A simulator for DC charging piles for new energy vehicles

Abstract

This invention relates to a DC charging pile simulator for new energy vehicles. This system realistically simulates the charging process and various functional states and fault simulations (overvoltage, undervoltage, overcurrent, overcharge, and other special states of the charging pile). It provides design and product verification units with accurate means and methods for quantitative and qualitative analysis of vehicle resistance to various complex and special conditions, avoiding potential vehicle damage due to charging pile malfunctions. It also provides verification means and methods for improving vehicle compatibility with charging facilities and resistance to charging interference. The test cabinet in this solution can operate at optimal efficiency in both natural cooling and forced cooling modes. In natural cooling (forced cooling) mode, the test cabinet achieves maximum cooling and heat dissipation efficiency, improving heat dissipation and ensuring the normal operation of each module unit within the test cabinet.

Description

Technical Field

[0001] This invention relates to the field of electric vehicle control and testing technology, and in particular to a DC charging pile simulator for new energy vehicles. Background Technology

[0002] New energy vehicle charging piles are devices that use electrical energy to charge electric vehicles. They can charge various models of electric vehicles according to different voltage levels. Currently, commonly used charging piles include DC charging piles and AC charging piles. Compared with AC charging piles, DC charging piles can provide DC power to the battery and can provide a larger output power, thereby achieving fast charging.

[0003] Currently, most DC charging testing systems on the market perform signal-level testing (generally, the charging process is simulated by simulating communication signals and low-voltage signals during the charging process, without real charging current, and can only verify the BMS charging logic). They cannot meet the fault simulation testing requirements of power-level charging process testers (power level refers to the ability to simulate the real charging process, with real charging current, and can directly test the battery pack), and the testing conditions for the charging process are relatively limited.

[0004] In addition, since various electrical components for testing are placed inside the DC charging pile test cabinet, these components generate heat during testing, causing the ambient temperature inside the test cabinet to rise. Existing test cabinets are usually equipped with cooling systems to cool the environment inside the test cabinet. For example, ventilation holes are set on the side wall of the cabinet and work with fans to achieve a cooling effect (when the ambient temperature inside the test cabinet rises to a certain level, the fan starts to achieve forced cooling). However, the above-mentioned cooling systems cannot achieve optimal working efficiency in both natural cooling and forced cooling modes, thus affecting the cooling effect.

[0005] In view of this, we provide a DC charging pile simulator for new energy vehicles to solve the above problems. Summary of the Invention

[0006] This invention provides a DC charging pile simulator for new energy vehicles. This system realistically simulates the charging process and various functional states and fault simulations (overvoltage, undervoltage, overcurrent, overcharge, and other special states of the charging pile). It provides design and product verification units with accurate means and methods for quantitative and qualitative analysis of vehicles' resistance to various complex and special conditions, avoiding potential vehicle damage caused by charging pile failures. It also provides verification means and methods for improving vehicle compatibility with charging facilities and resistance to charging interference. In addition, the test cabinet in this solution can operate with optimal efficiency in both natural cooling and forced cooling modes, improving the cooling effect.

[0007] A DC charging pile simulator for new energy vehicles includes a test cabinet, characterized in that several through holes are evenly distributed along the vertical direction on both sides of the test cabinet, and adjustment plates are movably installed on the upper and lower walls inside the through holes. A filter screen is connected to one end of the adjustment plate located on the top wall and facing the inside of the test cabinet and the other end of the adjustment plate located on the bottom wall and facing the outside of the test cabinet. The two adjustment plates are connected to a drive mechanism.

[0008] The test cabinet is equipped with a test system and the test system is connected to a bidirectional DC power grid simulator. The test system includes: a power management module, a low-voltage programmable power supply, an oscilloscope, a main control computer, and a DC charging control module.

[0009] The power management module is connected to the low-voltage programmable power supply, oscilloscope, and main controller respectively. The main controller is connected to the low-voltage programmable power supply, DC charging control module, bidirectional DC grid simulator, and oscilloscope. The charging gun cable is connected to the DC charging control module and bidirectional DC grid simulator respectively.

[0010] The beneficial effects of the above technical solution are as follows:

[0011] (1) This system realistically simulates the charging process and various functional states and fault simulations of DC charging piles (overvoltage, undervoltage, overcurrent, overcharge and other special states of charging piles), providing accurate means and methods for design and product verification units to quantitatively and qualitatively analyze the resistance of vehicles to various complex special conditions, avoiding the occurrence of vehicle damage caused by charging pile failures, and providing verification means and methods to improve the vehicle's compatibility with charging facilities and its ability to resist charging interference.

[0012] (2) This system supports charging simulation tests according to national standards, European standards and American standards, which can conduct more thorough tests on the charging process, improve the development efficiency of BMS and shorten the development cycle.

