A PTC heater for electric vehicles and a fault diagnosis method thereof

Abstract

The present invention relates to a pure electric vehicle PTC heater and a fault diagnosis method. The PTC heater body is provided with an abnormality detection module and an IGBT detection module. The abnormality detection module is controlled by the PTC heater body to perform abnormality detection actions. The IGBT detection module is controlled by the PTC heater body to perform abnormality detection actions. The PTC heater body receives error signals from the abnormality detection module and the IGBT detection module and sends them to a controller. The PTC high-voltage cut-off module controls the error signals received from the abnormality detection module and the IGBT detection module to perform a high-voltage cut-off operation on the PTC heater body. The present invention distinguishes between common faults and serious faults, distinguishes between different states of the PTC heater body, and uses the state jump of the PTC heater body to assist in fault diagnosis and processing, thereby effectively protecting the PTC heater from damage due to faults during operation.

Description

Technical Field

[0001] The present invention relates to the field of electric vehicles, and in particular to a pure electric vehicle PTC heater and a fault diagnosis method. Background Art

[0002] Electric vehicles (BEV) refer to vehicles that use onboard power as power, use motors to drive wheels, and comply with various requirements of road traffic and safety regulations;

[0003] Traditional pure electric vehicles mostly use PTC (Positive Temperature Coefficient) heaters to heat the passenger compartment. As pure electric vehicles become more and more intelligent, the functions of PTC heaters are becoming more and more complex. In order to ensure the personal safety of drivers and passengers and to prevent the vehicle and parts from being damaged, a fault diagnosis method and processing strategy for PTC heaters are needed.

[0004] Among them, the comparative example with application number 201410325916.4 and title “An electric vehicle PTC heating system and its fault diagnosis method” proposes the following technical solution: the faults are divided into primary faults and secondary faults. A primary fault means that the fault will not cause damage to the whole vehicle or parts, and the system is fully controllable; a secondary fault means that the fault may cause damage to the system or affect personal safety. If the PTC controller diagnoses a CAN (Controller Area Network) communication fault, it is classified as a primary fault and reported to the superior controller for processing; if the PTC controller diagnoses that the water temperature sensor value overflows or the value is unreasonable, it is classified as a secondary fault, and the PTC heater is powered off at low voltage, then at high voltage, and reported to the superior controller, so that the superior controller lights up the PTC fault light on the instrument cluster to remind the driver that the heating system has a fault and needs to be repaired in time;

[0005] The PTC controller of the above-mentioned PTC heating system diagnosis method diagnoses whether the heating system has a fault through the corresponding parameter status, and the parameters include water temperature value, heating time, and battery remaining power (SOC). Faults are divided into primary faults and secondary faults. Primary faults mean that the fault will not cause the whole vehicle or parts to fail, and the system is fully controllable; secondary faults mean that the fault may cause system damage or affect personal safety;

[0006] However, the above-mentioned PTC heating system diagnosis method has certain limitations and cannot distinguish different fault states of the PTC heater body. For example, for the IGBT (Insulated Gate Bipolar Transistor) in the PTC circuit, its specific faults may be: undervoltage, overvoltage, overcurrent and short circuit, etc., and the response methods required for these faults are also different. Therefore, the above-mentioned technical solution cannot fully protect the functional safety of the PTC heater and the personal safety of the driver and passengers if it cannot accurately distinguish the faults. Therefore, we propose a PTC fault diagnosis method for pure electric vehicles. Summary of the invention

[0007] An object of the present invention is to provide a new technical solution for a pure electric vehicle PTC heater and a fault diagnosis method.

[0008] According to a first aspect of the present invention, a pure electric vehicle PTC heater is provided, comprising a PTC heater body, a PTC high-voltage cut-off module and a controller, the PTC heater body is provided with an abnormality detection module and an IGBT detection module, the abnormality detection module is controlled by the PTC heater body to perform abnormality detection actions, the IGBT detection module is controlled by the PTC heater body to perform abnormality detection actions, the PTC heater body receives error signals from the abnormality detection module and the IGBT detection module and sends them to the controller, and the PTC high-voltage cut-off module controls the reception of the error signals from the abnormality detection module and the IGBT detection module to perform a high-voltage cut-off operation on the PTC heater body.

