PTC heater control method and system and computer readable medium

Abstract

The invention relates to the technical field of automotive electronic thermal management, and discloses a PTC heater control method and system and a computer readable medium. The method comprises the following steps: when the PTC heater enters a power stable state, obtaining the total thermal resistance from an IGBT junction to a temperature sensor based on a heat transfer path; obtaining the steady-state junction temperature of the IGBT according to the total thermal resistance based on the power integral; when the difference value of the steady-state junction temperature is greater than a preset junction temperature difference value threshold value, calculating the junction temperature deviation and the duty ratio adjusting quantity of the IGBT according to the steady-state junction temperature; and dynamically adjusting the PWM duty ratio of the IGBT according to the junction temperature deviation and the duty ratio adjusting quantity. Accurate estimation of the IGBT junction temperature is achieved by calculating the total thermal resistance and the steady-state junction temperature, the deviation between the temperature sensor and the actual junction temperature is corrected, and the timeliness and accuracy of over-temperature detection are improved; and realizing multi-channel IGBT junction temperature dynamic balance control through junction temperature deviation and duty ratio adjusting quantity. And the optimization of the heating performance of the PTC heater is realized through cooperation of the two.

Description

Technical Field

[0001] This invention relates to the field of automotive electronic thermal management technology, and in particular to a PTC heater control method, system, and computer-readable medium. Background Technology

[0002] With the rapid iteration of the global new energy vehicle industry, winter cabin heating and battery insulation have become core necessities for users. PTC heaters, with their advantages such as rapid heating response, adjustable output power, and self-limiting temperature safety features, have become the mainstream solution for thermal management systems of new energy vehicles and are widely used in various pure electric and plug-in hybrid models.

[0003] Currently, the power requirements of PTC heaters in new energy vehicles are typically between 2 and 10 kW, requiring direct connection to a 200-800V high-voltage power battery system. In such high-voltage, high-current applications, IGBTs, as core power devices with both low conduction losses and high-frequency switching characteristics, are responsible for the power regulation and on / off control of the PTC heater, making them a key component for ensuring the stable operation of the heating system. In actual operating conditions, PTC heaters suffer from performance degradation, shortened lifespan, and in severe cases, even thermal breakdown failure, threatening the safety of the entire vehicle's electrical system.

[0004] To address the aforementioned risks, temperature sensors are typically placed near the IGBTs to collect temperature data in real time and feed it back to the controller. When the temperature of a particular IGBT reaches a preset over-temperature threshold, a global power degradation or shutdown protection strategy is triggered. However, this technology cannot achieve precise detection of IGBT junction temperature and lacks an effective multi-IGBT junction temperature equalization control mechanism. This makes it difficult to balance safety and heating performance in PTC heaters, becoming a key bottleneck restricting the optimization and upgrading of thermal management systems for new energy vehicles. Summary of the Invention

[0005] The main objective of this invention is to provide a PTC heater control method, system, and computer-readable medium, which aims to solve at least one of the aforementioned technical problems.

[0006] In a first aspect, embodiments of the present invention provide a PTC heater control method, comprising:

[0007] When the PTC heater enters the power steady state, the total thermal resistance from the IGBT junction to the temperature sensor is obtained based on the heat transfer path.

[0008] The steady-state junction temperature of the IGBT is obtained based on the total thermal resistance using power integration.

[0009] When the difference in steady-state junction temperature is greater than a preset junction temperature difference threshold, the junction temperature deviation and duty cycle adjustment of the IGBT are calculated based on the steady-state junction temperature.

[0010] The PWM duty cycle of the IGBT is dynamically adjusted based on the junction temperature deviation and duty cycle adjustment amount.

[0011] In some embodiments, obtaining the total thermal resistance from the IGBT junction to the temperature sensor based on the heat transfer path includes:

[0012] The heat transfer path from the IGBT junction to the temperature sensor is quantified as IGBT junction, IGBT housing and temperature sensor.

[0013] Obtain the first thermal resistance from the IGBT junction to the IGBT case from the IGBT datasheet.

[0014] Calibrate the second thermal resistance from the IGBT case to the temperature sensor;

[0015] The total thermal resistance from the IGBT junction to the temperature sensor is obtained based on the first thermal resistance and the second thermal resistance.

[0016] In some embodiments, calibrating the second thermal resistance from the IGBT housing to the temperature sensor includes:

[0017] The PCB board of the PTC heater is placed in a constant temperature chamber for calibration testing; wherein, the PCB board includes an IGBT and a temperature sensor;

[0018] Based on the calibration test, the actual power consumption of the IGBT, the temperature sensor temperature, and the IGBT case temperature were obtained.

[0019] The second thermal resistance from the IGBT case to the temperature sensor is calculated based on the actual power consumption of the IGBT, the temperature of the temperature sensor, and the temperature of the IGBT case.

[0020] In some embodiments, obtaining the steady-state junction temperature of the IGBT based on the total thermal resistance using power integration includes:

[0021] The average power of the IGBT under the power steady-state condition of the PTC heater was calculated based on the integral method.

[0022] The temperature difference between the IGBT junction and the temperature sensor is obtained based on the average power and the total thermal resistance.

[0023] The steady-state junction temperature of the IGBT is obtained based on the temperature collected by the temperature sensor and the temperature difference.

[0024] In some embodiments, the calculation of the average power of the IGBT under the stable power state of the PTC heater based on the integral method includes:

[0025] Select one or more complete PWM switching cycles as the integral calculation period;

[0026] Obtain the collector-emitter voltage and collector current of the IGBT;

[0027] The instantaneous power at each sampling moment is calculated based on the collector-emitter voltage and collector current.

[0028] The instantaneous power is integrated based on the integration calculation period and sampling interval to obtain the average power of the IGBT.

[0029] In some embodiments, obtaining the collector-emitter voltage and collector current of the IGBT includes:

[0030] Collector-emitter voltage and collector current of the IGBT are acquired at a fixed sampling frequency;

[0031] or;

[0032] Obtain the collector-emitter voltage of the IGBT from its datasheet, and acquire the collector current by sampling the current in the corresponding heating circuit.

[0033] In some embodiments, calculating the junction temperature deviation and duty cycle adjustment of the IGBT based on the steady-state junction temperature includes:

[0034] The average junction temperature is obtained by calculating the average steady-state junction temperature of all IGBTs.

[0035] The junction temperature deviation of the IGBT is calculated based on the difference between the steady-state junction temperature of each IGBT and the average junction temperature.

