New energy cold chain vehicle control strategy

Abstract

The invention discloses a new energy cold chain vehicle control strategy which comprises a lower high voltage control module, a cold machine enabling control module, an energy management module, a power limiting module and a fault diagnosis module. The APU can continuously work to supply power to the whole vehicle, compared with a pure electric vehicle type, energy is supplemented through charging, a tandem type hybrid electric vehicle can be powered by oil or electricity, when charging is inconvenient or the requirement for transportation timeliness is high, energy can be supplemented through a refueling mode, refueling is very convenient for current high-speed networks or urban and rural areas, and the energy-saving and energy-saving effects are achieved. The tandem type hybrid power electric cold-chain logistics transport vehicle has the advantages that the tandem type hybrid power electric cold-chain logistics transport vehicle has incomparable advantages compared with a plurality of pure electric vehicle types as a cold-chain application scene, the problems of endurance anxiety and transportation worry feeling of a user are really solved, more possibilities are provided for creating more economic benefits for customers, and the transportation cost is reduced. And the vehicle use experience of the user is improved.

Description

Technical Field

[0001] The present invention belongs to the technical field of new energy vehicles. Specifically, the present invention relates to a control strategy for a new energy cold chain vehicle. Background Art

[0002] Energy commercial vehicles are applied to various logistics transportation scenarios, including cold chain logistics transportation that requires refrigeration or preservation. The requirements for the freshness and freezing of the transported products are extremely high. Therefore, the requirements for the vehicle's endurance and the continuous operation of the refrigerating unit are very high. Otherwise, it may cause certain economic losses to the user's cold chain transportation, seriously affecting the user experience. Instead of creating more value for the customer, it even affects the customer's creation of basic economic benefits.

[0003] In the current cold chain logistics transportation industry, pure electric cold chain logistics vehicles, as a relatively environmentally friendly means of transportation, have been applied to a certain extent. However, pure electric models have some significant limitations, which seriously restrict their wide application in the cold chain logistics field;

[0004] First of all, the cruising range of pure electric models is limited. Cold chain transportation often requires long-distance travel and long driving distances. In actual operation, it is very difficult for the battery power of pure electric models to meet the transportation needs of long hours and long distances. When the battery runs out of power, the vehicle cannot continue to drive, which may lead to the interruption of cargo transportation and seriously affect the quality of cold chain goods. For example, in some remote areas or areas with imperfect charging facilities, pure electric cold chain vehicles may be in trouble because they cannot find a suitable charging pile,

[0005] Secondly, the charging and energy replenishment time is too long. The charging process of pure electric models is relatively slow. Even with fast charging technology, it still takes a long time to fully charge the battery. In the case of tight transportation time, this long charging waiting will greatly affect the transportation efficiency and cannot meet the strict requirements of cold chain logistics for timeliness. For example, in the transportation of some fresh products, every minute of delay may lead to a decline in product quality and cause economic losses. Summary of the Invention

[0006] The present invention provides a control strategy for a new energy cold chain vehicle, which solves the problems raised in the above background art.

[0007] In order to achieve the above object, the technical solution adopted by the present invention is: a control strategy for a new energy cold chain vehicle, including a high-voltage control module, a refrigerating unit enabling control module, an energy management module, a power limit module, and a fault diagnosis module.

[0008] Preferably, the refrigerating unit enabling control module includes the following steps:

[0009] Step S10, after the vehicle is powered on and initialized, it enters the cold engine enable judgment module;

[0010] Step S11, the VCU will, according to the cold engine start request sent by the cold engine through the bus, the cold engine fault status (DCDC output fault, frequency converter fault), high-voltage status, available remaining power, SOC, remote function control status, and calibration permission. If so, it enters the next step; if not, the cold engine enable is prohibited;

[0011] Step S12, the VCU simultaneously judges whether to enable according to the real-time status of the cold engine. If there is no start request, or the pre-charging fails under the control of the cold engine within 5 seconds, or the cold engine feedbacks a fault status, the VCU prohibits the enable. If the above status does not exist, the judgment is repeated.