[0009] Based on the above purpose, the present invention also provides a pure electric vehicle PTC heater fault diagnosis method, comprising the following steps:

[0010] S1: PTC is powered on and initialized to detect whether CAN communication is normal. If normal, it goes to the next step. If abnormal, it reports to the controller, and the controller makes a response strategy.

[0011] S2: The abnormality detection module starts to detect whether the PTC temperature sensor is normal. If it is normal, it goes to the next step. If it is abnormal, it reports to the controller, and the controller makes a response strategy;

[0012] S3: The abnormality detection module starts to detect whether the PTC current sensor is normal. If it is normal, it goes to the next step. If it is abnormal, it reports to the controller, and the controller makes a response strategy;

[0013] S4: The IGBT detection module starts to detect whether the IGBT input high voltage is within the normal range. If it is normal, it goes to the next step. If it is abnormal, it reports to the controller, and the controller makes a response strategy;

[0014] S5: The IGBT detection module starts to detect whether the IGBT circuit is normally turned on. If it is normal, it goes to the next step. If it is abnormal, it reports to the controller, and the controller makes a response strategy;

[0015] S6: The IGBT detection module starts to detect whether the IGBT temperature is normal. If normal, it goes to the next step. If abnormal, it reports to the controller, and the controller makes a response strategy;

[0016] S7: The IGBT detection module starts to detect whether the IGBT current is within the normal range. If it is normal, it proceeds to the next step. If it is abnormal, it reports to the controller, and the controller makes a response strategy.

[0017] Optionally, the response strategy includes a common step S8 and a serious step S9, wherein:

[0018] S8: Stop the PTC heater body and feedback the fault information to the superior controller. The superior controller feedbacks the fault information to the driver and informs the driver to handle the fault. The PTC heater body is forced to be in a ready state and wait for the fault to be restored.

[0019] S9: Stop the PTC heater body, the PTC high-voltage cut-off module cuts off the PTC input high voltage, and feeds back the fault information to the superior controller, the superior controller feeds back the fault information to the driver, notifies the driver to deal with the fault, and the PTC heater body is forced to be in an error state, waiting for the fault to recover and wait for restart.

[0020] Optionally, the method further comprises the following steps:

[0021] S11: CAN communication is abnormal, the PTC heater body executes the corresponding processing strategy, and the PTC heater body executes S8.

[0022] Optionally, the method further comprises the following steps:

[0023] S21: The temperature sensor is abnormal, the PTC heater body executes the corresponding processing strategy, and the PTC heater body executes S9.

[0024] Optionally, S31: the current sensor is abnormal, the PTC heater body executes a corresponding processing strategy, and the PTC heater body executes S9.

[0025] Optionally, the method further comprises the following steps:

[0026] S41: The IGBT input high voltage is abnormal and is not within the normal range. The IGBT detection module determines whether it is an IGBT overvoltage fault or an IGBT undervoltage fault of the PTC heater body. If it is an IGBT undervoltage fault, the PTC heater body executes the corresponding processing strategy and the PTC heater body executes S8. If it is an IGBT overvoltage fault, the PTC heater body executes the corresponding processing strategy and the PTC heater body executes S8.

[0027] Optionally, the method further comprises the following steps:

[0028] S51: The IGBT circuit is abnormal, the PTC heater body executes the corresponding processing strategy, and the PTC heater body executes S8.

[0029] Optionally, the method further comprises the following steps:

[0030] S61: The IGBT temperature is abnormal, the PTC heater body executes the corresponding processing strategy, and the PTC heater body executes S9.

[0031] Optionally, the method further comprises the following steps:

[0032] S71: The IGBT current is abnormal, the PTC heater body executes the corresponding processing strategy, and the PTC heater body executes S9.

[0033] According to an embodiment of the present disclosure, the above-mentioned pure electric vehicle PTC fault diagnosis method distinguishes between common faults and serious faults, distinguishes between different states of the PTC heater body, and uses the state jump of the PTC heater body to assist in fault diagnosis and processing. First, the CAN communication, PTC temperature sensor and PTC current sensor are detected by the abnormal detection module, and then when the PTC heater body enters the working state, the IGBT input high voltage, IGBT circuit, IGBT temperature and IGBT current are detected by the IGBT detection module. After a fault occurs, the controller and the PTC high voltage cut-off module are used to perform corresponding processing according to the specific fault type;

[0034] Therefore, this method can enable pure electric vehicles to make different response strategies for different PTC heater faults, especially for IGBT circuit faults, and can make detailed distinctions. It can detect and handle IGBT undervoltage, overvoltage, overcurrent and short circuit faults differently, thereby effectively protecting the PTC heater from damage due to faults during operation, and effectively ensuring the personal safety of the driver and passengers.