[0013] (3) The test cabinet in this solution can work at the best efficiency in both natural cooling and forced cooling modes. In the natural cooling (forced cooling) mode, the test cabinet can cool and dissipate heat at the maximum efficiency, thus improving the heat dissipation effect. Attached Figure Description

[0014] Figure 1 This is a schematic diagram of the DC charging pile simulation system of the present invention;

[0015] Figure 2 This is a simulation diagram of the control and guidance circuit of the present invention;

[0016] Figure 3 This is a schematic diagram of the charging test process of the present invention;

[0017] Figure 4This is a schematic diagram of the controllable parameters of the DC charging simulation device according to national standards of the present invention;

[0018] Figure 5 This is a schematic diagram of the European standard controllable parameters of the DC charging simulation device of the present invention;

[0019] Figure 6 This is a schematic diagram of the American standard controllable parameters of the DC charging simulation device of the present invention;

[0020] Figure 7 This is a schematic diagram of the test cabinet of the present invention in the forced cooling mode;

[0021] Figure 8 This is a schematic diagram showing the state of the adjustment plate of the present invention in different modes;

[0022] Figure 9 This is a schematic diagram showing the connection relationship between the two air cylinders in this invention;

[0023] Figure 10 This is a schematic diagram of the test cabinet of the present invention in the natural cooling mode. Detailed Implementation

[0024] The foregoing and other technical contents, features and effects of the present invention will be clearly presented in the following detailed description with reference to the accompanying drawings and embodiments. The structural contents mentioned in the following embodiments are all based on the accompanying drawings.

[0025] See attached document Figure 7-10 The present invention first provides a test cabinet 1 for a new energy vehicle charging pile simulator, as shown in the attached figure. Figure 7 , 10 As shown, several modular units are installed inside test cabinet 1 (fans are installed between adjacent modular units, which activate and force cooling when the ambient temperature inside test cabinet 1 is too high), as shown in the attached diagram. Figure 7 As shown, several through holes 2 (with cross-sections of horizontal and vertical surfaces) are vertically spaced on the horizontal side walls of the test cabinet 1. Adjustment plates (including a bearing plate 4 rotatably mounted to the top and bottom walls of the through hole 2, a telescopic plate 5 slidably mounted within the bearing plate 4, and a sliding cavity cooperating with the telescopic plate 5) are provided within the bearing plate 4, as shown in the attached diagram. Figure 8(As shown), Note: The bearing plate 4, which is rotatably installed and cooperates with the top wall of the through hole 2, is rotatably installed on the top wall of the through hole 2 at one end close to the inside of the test cabinet 1, and the bearing plate 4, which is rotatably installed and cooperates with the bottom wall of the through hole 2, is rotatably installed on the bottom wall of the through hole 2 at the other end away from the inside of the test cabinet 1. The two telescopic plates 5 extend outward from the bearing plate 4 and are connected to a filter screen 3 (to filter dust in the external environment so as to prevent it from entering the test cabinet 1 with the airflow). The telescopic plate 5 extends outward from the bearing plate 4 and is connected to a transfer plate 6 that is vertically slidably installed in the wall of the test cabinet 1 and the transfer plate 6 is connected to a drive mechanism.

[0026] When the ambient temperature inside test cabinet 1 is not very high, i.e., in a natural cooling state, the vertical position of the transmission plate 6 connected to it is adjusted by the drive mechanism so that the bearing plate 4 and the telescopic plate 5 are in the following position. Figure 10 In the state shown, under the combined action of the two sets of bearing plates 4 and telescopic plates 5, the through hole 2, which originally had a horizontal and vertical cross-section, becomes as shown in the attached figure. Figure 10 In the state shown (the support plate 4 and the telescopic plate 5 cooperate to form an inclined plane), the heat generated by the operation of each module unit (electrical component) within the testing mechanism causes the air temperature inside the testing cabinet 1 to rise. Because hot air has a lower density (the density of hot air is less than that of cold air), it will move upwards within the testing cabinet 1. During this upward movement, the hot air is more easily expelled outwards under the guidance of the inclined plane formed by the support plate 4 and the telescopic plate 5. At this time, the external ambient temperature of the testing cabinet 1 is lower (within the environmental space where the testing cabinet 1 is located, the air temperature outside the testing cabinet 1 gradually decreases from top to bottom, as cold air has a higher density and the air temperature is lower closer to the bottom). Therefore, the external ambient temperature at the bottom area of ​​the testing cabinet 1 is lower. The cold air enters the lower space of the test cabinet 1 more effectively under the action of the inclined surface formed by the bearing plate 4 and the telescopic plate 5. That is, under the action of the bearing plate 4 and the telescopic plate 5, the hot air with a higher temperature inside the cabinet is discharged outward through several through holes 2 in the upper area of ​​the test cabinet 1 (under the guidance of the inclined surface formed by the bearing plate 4 and the telescopic plate 5), and the cold air with a lower ambient temperature is introduced into the test cabinet 1 through several through holes 2 in the lower area of ​​the test cabinet 1 (under the guidance of the inclined surface formed by the bearing plate 4 and the telescopic plate 5). The hot air is discharged outward through the through holes 2 in the upper part of the test cabinet 1, and the cold air is introduced through the through holes 2 in the lower part of the test cabinet 1, thus forming natural convection and achieving a highly efficient natural cooling effect.