[0012] Preferably, the following steps are included in the lower high-voltage control module:

[0013] Step S20, after the vehicle is powered on and initialized, it enters the cold engine enable judgment module. When the cold engine is in operation, it enters the next step;

[0014] Step S21, judge whether the user turns the key to Off to power off the whole vehicle. If so, it enters the next step; if not, the judgment is repeated;

[0015] Step S22, the VCU will immediately send a command to prohibit the cold engine enable to the cold engine, and the cold engine executes shutdown and active discharge;

[0016] Step S23, judge whether the busbar current is lower than the threshold value through the VCU, or the waiting time exceeds the threshold value. If so, the VCU sends a lower high-voltage command to the BMS; if not, the judgment is repeated;

[0017] Step S24, the BMS controls to disconnect the main positive and main negative relays in sequence.

[0018] Preferably, the following steps are included in the energy management module:

[0019] Step S30, after the vehicle is powered on and initialized, it enters the cold engine enable judgment module. When the cold engine is in operation, it enters the next step;

[0020] Step S31, the VCU will monitor the actual power consumption of the cold engine in real time, and the cold engine sends the actual power consumption Pcoolingact to the VCU through the bus;

[0021] Step S32, perform fixed-point power generation calibration correction on the VCU;

[0022] Step S33, judge whether the battery low-temperature protection is activated. If so, it enters the next step; if not, it goes to Step S35;

[0023] Step S34, the battery discharge capacity will also decrease at low temperatures. The VCU will control the APU to start running, and the power request formula is as follows:

[0024] Pbattlowtmp = Pdcdc + Pdcac + Pacm++Phvac + Pcoolingact + Pbattheating;

[0025] Step S35, determine whether the vehicle is in the state of plugging in for charging. If so, proceed to the next step; if not, proceed to Step S37;

[0026] Step S36, when plugging in for charging, the VCU will calculate the charging current that needs to be compensated to the BMS and send it to the BMS for execution. The charging compensation current formula calculated by the VCU is as follows:

[0027] Icomchrg = Idcdc + Idcac + Iacm++Ihvac + Icoolingact - Iapu;

[0028] Step S37, determine whether the vehicle is in the parked power generation state. If so, proceed to the next step; if not, it is judged as conventional control;

[0029] Step S38, the VCU will overall monitor the operating states of all high-voltage components and the state of charge of the battery, dynamically calculate the parked power generation power request of the APU, and send it to the APU for execution. The calculation formula is as follows:

[0030] PIdlchrg = Pdcdc + Pdcac + Phvac + Pcoolingact.

[0031] Preferably, the power limit module includes the following steps:

[0032] Step S40, after the vehicle is powered on and initialized, it enters the cold machine enable judgment module. When the cold machine is in operation, proceed to the next step;

[0033] Step S40, the cold machine filters and smooths the actual power consumption and sends it to the VCU;

[0034] Step S41, set the power consumption priority of the vehicle's high-voltage components: electric drive > cold machine > passenger compartment air conditioner > DCAC, and then sequentially perform the available power allocation calculation for power limit;

[0035] Step S42, calculate the available power of the electric drive: the available discharge power of the system (the available discharge power of the battery + the available discharge power of the APU);

[0036] Step S43, calculate the available power of the cold machine: the available discharge power of the system - the actual power consumption of the electric drive;

[0037] Step S44, Calculation of available power of the passenger compartment air conditioner: Available power of the chiller - Actual power consumption of the chiller;

[0038] Step S45, Calculation of available power of DCAC: Available power of the passenger compartment air conditioner - Actual power of the passenger compartment air conditioner;

[0039] Step S46, Then enter the DCMC enable control module for decision-making and send it to the chiller for execution.

[0040] Preferably, the fault diagnosis module includes the following steps:

[0041] Step S50, Initialize the vehicle power on to monitor the actual operating status of the chiller and timely remind the driver whether the whole vehicle cold chain operation is normal;

[0042] Step S51, When a chiller communication loss fault, a chiller enable failure fault, or a failure to close the chiller enable fault occurs, proceed to Step S52. When various vehicle-level faults of the chiller occur, proceed to Step S53;

[0043] Step S52, Determine whether the VCU reports a fault. If so, store the eeprom after the fault is reported. If not, repeat the determination;

[0044] Step S53, Determine whether the chiller controller reports a fault. If so, perform fault degradation according to the vehicle's various fault level handling strategies. If not, repeat the determination.