[0035] Further features and advantages of the present invention will become apparent from the following detailed description of exemplary embodiments of the present invention with reference to the attached drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] The accompanying drawings, which are incorporated in and constitute a part of the specification, illustrate embodiments of the invention and, together with the description, serve to explain the principles of the invention.

[0037] Figure 1 A schematic diagram of the overall process of a method for diagnosing a PTC heater fault in a pure electric vehicle in one embodiment;

[0038] Figure 2 for Figure 1 Schematic diagram of the anomaly detection module flow in;

[0039] Figure 3 for Figure 1 Schematic diagram of the IGBT detection module process;

[0040] Figure 4 It is a schematic diagram of the overall process of a method for diagnosing a PTC heater fault in a pure electric vehicle in another embodiment.

[0041] In the figure: 100, PTC heater body; 110, abnormality detection module; 120, IGBT detection module; 200, controller; 300, PTC high voltage cut-off module. DETAILED DESCRIPTION

[0042] Various exemplary embodiments of the present invention will now be described in detail with reference to the accompanying drawings. It should be noted that the relative arrangement of components and steps, numerical expressions and numerical values ​​set forth in these embodiments do not limit the scope of the present invention unless otherwise specifically stated.

[0043] The following description of at least one exemplary embodiment is merely illustrative in nature and is in no way intended to limit the invention, its application, or uses.

[0044] Technologies, methods, and equipment known to ordinary technicians in the relevant art may not be discussed in detail, but where appropriate, the technologies, methods, and equipment should be considered as part of the specification.

[0045] In all examples shown and discussed herein, any specific values ​​should be interpreted as merely exemplary and not limiting. Therefore, other examples of the exemplary embodiments may have different values.

[0046] like Figure 1 , Figure 2 , Figure 3 and Figure 4As shown, in one embodiment, a pure electric vehicle PTC heater includes a PTC heater body 100, a PTC high-voltage cut-off module 300 and a controller 200. The PTC heater body 100 is provided with an abnormality detection module 110 and an IGBT detection module 120. The abnormality detection module 110 is controlled by the PTC heater body 100 to perform an abnormality detection action, and the IGBT detection module 120 is controlled by the PTC heater body 100 to perform an abnormality detection action. The PTC heater body 100 receives error signals from the abnormality detection module 110 and the IGBT detection module 120 and sends them to the controller 200. The PTC high-voltage cut-off module 300 controls the error signals received from the abnormality detection module 110 and the IGBT detection module 120 to perform a high-voltage cut-off operation on the PTC heater body 100. By distinguishing between common faults and serious faults for diagnosis and processing, different states of the PTC heater body 100 are distinguished, and the state jump of the PTC heater body 100 is used to assist in fault diagnosis and processing. First, the CAN communication, PTC temperature sensor and PTC current sensor are detected by the abnormal detection module 110. Then, when the PTC heater body 100 enters the working state, the IGBT input high voltage, IGBT circuit, IGBT temperature and IGBT current are detected by the IGBT detection module 120. After a fault occurs, the controller 200 and the PTC high-voltage cut-off module 300 are used to perform corresponding processing according to the specific fault type, thereby comprehensively protecting the PTC functional safety and the personal safety of the driver and passengers.

[0047] Based on the above purpose, the present invention also provides a pure electric vehicle PTC heater fault diagnosis method, comprising the following steps:

[0048] S1: PTC is powered on and initialized to detect whether CAN communication is normal. If normal, it goes to the next step. If abnormal, it reports to the controller, and the controller makes a response strategy.

[0049] S2: The abnormality detection module 110 starts to detect whether the PTC temperature sensor is normal. If it is normal, it proceeds to the next step. If it is abnormal, it reports to the controller, and the controller makes a response strategy;

[0050] S3: The abnormality detection module 110 starts to detect whether the PTC current sensor is normal. If it is normal, it proceeds to the next step. If it is abnormal, it reports to the controller, and the controller makes a response strategy;

[0051] S4: The IGBT detection module 120 starts to detect whether the IGBT input high voltage is within the normal range. If it is normal, it proceeds to the next step. If it is abnormal, it reports to the controller, and the controller makes a response strategy;

[0052] S5: The IGBT detection module 120 starts to detect whether the IGBT circuit is normally turned on. If it is normal, it proceeds to the next step. If it is abnormal, it reports to the controller, and the controller makes a response strategy;

[0053] S6: The IGBT detection module 120 starts to detect whether the IGBT temperature is normal. If normal, it proceeds to the next step. If abnormal, it reports to the controller, and the controller makes a response strategy;

[0054] S7: The IGBT detection module 120 starts to detect whether the IGBT current is within the normal range. If it is normal, it proceeds to the next step. If it is abnormal, it reports to the controller, and the controller makes a response strategy.