[0027] If the support plate 4 and the telescopic plate 5 are not installed, so that the cross-section of the through hole 2 is in a horizontal and vertical state, the hot air cannot be easily discharged outward through the through hole 2 during the rising process in the cabinet (the hot air has an upward speed during the rising process, and when it hits the inclined surface formed by the support plate 4 and the telescopic plate 5, it will be discharged outward under the guidance of the inclined surface. If the cross-section of the through hole 2 is in a horizontal and vertical state, when the hot air hits the top wall of the through hole 2, it will be obstructed by the top wall and the hot air flow cannot be guided, thus inhibiting the efficiency of the hot air being discharged outward).

[0028] When the ambient temperature inside test cabinet 1 is too high (exceeding the set value), the fan inside test cabinet 1 is activated to achieve forced cooling. Simultaneously, the vertical position of transfer plate 6 is adjusted via the drive mechanism; that is, the transfer plate 6 located at the top wall of through hole 2 rises, and the transfer plate 6 located at the bottom wall of through hole 2 descends. This changes the positional relationship between the support plate 4, the telescopic plate 5, and the transfer plate 6. Figure 8 The lower side view is transformed into the upper side view. At this time, the cross-section of through hole 2 returns to a horizontal and vertical state, as shown in the attached figure. Figure 7 As shown, with the fan activated, cool outside air is drawn into the test cabinet 1 from one side and discharged outwards through several through-holes 2 on the other side, thus forcibly cooling the environment inside the test cabinet 1. At this time, the vertical distance h1 of the cross-section of the through-holes 2 that allows for rapid airflow is maximized (the effective ventilation cross-section of the through-holes 2 is at its maximum). Under the suction of the fan, cool outside air can enter the test cabinet 1 with maximum efficiency and be discharged outwards through the through-holes 2 on the other side. If the positional relationship between the support plate 4 and the telescopic plate 5 is not adjusted, and the support plate 4 and the telescopic plate 5 remain in the attached position... Figure 10 In the state shown, the cross-sectional distance of the through hole 2 that allows airflow to pass through quickly is h2 (h2 is less than h1), which affects the efficiency of external airflow entering the test cabinet 1 (and the efficiency of airflow exhausting from the test cabinet 1), as shown in the attached figure. Figure 10 As shown, the vertical distance of the cross section that allows airflow to pass through quickly is h2. This is because the airflow will not be obstructed when it moves within this space. If the airflow deviates from the above area, it will collide with the inclined plane composed of the bearing plate 4 and the telescopic plate 5 (the airflow speed is reduced due to the obstruction of the inclined plane), thereby reducing the efficiency of airflow entering (exiting) and affecting the cooling effect.

[0029] As attached Figure 9As shown, a specific structure of a drive mechanism is provided, including an air cylinder 7 disposed in the wall of a test cabinet 1, and a piston 8 disposed inside the air cylinder 7. The piston 8 is connected to a piston rod and a corresponding transmission plate 6. The two air cylinders 7 located in a through hole 2 are connected by a pipe. Specifically, the upper and lower ends of the air cylinder 7 located at the top wall of the through hole 2 are respectively provided with pipe a and pipe b, and the upper and lower ends of the air cylinder 7 located at the bottom wall of the through hole 2 are respectively provided with pipe c and pipe d. Pipe a and pipe c are connected (pipe b and pipe d are connected). This embodiment provides a specific structure of a magnetic drive component: an electromagnet 10 is installed in the upper air cylinder 7 (the electromagnet 10 is connected to an electrical circuit and is a de-energized electromagnet 10, that is, when the electrical circuit is energized, the electromagnet 10 loses its magnetic force, and when the electrical circuit is disconnected, it generates magnetic force), and a magnet 11 is provided on the corresponding piston 8.

[0030] When in a natural cooling state (which is the case in most cases), the electrical circuit of the control electromagnet 10 is disconnected, and the electromagnet 10 generates a magnetic force (which repels the magnetic force of the magnet 11). This magnetic repulsion forces the piston 8 to move downwards within the air cylinder 7. Since the two air cylinders 7 are connected by pipes a, b, c, and d, as the piston 8 moves downwards, the airflow causes the piston 8 in the lower air cylinder 7 to move synchronously, causing the two transmission plates 6 to move closer to each other (compressing the springs), ultimately resulting in the following... Figure 8 The state shown in the lower middle side view (the movement distance of the two transmission plates 6 is controlled by selecting a magnet 11 with a corresponding magnetic force), thereby making the final position of the two adjustment plates in the set state.