[0045] The beneficial effects of adopting the above technical solutions are as follows:

[0046] First, in terms of the cruising range, the present invention completely solves the problem of insufficient cruising range of pure electric vehicles. That is, the presence of the APU enables the vehicle to continue driving without worrying about the battery running out during long-distance transportation, greatly increasing the driving range of the vehicle, meeting the needs of long-distance cold chain logistics transportation. This not only reduces the risk of transportation interruption caused by cruising range problems but also expands the transportation scope for users, enabling them to undertake cold chain transportation services over longer distances, thereby increasing business opportunities and economic benefits.

[0047] Second, in terms of refueling convenience and timeliness, the refueling method that can be either fuel or electricity of the present invention provides great convenience for users. Compared with the long charging waiting time of pure electric vehicles, refueling is fast and convenient and can be easily achieved on the highway network and in urban and rural areas. This enables the vehicle to quickly replenish energy and continue to be put into transportation work when the transportation time is tight, significantly improving transportation efficiency and meeting the strict requirements of cold chain logistics for timeliness. At the same time, the flexibility of this refueling method also reduces users' anxiety about cruising range, allowing users to arrange transportation tasks more calmly.

[0048] III. For the stable operation of the cold chain refrigeration system, the VCU cold chain control interaction strategy of the present invention plays a key role. Through real-time monitoring and intelligent adjustment, the VCU ensures that the cold chain refrigeration system can obtain sufficient and stable power supply under various working conditions, maintains the low-temperature environment in the carriage, ensures the quality of cold chain goods is not affected, reduces the loss of goods caused by unstable refrigeration systems, and improves the economic benefits and market competitiveness of users.

[0049] IV. In terms of energy management and operating costs, the intelligent energy distribution strategy and driving scenario adaptive adjustment function of the VCU of the present invention optimize the energy utilization efficiency of the whole vehicle, reduce energy consumption and operating costs. By reasonably controlling the working mode and power output of the APU, as well as the energy distribution between the battery and the APU, energy waste is avoided, and the energy usage time of the vehicle is extended. This not only reduces the fuel and electricity expenses of users, but also reduces the impact on the environment, meeting the requirements of sustainable development. BRIEF DESCRIPTION OF THE DRAWINGS

[0050] Figure 1 is the overall control strategy architecture diagram of the present invention;

[0051] Figure 2 is the flowchart of the chiller enabling control of the present invention;

[0052] Figure 3 is the flowchart of the lower high-voltage control of the present invention;

[0053] Figure 4 is the flowchart of the energy management control of the present invention;

[0054] Figure 5 is the flowchart of the power limit control of the present invention;

[0055] Figure 6 is the flowchart of the fault diagnosis control of the present invention; DETAILED DESCRIPTION OF THE EMBODIMENTS

[0056] The following further describes in detail the specific embodiments of the present invention with reference to the accompanying drawings and through the description of the embodiments, aiming to help those skilled in the art have a more complete, accurate and in-depth understanding of the concept and technical solution of the present invention and facilitate its implementation.

[0057] Specifically, as Figures 1 to 6 shown, a new energy cold chain vehicle control strategy includes a lower high-voltage control module, a chiller enabling control module, an energy management module, a power limit module, and a fault diagnosis module.

[0058] It should be noted that the lower high-voltage control module, the chiller enabling control module, the energy management module, the power limit module, and the fault diagnosis module constitute the entire control strategy architecture.

[0059] The cold machine enabling control module includes the following steps:

[0060] Step S10: After the vehicle is powered on and initialized, it enters the cold machine enabling judgment module;

[0061] Step S11: The VCU will, based on the cold machine start request sent by the cold machine via the bus, the cold machine fault status (DCDC output fault, frequency converter fault), high-voltage status, available remaining power, SOC, remote function control status, and calibration permission, enter the next step if yes, otherwise prohibit the cold machine enabling;

[0062] Step S12: The VCU simultaneously determines whether to enable based on the real-time status of the cold machine. If there is no start request, or the pre-charging fails under the control of the cold machine within 5 seconds, or the cold machine feedbacks a fault status, the VCU prohibits the enabling. If the above status does not exist, the determination is repeated.