[0036] Substituting the junction temperature deviation into the temperature difference-duty cycle conversion model, the duty cycle adjustment amount for each IGBT is obtained.

[0037] In some embodiments, dynamically adjusting the PWM duty cycle of the IGBT based on the junction temperature deviation and the duty cycle adjustment amount includes:

[0038] When the junction temperature deviation is greater than zero, the PWM duty cycle of the IGBT is reduced according to the duty cycle adjustment amount;

[0039] When the junction temperature deviation is less than zero, the PWM duty cycle of the IGBT is increased according to the duty cycle adjustment amount;

[0040] When the junction temperature deviation is zero, the PWM duty cycle of the IGBT is kept constant.

[0041] In a second aspect, embodiments of the present invention provide a PTC heater control system, comprising:

[0042] The total thermal resistance acquisition module is used to obtain the total thermal resistance from the IGBT junction to the temperature sensor based on the heat transfer path when the PTC heater enters the power steady state.

[0043] The steady-state junction temperature calculation module is used to obtain the steady-state junction temperature of the IGBT based on the total thermal resistance according to the power integral.

[0044] The junction temperature equalization determination module is used to calculate the junction temperature deviation and duty cycle adjustment of the IGBT based on the steady-state junction temperature when the difference in the steady-state junction temperature is greater than a preset junction temperature difference threshold.

[0045] The dynamic control module is used to dynamically adjust the PWM duty cycle of the IGBT based on the junction temperature deviation and the duty cycle adjustment amount.

[0046] Thirdly, embodiments of the present invention provide a computer-readable medium on which a computer program is stored, wherein the computer program, when executed by a processor, implements the steps of any of the methods described above.

[0047] This invention provides a PTC heater control method, comprising: when the PTC heater enters a power steady state, obtaining the total thermal resistance from the IGBT junction to the temperature sensor based on the heat transfer path; obtaining the steady-state junction temperature of the IGBT based on the total thermal resistance using power integration; when the difference between the steady-state junction temperatures is greater than a preset junction temperature difference threshold, calculating the junction temperature deviation and duty cycle adjustment of the IGBT based on the steady-state junction temperature; and dynamically adjusting the PWM duty cycle of the IGBT based on the junction temperature deviation and duty cycle adjustment. In this invention, accurate estimation of the IGBT junction temperature is achieved by calculating the total thermal resistance and steady-state junction temperature, correcting the deviation between the temperature sensor and the actual junction temperature, and improving the timeliness and accuracy of over-temperature detection; dynamic equalization control of the junction temperature of multiple IGBTs is achieved through the junction temperature deviation and duty cycle adjustment, reducing the junction temperature difference between multiple IGBTs, lowering the highest IGBT junction temperature in the system, and reducing the frequency of unnecessary global power degradation or shutdown protection triggering. The two work together to optimize the heating performance of the PTC heater, thereby maximizing the heating performance of the PTC heater while ensuring the safe operation of the IGBT, thus balancing system safety and user comfort. Attached Figure Description

[0048] Figure 1 A schematic flowchart of a PTC heater control method provided in an embodiment of the present invention;

[0049] Figure 2 This is a general block diagram of the multi-channel IGBT junction temperature dynamic equalization control strategy involved in the embodiments of the present invention;

[0050] Figure 3 This is a flowchart illustrating the calculation of the steady-state junction temperature of the IGBT involved in the embodiments of the present invention;

[0051] Figure 4This is a flowchart illustrating the multi-channel IGBT junction temperature equalization determination and power regulation scheme in an embodiment of the present invention;

[0052] Figure 5 A structural block diagram of a PTC heater control system provided in an embodiment of the present invention;

[0053] Figure 6 This is a structural block diagram of an electronic device provided in an embodiment of the present invention.

[0054] The realization of the objective, functional features and advantages of the present invention will be further explained in conjunction with the embodiments and with reference to the accompanying drawings. Detailed Implementation

[0055] To enable those skilled in the art to better understand the technical solutions of the present invention, exemplary embodiments of the present invention are described below in conjunction with the accompanying drawings, including various details of the embodiments of the present invention to aid understanding. These should be considered merely exemplary. Therefore, those skilled in the art should recognize that various changes and modifications can be made to the embodiments described herein without departing from the scope and spirit of the present invention. Similarly, for clarity and brevity, descriptions of well-known functions and structures are omitted in the following description.

[0056] Where there is no conflict, the various embodiments of the present invention and the features thereof may be combined with each other.

[0057] As used herein, the term “and / or” includes any and all combinations of one or more related enumerated entries.

[0058] The terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the invention. As used herein, the singular forms “a” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will also be understood that when the terms “comprising” and / or “made of” are used in this specification, the presence of the stated feature, integral, step, operation, element, and / or component is specified, but the presence or addition of one or more other features, integrals, steps, operations, elements, components, and / or groups thereof is not excluded. Terms such as “connected” or “linked” are not limited to physical or mechanical connections but can include electrical connections, whether direct or indirect.

[0059] Unless otherwise specified, all terms used herein (including technical and scientific terms) have the same meaning as commonly understood by one of ordinary skill in the art. It will also be understood that terms such as those defined in commonly used dictionaries should be interpreted as having the meaning consistent with their meaning in the context of the relevant art and the invention, and will not be interpreted as having an idealized or overly formal meaning unless expressly so defined herein.

[0060] In the technical solution of this invention, the collection, storage, use, processing, transmission, provision, and disclosure of user personal information all comply with relevant laws and regulations and do not violate public order and good morals. The use of user data in this technical solution follows relevant national laws and regulations (e.g., the "Information Security Technology - Personal Information Security Specification"). For example: appropriate measures are taken for personal information access control; restrictions are imposed on the display of personal information; the purpose of using personal information does not exceed the scope of direct or reasonable association; and explicit identity targeting is eliminated when using personal information to avoid precisely locating a specific individual.

[0061] In related technologies, PTC heaters generally adopt a topology of multiple heating cores connected in parallel. Each heating core is equipped with an independent IGBT for drive and control. The controller outputs multiple PWM signals to adjust the conduction time of the corresponding IGBT, thereby achieving precise distribution of the overall heating power. However, in actual operating conditions, IGBTs need to withstand tens of amperes of operating current for a long time, inevitably generating conduction and switching losses, which causes their junction temperature to rise continuously. If the junction temperature exceeds the rated threshold (usually 150~175℃), it will cause device performance degradation, shortened lifespan, and in severe cases, even thermal breakdown failure, threatening the safety of the entire vehicle's electrical system.