[0031] Note: In this scheme, the length of the filter screen 3 connected between the two telescopic plates 5 satisfies the following condition: when the two adjusting plates are in the position shown in the attached diagram... Figure 8 In the upper-middle side view, filter 3 is in a taut state, and when the two adjusting plates are in the attached position... Figure 8 In the lower middle position, filter 3 is in a loose, drooping state (regardless of its state, it can filter dust from the external environment). When switching from natural cooling mode to forced cooling mode, the operator can control the electrical circuit of electromagnet 10 and energize it. Electromagnet 10 loses its electromagnetic force, causing piston 8 to move rapidly to its initial position under the action of the corresponding spring. This, in turn, synchronously drives the transfer plate 6 to move rapidly in a direction away from each other, so that the bearing plate 4 and the telescopic plate 5 move from the attached... Figure 8 The filter 3 changes from its lower to its upper state. With this change, the filter 3, which was originally in a loose, sagging state, quickly becomes taut. Note: Because the test cabinet 1 operates in natural cooling mode for most of the time, the surface (outer side) of the filter 3 will have a considerable amount of dust adhering to it when it is in a loose, sagging state. When the filter 3 changes from its lower to its upper state... Figure 8When the filter 3 changes from the lower to the upper state (within a short period of time), that is, the filter 3 changes from the lower state to the upper state at a relatively fast speed. During the process of the filter 3 changing from loose to tight, the dust attached to its outer surface will be shaken off (equivalent to: holding both ends of the filter 3 with both hands and forcefully and quickly pulling the loose filter 3 straight and tight, which will generate a large vibration and shaking). The dust will roll off along the slope where the filter 3 is located (achieving the effect of cleaning the dust attached to the outer side of the filter 3).

[0032] For better cleaning results, see attached Figure 8 As shown, an exhaust nozzle 9 is provided on the lower end face of the upper telescopic plate 5, and the nozzle 9 is in an inclined state. Furthermore, an air passage communicating with the nozzle 9 is provided within the telescopic plate 5 (the air passage communicates with the sliding cavity located within the support plate 4). When the support plate 4 and the telescopic plate 5... Figure 8 When the lower side changes to the upper side, the telescopic plate 5 retracts into the support plate 4, thereby squeezing the air that was originally in the sliding cavity into the air nozzle 9 through the air passage, and finally blowing it out through the air nozzle 9. The airflow and the adjustment of the filter screen 3 from a loose to a tight state are carried out simultaneously. Thus, under the action of the airflow, the dust that bounces off the outer surface of the filter screen 3 can be blown away directly to improve the cleaning effect (a hole can be provided on the support plate 4 below so that its internal sliding cavity can be connected to the external environment to cooperate with the relative sliding between the telescopic plate 5 and the support plate 4).

[0033] See attached document Figure 1-6 The DC charging pile simulation test system inside the test cabinet is described in detail below:

[0034] The test cabinet contains a power management module, a low-voltage programmable power supply, an oscilloscope, a main control unit, a DC charging control module, charging gun cables, etc. The connection methods between the various modules and components are shown in the attached diagram. Figure 1 As shown, the bidirectional DC grid simulator serves as the power source output in this system (the bidirectional DC grid simulator is a key component in the power circuit of this solution), simulating the state changes of the DC source, including output power control, voltage control, current limit control, and switching between constant voltage and constant current modes, to achieve DC charging of the whole vehicle (the bidirectional DC grid simulator provides power stage charging process simulation test). The test system and the bidirectional DC grid simulator are connected via RS232 communication. The power circuit is connected via a high-voltage disconnection test box (BOB), and the power circuit can be switched between normal charging state and fault state through the BOB.

[0035] The power management module serves as the overall unit for system power management and includes a main switch, air duct, power indicator light, and emergency stop button (to be used in case of emergency power failure; its use is prohibited under other circumstances).

[0036] The test cabinet contains two low-voltage programmable power supplies. Low-voltage programmable power supply 1 simulates the low-voltage wake-up signals of system K3 / K4 (as attached). Figure 4 K3 and K4 in the DC charging simulation system (where the off-board charger controller simulation box is the DC charging pile) simulate the amplitude of the low-voltage auxiliary power supply in the DC charging simulation system to verify the impact of the change of the amplitude of the low-voltage auxiliary power supply on the DC charging process; the low-voltage programmable power supply 2 is used to drive the electronic lock action of the Chinese standard charging gun in the DC charging simulation system, locks the Chinese standard DC charging gun during the charging process, and prevents accidental plugging and unplugging of the charging gun while it is energized due to human error.