[0063] Specifically, the VCU will judge according to conditions such as the cold machine start request sent by the cold machine via the bus, the cold machine fault status (DCDC output fault, frequency converter fault), high-voltage status, available remaining power, SOC, remote function control status, and calibration permission. If the conditions are met, enabling is allowed, otherwise it is not allowed;

[0064] In addition, the VCU simultaneously determines whether to enable according to the real-time status of the cold machine, that is, if there is no start request, or the pre-charging fails under the control of the cold machine within 5 seconds, or the cold machine feedbacks a fault, the VCU prohibits the enabling.

[0065] The following high-voltage control module includes the following steps:

[0066] Step S20: After the vehicle is powered on and initialized, it enters the cold machine enabling judgment module. When the cold machine is in operation, enter the next step;

[0067] Step S21: Judge whether the user turns the key to Off to power off the whole vehicle. If yes, enter the next step, otherwise repeat the determination;

[0068] Step S22: The VCU will immediately send a command to the cold machine to prohibit the cold machine enabling, and the cold machine performs shutdown and active discharging;

[0069] Step S23: The VCU judges whether the busbar current is lower than the threshold value, or the waiting time exceeds the threshold value. If yes, the VCU sends a high-voltage-down instruction to the BMS, otherwise repeat the determination;

[0070] Step S24: The BMS controls to disconnect the main positive and main negative relays in sequence.

[0071] It should be noted that for the lower high-voltage control module, if the user normally shuts down the cold machine by turning off the I / O switch, a request to disable the cold machine is sent to the VCU, and the VCU then issues an instruction to prohibit the cold machine enablement.

[0072] Specifically, if the cold machine is running and the user turns the key to Off to power off the whole vehicle, the VCU will immediately send a command to prohibit the cold machine enablement to the cold machine, and then proceed with the lower high-voltage process. The VCU will judge the DC bus current and the lower high-voltage delay time to ensure that the DC bus current is lower than the threshold value, thus protecting the main positive relay from disconnecting under a high load condition, causing arcing or even damage to the main positive relay. The lower high-voltage of the cold machine is generally completed within 5 seconds, including its internal active discharge. When the VCU determines that the bus current is lower than the threshold value, it directly performs the lower high-voltage operation; otherwise, it directly performs the lower high-voltage operation after judging that the lower high-voltage waiting time exceeds the threshold value, preventing the lower high-voltage process from being stuck due to abnormal states of the high-voltage system or the cold machine system and avoiding the risk of electric shock caused by the user's unconscious contact with high-voltage components when the lower high-voltage cannot be performed.

[0073] The energy management module includes the following steps:

[0074] Step S30: After the vehicle is powered on and initialized, it enters the cold machine enablement judgment module. When the cold machine is running, it proceeds to the next step.

[0075] Step S31: The VCU will monitor the actual power consumption of the cold machine in real time, and the cold machine sends the actual power consumption Pcoolingact to the VCU through the bus.

[0076] Step S32: Calibrate and correct the fixed-point power generation of the VCU.

[0077] Step S33: Judge whether the battery low-temperature protection is activated. If so, proceed to the next step; otherwise, proceed to step S35.

[0078] Step S34: At low temperatures, the battery's discharge capacity will also decrease. The VCU will control the APU to start running, and the requested power formula is as follows:

[0079] Pbattlowtmp = Pdcdc + Pdcac + Pacm++Phvac + Pcoolingact + Pbattheating;

[0080] Step S35: Judge whether the vehicle is in the state of charging with the charging gun inserted. If so, proceed to the next step; otherwise, proceed to step S37.

[0081] Step S36: When charging with the charging gun inserted, the VCU will calculate the charging current that needs to be compensated to the BMS and send it to the BMS for execution. The formula for the charging compensation current calculated by the VCU is as follows:

[0082] Icomchrg = Idcdc + Idcac + Iacm++ + Ihvac + Icoolingact - Iapu;

[0083] Step S37, determine whether the vehicle is in parking power generation. If so, proceed to the next step; otherwise, it is determined as conventional control.

[0084] Step S38, the VCU will comprehensively monitor the operating states of all high-voltage components and the state of charge of the battery, dynamically calculate the parking power generation power request of the APU, and send it to the APU for execution. The calculation formula is as follows:

[0085] PIdlchrg = Pdcdc + Pdcac + Phvac + Pcoolingact.

