PTC (Positive Temperature Coefficient) control system and method for new energy automobile

Abstract

The invention discloses a PTC control system and method of a new energy automobile, and belongs to the field of automobile air conditioners. The system comprises a central control large screen, a battery management system BMS, a vehicle control unit, a high voltage control module HVCM, a PTC controller, a PTC temperature sensor and a PTC, and the vehicle control unit is connected with the central control large screen, the battery management system BMS, the HVCM and the PTC controller; the PTC controller is respectively connected with the PTC temperature sensor and the PTC; and the HVCM is connected with the BMS. According to the invention, reasonable distribution of PTC power when the passenger compartment and the battery pack have heating requirements is realized.

Description

Technical Field

[0001] The present invention belongs to the field of automobile air conditioning, and in particular, relates to a PTC control system and method for a new energy automobile. Background Art

[0002] Nowadays, with the increasingly serious problems of environmental pollution and global warming, the development of new energy vehicles has emerged in order to save energy efficiency and protect the environment. However, in the cold winter, maintaining a comfortable temperature in the car is particularly important for drivers and passengers.

[0003] When the vehicle is driving, if the temperature of the power battery pack cannot be controlled within a reasonable range, it will affect the activity of the battery and even the life of the battery. Similarly, if the temperature of the passenger compartment is unreasonable when the temperature is low, it will affect driving comfort and even cause safety hazards.

[0004] As an important component of automobile air conditioning heating, the control of PTC (car heater) is crucial to maintain the temperature of the passenger compartment and the power battery pack within a reasonable and safe range.

[0005] However, the PTC control algorithm currently used in new energy vehicles is relatively simple, and does not fully consider the heating strategy during charging and the heating needs of the battery. The PTC power distribution is unbalanced and consumes power quickly, which greatly reduces the vehicle's range in severe cold weather. Summary of the invention

[0006] The present invention aims to overcome the deficiencies of the prior art and proposes a PTC control system and method for new energy vehicles to achieve the following objectives: to achieve reasonable distribution of PTC power when there is a heating demand for the passenger compartment and the battery pack.

[0007] In order to achieve the above-mentioned purpose, the technical solution adopted by the present invention is: a PTC control system for new energy vehicles, the system includes a central control screen, a battery management system BMS, a vehicle controller, a high-voltage control module HVCM, a PTC controller, a PTC temperature sensor, and a PTC, wherein the vehicle controller is respectively connected to the central control screen, the battery management system BMS, the HVCM, and the PTC controller; the PTC controller is respectively connected to the PTC temperature sensor and the PTC; the HVCM is connected to the BMS; the central control screen panel is equipped with a panel temperature gear knob, a panel air volume gear knob, a defrost and defog button, and a PTC switch, and their respective status signals are acquired by the central control screen The BMS is used to monitor the battery status and send a battery heating request signal to the vehicle controller; the HVCM is used to monitor the high voltage status of the vehicle and feed back the battery charging status signal to the vehicle controller; the PTC temperature sensor is used to collect the PTC water outlet temperature and send it to the vehicle controller through the PTC controller; the vehicle controller is used to process the received signal and then output the PTC control signal to the PTC controller to control the output power of the PTC; the PTC controller is also used to monitor the actual output power of the PTC, diagnose the PTC and obtain the fault level, and the monitoring and diagnosis results are fed back to the vehicle controller.

[0008] At the same time, the present application also proposes a PTC control method for a new energy vehicle based on the above system, the method comprising the following steps:

[0009] Step S1, the vehicle controller collects signals when the system components are working, including PTC switch signal, panel temperature knob gear signal, air volume knob signal, defrost and defog button signal, PTC temperature sensor signal, battery status, vehicle high voltage status, BMS battery heating request signal, HVCM battery charging status signal, PTC actual output power, and PTC fault level;

[0010] Step S2: The vehicle controller processes the collected signal and outputs a PTC control signal to the PTC controller to control the output power of the PTC.