[0055] The response strategy includes a common step S8 and a serious step S9, wherein:

[0056] S8: Stop the PTC heater body 100 and feedback the fault information to the upper controller 200. The upper controller 200 feedbacks the fault information to the driver to inform the driver to handle the fault. The PTC heater body 100 is forced to be in a ready state and wait for the fault to be restored.

[0057] S9: Stop the operation of the PTC heater body 100, the PTC high-voltage cut-off module 300 cuts off the PTC input high voltage, and feeds back the fault information to the superior controller 200, the superior controller 200 feeds back the fault information to the driver, notifies the driver to handle the fault, and the PTC heater body 100 is forced to be in an error state, waiting for the fault to recover and waiting to restart.

[0058] In order to facilitate the distinguishing diagnosis and processing of common faults and serious faults, the above-mentioned pure electric vehicle PTC distinguishes different states of the PTC heater body 100, and uses the state jump of the PTC heater body 100 to assist in fault diagnosis and processing. After the PTC heater body 100 completes power-on initialization, the PTC heater body 100 enters the ready state. At this time, CAN communication fault detection, PTC temperature sensor fault detection, PTC current sensor fault detection, PTC heater body 100 IGBT voltage detection are performed. When the PTC heater body 100 fails and enters S8, the PTC heater body 100 will remain in the ready state; when the PTC heater body 100 fails and enters S9, the PTC heater body 100 enters an error state and exits the ready state. When there is no fault in the PTC heater body 100, and When the PTC heater body 100 is in the ready state, if it receives a working instruction from the superior controller 200, the PTC heater body 100 can start working. When the PTC heater body 100 starts working, the PTC heater body 100 is in the working state and exits the ready state. When the PTC heater body 100 is in the working state, the IGBT circuit conduction detection of the PTC heater body 100, the IGBT temperature detection of the PTC heater body 100, and the IGBT current detection of the PTC heater body 100 are performed. When the PTC heater body 100 fails and enters S8, the PTC heater body 100 will enter the ready state, exit the working state, and the PTC heater body 100 is always in the ready state; when the PTC heater body 100 fails and enters S9, the PTC enters an error state and exits the working state. When no fault occurs in the PTC heater body 100 and the PTC heater body 100 is in a ready state, if a working instruction from the superior controller 200 is received, the PTC heater body 100 can start working. When no fault occurs in the PTC and the PTC heater body 100 is in an error state, if a working instruction from the superior controller 200 is received, the PTC heater body 100 cannot continue to work and must be restarted.

[0059] In another embodiment, the following steps are also included: S11: CAN communication is abnormal, the PTC heater body 100 executes a corresponding processing strategy, and the PTC heater body 100 executes S8.

[0060] Abnormal CAN communication directly affects the information transmission between the PTC heater body and the upper controller 200. When this fault occurs, it will not directly cause functional damage to the PTC heater body, that is, the PTC heater body can continue to work under normal circumstances, but during the working operation, the upper controller 200 will not be able to monitor whether there are other faults in the PTC heater body. Therefore, there is a great safety hazard, and the driver needs to be notified immediately to handle the fault. In addition, when detecting, repairing and eliminating the fault, the PTC heater body and the upper controller 200 need to be powered on to test the communication between the two. Therefore, the better way to handle the fault is to force the PTC heater body 100 to be powered on, but not to start running, and feedback the fault information to the driver for processing;

[0061] In this embodiment, the following steps are also included: S21: the temperature sensor is abnormal, and the PTC heater body 100 executes a corresponding processing strategy, and the PTC heater body 100 executes S9.