[0086] It should be noted that when considering the operation of the chiller, the power request calculation during APU operation needs to be considered, including the conventional vehicle operating state, battery low-temperature protection scenario, battery charging current compensation, and parking power generation working conditions, etc.

[0087] Specifically, the CU will monitor the actual power consumption of the chiller in real time. The chiller sends the actual power consumption Pcoolingact to the VCU through the bus. Before sending out the power consumption, the chiller needs to perform filtering and smoothing processing on the actual power consumption to prevent power fluctuations from causing fluctuations in the results of the energy management numerical calculation on the VCU side, which in turn causes jitter in the states of related components. For example, during APU power generation control, the fluctuating APU power generation power request will cause fluctuations in the APU speed and engine noise, affecting the user's vehicle use experience.

[0088] On the basis of the basic APU requested power generation power, the VCU further increases the actual power consumption Pcoolingact of the chiller. For different power generation strategies of the VCU, the actual power consumption of the chiller only acts on the power following strategy. For the fixed-point power generation control strategy with the best NVH, the actual power consumption of the chiller does not need to be considered, avoiding the power fluctuation of the chiller operation causing the power request of the APU calculated by the VCU to fluctuate, which in turn causes fluctuations in the engine speed and noise, reducing the NVH performance of the whole vehicle and affecting the user's vehicle use experience.

[0089] For the fixed-point power generation strategy of the VCU, the actual power consumption compensation of the chiller needs to be considered. On the basis of the basic calibration, the fixed-point power generation power request value during driving is further increased to make the peak shaving and valley filling effect smooth out the average power consumption of the whole vehicle increased by the chiller operation, so as to ensure the balance of the whole vehicle SOC and the safety of energy management.

[0090] The VCU battery low-temperature protection strategy is used for battery protection when charging is not allowed at low temperatures. At low temperatures, the battery's discharge capacity will also decrease. The VCU will control the APU to start running. Since the required power at the driving end of the vehicle's dynamic operation changes rapidly, the responsiveness of the drive motor is much higher than that of the APU. Therefore, there is a time lag in the control of the power consumption and power generation. This lag will cause excess electrical energy to be charged into the battery, resulting in overcharging of the battery. Therefore, when the battery is protected at low temperatures, the VCU only requests the high-voltage accessories to consume power, including the actual power consumption of the cold machine, to reduce the battery power consumption. After the battery is heated, the vehicle can restore normal power performance;

[0091] In addition, before sending out Icomchrg, the VCU will perform first-order filtering and smoothing on it to prevent the compensation current fluctuation from affecting the BMS to request the charging current, and also prevent the current fluctuation at the end of charging from causing overcharging of the battery and other impacts on the battery life.

[0092] The power limit module includes the following steps:

[0093] Step S40: After the vehicle is powered on and initialized, it enters the cold machine enable judgment module. When the cold machine is in operation, it enters the next step;

[0094] Step S40: The cold machine filters and smooths the actual power consumption and sends it to the VCU;

[0095] Step S41: Set the power consumption priority of the vehicle's high-voltage components as follows: electric drive > cold machine > passenger compartment air conditioner > DCAC, and then perform the available power distribution calculation for power limit in sequence;

[0096] Step S42: Calculate the available power of the electric drive: the system available discharge power (battery available discharge power + APU available discharge power);

[0097] Step S43: Calculate the available power of the cold machine: the system available discharge power - the actual power consumption of the electric drive;

[0098] Step S44: Calculate the available power of the passenger compartment air conditioner: the available power of the cold machine - the actual power consumption of the cold machine;

[0099] Step S45: Calculate the available power of DCAC: the available power of the passenger compartment air conditioner - the actual power of the passenger compartment air conditioner;

[0100] Step S46: Then enter the decision of the DCMC enable control module and send it to the cold machine for execution.