[0037] The DC charging control module is the core of the DC charging simulation system, comprising a resistance simulation board, low-voltage circuit relays, power circuit contactors, an energy meter, a switching power supply, a relay control module, a digital reconfigurable I / O board (NIPCI-7811), a multi-function analog input / output board (NIPCI-6229), an industrial digital I / O group isolation board (NIPCI-6516), a CAN communication board (NIPCI-8512 / 2), and a PCL communication module. The specific functions of each module are shown in Table 1. The modules are connected via custom wiring harnesses according to connection requirements.

[0038]

[0039] Table 1 shows that the charging gun harness includes one each of Chinese standard, European standard, and American standard, making it convenient for testers to quickly connect vehicles and test equipment.

[0040] National Standard DC Charging Gun Rated current 250A, wire length 5m European standard DC charging gun CC1 combination gun head, rated current 200A, cable length 5m American Standard DC Charging Gun CC2 combination gun head, rated current 200A, cable length 5m

[0041] The test cabinet contains a main control unit, which is an Advantech IPC-610L. It serves as the host computer software platform for the DC charging simulation equipment, the physical carrier for external communication interfaces and hardware I / O interface boards. It realizes the communication and control functions of the bidirectional DC grid simulator, energy meter, low-voltage programmable power supply, resistor simulation board, oscilloscope and I / O board in the system. It can also remotely interact with other control systems.

[0042] The oscilloscope used is a Tektronix MDO3014, which monitors the voltage, current, and PWM signal status throughout the charging process. Its main functions are as follows:

[0043] 1. Main power return voltage status monitoring: Using a high-voltage probe P1300, the output voltage status is monitored during the charging process;

[0044] 2. Main power return current status monitoring: The CPL2000A current probe is used to monitor the status of the output current during the charging process;

[0045] 3. PWM signal status monitoring: The DP6020 low-voltage differential probe is used to monitor the status of the output PWM during the charging process.

[0046] The adjustable parameters of DC charging simulation equipment are divided into two categories: the first category is power signals; the second category is control and guidance circuit signals.

[0047] Power signal refers to DC+ / DC- parameter simulation, including power circuit on / off control, DC pile output voltage simulation, DC pile output power limit simulation, and DC pile output grid stability simulation (overvoltage, undervoltage) to realize the output characteristics simulation of the power circuit during the charging process and verify the adaptability of the battery pack to the DC pile.

[0048] The control guidance circuit signals refer to the CAN signal, PWM signal, resistance signal, and low-voltage circuit on / off control of the low-voltage control circuit, including the on / off of the CAN circuit, message ID, message enable / disable, PLC communication simulation, frequency, amplitude, duty cycle of the PWM signal, resistance value of resistors such as R3, and on / off of circuits such as CC2 to realize the rated output capacity of the charging pile and the automatic plugging and unplugging simulation of the charging gun.

[0049] The simulation principle of the control guidance circuit (implemented by the DC charging control module) in this scheme is shown in the attached figure. Figure 2 As shown, the off-board charger communication simulation software includes four items and can perform simulation tests such as standard charging test, interoperability test, fault simulation test, and communication consistency test. The off-board charger control simulation circuit consists of the hardware modules in Table 1.

[0050] I. Standard Charging Test

[0051] The standard charging test simulates the normal charging process of a vehicle: it includes the Chinese standard DC charging test, the European standard DC charging test, and the American standard DC charging test. The standard charging process follows the Chinese, European, and American standard charging standard processes respectively, and the parameter configuration is executed according to the corresponding standard. The test process is consistent for different standards. During the European and American standard charging tests, the PCL conversion module is used to convert the European and American standards to the Chinese standard for charging tests.

[0052] II. DC Interoperability Test

[0053] DC interoperability testing includes charging process control testing, charging connection control timing testing, charging abnormal state testing, and control guide boundary voltage value testing.

[0054] The electric vehicle DC charging interoperability test system monitors the following variables or states by controlling a pilot circuit to simulate the system:

[0055] 1. Voltage value at detection point 1: Voltage value across vehicle resistor R4;

[0056] 2. Voltage value at detection point 2: Voltage value between vehicle socket CC2 and PE;

[0057] 3. K5 and K6 status: Measure the voltage change between DC+ and DC- of the vehicle socket to determine the opening and closing status of contactors K5 and K6;

[0058] 4. Charging Status: Check the charging status of the electric vehicle; if it is charging, measure the current charging voltage and current values.

[0059] 5. Communication Status: Check the vehicle's communication messages.

[0060] During the power-on configuration phase, the initial output data of each hardware device in the system is set. The basic setting parameters are shown in Table 2.