[0062] To address these risks, relevant technologies typically employ temperature sensors placed near the IGBTs to collect temperature data in real time and feed it back to the controller. When the temperature of a particular IGBT reaches a preset over-temperature threshold, a global power degradation or shutdown protection strategy is triggered. However, this approach suffers from two major technical flaws: First, due to the thermal resistance formed by the packaging and heat dissipation substrate between the temperature sensor and the IGBT junction, the temperature signal collected by the sensor exhibits significant lag and is consistently lower than the actual junction temperature of the IGBT. This results in untimely over-temperature detection response and even protection failures caused by excessive sampling deviations. Second, due to factors such as the dispersion of device parameters, differences in heat dissipation conditions, and uneven load distribution among multiple IGBTs, the junction temperature rise varies significantly. Existing protection strategies rely solely on the highest detected IGBT temperature for global control, often forcibly reducing overall power or shutting down when most IGBTs are still within safe operating temperatures. This causes unnecessary loss of heating performance and severely impacts cabin heating comfort and battery insulation in winter.

[0063] To address at least one of the technical problems existing in the aforementioned related technologies, the present invention provides a PTC heater control method. Figure 1 This is a flowchart illustrating a PTC heater control method provided in an embodiment of the present invention.

[0064] As one embodiment of the present invention, such as Figure 1 As shown, the PTC heater control method includes:

[0065] Step S100: When the PTC heater enters the power steady state, obtain the total thermal resistance from the IGBT junction to the temperature sensor based on the heat transfer path;

[0066] Step S200: Obtain the steady-state junction temperature of the IGBT based on the total thermal resistance using power integration;

[0067] Step S300: When the difference in steady-state junction temperature is greater than a preset junction temperature difference threshold, calculate the junction temperature deviation and duty cycle adjustment of the IGBT based on the steady-state junction temperature.

[0068] Step S400: Dynamically adjust the PWM duty cycle of the IGBT according to the junction temperature deviation and duty cycle adjustment amount.

[0069] It should be noted that the execution subject in this embodiment can be an electronic device, which can be a computer device with data processing function, or other devices that can achieve the same or similar functions. This embodiment does not limit this. In this embodiment, a computer device is used as an example for explanation.

[0070] For example, addressing the technical problems in related technologies such as large IGBT junction temperature detection deviation, slow response, and unnecessary performance loss of PTC heaters due to uneven junction temperatures among multiple IGBTs, this embodiment provides a PTC heater control method. This method is based on multi-IGBT junction temperature equalization control to optimize the heating performance of the PTC heater. The core objective of this method is to: achieve accurate estimation of IGBT junction temperature, correct the deviation between the temperature sensor and the actual junction temperature, and improve the timeliness and accuracy of over-temperature detection; establish a dynamic equalization control strategy for multi-IGBT junction temperatures, reduce the junction temperature difference between multiple IGBTs, lower the highest IGBT junction temperature in the system, and reduce the frequency of unnecessary global power degradation or shutdown protection triggering; and maximize the maintenance of PTC heater heating performance while ensuring IGBT operational safety, balancing system safety and user comfort.

[0071] like Figure 2 As shown, the multi-IGBT junction temperature dynamic equalization control strategy includes four processes. In practice, the first step is to determine the power stability state of the PTC heater. Specifically, by monitoring the deviation between the actual output power and the target power of the PTC heater in real time, it is determined whether the PTC heater has entered / exited the power stability state, and subsequent processes are started or stopped based on the changes in the PTC heater's state.

[0072] For example, if the state of the PTC heater remains unchanged, power monitoring continues; if the PTC heater transitions from an unstable state to a stable power state, the IGBT junction temperature detection and IGBT junction temperature equalization determination process is initiated; if the PTC heater transitions from a stable power state to an unstable state, the IGBT junction temperature detection, IGBT junction temperature equalization determination, and power regulation process are stopped.

[0073] In this embodiment, when the PTC heater enters a stable power state, the IGBT junction temperature detection and IGBT junction temperature equalization determination process is initiated. This process includes two parts: an IGBT junction temperature accurate estimation process and a multi-channel IGBT junction temperature dynamic equalization control strategy. The two work together to optimize the heating performance of the PTC heater. The technical details are described below with reference to the specific steps.

[0074] In some embodiments, obtaining the total thermal resistance from the IGBT junction to the temperature sensor based on the heat transfer path includes: quantifying the heat transfer path from the IGBT junction to the temperature sensor into the IGBT junction, the IGBT case, and the temperature sensor; obtaining a first thermal resistance from the IGBT junction to the IGBT case according to the IGBT datasheet; calibrating a second thermal resistance from the IGBT case to the temperature sensor; and obtaining the total thermal resistance from the IGBT junction to the temperature sensor based on the first thermal resistance and the second thermal resistance.

[0075] In some embodiments, calibrating the second thermal resistance from the IGBT case to the temperature sensor includes: placing the PCB board of the PTC heater in a constant temperature chamber for calibration testing; wherein the PCB board includes an IGBT and a temperature sensor; obtaining the actual power consumption of the IGBT, the temperature of the temperature sensor, and the IGBT case temperature based on the calibration test; and calculating the second thermal resistance from the IGBT case to the temperature sensor based on the actual power consumption of the IGBT, the temperature of the temperature sensor, and the IGBT case temperature.

[0076] Specifically, the IGBT junction temperature accurate estimation process is as follows: by quantifying the heat transfer path loss from the IGBT junction to the temperature sensor, and combining it with the actual operating power of the IGBT, the junction temperature is accurately estimated, effectively correcting the sensor acquisition deviation. This includes two parts: obtaining the total thermal resistance from the IGBT junction to the temperature sensor and calculating the steady-state junction temperature of the IGBT.

[0077] For example, the total thermal resistance from the IGBT junction to the temperature sensor is obtained as follows: The heat transfer path from the IGBT junction to the temperature sensor can be simplified to "IGBT junction → IGBT case → temperature sensor", and the total thermal resistance is... This path represents the sum of the thermal resistances of each segment along that path, specifically the thermal resistance from the IGBT junction to the casing. Thermal resistance from IGBT case to temperature sensor The composition and specific steps are as follows:

[0078] Step 1: Directly consult the IGBT datasheet to obtain the junction-to-shell thermal resistance. .

