A pure electric vehicle BDU integrated test system based on circuit reconstruction

Abstract

A pure electric vehicle BDU integrated test system based on circuit reconstruction belongs to the field of BDU testing technology. The present invention is based on a set of overall reconstruction circuits, a variable step voltage test module is used to test the pull-in and release voltage of the relay in the tested BDU, a dynamic response compensation time test module is used to test the pull-in and release time of the relay in the tested BDU, a sampling window adaptive sensor test module is used to test the accuracy of the current sensor in the tested BDU, and a large current-based contact resistance test module is used to test the contact resistance of the relay in the closed state in the tested BDU. The present invention can perform multi-item and multi-object testing on the pure electric vehicle BDU, and has the characteristics of high testing efficiency, high automation and integration of the test process, low dependence on manual labor, powerful data management and analysis functions, strong test robustness, friendly human-computer interaction interface and simple operation.

Description

Technical Field

[0001] The invention belongs to the technical field of BDU testing, and in particular relates to a pure electric vehicle BDU integrated testing system based on circuit reconstruction. Background Art

[0002] At present, with the increasing requirements of the country on carbon emissions, new energy vehicles represented by pure electric vehicles have become an important direction for the development of the automobile industry. At present, the vehicle component with the highest safety requirements on pure electric vehicles is its power battery system. In order to meet the needs of high-power electric drive, the current passing through the high-voltage circuit of pure electric vehicles is as high as hundreds of amperes. The battery energy distribution unit (BDU) is a device that controls the disconnection and connection of high-voltage electricity of the power battery of pure electric vehicles. It plays a vital role in the safety of the battery system. The multiple high-current relays contained in the BDU are key electrical components that control the connection or disconnection of the power bus. Whether its pull-in and release parameter performance meets the requirements affects the safety of the vehicle battery system to a considerable extent; at the same time, the current parameters provided by the current sensor contained in the BDU are an important basis for the battery controller to calculate the battery state parameters such as SOC, SOP, SOH, etc. The accuracy of the current sensor directly affects the battery controller's fine management of the battery system. Therefore, before the BDU leaves the factory, testing the components carried on the BDU is a key link in the mass production process of manufacturers. Since the BDU carries a variety of components, and the testing of different components requires the use of different test equipment to manually build different test environments, the professional requirements for testers are high, and the test efficiency and test robustness are low, which are important factors affecting the mass production efficiency of BDU. In order to solve the above problems, the present invention proposes a pure electric vehicle BDU integrated test system with high integration and automation and simple operation. Summary of the invention

[0003] The present invention mainly solves the technical problems existing in the above-mentioned prior art, and provides a pure electric vehicle BDU integrated testing system based on circuit reconstruction, which can automatically reconstruct the circuit during the testing process according to the test environment required by the BDU for different test items. It has a high degree of integration and automation, can achieve the purpose of improving test efficiency and ensuring product quality, and solves the problem of low test efficiency caused by the need to manually build different test environments for different test items in the current testing process. At the same time, the system has powerful data recording and analysis functions, which solves the problem of poor product traceability and low test accuracy caused by the difficulty in managing current test data.

[0004] The above technical problems of the present invention are mainly solved by the following technical solutions: a pure electric vehicle BDU integrated test system based on circuit reconstruction, the integrated test system is based on a set of overall reconstruction test circuits, and can realize two-dimensional online reconstruction operations by reusing different electrical components and changing electrical connections during the test process. The online reconstruction is defined as two parts, namely, the reconstruction between multiple test modules according to different test item requirements, and the reconstruction within a single test module according to different test object requirements;

[0005] The test module includes at least one of a variable step voltage test module, a dynamic response compensation time test module, an adaptive sampling window sensor test module and a contact resistance test module based on a large current. The test module also includes a main control system and a human-computer interaction system. The variable step voltage test module and the dynamic response compensation time test module reuse a set of hardware systems, which are connected to both ends of the driving coil and the main contacts of the relay in the tested BDU. The adaptive sampling window sensor test module and the contact resistance test module based on a large current reuse a set of hardware systems, except for the connection to the driving coil of the relay in the tested BDU. In addition to the two ends of the coil and the main contact, it is also connected to the external high-voltage interface of the BDU under test to form a closed-loop test circuit; the main control system and the human-computer interaction system are connected to each test module, and the main control system is used to coordinate the reconstruction operations in two dimensions and the operation of each component during the test; the human-computer interaction system is used to send reconstruction instructions and receive the original test data sent by each test module through the hybrid bus, promote the test process and the analysis, storage and interface display of the test data, and realize the integrated test of the relay pull-in and release voltage, relay pull-in and release time, current sensor accuracy and relay contact resistance of the pure electric vehicle BDU.