[0061] Low-voltage auxiliary power supply voltage Output voltage value of the low-voltage auxiliary power supply. Low-voltage auxiliary power supply current Output current value of the low-voltage auxiliary power supply. Resistor R3 resistance value The current resistance value of R3 in the CC2 circuit. Authorization timeout period Set the authorization timeout period. Charging gun connection timeout Set the charging gun connection timeout. Maximum charging voltage value Set the maximum charging output voltage. Minimum charging voltage value Set the minimum charging output voltage. Maximum charging current value Set the maximum charging output current value. Minimum charging current value Set the minimum charging output current value. Charging station location area code Set the area code value of the charging station Charger coding Set charger code value High charger communication protocol version number Set the charger communication protocol version number to a high parameter value. Low charger communication protocol version Set the charger communication protocol version number to a low value. Maximum power of charging pile Set the maximum allowable output power value of the charging pile

[0062] Table 2

[0063] The charging process control test includes: connection confirmation test, self-test phase test, charging readiness test, startup and charging phase test, and normal charging end test.

[0064] The connection verification test is achieved by judging the voltage values ​​of test point 1 and test point 2. The voltage value of test point 2 should meet the U2b requirement of Table B.1 in GB / T18487.1-2015; the voltage value of test point 1 should meet the U1c requirement of Table B.1 in GB / T18487.1-2015.

[0065] The self-test phase is achieved by judging the voltage value of test point 2 and the handshake phase message. The voltage value of test point 2 should meet the requirements of Table B.1U2b in GB / T18487.1-2015. After the test system sends the charger handshake message, the vehicle should send the vehicle handshake message. After the test system sends the charger identification message (0x00), where (0x00) belongs to the hexadecimal message signal in the national standard (GB / T27930), the vehicle should send the BMS and vehicle identification messages.

[0066] The charging readiness test is performed by judging the messages sent by the vehicle before and after K5 and K6 are closed. After the test system sends the charger identification message, the vehicle should send a power battery parameter message. Before K5 and K6 are closed, the vehicle should send a BMS charging readiness message (0x00); after K5 and K6 are closed, the vehicle should send a BMS charging readiness message (0xAA), where (0xAA) is a hexadecimal message signal in the national standard.

[0067] The starter charging phase test determines the battery charging demand message and battery charging status message sent by the vehicle. After the test system sends the charger charging status message, the vehicle should start charging. During the charging process, the vehicle should send power battery status information messages in real time.

[0068] The normal charging completion phase test is performed by analyzing the messages sent by the vehicle and the status of K5 and K6. Once the vehicle meets the charging completion conditions, it should send a BMS stop charging message; after the test system sends a charger stop charging message, the vehicle should send a BMS statistics message; once the charging current is less than 5A, the vehicle should disconnect K5 and K6.

[0069] The charging connection control timing test determines whether the voltage values ​​at detection point 1 and detection point 2, the states of K5 and K6, the charging state, the communication state, and the state transitions and intervals of the vehicle charging connection in the normal charging process comply with the provisions of B.5 and B.6 in GB / T18487.1-2015.

[0070] Charging abnormal state tests include: insulation fault test, communication interruption test, and PE pin breakage test.

[0071] The insulation fault test method is as follows:

[0072] a: During normal charging, set the charging current to less than 5A;

[0073] b: Use test resistors to perform insulation tests between DC+ and PE, and DC- and PE in the vehicle charging DC circuit. Select test resistors Rt ≥ 100Ω / V, Rt ≤ 500Ω / V, and Rt ≤ 100Ω / V respectively; c: Check the vehicle's communication status, K5 and K6 status.

[0074] The vehicle insulation fault monitoring function should respond within 100s, in accordance with the provisions of B.4.1 in GB / T18487.1-2015; when Rt≤100Ω / V, the vehicle should comply with the provisions of B.3.7.2 in GB / T18487.1-2015.

[0075] The communication interruption test mainly checks the vehicle's response when communication is interrupted. The test method is as follows:

[0076] a: During normal charging, set the charging current to less than 5A;

[0077] b: Simulate communication timeout of off-board charger by setting up communication faults in the test system;

[0078] c: Check the vehicle's charging status, K5 and K6 status;

[0079] d: Restore communication and repeat step c;

[0080] e: Simulate a non-vehicle charger communication interruption by repeating step b three times, and then repeat step d).

[0081] Communication timeout: The vehicle should disconnect K5 and K6 within 10 seconds; after communication is restored, the vehicle should re-establish the handshake connection. Communication interruption: The vehicle cannot charge after communication is restored.

[0082] The PE pin breakage test simulates a PE pin breakage during normal charging. Specifically, the voltage is set to 15.2V < U2 < 31V with an accuracy of no more than 1%, or 22V < U2 < 30V with an accuracy of no more than 5%. At this time, the vehicle communication status is checked, and the vehicle sends a BMS termination charging message.

[0083] The control guide voltage boundary value test includes: the boundary voltage value test at detection point 2 and the auxiliary power supply boundary voltage value test.

