required to reach the second specified output power after the third specified time period, the second duty cycle adjustment time interval required for each adjustment of the duty cycle of the second duty cycle adjustment gradient is calculated.

4. The dry burning detection system for a film heater according to claim 3, characterized in that: After each time interval of the first duty cycle adjustment time interval or the second duty cycle adjustment time interval, a threshold value is determined for the current output current of the film heating plate: When the current output current is greater than the specified expected current, the duty cycle is adjusted according to the first duty cycle adjustment gradient or the second duty cycle adjustment gradient.

5. The dry burning detection system for a film heater according to claim 3, characterized in that: The process of obtaining the temperature rise threshold includes: in, is the temperature rise threshold, is the temperature rise data of the film temperature sensor when the first specified time and the second specified time have passed and the corresponding average flow rate of the coolant is 0, is the average flow rate of the coolant after the first specified time and the second specified time. The temperature rise data of the film temperature sensor at is the actual average coolant flow rate corresponding to the first specified time and the second specified time, and are the corresponding coefficients, and , The average flow rate of the coolant is The corresponding initial value.

6. The dry burning detection system for a film heater according to claim 1, characterized in that: It also includes a high-voltage battery, a high-voltage relay, a low-voltage battery, a low-voltage fuse and an air-conditioning controller connected to the film heater assembly; the high-voltage relay is connected to the high-voltage connector, and the low-voltage fuse and the air-conditioning controller are connected to the low-voltage connector.

7. The dry burn detection system for a film heater according to claim 1, characterized in that: The film heating plate comprises a substrate, a dielectric layer, an electrode layer, a resistance layer and a protective layer which are connected in sequence; and the film temperature sensor is arranged on the protective layer.

8. A dry burning detection method for a film heater, characterized in that: The dry burning detection system for a film heater is applied as claimed in any one of claims 1 to 7.

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