[0006] Preferably, the electrical components of the overall reconstruction test circuit include an industrial computer, an embedded controller, a voltage isolation relay group, a current isolation relay group, a programmable voltage source, a programmable current source and a reference current sensor;

[0007] The industrial computer is equipped with human-computer interaction system software, and is connected to the embedded controller, the voltage isolation relay group, the programmable voltage source, the programmable current source and the reference current sensor through a hybrid bus, and is used to coordinate the actions of the electrical components during the operation of the test system, and complete the online reconstruction operation between and within the test modules;

[0008] The embedded controller is equipped with a main control system, which is connected to the CAN bus of the industrial computer, the relay coil drive port of the current isolation relay group, the relay coil drive port of the BDU under test, the 12V switch signal, the differential A / D sampling port and the ground A / D sampling port, and is used to receive network message instructions sent by the industrial computer, and control the current isolation relay group and the relay carried by the BDU under test; the differential A / D sampling port is connected to the two ends of the main contact of the BDU under test and the output end of the programmable voltage source, and performs A / D sampling on the relay-related voltage signal of the BDU under test; the ground A / D sampling port is connected to the secondary side output ports of the current sensor I and the current sensor II of the BDU under test, and samples the secondary side output voltage of the current sensor I and the current sensor II in the BDU under test;

[0009] The current isolation relay group, whose main contacts are connected in series between the programmable current source and the external high-voltage output port of the BDU under test, and whose driving coil is connected to the embedded controller, is used to control the on-off of the main circuit in the test process and cooperate to complete the reconstruction operation. The closing and opening of the relays in the current isolation relay group are controlled by the embedded controller;

[0010] A programmable current source, whose output port is connected in series between the current isolation relay group and the external high-voltage output port of the BDU under test, and whose communication interface is connected to the industrial computer through the RS485 bus, is used to provide the current excitation signal required for the BDU loop test under test during the test process. The output current of the programmable current source is controlled by the command of the industrial computer;

[0011] A program-controlled voltage source, whose output port is connected to the relay drive coil in the BDU under test, and whose communication interface is connected to the industrial computer through the RS485 bus, is used to provide the voltage signal required for the BDU relay test during the test process, and the output voltage of the program-controlled voltage source is controlled by the command of the industrial computer;

[0012] The voltage isolation relay group, whose contacts are connected in series between the switch output port of the embedded system and the main contacts of the BDU under test, and whose communication interface is connected to the industrial computer through the RS485 bus, is used for circuit reconstruction operation in the test process. The closing and opening of the relays in the voltage isolation relay group are controlled by the industrial computer;

[0013] The reference current sensor is used to measure the real current value in the circuit under test. It is connected to the industrial computer and sends the current value at the collection point to the industrial computer through the CAN bus. The human-computer interaction system coordinates the electrical components to implement the reconstruction operations between and within the modules during the test.

[0014] Preferably, the overall reconstruction test circuit adopts a hybrid bus architecture design, and the hybrid bus includes a first CAN bus, a second CAN bus, and an RS485 bus. The first CAN bus is connected between the industrial computer and the embedded controller, and is used to transmit the reconstruction instructions sent by the human-computer interaction system carried by the industrial computer and the test data sent by the embedded system; the second CAN bus is connected between the industrial computer and the reference current sensor, and is used for the industrial computer to read the bus current value sent by the reference current sensor; the RS485 bus is connected between the industrial computer, the voltage isolation relay group, the programmable voltage source and the programmable current source, and is used for the industrial computer to send the on-off control instructions of the voltage isolation relay group and read the on-off status information of its relays, and the industrial computer sends the output control instructions of the programmable voltage source and the programmable current source. The hybrid bus realizes the interaction of control instructions and status information of the overall reconstruction test circuit during the reconstruction operation and testing process.

[0015] Preferably, the electrical components of the hardware system reused by the variable step voltage test module and the dynamic response compensation time test module include an industrial computer, an embedded controller, a voltage isolation relay group and a programmable voltage source. The human-computer interaction system carried by the industrial computer sends circuit reconstruction instructions and test instructions to the main control system of the embedded controller through the first CAN bus. The main control system operates the embedded controller to output relay coil drive signals, contact closure reference excitation signals and collects the voltage difference between the two ends of the main contacts of the relay under test; the human-computer interaction system sends instructions to the voltage isolation relay group through the RS485 bus to close the corresponding relay in the group to introduce the contact closure reference excitation signal to one end of the main contact of the current relay under test, and the other relays in the group remain in the disconnected state to isolate the contact closure reference excitation signals of each circuit to realize the fool-proof test of the BDU relay under test; the human-computer interaction system sends instructions to the programmable voltage source through the RS485 bus to control its output voltage to change according to the instructions.