[0079] Step 2: Calibrate the thermal resistance from the IGBT case to the temperature sensor The specific calibration methods include:

[0080] a. Place the actual PTC heater's PCB board (with IGBTs and temperature sensors already installed) in a constant temperature chamber;

[0081] b. Apply the rated drive voltage (e.g., 15V) to the IGBT gate to bring the IGBT to full conduction and configure a constant current load;

[0082] c. Start the load, keep the IGBT continuously conducting, and after the IGBT's heat dissipation stabilizes, record the actual power consumption P of the IGBT. IGBT功耗 Temperature sensor temperature T 传感器温度 and IGBT case temperature T IGBT ;

[0083] d. Calculate the thermal resistance from the tube shell to the temperature sensor: .

[0084] Step 3: Calculate the total thermal resistance. Add the thermal resistance from the junction to the casing to the thermal resistance from the casing to the temperature sensor to obtain the total thermal resistance: .

[0085] Understandably, a datasheet (often called a data manual, specification sheet, or parameter table) is a detailed technical document published by an electronic component manufacturer. It describes all the performance, parameters, limits, usage methods, and physical dimensions of a specific electronic component (such as IGBTs, chips, resistors, sensors, etc.) and serves as a reference when designing circuits, selecting components, simulating, and troubleshooting.

[0086] In some embodiments, obtaining the steady-state junction temperature of the IGBT based on the total thermal resistance using power integration includes: calculating the average power of the IGBT under stable power conditions of the PTC heater using an integral method; obtaining the temperature difference between the IGBT junction and the temperature sensor based on the average power and the total thermal resistance; and obtaining the steady-state junction temperature of the IGBT based on the temperature collected by the temperature sensor and the temperature difference.

[0087] In some embodiments, calculating the average power of the IGBT under the stable power state of the PTC heater based on the integration method includes: selecting one or more complete PWM switching cycles as the integration calculation period; obtaining the collector-emitter voltage and collector current of the IGBT; calculating the instantaneous power at each sampling moment based on the collector-emitter voltage and collector current; integrating the instantaneous power based on the integration calculation period and the sampling interval to obtain the average power of the IGBT.

[0088] Specifically, after the PTC heater enters a power steady-state, the junction temperature is accurately calculated through power integration and thermal resistance conversion. The specific steps are as follows: Step 1: Calculate the average power of the IGBT. Step 1: Calculate the average power of the IGBT under steady-state power using the integral method; Step 2: Calculate the temperature difference ΔT between the IGBT junction and the temperature sensor, based on the product of the average power and the total thermal resistance. Step 3: Calculate the steady-state junction temperature of the IGBT. Superimpose the temperature sensor readings with the above temperature difference to obtain the steady-state junction temperature of the IGBT. , among which, T S This indicates the temperature collected by the temperature sensor.

[0089] For example, step 1: Calculate the average power of the IGBT The average power of the IGBT under steady-state power is calculated using the integral method, as follows:

[0090] a. Select one or more complete PWM switching cycles as the integration calculation period T. I ;

[0091] b. Acquire the collector-emitter voltage V of the IGBT at a fixed sampling frequency. ce [n] and collector current I c [n], where n represents the sampling point number, which discretizes the continuous voltage and current signals into a sampling point sequence;

[0092] c. Calculate the instantaneous power at each sampling time: ;

[0093] d. Integrate the instantaneous power to obtain the average power, for example, using the rectangular integration method: , among which, T smp Let N represent the sampling interval, and N represent the number of sampling points within one integration calculation period. By simplification, this formula can be expressed as: .

[0094] In some embodiments, obtaining the collector-emitter voltage and collector current of the IGBT includes: acquiring the collector-emitter voltage and collector current of the IGBT at a fixed sampling frequency; or: acquiring the collector-emitter voltage of the IGBT according to the IGBT datasheet, and acquiring the collector current by acquiring the current of the corresponding heating circuit.

[0095] It should be noted that, to ensure the continuous voltage and current signals are not distorted after discretization, the sampling frequency should be much higher than the PWM switching frequency, typically 10-20 times the operating frequency. In particular, if the hardware design cannot meet the collector-emitter voltage V... ce For direct data acquisition, the typical value V for conduction under appropriate conditions can be selected from the IGBT datasheet, based on the actual working scenario. ce(on) (e.g., gate-emitter voltage V) GE =15V, collector current I c =10A, junction temperature T j (parameters under 125℃ operating conditions) are replaced; collector current I c It can be indirectly obtained by collecting the current of the corresponding heating circuit.

[0096] In this embodiment, by introducing the loss of the heat transfer path, the deviation between the temperature sensor and the actual junction temperature of the IGBT is effectively corrected, and the junction temperature estimation deviation is ≤5℃. At the same time, the response speed to temperature changes is improved, and the junction temperature change of the IGBT can be captured in time, avoiding the risk of failure due to overheating, and significantly improving the accuracy of junction temperature detection.

[0097] In some embodiments, when the difference in steady-state junction temperatures is greater than a preset junction temperature difference threshold, the junction temperature deviation and duty cycle adjustment of the IGBT are calculated based on the steady-state junction temperatures.

[0098] In some embodiments, calculating the junction temperature deviation and duty cycle adjustment of the IGBT based on the steady-state junction temperature includes: calculating the average junction temperature based on the steady-state junction temperature of all IGBTs; calculating the junction temperature deviation of the IGBT based on the difference between the steady-state junction temperature of each IGBT and the average junction temperature; and substituting the junction temperature deviation into the temperature difference-duty cycle conversion model to obtain the duty cycle adjustment of each IGBT.

[0099] In some embodiments, dynamically adjusting the PWM duty cycle of the IGBT according to the junction temperature deviation and the duty cycle adjustment amount includes: when the junction temperature deviation is greater than zero, decreasing the PWM duty cycle of the IGBT according to the duty cycle adjustment amount; when the junction temperature deviation is less than zero, increasing the PWM duty cycle of the IGBT according to the duty cycle adjustment amount; and maintaining the PWM duty cycle of the IGBT unchanged when the junction temperature deviation is equal to zero.

[0100] Specifically, the multi-IGBT junction temperature dynamic balancing control strategy is as follows: Based on the calculated IGBT junction temperature data (steady-state junction temperature) mentioned above, the temperature balancing of multiple IGBTs is achieved by dynamically adjusting the PWM duty cycle of each IGBT. The specific steps are as follows:

[0101] 1) Set control parameters: Set the maximum threshold for the junction temperature difference between multiple IGBTs (preset junction temperature difference threshold). For example, determine the maximum allowable junction temperature difference through experimental calibration based on IGBT device characteristics, system heat dissipation capacity, and safety requirements. Set the execution cycle for IGBT junction temperature equalization judgment and power regulation tasks. For example, based on the actual system power response, the execution cycle must ensure that the power regulation response is completed and initially stabilized.