[0084] The boundary voltage value test at test point 2 is performed by adjusting the resistance value of R3 in the test system to make the voltage value at test point 2 the boundary value specified in Table B.1 of GB / T18487.1-2015. Then, charging is started, and the vehicle's communication status and charging status are checked.

[0085] The auxiliary power supply boundary voltage value test is performed by adjusting the auxiliary power supply voltage value of the test system to the boundary value specified in Section 3.2.1, and then starting charging.

[0086] III. DC Fault Simulation Test

[0087] DC fault simulation testing: includes boundary anomaly simulation testing and custom simulation testing of the charging process;

[0088] The custom simulation test of the charging process allows for the customization and configuration of charging process parameters based on testing requirements.

[0089] Boundary anomaly simulation tests include: CC2 interruption test, CC2 resistance value change test, PE interruption test, DC output overvoltage test, DC output undervoltage test, power supply disturbance test, auxiliary power supply status test, and insulation fault simulation test.

[0090] The CC2 interruption test checks the vehicle's communication status, K5 and K6 status by controlling the CC2 resistor (R3 resistor) to disconnect. At this time, the vehicle should send a BMS to stop charging message. The K5 and K6 status should comply with the provisions of B.3.7.2 in GB / T18487.1-2015.

[0091] The CC2 analog resistor value change test checks the vehicle's communication status, K5 and K6 status by changing the resistance value of the CC2 resistor (R3 resistor). At this time, the vehicle should send a BMS to stop charging message. The K5 and K6 status should comply with the provisions of B.3.7.2 in GB / T18487.1-2015.

[0092] The PE interruption test simulates a PE interruption fault to check the vehicle's communication status, K5 and K6 status. At this time, the vehicle should send a BMS to stop charging message. The K5 and K6 status should comply with the provisions of B.3.7.2 in GB / T18487.1-2015.

[0093] The DC output overvoltage test is performed by controlling the DC charging voltage output by the charging pile simulator to be greater than the charging voltage requested by the vehicle by 10V, and checking the vehicle's communication status, K5 and K6 status. At this time, the vehicle should send a BMS to stop charging message. The K5 and K6 status should comply with the provisions of B.3.7.2 in GB / T18487.1-2015.

[0094] The DC output undervoltage test is performed by controlling the DC charging voltage output by the charging pile simulator to be less than 10V of the charging voltage requested by the vehicle. The communication status, K5 and K6 status are checked. At this time, the vehicle should send a BMS to stop charging message. The K5 and K6 status should comply with the provisions of B.3.7.2 in GB / T18487.1-2015.

[0095] The power supply disturbance test is performed by controlling the DC charging voltage disturbance offset value output by the charging pile simulator to be ±10V of the charging voltage requested by the vehicle. The communication status, K5 and K6 status are checked. At this time, the vehicle should send a BMS to stop charging message. The K5 and K6 status should comply with the provisions of B.3.7.2 in GB / T18487.1-2015.

[0096] The auxiliary power supply status test is achieved by controlling the output voltage change of the low-voltage programmable power supply 2. At this time, the vehicle should send a BMS stop charging message. The K5 and K6 statuses should comply with the provisions of B.3.7.2 in GB / T18487.1-2015.

[0097] The insulation fault simulation test is performed by using test resistors to test the insulation between DC+ and PE, and DC- and PE in the vehicle's charging DC circuit. The selected test resistors Rt satisfy the following conditions: 100Ω / V < Rt ≤ 500Ω / V and Rt ≤ 100Ω / V, respectively. Then, the vehicle's communication status, K5 and K6 status are checked. At this time, the vehicle's insulation fault monitoring function should respond within 100s, which complies with the provisions of B.4.1 in GB / T18487.1-2015. When Rt ≤ 100Ω / V, the vehicle should comply with the provisions of B.3.7.2 in GB / T18487.1-2015.

[0098] IV. Communication Consistency Test

[0099] Communication conformance testing is a type of functional testing. It involves testing the implementation of a protocol under test using a set of test sequences in a specific network environment. By comparing the actual output with the expected output, it determines the extent to which the implementation under test conforms to the description standard. Protocol conformance testing can reduce the risk of errors occurring in the product during field operation.

[0100] The communication consistency test items include: low-voltage auxiliary power-on and charging handshake phase, charging parameter configuration phase, charging phase, and stop phase.

[0101] The testing of the low-voltage auxiliary power-on and charging handshake phase mainly focuses on the communication logic, BHM message, and BRM message of this phase.

[0102] The testing during the charging parameter configuration phase mainly focuses on the communication logic, BCP messages, and BRO messages of this phase.

[0103] The testing during the charging phase mainly focuses on the communication logic, BCL messages, BCS messages, BSM messages, BMV messages, BMT messages, BSP messages, and BST messages during this phase.