[0062] The abnormality of the temperature sensor directly affects the real-time monitoring of the temperature. At this time, the PTC heater body 100 stops working, the PTC high-voltage cut-off module 300 cuts off the PTC input high voltage, and feeds back the fault information to the superior controller 200. The superior controller 200 feeds back the fault information to the driver, notifying the driver to deal with the fault. The PTC heater body 100 is forced to be in an error state, waiting for the fault to recover, and resumes operation after receiving the valid temperature data transmitted by the temperature sensor.

[0063] In this embodiment, the following steps are also included: S31: the current sensor is abnormal, the PTC heater body 100 executes a corresponding processing strategy, and the PTC heater body 100 executes S9.

[0064] The abnormality of the current sensor directly affects the real-time monitoring of the temperature. At this time, the PTC heater body 100 stops working, the PTC high-voltage cut-off module 300 cuts off the PTC input high voltage, and feeds back the fault information to the superior controller 200. The superior controller 200 feeds back the fault information to the driver, notifying the driver to deal with the fault. The PTC heater body 100 is forced to be in an error state, waiting for the fault to recover, and resumes operation after receiving the valid current data transmitted by the current sensor.

[0065] In this embodiment, the following steps are also included: S41: the IGBT input high voltage is abnormal and is not within the normal range. The IGBT detection module 120 determines whether it is an IGBT overvoltage fault or an IGBT undervoltage fault of the PTC heater body 100. If it is an IGBT undervoltage fault, the PTC heater body 100 executes a corresponding processing strategy, and the PTC heater body 100 executes S8. If it is an IGBT overvoltage fault, the PTC heater body 100 executes a corresponding processing strategy, and the PTC heater body 100 executes S9.

[0066] The IGBT undervoltage fault directly affects the operation of the IGBT. When this fault occurs, it will not directly cause functional damage to the PTC heater body and the IGBT, that is, the PTC heater body can continue to work under normal circumstances. At this time, the PTC heater body 100 stops working and feedbacks the fault information to the superior controller 200. The superior controller 200 feedbacks the fault information to the driver, notifies the driver to handle the fault, and forces the PTC heater body 100 to be powered on, but does not start running. After receiving normal IGBT voltage data, it resumes operation;

[0067] The IGBT overvoltage fault directly affects the operation of the IGBT. This fault will directly cause functional damage to the PTC heater body and the IGBT, stop the PTC heater body 100 from working, and the PTC high-voltage cut-off module 300 cuts off the PTC input high voltage and feeds back the fault information to the superior controller 200. The superior controller 200 feeds back the fault information to the driver, notifying the driver to handle the fault. The PTC heater body 100 is forced to be in an error state, waiting for the fault to recover, and restarting the PTC heater body 100 after the IGBT voltage data is normal.

[0068] In this embodiment, the following steps are also included: S51: the IGBT circuit is abnormal, and the PTC heater body 100 executes a corresponding processing strategy, and the PTC heater body 100 executes S8.

[0069] In this embodiment, the following steps are also included: S61: the IGBT temperature is abnormal, and the PTC heater body 100 executes a corresponding processing strategy, and the PTC heater body 100 executes S9.

[0070] In this embodiment, the following steps are also included: S71: the IGBT current is abnormal, and the PTC heater body 100 executes a corresponding processing strategy, and the PTC heater body 100 executes S9.

[0071] Abnormal IGBT temperature and abnormal IGBT current directly affect the operation of the IGBT. This fault will directly cause functional damage to the PTC heater body and the IGBT, stop the PTC heater body 100 from working, and the PTC high-voltage cut-off module 300 cuts off the PTC input high voltage and feeds back the fault information to the superior controller 200. The superior controller 200 feeds back the fault information to the driver, notifying the driver to deal with the fault. The PTC heater body 100 is forced to be in an error state, waiting for the fault to recover, and restarting the PTC heater body 100 after the temperature and current of the IGBT are normal.

[0072] Among the above faults, CAN communication fault, IGBT undervoltage fault and IGBT circuit conduction fault are common faults. When common faults occur, execute S8. Temperature sensor fault, current sensor fault and IGBT overvoltage fault, IGBT overcurrent fault and IGBT overtemperature fault are serious faults. When serious faults occur, execute S9.

[0073] Although some specific embodiments of the present invention have been described in detail by way of example, it will be appreciated by those skilled in the art that the above examples are for illustration only and are not intended to limit the scope of the present invention. It will be appreciated by those skilled in the art that the above embodiments may be modified without departing from the scope and spirit of the present invention. The scope of the present invention is defined by the appended claims.