[0102] 2) Determine the power stability of the PTC heater: After the PTC heater is started, monitor the deviation between its actual output power and the target power. When the deviation is within the design allowable range and the duration exceeds the judgment time (e.g., power deviation ≤ 5% and duration > 15s), the PTC heater is determined to have entered the power stability state.

[0103] 3) Junction temperature detection: After the PTC heater enters the power stable state, the steady-state junction temperature of all IGBTs is periodically detected according to the junction temperature calculation process (IGBT junction temperature accurate estimation process) described above.

[0104] 4) Junction temperature equilibrium determination, including:

[0105] Step 1: After the PTC heater enters a stable power state, periodically acquire the steady-state junction temperature data of all IGBTs calculated by the junction temperature detection above;

[0106] Step 2: Calculate the maximum difference in junction temperatures among multiple IGBTs: Find the maximum and minimum junction temperatures of all IGBTs, and calculate the maximum junction temperature difference. ;

[0107] Step 3: Junction Temperature Equilibrium Determination: Compare the maximum junction temperature difference with the set threshold (preset junction temperature difference threshold). If... > Set threshold, initiate power regulation process; if If the threshold is set, the PWM duty cycle of all IGBTs will remain unchanged.

[0108] 5) Dynamic power regulation, including:

[0109] Step 1. Calculate the average junction temperature: Calculate the average junction temperature of all IGBTs. Where M represents the number of IGBTs and i represents the IGBT serial number.

[0110] Step 2. Calculate the junction temperature deviation of a single IGBT: Calculate the deviation between the junction temperature of each IGBT and the average junction temperature (junction temperature deviation). .

[0111] Step 3. Determine the PWM duty cycle adjustment amount: Substitute the junction temperature deviation into the temperature difference-duty cycle conversion model to obtain the duty cycle adjustment amount for each IGBT.

[0112] Step 4. Perform duty cycle adjustment: Adjust the PWM duty cycle of each IGBT according to the junction temperature deviation and duty cycle adjustment amount mentioned above. The specific adjustment method is as follows:

[0113] If ΔT i >0 (IGBT junction temperature is higher than the average junction temperature), adjust its PWM duty cycle according to the corresponding adjustment amount to reduce the power output of the heating core and reduce IGBT losses and heat generation;

[0114] If ΔT i <0 (IGBT junction temperature is lower than the average junction temperature), increase its PWM duty cycle according to the corresponding adjustment amount to increase the power output of the heating core;

[0115] If ΔT i =0 (IGBT junction temperature equals average junction temperature), maintaining the current PWM duty cycle unchanged.

[0116] Here, the temperature difference-duty cycle conversion model can be constructed through testing and calibration. The specific construction process includes: testing and recording the data of duty cycle adjustment and corresponding junction temperature change of each IGBT under different operating conditions, and organizing them into a mapping relationship model.

[0117] It should be noted that during the adjustment process, the algebraic sum of the adjustment amounts of all IGBT duty cycles must be close to 0 to ensure that the total output power of the PTC heater remains basically stable and to avoid significant fluctuations in heating performance.

[0118] 6) Cyclic Execution: The junction temperature calculation process described above is repeated according to the set integral calculation cycle, continuously monitoring the steady-state junction temperature of all IGBTs until the PTC heater stops working or exits the power stability state. The junction temperature equalization determination and power regulation process described above is repeated according to the set execution cycle, continuously and dynamically maintaining the junction temperature equalization of multiple IGBTs until the PTC heater stops working or exits the power stability state.

[0119] In this embodiment, by dynamically adjusting the PWM duty cycle of multiple IGBTs, the junction temperature difference between the multiple IGBTs can be controlled within 5-10℃, effectively reducing the highest IGBT junction temperature in the system and making the IGBT operating temperature more uniform, resulting in good junction temperature balance. This avoids global power degradation or shutdown caused by overheating of a single IGBT, and maximizes the output power of the PTC heater while ensuring the safe operation of the IGBTs, minimizing heating performance loss.

[0120] In one example, with Figures 2-4 The execution flow will be explained using an example. (Reference) Figure 2 The overall block diagram of the multi-IGBT junction temperature dynamic equalization control strategy shown includes four processes, and the specific execution flow is as follows:

[0121] 1. Determining the power stability of the PTC heater: By monitoring the deviation between the actual output power and the target power of the PTC heater in real time, it is determined whether the PTC heater has entered / exited the power stability state. Based on the changes in the state of the PTC heater, subsequent processes are started or stopped, specifically including:

[0122] If the status of the PTC heater remains unchanged, continue power monitoring;

[0123] If the PTC heater transitions from an unstable state to a power stable state, the IGBT junction temperature detection and IGBT junction temperature equalization determination process is initiated.

[0124] If the PTC heater changes from a stable power state to an unstable state, the IGBT junction temperature detection, IGBT junction temperature equalization determination, and power regulation process will be stopped.

[0125] 2. IGBT Junction Temperature Detection: After the PTC heater enters a power stabilization state, the steady-state junction temperature calculation of the IGBTs begins. Following the integral calculation cycle, the steady-state junction temperature data of all IGBTs is periodically output for IGBT junction temperature equalization detection and IGBT over-temperature detection. (Reference) Figure 3 The flowchart shown below illustrates the calculation of the IGBT steady-state junction temperature. The specific steps include:

[0126] S101: Acquire the collected IGBT voltage and current data, obtain the collector-emitter voltage and collector current signals of the IGBT through ADC sampling, and then calculate the voltage and current data by the software.

[0127] S102: Calculate the instantaneous power of the IGBT. Based on the voltage and current data above, calculate the instantaneous power.

[0128] S103: Calculate the integral sum of the instantaneous power of the IGBT, and perform integral summation on the instantaneous power of the IGBT.

[0129] S104: Determine whether the accumulation calculation of instantaneous power within one integration calculation cycle has been completed. If not, repeat S101-S104; if completed, proceed to the next step.

[0130] S105: Calculate the average power of the IGBT. The average power of the IGBT is calculated based on the integral and accumulated data of the instantaneous power.

[0131] S106: Calculate the temperature difference between the IGBT junction and the temperature sensor.

[0132] S107: Calculate the steady-state junction temperature of the IGBT.

[0133] It should be noted that, Figure 3 S101-S104 shown will be executed cyclically according to the sampling period, while the entire IGBT junction temperature calculation process will be executed cyclically according to the integration calculation period, and the steady-state junction temperature data of all IGBTs will be output once in each integration period.