[0011] Preferably, the processing of the received signal by the vehicle controller includes determining whether to issue a PTC enable request, wherein the PTC enable request is triggered only when the following conditions are met at the same time:

[0012] (1) The power-on mode is in a non-OFF state, and the main positive and negative relays are closed; or in the battery charging state, the high-voltage control module feedback battery pack charging state is: charging and heating state, or pure heating state;

[0013] (2) The PTC heater failure level does not exceed the preset level;

[0014] (3) The communication between the vehicle controller and the PTC controller is normal;

[0015] (4) The panel temperature knob is within the preset range and the panel air volume knob is activated;

[0016] (5) The PTC switch is in the on state; or the BMS issues a battery heating request in non-slow charging mode; or the BMS issues a battery heating request in slow charging mode and the charging state is not in the initialization and pending states;

[0017] (6) No PTC fault signal is received.

[0018] Preferably, after receiving the PTC control signal from the vehicle controller, the PTC controller drives the working power of the PTC to increase or decrease at a rate of 2kw / s. After there is no PTC enable request, the power working of the PTC is immediately reset to 0.

[0019] Preferably, after the PTC enable is triggered, the vehicle controller processes the received signal including calculating the bus output PTC power P of the vehicle controller. 总线 ,in:

[0020] (1) When the vehicle is not charging,

[0021] P Req =P 面板 +P BMS ;

[0022] P 总线 =Min(P BMSLimit , P Req )

[0023] Among them, P Req Indicates the panel PTC request power P of the central control screen 面板 and the BMS battery pack heating PTC request power P BMS The sum of BMSLimit Indicates the maximum available power of the battery pack allocated to the PTC;

[0024] (2) When the vehicle is in charging state and the main positive and negative relays are closed,

[0025] P 总线 =Min{(P HVCM +P BMSLimit ), P Req};

[0026] When the vehicle is in charging state and the main positive relay is disconnected,

[0027] P 总线 =Min(P HVCM , P Req );

[0028] Among them, P HVCM Indicates the PTC power that the high voltage control module allows the vehicle controller to request;

[0029] Preferably, for the P Req , when only the central control screen panel PTC heating request, obviously there is P Req =P 面板 ; When only the BMS requests the battery pack to heat, there is obviously P Req =P BMS ,in:

[0030] If the vehicle is in the Ready state, that is, ready to drive, then P BMS =0;

[0031] If the main positive and negative relays are closed after the charging gun is inserted but the BMS does not allow charging, then P BMS =3KW;

[0032] If the main positive and negative relays are closed after the charging gun is inserted and the BMS allows charging, the P value is obtained by looking up the table based on the difference between the target heating temperature of the battery pack and the water inlet temperature of the battery pack. BMS .

[0033] Preferably, for the P Req , only the P Req When the power is greater than the preset power threshold, the P Req , otherwise, let the output P Req =0.

[0034] Preferably, after the PTC enable is triggered, the vehicle controller processes the received signal including requesting the panel PTC power P of the central control screen. 面板 Restrictions are imposed, including:

[0035] Limitation 1: When the defogger and defrost button is not detected and there is no battery heating request, the panel PTC of the central control screen requests power P 面板 Restrictions are made, namely:

[0036] If T OutTemp ≥55℃, then P Max =1.5KW;

[0037] If T OutTemp ≤45℃, then P Max =8.5KW;

[0038] If 45℃<TOutTemp <55℃, then according to T OutTemp Lookup table for P 面板 impose restrictions;

[0039] Among them, T OutTemp Indicates the PTC water outlet temperature; P Max Indicates the maximum requested power allowed for the panel PTC;

[0040] Limitation 2: Look up the table based on the panel temperature knob position and air volume knob position, and 面板 impose restrictions;

[0041] The final output of the central control screen panel PTC request power P 面板 , take the restrictions 1 and 2 under P 面板 The minimum value of .