[0101] It should be noted that it is necessary to control all charging and discharging not to exceed the allowable limit of the battery to fully protect the battery, avoid affecting the battery life or reporting faults, which may affect the safety of the vehicle's high-voltage operation and driving safety;

[0102] Specifically, there are different high-voltage components on the vehicle, and it is necessary to set their power consumption priorities according to the importance of the high-voltage components, so as to ensure the safe operation of important components while further limiting the available discharge power, and prevent over-discharge of the battery;

[0103] In addition, when setting the power consumption priorities of the vehicle's high-voltage components, the motor drive > the chiller > the passenger compartment air conditioner > the DCAC. When calculating the power limit, the high-priority power-consuming components are preferentially allocated the available discharge power of the system. If the available discharge power of this component is lower than the preset threshold, then this component is prohibited from being enabled, which not only ensures the priority of high-level power consumption but also ensures that the battery will not be over-discharged.

[0104] The fault diagnosis module includes the following steps:

[0105] Step S50, the vehicle is powered on and initialized to monitor the actual operating status of the chiller and timely remind the driver whether the vehicle's cold chain operation is normal;

[0106] Step S51, when a chiller communication loss fault, a chiller enable failure fault, or a failure to turn off the chiller enable occurs, proceed to step S52. When various vehicle-level faults of the chiller occur, proceed to step S53;

[0107] Step S52, determine whether the VCU reports a fault. If so, store the eeprom after the fault is reported. If not, repeat the determination;

[0108] Step S53, determine whether the chiller controller reports a fault. If so, perform fault degradation according to the vehicle's fault level handling strategy. If not, repeat the determination;

[0109] It should be noted that the development of faults related to the chiller control interaction of the cold chain is to monitor the actual operating status of the chiller, timely remind the driver whether the vehicle's cold chain operation is normal, and protect the safety of transported goods, including chiller communication loss faults, chiller enable failure faults, failure to turn off the chiller enable faults, and various vehicle-level faults of the chiller;

[0110] Specifically, for the determination of the chiller communication loss fault, the VCU bottom-layer software first needs to perform communication timeout determination. If the communication times out, then perform debounce filtering confirmation and then report the fault by the application layer;

[0111] The chiller enable failure fault is completely diagnosed by the application layer. When the chiller requests to be enabled and the VCU determines that it is allowed to be enabled, but the chiller fails to start working normally and the feedback status is invalid. After debounce filtering confirmation, the VCU reports the chiller enable failure fault;

[0112] The failure of disabling the cold machine enabling function means that after the VCU determines that it is necessary to prohibit the cold machine enabling function to stop the cold machine from working, it sends a disabling instruction to the cold machine. However, the cold machine is still in the working state, and the feedback of the cold machine working state is valid.

[0113] In addition, the vehicle-level faults of the cold machine are set according to the fault levels of the vehicle. The fault levels are set by combining the influence degrees of its own various faults on the vehicle operation. The different fault state information of the same level is summarized into the fault level signals of the same level in the cold machine controller. The cold machine controller monitors its own faults in real time and updates the fault level signals of the cold machine controller in real time and sends them to the VCU. After receiving them, the VCU performs fault degradation processing in combination with its own fault level processing strategy.

[0114] The above has made an exemplary description of the present invention in combination with the accompanying drawings. Obviously, the specific implementation of the present invention is not limited by the above methods. As long as various non-substantive improvements are made by adopting the method concept and technical solution of the present invention; or without improvement, the above concept and technical solution of the present invention are directly applied to other occasions, they are all within the protection scope of the present invention.

Claims

1. A new energy cold chain vehicle control strategy, characterized in that: It includes a lower high-pressure control module, a cooling machine enabling control module, an energy management module, a power limiting module and a fault diagnosis module.

2. A new energy cold chain vehicle control strategy according to claim 1, characterized in that: The cooling machine enabling control module comprises the following steps: Step S10, after the vehicle is powered on and initialized, it enters the cold engine enabling judgment module; Step S11, VCU will determine whether the cooling machine is allowed according to the cooling machine start request sent by the cooling machine through the bus, the cooling machine fault status (DCDC output fault, inverter fault), high voltage status, available remaining power, SOC, remote function control status and calibration. If yes, it will enter the next step, otherwise it will prohibit the cooling machine from being enabled; In step S12, the VCU determines whether to allow enabling according to the real-time status of the refrigerator. If there is no start request, or the pre-charging of the refrigerator itself fails within 5 seconds, or the refrigerator feedbacks a fault state, the VCU prohibits enabling. If the above state does not exist, the determination is repeated.