Claims

1. A pure electric vehicle PTC heater, characterized in that: The invention comprises a PTC heater body (100), a PTC high-voltage cut-off module (300) and a controller (200); the PTC heater body (100) is provided with an abnormality detection module (110) and an IGBT detection module (120); the abnormality detection module (110) is controlled by the PTC heater body (100) to perform an abnormality detection action; the IGBT detection module (120) is controlled by the PTC heater body (100) to perform an abnormality detection action; the PTC heater body (100) receives error signals from the abnormality detection module (110) and the IGBT detection module (120) and sends them to the controller (200); the PTC high-voltage cut-off module (300) controls the PTC heater body (100) to perform a high-voltage cut-off operation upon receiving the error signals from the abnormality detection module (110) and the IGBT detection module (120); Specifically, it includes executing the following pure electric vehicle PTC fault diagnosis method and executing the response strategy corresponding to the ordinary step S8 or the serious step S9: S1: The PTC heater is powered on and initialized to detect whether the CAN communication is normal. If normal, the next step is entered. If abnormal, the controller (200) is reported, and the controller (200) makes a response strategy; S2: the abnormality detection module (110) starts to detect whether the PTC temperature sensor is normal, and if it is normal, proceeds to the next step; if it is abnormal, reports to the controller (200), and the controller (200) makes a response strategy; specifically, the temperature sensor is abnormal, the PTC heater body (100) executes a corresponding processing strategy, and the PTC heater body (100) executes S9; S3: the abnormality detection module (110) starts to detect whether the PTC current sensor is normal, and if it is normal, proceeds to the next step; if it is abnormal, reports to the controller (200), and the controller (200) makes a response strategy; specifically, the current sensor is abnormal, the PTC heater body (100) executes a corresponding processing strategy, and the PTC heater body (100) executes S9; S4: the IGBT detection module (120) starts to detect whether the IGBT input high voltage is within a normal range. If it is normal, the next step is entered. If it is abnormal, the controller (200) is reported, and the controller (200) makes a response strategy; specifically, the IGBT input high voltage is abnormal and is not within the normal range, and the IGBT detection module (120) determines whether it is an IGBT overvoltage fault or an IGBT undervoltage fault of the PTC heater body (100); if it is an IGBT undervoltage fault, the PTC heater body (100) executes a corresponding processing strategy, and the PTC heater body (100) executes S8; if it is an IGBT overvoltage fault, the PTC heater body (100) executes a corresponding processing strategy, and the PTC heater body (100) executes S9; S5: the IGBT detection module (120) starts to detect whether the IGBT circuit is normally turned on. If it is normal, the next step is entered. If it is abnormal, the controller (200) is reported, and the controller (200) makes a response strategy; specifically, if the IGBT circuit is abnormal, the PTC heater body (100) executes a corresponding processing strategy, and the PTC heater body (100) executes S8; S6: the IGBT detection module (120) starts to detect whether the IGBT temperature is normal. If normal, the next step is entered. If abnormal, the controller (200) is reported, and the controller (200) makes a response strategy; specifically, if the IGBT temperature is abnormal, the PTC heater body (100) executes a corresponding processing strategy, and the PTC heater body (100) executes S9; S7: the IGBT detection module (120) starts to detect whether the IGBT current is within a normal range. If it is normal, the PTC enters a working state. If it is abnormal, the controller (200) is reported, and the controller (200) makes a response strategy; specifically, the IGBT current is abnormal, the PTC heater body (100) executes a corresponding processing strategy, and the PTC heater body (100) executes S9; S8: stopping the operation of the PTC heater body (100) and feeding back fault information to the upper controller (200); the upper controller (200) feeding back the fault information to the driver to notify the driver to handle the fault; the PTC heater body (100) is forced to be in a ready state and wait for the fault to be restored; S9: the PTC heater body (100) stops working, the PTC high-voltage cut-off module (300) cuts off the PTC input high voltage, and feeds back fault information to the upper-level controller (200), the upper-level controller (200) feeds back the fault information to the driver, notifies the driver to handle the fault, and the PTC heater body (100) is forced to be in an error state, waiting for the fault to be recovered and waiting for restarting.

2. The pure electric vehicle PTC heater according to claim 1, characterized in that: S1 of the PTC fault diagnosis method further includes the following steps: S11: CAN communication is abnormal, the PTC heater body (100) executes a corresponding processing strategy, and the PTC heater body (100) executes S8.

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