[0104] The testing during the stop phase mainly focuses on testing the BSD messages of the communication logic during this phase;

[0105] For communication conformance testing projects, relevant standard parameters can be found in the corresponding standards in national standards GB / T34658 and GB / T27930.

[0106] The DC charging pile simulator's DC charging test simulation software includes four test items: charging test, interoperability test, fault simulation test, and communication consistency test. Each test item contains multiple test sub-items. Users can select the required test items, set the parameters for each test item, save them as test files, and open them directly in the "Test Run" interface to perform the test.

[0107] The above is merely for illustrating the present invention. It should be understood that the present invention is not limited to the above embodiments, and various modifications that conform to the spirit of the present invention are within the protection scope of the present invention.

Claims

1. A DC charging pile simulator for new energy vehicles, comprising a test cabinet (1), characterized in that, The test cabinet (1) has several through holes (2) evenly distributed vertically on both sides of the horizontal side wall, and adjustment plates are movably installed on the upper and lower walls inside the through holes (2). A filter screen (3) is connected to one end of the adjustment plate located at the top wall position and facing the inside of the test cabinet (1) and the other end of the adjustment plate located at the bottom wall position and facing the outside of the test cabinet (1). The two adjustment plates are connected to a drive mechanism. The test cabinet is equipped with a test system and the test system is connected to a bidirectional DC power grid simulator. The test system includes: a power management module, a low-voltage programmable power supply, an oscilloscope, a main control computer, and a DC charging control module. The power management module is connected to the low-voltage programmable power supply, the oscilloscope, and the main control computer, respectively. The main control computer is connected to the low-voltage programmable power supply, the DC charging control module, the bidirectional DC grid simulator, and the oscilloscope. The adjusting plate includes a bearing plate (4) rotatably mounted to the side wall of the through hole (2) and a telescopic plate (5) slidably mounted inside the bearing plate (4). The telescopic plate (5) extends outward from one end of the bearing plate (4) and is rotatably mounted to a transfer plate (6) slidably mounted in the wall of the test mechanism. The transfer plate (6) is driven by a driving mechanism. The drive mechanism includes an air cylinder (7) located in the wall of the test cabinet (1) and a piston (8) elastically connected thereto inside the air cylinder (7). The piston (8) is connected to the transfer plate (6) via a piston rod integrally formed thereto. The two air cylinders (7) corresponding to the same through hole (2) are connected by a pipe and form a gas circuit; The air cylinder (7) is equipped with a magnetic drive component, which enables the piston (8) to move within the air cylinder (7); The telescopic plate (5) located at the top wall of the through hole (2) extends outward from the lower end of the bearing plate (4) and is provided with several inclined air nozzles (9). The telescopic plate (5) is provided with an air passage that communicates with the air nozzles (9), and the air passage communicates with the sliding cavity provided in the bearing plate (4). The driving mechanism includes an air cylinder (7) located in the wall of the test cabinet (1) and a piston (8) inside the air cylinder (7). The piston (8) is connected to the piston rod and the corresponding transmission plate (6). The two air cylinders (7) located in a through hole (2) are connected by a pipe. The air cylinder (7) located at the top wall of the through hole (2) has a pipe a and a pipe b at its upper and lower ends respectively. The air cylinder (7) located at the bottom wall of the through hole (2) has a pipe c and a pipe d at its upper and lower ends respectively. The pipe a and the pipe c are connected, and the pipe b and the pipe d are connected. An electromagnet (10) is installed in the upper air cylinder (7) and a magnet (11) is provided on the corresponding piston (8).

2. The new energy vehicle DC charging pile simulator according to claim 1, characterized in that, The low-voltage programmable power supply includes low-voltage programmable power supply 1 and low-voltage programmable power supply 2. The low-voltage programmable power supply 1 is used to simulate the amplitude of the low-voltage auxiliary power supply in the DC charging simulation system. The low-voltage programmable power supply 2 is used to drive the electronic lock action of the charging gun in the DC charging simulation system, and to lock the DC charging gun during the charging process.

3. A new energy vehicle DC charging pile simulator according to claim 1, characterized in that, The DC charging control module includes a resistor simulation board, a low-voltage circuit relay, a power circuit contactor, an energy meter, a switching power supply, a relay control module, a digital reconfigurable I / O board, a multi-functional analog input / output board, an industrial digital I / O group isolation board, a CAN communication board, and a PCL communication module.

4. A new energy vehicle DC charging pile simulator according to claim 3, characterized in that, The main control unit realizes communication and control functions between the bidirectional DC power grid simulator, low-voltage programmable power supply, oscilloscope, energy meter, resistor simulation board, and I / O board.

5. A new energy vehicle DC charging pile simulator according to claim 1, characterized in that, The bidirectional DC grid simulator serves as a power source output, simulating the state changes of a DC source, including output power control, voltage control, current limit control, and switching between constant voltage and constant current modes, thereby enabling DC charging of the entire vehicle.

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