[0042] Preferably, after the PTC enable is triggered, the vehicle controller processes the received signal including PTC fault judgment, wherein:

[0043] When the vehicle is not charging and not in high voltage state, the PTC fault is not determined, except:

[0044] (1) When the actual output power of the PTC is equal to the bus output PTC power P 总线 When the error exceeds the preset error threshold, the PTC enable signal is turned off with a delay, and the PTC fault is determined and recorded;

[0045] (2) After the PTC enable is triggered, if it is detected that the PTC does not start working within a preset time, a PTC enable failure is determined and recorded.

[0046] Preferably, once a PTC fault occurs, the vehicle will keep the fault record in the corresponding working cycle and will not be automatically cleared until it is manually reset after the fault is repaired.

[0047] The technical effect of the present invention is as follows: the present invention takes into full consideration the opening and closing of the PTC, as well as the safety limit of the output power, and can accurately determine the power distribution of the PTC when the central control panel and the battery pack are working independently and simultaneously, and can quickly respond to requests and heat, so that the temperature of the passenger compartment and the temperature of the power battery pack are maintained within a comfortable and safe range, the production cost of the whole vehicle is low, and the heating effect is good. BRIEF DESCRIPTION OF THE DRAWINGS

[0048] Figure 1 The figure is a structural diagram of a PTC control system for a new energy vehicle according to an embodiment of the present invention. DETAILED DESCRIPTION

[0049] The following is a further detailed description of the specific implementation of the present invention by describing the embodiments with reference to the accompanying drawings, with the purpose of helping those skilled in the art to have a more complete, accurate and in-depth understanding of the inventive concept and technical solution of the present invention and to facilitate its implementation. In order to make the technical solution of the present invention clearer, the present invention is explained by the following embodiments.

[0050] This embodiment provides a PTC control system for a new energy vehicle, such as Figure 1 As shown, the system includes a central control screen, a battery management system BMS, a vehicle controller (VCU), a high-voltage control module HVCM, a PTC controller, a PTC temperature sensor, and a PTC, wherein the vehicle controller is respectively connected to the central control screen, the battery management system BMS, the HVCM, and the PTC controller, and they are all connected by a CAN bus. The CAN bus is simple to lay out, which reduces costs while ensuring data transmission rate and stability; the PTC controller is respectively connected to the PTC temperature sensor and the PTC; the HVCM is connected to the BMS. In this embodiment, the PTC controller uses a microcontroller MCU, which has the advantages of high integration and low cost.

[0051] In this embodiment, the central control large screen panel is equipped with a panel temperature gear knob, a panel air volume gear knob, a defrost and defogger button, and a PTC switch. Their respective status signals are collected by the central control large screen and sent to the vehicle controller; the BMS is used to monitor the battery status (battery voltage, current, temperature, charge and discharge status, etc.) and send a battery heating request signal to the vehicle controller, wherein the battery status can also be synchronized to the HVCM; the HVCM is used to monitor the vehicle high voltage state and at the same time feed back the battery charging status signal to the vehicle controller; the PTC temperature sensor is used to collect the PTC water outlet temperature and send it to the vehicle controller through the PTC controller; the vehicle controller is used to process the received signal and output a PTC control signal to the PTC controller to control the output power of the PTC; the PTC controller is also used to monitor the actual output power of the PTC, as well as to diagnose the PTC and obtain the fault level, and the monitoring and diagnosis results are fed back to the vehicle controller.

[0052] At the same time, based on the above-mentioned PTC control system of a new energy vehicle, this embodiment also proposes a PTC control method of a new energy vehicle, and the method includes the following steps:

[0053] Step S1, the vehicle controller collects signals when the system components are working, including PTC switch signal, panel temperature knob gear signal, air volume knob signal, defrost and defog button signal, PTC temperature sensor signal, battery status, vehicle high voltage status, BMS battery heating request signal, HVCM battery charging status signal, PTC actual output power, and PTC fault level;

[0054] Step S2: The vehicle controller processes the collected signal and outputs a PTC control signal to the PTC controller to control the output power of the PTC.