3. A new energy cold chain vehicle control strategy according to claim 1, characterized in that: The lower high-voltage control module comprises the following steps: Step S20, after the vehicle is powered on and initialized, it enters the cooling engine enabling judgment module, and when the cooling engine is in operation, it enters the next step; Step S21, determine whether the user turns the key Off to power off the vehicle, if yes, proceed to the next step, if no, repeat the determination; Step S22, the VCU will immediately send a message to the cooling machine to prohibit the cooling machine from being enabled, and the cooling machine will stop and discharge actively; Step S23, the VCU determines whether the bus current is lower than the threshold, or the waiting time exceeds the threshold. If yes, the VCU sends a high voltage command to the BMS, otherwise, the determination is repeated; Step S24, the BMS controls to disconnect the main positive relay and the main negative relay in sequence.

4. A new energy cold chain vehicle control strategy according to claim 1, characterized in that: The energy management module comprises the following steps: Step S30, after the vehicle is powered on and initialized, it enters the cooling engine enabling judgment module, and when the cooling engine is in operation, it enters the next step; Step S31, the VCU monitors the actual power consumption of the cooling machine in real time, and the cooling machine sends the actual power consumption Pcoolingact to the VCU through the bus; Step S32, correcting the fixed-point power generation calibration of the VCU; Step S33, determine whether the battery low temperature protection is activated, if yes, proceed to the next step, if not Step S35; Step S34: At low temperatures, the battery discharge capacity will also weaken, and the VCU will control the APU to start running. The power request formula is as follows: Pbattlowtmp=Pdcdc+Pdcac+Pacm++Phvac+Pcoolingact+Pbattheating; Step S35, determining whether the vehicle is in a plug-in charging state, if yes, proceed to the next step, if no, proceed to step S37; Step S36: When charging with a plug, the VCU will calculate the charging current that needs to be compensated to the BMS and send it to the BMS for execution. The charging compensation current formula calculated by the VCU is as follows: Icomchrg=Idcdc+Idcac+Iacm++Ihvac+Icoolingact-Iapu; Step S37, determining whether the vehicle is in parking power generation, if yes, proceed to the next step, if no, determine it as normal control; In step S38, the VCU will comprehensively monitor the operating status of all high-voltage components and the battery charge status to dynamically calculate the parking power request of the APU and send it to the APU for execution. The calculation formula is as follows: PIdlchrg=Pdcdc+Pdcac+Phvac+Pcoolingact.

5. A new energy cold chain vehicle control strategy according to claim 1, characterized in that: The power limiting module comprises the following steps: Step S40, after the vehicle is powered on and initialized, it enters the cooling engine enabling judgment module, and when the cooling engine is in operation, it enters the next step; Step S40, the refrigerator filters and smoothes the actual power consumption and sends it to the VCU; Step S41, setting the power usage priority of the high-voltage components of the vehicle, electric drive>refrigeration machine>passenger cabin air conditioning>DCAC, and then performing power limit available power allocation calculation in sequence; Step S42, calculation of available power of electric drive: available discharge power of system (available discharge power of battery + available discharge power of APU); Step S43, calculating the available power of the cooling machine: the available discharge power of the system minus the actual power consumption of the electric drive; Step S44, calculating the available power of the air conditioner in the passenger compartment: available power of the refrigeration machine minus actual power consumption of the refrigeration machine; Step S45, DCAC available power calculation: passenger compartment air conditioner available power minus passenger compartment air conditioner actual power; Step S46, then enter the DCMC enabling control module to make a decision, and then send it to the cold machine for execution.

6. A new energy cold chain vehicle control strategy according to claim 1, characterized in that: The fault diagnosis module comprises the following steps: Step S50, the vehicle is powered on and initialized to monitor the actual operating status of the refrigerator and promptly remind the driver whether the cold chain of the vehicle is operating normally; Step S51, when a cooling machine communication loss fault, a cooling machine enabling failure fault, or a cooling machine enabling failure shutdown fault occurs, proceed to step S52, and when a cooling machine vehicle level fault occurs, proceed to step S53; Step S52, determine whether the VCU reports a fault, if so, store the eeprom after the fault is reported, if not, repeat the determination; Step S53, whether the cold machine controller reports a fault, if so, perform fault downgrade according to the fault level processing strategy of the whole vehicle, if not, repeat the determination.

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