[0134] 3. IGBT Junction Temperature Equilibrium Determination and Dynamic Power Adjustment: Based on the IGBT steady-state junction temperature data output from the IGBT junction temperature detection process, the IGBT junction temperature equilibrium is determined. If the IGBT junction temperature difference exceeds a set threshold, a power adjustment process is executed. (Reference) Figure 4 The flowchart shown illustrates the IGBT junction temperature equalization determination and power regulation process. The specific steps are as follows:

[0135] S201: Obtain the steady-state junction temperature of all IGBTs, and obtain the steady-state junction temperature data output from the IGBT junction temperature calculation process.

[0136] S202: Based on the obtained IGBT steady-state junction temperature data, calculate the maximum difference between the junction temperatures of all IGBTs.

[0137] S203: Determine whether the maximum junction temperature difference exceeds the set threshold. If it exceeds the set threshold, start the power regulation process; if it does not exceed the set threshold, maintain the PWM duty cycle of all IGBTs unchanged.

[0138] S204: Start executing the power regulation process, first calculate the average value of the junction temperature of all IGBTs.

[0139] S205: Calculate the difference between the junction temperature of all IGBTs and the average junction temperature.

[0140] S206: Determine the PWM duty cycle adjustment for each IGBT. Substitute the junction temperature and the average junction temperature difference mentioned above into the conversion model to determine the PWM duty cycle adjustment for each IGBT.

[0141] S207: Adjust the PWM duty cycle of all IGBTs. The adjustment method has been described in the technical solution.

[0142] Understandable, Figure 4 S201-203 shown is the IGBT junction temperature equalization determination process, and S204-207 is the dynamic power adjustment process. The above two processes perform junction temperature equalization determination and power adjustment processes periodically according to the set execution cycle.

[0143] It should be noted that this embodiment includes two parts: IGBT junction temperature estimation and multi-channel IGBT junction temperature balancing control. First, by calibrating the total thermal resistance from the IGBT junction to the temperature sensor and combining it with the average IGBT power calculated by the integral method, the steady-state junction temperature of the IGBT is accurately estimated, correcting the deviation between the sensor temperature and the actual junction temperature. Then, the maximum threshold for the junction temperature difference between IGBTs and the detection and adjustment cycle are set. By calculating the maximum difference and average value of the junction temperatures of multiple IGBTs, the corresponding PWM duty cycle is dynamically adjusted according to the deviation of each IGBT junction temperature from the average value to achieve junction temperature balancing. This method in this embodiment can quickly respond to changes in IGBT junction temperature, reduce the maximum junction temperature, reduce the frequency of over-temperature protection triggering, and ensure the safety of the heating system while avoiding unnecessary heating performance loss.

[0144] This embodiment provides a PTC heater control method, including: when the PTC heater enters a power steady state, obtaining the total thermal resistance from the IGBT junction to the temperature sensor based on the heat transfer path; obtaining the steady-state junction temperature of the IGBT based on the total thermal resistance using power integration; when the difference between the steady-state junction temperatures is greater than a preset junction temperature difference threshold, calculating the junction temperature deviation and duty cycle adjustment of the IGBT based on the steady-state junction temperature; and dynamically adjusting the PWM duty cycle of the IGBT based on the junction temperature deviation and duty cycle adjustment. In this embodiment, accurate estimation of the IGBT junction temperature is achieved by calculating the total thermal resistance and steady-state junction temperature, correcting the deviation between the temperature sensor and the actual junction temperature, and improving the timeliness and accuracy of over-temperature detection; dynamic equalization control of the junction temperature of multiple IGBTs is achieved through the junction temperature deviation and duty cycle adjustment, reducing the junction temperature difference between multiple IGBTs, lowering the highest IGBT junction temperature in the system, and reducing the frequency of unnecessary global power degradation or shutdown protection triggering. The two work together to optimize the heating performance of the PTC heater, thereby maximizing the heating performance of the PTC heater while ensuring the safe operation of the IGBT, thus balancing system safety and user comfort.

[0145] Reference Figure 5 , Figure 5 This is a structural block diagram of an embodiment of the PTC heater control system of the present invention. Figure 5 As shown, the PTC heater control system includes:

[0146] The total thermal resistance acquisition module 10 is used to acquire the total thermal resistance from the IGBT junction to the temperature sensor based on the heat transfer path when the PTC heater enters the power steady state.

[0147] The steady-state junction temperature calculation module 20 is used to obtain the steady-state junction temperature of the IGBT based on the total thermal resistance according to the power integral.

[0148] The junction temperature equalization determination module 30 is used to calculate the junction temperature deviation and duty cycle adjustment of the IGBT based on the steady-state junction temperature when the difference in the steady-state junction temperature is greater than a preset junction temperature difference threshold.

[0149] The dynamic control module 40 is used to dynamically adjust the PWM duty cycle of the IGBT according to the junction temperature deviation and the duty cycle adjustment amount.

[0150] Specifically, this embodiment of the PTC heater control system optimizes the heating performance of the PTC heater based on multi-channel IGBT junction temperature equalization control, aiming to solve the problems of large IGBT junction temperature detection deviation and uneven junction temperatures among multiple IGBTs leading to performance loss in the PTC heater in existing technologies. The system comprises two parts: IGBT junction temperature estimation and multi-channel IGBT junction temperature equalization control. First, by calibrating the total thermal resistance from the IGBT junction to the temperature sensor and combining it with the average IGBT power calculated using the integral method, the steady-state junction temperature of the IGBT is accurately estimated, correcting the deviation between the sensor temperature and the actual junction temperature. Then, the maximum threshold for the junction temperature difference between IGBTs and the detection adjustment cycle are set. By calculating the maximum difference and average value of the junction temperatures of multiple IGBTs, the corresponding PWM duty cycle is dynamically adjusted according to the deviation between each IGBT junction temperature and the average value to achieve junction temperature equalization. This PTC heater control system in this embodiment can quickly respond to changes in IGBT junction temperature, reduce the maximum junction temperature, and decrease the frequency of over-temperature protection triggering, ensuring the safety of the heating system while avoiding unnecessary performance loss.