[0055] Specifically, the processing of the received signal by the vehicle controller of this embodiment includes determining whether to issue a PTC enable request, wherein the PTC enable request is triggered only when the following conditions are met at the same time:

[0056] (1) The power-on mode is in a non-OFF state, and the main positive and negative relays are closed (the vehicle's electrical system has been activated, and the circuit that supplies energy to the PTC has formed a path); or in the battery charging state, the high-voltage control module feedbacks the battery pack charging state as: charging and heating state, or pure heating state (battery temperature plays an important role when charging, especially at low temperatures, the battery needs to be heated to ensure charging efficiency. At this time, the PTC can be powered by an external charging device);

[0057] (2) The fault level of the PTC heater does not exceed the preset level to ensure that the PTC itself is in a relatively good working state (the preset level in this embodiment is level 2, which can be flexibly set according to actual conditions during implementation, and is not intended to limit the present invention);

[0058] (3) The vehicle controller and the PTC controller communicate normally to ensure that the PTC enable signal is sent to the PTC controller in a timely manner;

[0059] (4) The panel temperature knob is in the preset range (9 to 16 in this embodiment), and the panel air volume knob is in an activated state, indicating that the user expects to increase the temperature inside the vehicle through PTC heating, and the air circulation system is also in an on-coordinated state;

[0060] (5) The PTC switch is in the on state (the most direct passenger compartment heating request); or the BMS issues a battery heating request in non-slow charging mode (which means that the battery needs to be heated to maintain performance and ensure charging efficiency, etc.); or the BMS issues a battery heating request in slow charging mode and the charging status is not in the initialization and pending states (which means that the battery does have an actual need to be heated during the slow charging process and the charging has passed the unstable stage such as initialization);

[0061] (6) No PTC fault signal is received (in the event of a PTC fault, the PTC enable cannot be triggered, thereby ensuring safe system operation).

[0062] In this embodiment, after receiving the PTC control signal from the vehicle controller, the PTC controller drives the working power of the PTC to increase or decrease at a rate of 2kw / s. This is a stable adjustment method to avoid the instantaneous impact of too fast adjustment on the system. At the same time, it can also enable the PTC to achieve the required working power more accurately. After there is no PTC enable request, the power working of the PTC is immediately reset to 0, thereby reducing energy consumption.

[0063] After the PTC enable is triggered, the vehicle controller of this embodiment processes the received signal by calculating the bus output PTC power P of the vehicle controller. 总线 ,in:

[0064] (1) When the vehicle is not charging,

[0065] P Req =P 面板 +P BMS ;

[0066] P 总线 =Min(P BMSLimit , P Req )

[0067] Among them, Min means taking the minimum value; P Req Indicates the panel PTC request power P of the central control screen 面板 and the BMS battery pack heating PTC request power P BMS The sum of BMSLimit Indicates the maximum available power allocated to the PTC by the battery pack. In the non-charging state, the vehicle's high-voltage system is mainly used for the normal operation of the equipment in the vehicle (including PTC). At this time, the bus output PTC power is mainly set according to the actual needs of the vehicle, especially the panel PTC request issued by the passenger compartment through the central control screen, and the battery heating request of the BMS.

[0068] 2) When the vehicle is in charging state and the main positive and negative relays are closed,

[0069] P 总线 =Min{(P HVCM +P BMSLimit ), P Req};

[0070] When the vehicle is in charging state and the main positive relay is disconnected,

[0071] P 总线 =Min(PHVCM , P Req );

[0072] Among them, P HVCM Indicates the PTC power that the high-voltage control module allows the vehicle controller to request. When the vehicle is in charging state and the main positive relay is disconnected, the vehicle's high-voltage electrical equipment cannot work, but considering the temperature regulation of the battery during charging, the vehicle controller can enable battery pack heating according to the battery charging status feedback from the HVCM. When the vehicle is in charging state and the main positive and negative relays are closed, it means that the main path of the vehicle's high-voltage system is connected. Considering the heating requirements of the battery pack during low-temperature charging, there may also be other requirements such as temperature regulation in the vehicle, so there will be P Req .