[0151] The PTC heater control system provided in this embodiment achieves accurate estimation of IGBT junction temperature by calculating total thermal resistance and steady-state junction temperature, correcting the deviation between the temperature sensor and the actual junction temperature, and improving the timeliness and accuracy of over-temperature detection. It also achieves dynamic balancing control of multi-IGBT junction temperatures through junction temperature deviation and duty cycle adjustment, reducing the junction temperature differences between multiple IGBTs, lowering the highest IGBT junction temperature in the system, and reducing the frequency of unnecessary global power degradation or shutdown protection triggers. These two aspects work together to optimize the heating performance of the PTC heater, thereby maximizing the maintenance of PTC heater heating performance while ensuring IGBT operational safety, balancing system safety and user comfort.

[0152] It should be noted that technical details not described in detail in this embodiment of the PTC heater control system can be found in any embodiment of the present invention applied to the PTC heater control method as described above, and will not be repeated here.

[0153] Based on the same inventive concept, embodiments of the present invention also provide an electronic device. Figure 6 This is a structural block diagram of an electronic device provided in an embodiment of the present invention. Figure 6 As shown, an embodiment of the present invention provides an electronic device including: one or more processors 101, a memory 102, and one or more I / O interfaces 103. The memory 102 stores one or more programs, which, when executed by the one or more processors, cause the one or more processors to implement any of the PTC heater control methods described in the above embodiments; the one or more I / O interfaces 103 are connected between the processors and the memory, configured to enable information interaction between the processors and the memory.

[0154] The processor 101 is a device with data processing capabilities, including but not limited to a central processing unit (CPU); the memory 102 is a device with data storage capabilities, including but not limited to random access memory (RAM, more specifically SDRAM, DDR, etc.), read-only memory (ROM), electrically erasable programmable read-only memory (EEPROM), and flash memory (FLASH); the I / O interface (read / write interface) 103 is connected between the processor 101 and the memory 102, and can realize information interaction between the processor 101 and the memory 102, including but not limited to a data bus (Bus).

[0155] In some embodiments, the processor 101, memory 102, and I / O interface 103 are interconnected via bus 104, and thus connected to other components of the computing device.

[0156] In some embodiments, the one or more processors 101 include a field-programmable gate array.

[0157] This invention also provides a computer-readable medium. The computer-readable medium stores a computer program, which, when executed by a processor, implements the steps of any of the PTC heater control methods described in the above embodiments. The computer-readable storage medium may be volatile or non-volatile.

[0158] This invention also provides a computer program product, including computer-readable code, or a non-volatile computer-readable storage medium carrying computer-readable code. When the computer-readable code is run in the processor of an electronic device, the processor in the electronic device executes the above-described PTC heater control method.

[0159] Those skilled in the art will understand that all or some of the steps, systems, and apparatuses disclosed above, and their functional modules / units, can be implemented as software, firmware, hardware, or suitable combinations thereof. In hardware implementations, the division between functional modules / units mentioned above does not necessarily correspond to the division of physical components; for example, a physical component may have multiple functions, or a function or step may be performed collaboratively by several physical components. Some or all physical components may be implemented as software executed by a processor, such as a central processing unit, digital signal processor, or microprocessor, or as hardware, or as an integrated circuit, such as an application-specific integrated circuit (ASIC). Such software can be distributed on a computer-readable storage medium, which may include computer storage media (or non-transitory media) and communication media (or transient media).

[0160] As is known to those skilled in the art, the term computer storage medium includes volatile and non-volatile, removable and non-removable media implemented in any method or technology for storing information, such as computer-readable program instructions, data structures, program modules, or other data. Computer storage media includes, but is not limited to, random access memory (RAM), read-only memory (ROM), erasable programmable read-only memory (EPROM), static random access memory (SRAM), flash memory or other memory technologies, portable compact disc read-only memory (CD-ROM), digital versatile disc (DVD) or other optical disc storage, magnetic cartridges, magnetic tape, disk storage or other magnetic storage devices, or any other medium that can be used to store desired information and is accessible to a computer. Furthermore, it is known to those skilled in the art that communication media typically contain computer-readable program instructions, data structures, program modules, or other data in modulated data signals such as carrier waves or other transmission mechanisms, and may include any information delivery medium.

[0161] The computer-readable program instructions described herein can be downloaded from computer-readable storage media to various computing / processing devices, or downloaded via a network, such as the Internet, local area network, wide area network, and / or wireless network, to an external computer or external storage device. The network may include copper transmission cables, fiber optic transmission, wireless transmission, routers, firewalls, switches, gateway computers, and / or edge servers. A network adapter card or network interface in each computing / processing device receives the computer-readable program instructions from the network and forwards them to the computer-readable storage media in the respective computing / processing device.

[0162] The computer program instructions used to perform the operations of this invention may be assembly instructions, instruction set architecture (ISA) instructions, machine instructions, machine-dependent instructions, microcode, firmware instructions, state setting data, or source code or object code written in any combination of one or more programming languages, including object-oriented programming languages ​​such as Smalltalk, C++, etc., and conventional procedural programming languages ​​such as the "C" language or similar programming languages. The computer-readable program instructions may be executed entirely on the user's computer, partially on the user's computer, as a standalone software package, partially on the user's computer and partially on a remote computer, or entirely on a remote computer or server. In cases involving a remote computer, the remote computer may be connected to the user's computer via any type of network—including a local area network (LAN) or a wide area network (WAN)—or may be connected to an external computer (e.g., via the Internet using an Internet service provider). In some embodiments, electronic circuitry, such as programmable logic circuitry, field-programmable gate arrays (FPGAs), or programmable logic arrays (PLAs), is personalized by utilizing state information from the computer-readable program instructions. This electronic circuitry can execute the computer-readable program instructions to implement various aspects of the invention.

[0163] The computer program product described herein can be implemented specifically through hardware, software, or a combination thereof. In one alternative embodiment, the computer program product is specifically embodied in a computer storage medium; in another alternative embodiment, the computer program product is specifically embodied in a software product, such as a software development kit (SDK), etc.

[0164] Various aspects of the present invention are described herein with reference to flowchart illustrations and / or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of the invention. It should be understood that each block of the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer-readable program instructions.

[0165] These computer-readable program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, or other programmable data processing apparatus to produce a machine such that, when executed by the processor of the computer or other programmable data processing apparatus, they create means for implementing the functions / actions specified in one or more blocks of the flowchart and / or block diagram. These computer-readable program instructions can also be stored in a computer-readable storage medium that causes a computer, programmable data processing apparatus, and / or other device to operate in a particular manner; thus, the computer-readable medium storing the instructions comprises an article of manufacture that includes instructions for implementing aspects of the functions / actions specified in one or more blocks of the flowchart and / or block diagram.