[0073] For the P Req , when only the central control screen panel PTC heating request, obviously there is P Req =P 面板 When only the BMS requests heating of the battery pack, there is obviously a P Req =P BMS ,in:

[0074] If the vehicle is in the Ready state, that is, ready to drive, then P BMS = 0. At this time, the vehicle has completed all preparations, and the battery temperature is in a suitable range, and no additional heating is required to maintain battery performance.

[0075] If the main positive and negative relays are closed after the charging gun is inserted but the BMS does not allow charging, then P BMS =3KW. The main positive and negative relays are closed, indicating that the vehicle high voltage system is powered on, but the BMS does not allow charging, indicating that the battery status may not meet the charging requirements. At this time, set P BMS =3KW, which can maintain the battery pack in a relatively suitable temperature environment to avoid the inability to charge due to temperature factors. At the same time, the suitable temperature also helps to protect the battery performance.

[0076] If the main positive and negative relays are closed after the charging gun is inserted and the BMS allows charging, the P value is obtained by looking up the table based on the difference between the target heating temperature of the battery pack and the water inlet temperature of the battery pack. BMS The specific table is obtained in advance through a large number of experimental tests, and the rules are followed: when the difference is large, it means that the battery temperature is low and a higher heating power is required to quickly increase the temperature; when the difference is small, it means that the battery temperature is close to the target temperature and only a lower heating power is needed to reach the target temperature.

[0077] In this embodiment, for the P Req , only the P ReqWhen the power threshold is greater than a preset power threshold (the power threshold in this embodiment is set to 0.8kw, which can be flexibly set according to actual conditions), the P Req , otherwise, let the output P Req = 0. When the PTC power is lower than 0.8kW, the useful heat generated is very small, but a certain amount of electrical energy will still be consumed to maintain its working state. From the perspective of energy utilization efficiency, this energy waste in the low-power working state is uneconomical.

[0078] In addition, after the PTC enable is triggered, the vehicle controller of this embodiment processes the received signal and also requests the panel PTC power P of the central control screen. 面板 Restrictions are imposed to fully respect user wishes and ensure system security, including:

[0079] Limitation 1: When the defogger and defrost button is not detected and there is no battery heating request, the panel PTC of the central control screen requests power P 面板 Restrictions are made, namely:

[0080] If T OutTemp ≥55℃, then P Max =1.5KW;

[0081] If T OutTemp ≤45℃, then P Max =8.5KW;

[0082] If 45℃<T OutTemp <55℃, then according to T OutTemp Lookup table for P 面板 impose restrictions;

[0083] Among them, T OutTemp Indicates the PTC water outlet temperature; P Max Indicates the maximum allowed panel PTC requested power.

[0084] T OutTemp ≥55℃ indicates that the PTC has generated enough heat. Running at a higher power may cause the system to overheat, so the power is limited. OutTemp ≤45℃ means that PTC needs more heat to reach the appropriate operating temperature, but in order to avoid excessive power and a sharp rise in system temperature, which may lead to safety hazards, as well as waste of resources caused by excess power, the power is limited. OutTemp In the range of <55℃, different temperatures may correspond to different optimal powers. For higher working efficiency, the power is limited. Similarly, the table is calibrated in advance based on a large amount of experimental data.

[0085] Limitation 2: According to the panel temperature knob gear and air volume knob gear table (the table is pre-calibrated based on a large amount of experimental data), P 面板 The panel temperature knob position and air volume knob position represent the user's subjective wishes. 面板 This ensures that the user's wishes are fully respected.

[0086] The final output of the central control screen panel PTC request power P 面板 , take the restrictions 1 and 2 under P 面板 This not only avoids the damage to the system and unnecessary energy waste caused by excessive PTC power, but also ensures that P 面板 It just meets the actual needs, whether it is the user's demand for the temperature inside the car or the safe and stable operation requirements of the system itself.

[0087] In an embodiment, after the PTC enable is triggered, the vehicle controller processes the received signal and further includes PTC fault judgment, wherein:

[0088] When the vehicle is not charging and not in high voltage state, the PTC fault is not judged. At this time, the vehicle's electrical system may be in a relatively low power or standby state, and the PTC is not powered and activated. Therefore, the PTC failure will not have a substantial impact on the overall operation of the vehicle. Therefore, the judgment of its fault is temporarily ignored to reduce unnecessary false fault alarms and the occupation of system resources.

[0089] besides:

[0090] (1) When the actual output power of the PTC is equal to the bus output PTC power P 总线 When the error exceeds the preset error threshold, the PTC enable signal is turned off with a delay, and the PTC fault is determined and recorded;

[0091] (2) After the PTC enable is triggered, if it is detected that the PTC does not start working within a preset time, a PTC enable failure is determined and recorded.

[0092] It should be noted that once a PTC fault occurs, the vehicle will maintain the fault record in the corresponding working cycle and will not be automatically cleared until the fault is repaired and reset manually.

[0093] The present invention takes into full consideration the opening and closing of the PTC, as well as the safety limit of the output power, and can accurately determine the power distribution of the PTC when the central control panel and the battery pack are working independently and simultaneously. It can quickly respond to requests and heat up, so that the temperature of the passenger compartment and the temperature of the power battery pack are maintained within a comfortable and safe range. The production cost of the whole vehicle is low and the heating effect is good.

[0094] The present invention is described above by way of example in conjunction with the accompanying drawings. Obviously, the specific implementation of the present invention is not limited to the above-mentioned methods. As long as various non-substantial improvements are made using the method concept and technical solution of the present invention; or the above concept and technical solution of the present invention are directly applied to other occasions without improvement, they are all within the protection scope of the present invention.

Claims

1. A PTC control system for a new energy vehicle, characterized in that: The system includes a central control screen, a battery management system BMS, a vehicle controller, a high-voltage control module HVCM, a PTC controller, a PTC temperature sensor, and a PTC, wherein the vehicle controller is respectively connected to the central control screen, the battery management system BMS, the HVCM, and the PTC controller; the PTC controller is respectively connected to the PTC temperature sensor and the PTC; the HVCM is connected to the BMS; the central control screen panel is equipped with a panel temperature gear knob, a panel air volume gear knob, a defrost and defog button, and a PTC switch, and their respective status signals are collected by the central control screen and sent to the vehicle controller; the BMS uses The HVCM is used to monitor the battery status and send a battery heating request signal to the vehicle controller; the HVCM is used to monitor the high voltage status of the vehicle and feed back the battery charging status signal to the vehicle controller; the PTC temperature sensor is used to collect the PTC water outlet temperature and send it to the vehicle controller through the PTC controller; the vehicle controller is used to process the received signal and then output the PTC control signal to the PTC controller to control the output power of the PTC; the PTC controller is also used to monitor the actual output power of the PTC, diagnose the PTC and obtain the fault level, and the monitoring and diagnosis results are fed back to the vehicle controller.

2. A PTC control method for a new energy vehicle according to the system of claim 1, characterized in that: The method comprises the following steps: Step S1, the vehicle controller collects signals when the system components are working, including PTC switch signal, panel temperature knob gear signal, air volume knob signal, defrost and defog button signal, PTC temperature sensor signal, battery status, vehicle high voltage status, BMS battery heating request signal, HVCM battery charging status signal, PTC actual output power, and PTC fault level; Step S2: The vehicle controller processes the collected signal and outputs a PTC control signal to the PTC controller to control the output power of the PTC.

3. A PTC control method for a new energy vehicle according to claim 2, characterized in that: The vehicle controller processes the received signal by determining whether to issue a PTC enable request, wherein the PTC enable request is triggered only when the following conditions are met at the same time: (1) The power-on mode is in a non-OFF state, and the main positive and negative relays are closed; or in the battery charging state, the high-voltage control module feedback battery pack charging state is: charging and heating state, or pure heating state; (2) The PTC heater failure level does not exceed the preset level; (3) The communication between the vehicle controller and the PTC controller is normal; (4) The panel temperature knob is within the preset range and the panel air volume knob is activated; (5) The PTC switch is in the on state; or the BMS issues a battery heating request in non-slow charging mode; or the BMS issues a battery heating request in slow charging mode and the charging state is not in the initialization and pending states; (6) No PTC fault signal is received.