[0166] Computer-readable program instructions may also be loaded onto a computer, other programmable data processing apparatus, or other device to cause a series of operational steps to be performed on the computer, other programmable data processing apparatus, or other device to produce a computer-implemented process, thereby causing the instructions executed on the computer, other programmable data processing apparatus, or other device to perform the functions / actions specified in one or more boxes of a flowchart and / or block diagram.

[0167] The flowcharts and block diagrams in the accompanying drawings illustrate the architecture, functionality, and operation of possible implementations of systems, methods, and computer program products according to various embodiments of the present invention. In this regard, each block in a flowchart or block diagram may represent a module, segment, or portion of an instruction, which contains one or more executable instructions for implementing a specified logical function. In some alternative implementations, the functions marked in the blocks may occur in a different order than those shown in the drawings. For example, two consecutive blocks may actually be executed substantially in parallel, and they may sometimes be executed in reverse order, depending on the functions involved. It should also be noted that each block in the block diagrams and / or flowcharts, and combinations of blocks in the block diagrams and / or flowcharts, may be implemented using a dedicated hardware-based system that performs the specified function or action, or using a combination of dedicated hardware and computer instructions.

[0168] Example embodiments have been disclosed herein, and while specific terminology has been used, it is for illustrative purposes only and should be construed as such, and is not intended to be limiting. In some instances, it will be apparent to those skilled in the art that features, characteristics, and / or elements described in conjunction with particular embodiments may be used alone, or in combination with features, characteristics, and / or elements described in conjunction with other embodiments, unless otherwise expressly indicated. Therefore, those skilled in the art will understand that various changes in form and detail may be made without departing from the scope of the invention as set forth in the appended claims.

Claims

1. A PTC heater control method, characterized in that, include: When the PTC heater enters the power steady state, the total thermal resistance from the IGBT junction to the temperature sensor is obtained based on the heat transfer path. The steady-state junction temperature of the IGBT is obtained based on the total thermal resistance using power integration. When the difference in steady-state junction temperature is greater than a preset junction temperature difference threshold, the junction temperature deviation and duty cycle adjustment of the IGBT are calculated based on the steady-state junction temperature. The PWM duty cycle of the IGBT is dynamically adjusted based on the junction temperature deviation and duty cycle adjustment amount.

2. The method as described in claim 1, characterized in that, The method of obtaining the total thermal resistance from the IGBT junction to the temperature sensor based on the heat transfer path includes: The heat transfer path from the IGBT junction to the temperature sensor is quantified as IGBT junction, IGBT housing and temperature sensor. Obtain the first thermal resistance from the IGBT junction to the IGBT case from the IGBT datasheet. Calibrate the second thermal resistance from the IGBT case to the temperature sensor; The total thermal resistance from the IGBT junction to the temperature sensor is obtained based on the first thermal resistance and the second thermal resistance.

3. The method as described in claim 2, characterized in that, The calibration of the second thermal resistance from the IGBT housing to the temperature sensor includes: The PCB board of the PTC heater is placed in a constant temperature chamber for calibration testing; wherein, the PCB board includes an IGBT and a temperature sensor; Based on the calibration test, the actual power consumption of the IGBT, the temperature sensor temperature, and the IGBT case temperature were obtained. The second thermal resistance from the IGBT case to the temperature sensor is calculated based on the actual power consumption of the IGBT, the temperature of the temperature sensor, and the temperature of the IGBT case.

4. The method as described in claim 1, characterized in that, The method of obtaining the steady-state junction temperature of the IGBT based on the total thermal resistance using power integration includes: The average power of the IGBT under the power steady-state condition of the PTC heater was calculated based on the integral method. The temperature difference between the IGBT junction and the temperature sensor is obtained based on the average power and the total thermal resistance. The steady-state junction temperature of the IGBT is obtained based on the temperature collected by the temperature sensor and the temperature difference.

5. The method as described in claim 4, characterized in that, The calculation of the average power of the IGBT under the stable power state of the PTC heater based on the integral method includes: Select one or more complete PWM switching cycles as the integral calculation period; Obtain the collector-emitter voltage and collector current of the IGBT; The instantaneous power at each sampling moment is calculated based on the collector-emitter voltage and collector current. The instantaneous power is integrated based on the integration calculation period and sampling interval to obtain the average power of the IGBT.

6. The method as described in claim 5, characterized in that, The acquisition of the collector-emitter voltage and collector current of the IGBT includes: Collector-emitter voltage and collector current of the IGBT are acquired at a fixed sampling frequency; or; Obtain the collector-emitter voltage of the IGBT from its datasheet, and acquire the collector current by sampling the current in the corresponding heating circuit.

7. The method as described in claim 1, characterized in that, The calculation of the junction temperature deviation and duty cycle adjustment of the IGBT based on the steady-state junction temperature includes: The average junction temperature is obtained by calculating the average steady-state junction temperature of all IGBTs. The junction temperature deviation of the IGBT is calculated based on the difference between the steady-state junction temperature of each IGBT and the average junction temperature. Substituting the junction temperature deviation into the temperature difference-duty cycle conversion model, the duty cycle adjustment amount for each IGBT is obtained.

8. The method as described in claim 7, characterized in that, The step of dynamically adjusting the PWM duty cycle of the IGBT based on the junction temperature deviation and the duty cycle adjustment amount includes: When the junction temperature deviation is greater than zero, the PWM duty cycle of the IGBT is reduced according to the duty cycle adjustment amount; When the junction temperature deviation is less than zero, the PWM duty cycle of the IGBT is increased according to the duty cycle adjustment amount; When the junction temperature deviation is zero, the PWM duty cycle of the IGBT is kept constant.

9. A PTC heater control system, characterized in that, include: The total thermal resistance acquisition module is used to obtain the total thermal resistance from the IGBT junction to the temperature sensor based on the heat transfer path when the PTC heater enters the power steady state. The steady-state junction temperature calculation module is used to obtain the steady-state junction temperature of the IGBT based on the total thermal resistance according to the power integral. The junction temperature equalization determination module is used to calculate the junction temperature deviation and duty cycle adjustment of the IGBT based on the steady-state junction temperature when the difference in the steady-state junction temperature is greater than a preset junction temperature difference threshold. The dynamic control module is used to dynamically adjust the PWM duty cycle of the IGBT based on the junction temperature deviation and the duty cycle adjustment amount.

10. A computer-readable medium having a computer program stored thereon, characterized in that, When the computer program is executed by a processor, it implements the steps of the method as described in any one of claims 1 to 8.

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