4. A PTC control method for a new energy vehicle according to claim 3, characterized in that: After receiving the PTC control signal from the vehicle controller, the PTC controller drives the working power of the PTC to increase or decrease at a rate of 2kw / s. After there is no PTC enable request, the power working of the PTC is immediately reset to 0.

5. The PTC control method for a new energy vehicle according to claim 3, characterized in that: After the PTC enable is triggered, the vehicle controller processes the received signal including calculating the bus output PTC power P of the vehicle controller. 总线 ,in: (1) When the vehicle is not charging, P Req =P 面板 +P BMS ; P 总线 =Min(P BMSLimit ,P Req ) Among them, P Req Indicates the panel PTC request power P of the central control screen 面板 and the BMS battery pack heating PTC request power P BMS The sum of BMSLimit Indicates the maximum available power of the battery pack allocated to the PTC; (2) When the vehicle is in charging state and the main positive and negative relays are closed, P 总线 =Min{(P HVCM +P BMSLimit ),P Req }; When the vehicle is in charging state and the main positive relay is disconnected, P 总线 =Min(P HVCM ,P Req ); Among them, P HVCM Indicates the PTC power that the high voltage control module allows the vehicle controller to request.

6. A PTC control method for a new energy vehicle according to claim 5, characterized in that: For the P Req , when only the central control screen panel PTC heating request, obviously there is P Req =P 面板 ; When only the BMS requests the battery pack to heat, there is obviously P Req =P BMS ,in: If the vehicle is in the Ready state, that is, ready to drive, then P BMS =0; If the main positive and negative relays are closed after the charging gun is inserted but the BMS does not allow charging, then P BMS =3KW; If the main positive and negative relays are closed after the charging gun is inserted and the BMS allows charging, the P value is obtained by looking up the table based on the difference between the target heating temperature of the battery pack and the water inlet temperature of the battery pack. BMS .

7. A PTC control method for a new energy vehicle according to claim 5 or 6, characterized in that: For the P Req , only the P Req When the power is greater than the preset power threshold, the P Req , otherwise, let the output P Req =0.

8. A PTC control method for a new energy vehicle according to claim 5 or 6, characterized in that: After the PTC is enabled, the vehicle controller processes the received signal, including requesting the panel PTC power P of the central control screen. 面板 Restrictions are imposed, including: Limitation 1: When the defogger and defrost button is not detected and there is no battery heating request, the panel PTC of the central control screen requests power P 面板 Restrictions are made, namely: If T OutTemp ≥55℃, then P Max =1.5KW; If T OutTemp ≤45℃, then P Max =8.5KW; If 45℃<T OutTemp <55℃, then according to T OutTemp Lookup table for P 面板 impose restrictions; Among them, T OutTemp Indicates the PTC water outlet temperature; P Max Indicates the maximum requested power allowed for the panel PTC; Limitation 2: Look up the table based on the panel temperature knob position and air volume knob position, and 面板 impose restrictions; The final output of the central control screen panel PTC request power P 面板 , take the restrictions 1 and 2 under P 面板 The minimum value of .

9. A PTC control method for a new energy vehicle according to claim 5, characterized in that: After the PTC enable is triggered, the vehicle controller processes the received signal including PTC fault judgment, where: When the vehicle is not charging and not in high voltage state, the PTC fault is not determined, except: (1) When the actual output power of the PTC is equal to the bus output PTC power P 总线 When the error exceeds the preset error threshold, the PTC enable signal is turned off with a delay, and the PTC fault is determined and recorded; (2) After the PTC enable is triggered, if it is detected that the PTC does not start working within a preset time, a PTC enable failure is determined and recorded.

10. A PTC control method for a new energy vehicle according to claim 9, characterized in that: Once a PTC fault occurs, the vehicle will maintain the fault record in the corresponding working cycle and will not be automatically cleared until the fault is corrected and reset manually.

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