[0016] Preferably, the electrical components of the hardware system reused by the adaptive sampling window sensor test module and the large current-based contact resistance test module include an industrial computer, an embedded controller, a current isolation relay group, a programmable current source, a programmable voltage source, a voltage isolation relay group and a reference current sensor. The human-computer interaction system carried by the industrial computer sends circuit reconstruction instructions and test instructions to the main control system of the embedded controller through the first CAN bus. The main control system operates the embedded controller to output relay coil drive signals, contact closure reference excitation signals and collects the voltage difference between the two ends of the main contacts of the relay under test. The human-computer interaction system sends instructions to the voltage isolation relay group through the RS485 bus, and the closed group The corresponding relay is used to introduce a contact closure reference excitation signal to one end of the main contact of the current relay under test, while other relays in the group remain in the disconnected state, isolating the contact closure reference excitation signal of each circuit to achieve fool-proof testing of the BDU relay under test; the human-computer interaction system sends instructions to the programmable voltage source through the RS485 bus to control its output voltage to change according to the instructions; the human-computer interaction system also sends instructions to the programmable current source through the RS485 bus to control its output voltage to change according to the instructions, and reads the bus current value fed back to the bus by the reference current sensor through the first CAN bus; the current isolation relay group is controlled by the embedded system, and the current isolation relay of the circuit under test is connected to form a closed-loop test circuit.

[0017] Preferably, the variable step voltage test module operates during the test process including: the human-computer interaction system controls the corresponding relay in the voltage isolation relay group connected to the relay coil under test in the BDU to be in a closed state through the industrial computer, and provides a V connected to point M for judging whether the relay is closed. judge_in =12V contact closure reference excitation signal, the main control system samples the two ends of the relay under test through the A / D sampling port A1~A8 of the embedded controller to obtain V diff1 , use the A / D sampling port to sample the output ports A9 and A10 of the programmable voltage source to obtain V judge_out The human-computer interaction system controls the programmable voltage source to output V drive_in =0V, making the relay under test in the disconnected state. The human-computer interaction system sends RS485 bus instructions through the industrial computer to control the program-controlled voltage source to use 0V as the starting voltage, and use 1.5V, 1V, 0.5V, and 0.1V as the voltage climbing step. The voltage is increased every 200 milliseconds, and 1.5V is cycled twice, 1V is cycled twice, and 0.5V is cycled twice. After the voltage reaches 50% of the rated pull-in voltage, that is, 6V, it is cycled to 12V with a step of 0.1V until the port connected to A1~A8 samples |V judge_out|<0.1V, record the output voltage V of the programmable voltage source collected by the ports connected to points A9 and A10 at this time drive_out , and at the same time stop the rising operation of the programmable voltage source output voltage, V close =V drive_out The pull-in voltage is V. After the pull-in voltage test is completed, the human-computer interaction system sends RS485 bus instructions through the industrial computer to control the program-controlled voltage source to V drive_in =12V is the starting voltage, and the voltage is decreased in steps of 1.5V, 1V, 0.5V, and 0.1V respectively. The voltage is decreased every 200 milliseconds, and 1.5V is cycled twice, 1V is cycled twice, and 0.5V is cycled twice. When the voltage reaches 50% of the rated pull-in voltage, that is, 6V, it is cycled down to 0V in steps of 0.1V until the ports connected to A1~A8 are sampled and |V judge_out |>10V, record the output voltage V of the programmable voltage source collected by the port connected to points A9 to A10 at this time drive_out , V release =V drive_out That is the release voltage of the relay under test. After completing the pull-in release voltage test of the current relay under test, the variable step voltage test module reconstructs the circuit inside the module according to the instructions of the human-computer interaction system, reselects the object under test, and performs the next round of testing, and performs the pull-in release voltage test on all the relays under test in turn.

[0018] Preferably, the operation of the dynamic response compensation time test module during the test process includes: the human-computer interaction system controls the voltage isolation relay group through the industrial computer to connect the corresponding relay connected to the relay coil under test to a closed state, and provides a V connected to point M for judging whether the relay is closed. judge_in =12V contact closure sampling excitation signal, the main control system samples the two ends of the relay under test through the A / D sampling port A1~A8 of the embedded controller to obtain V judge_out , use the A / D sampling ports A9 and A10 to sample the output port of the programmable voltage source to obtain V drive_out The human-computer interaction system controls the programmable voltage source to output V drive_in =0V, so that the relay under test is in the disconnected state. During the test, the human-computer interaction system controls the program-controlled voltage source to output V judge_in =12V, the programmable voltage source V is collected at the ports connected to points A9 and A10. judge_out >V close , that is, when the relay is energized, record the time t a The main control system starts timing through the 1ms timing interrupt inside the embedded controller until |V judge_out|<0.1V, record time t b , and then after dynamic compensation, the interval time T close =t b -t a -t compensation_close , which is the closing time of the relay under test. After completing the closing time test, the human-computer interaction system controls the programmable voltage source to output 0V through the industrial computer, and collects the programmable voltage source V at the port connected to point A9 and point A10. out2 <V release , that is, when the relay releases the voltage, record the time t c The main control system starts timing through the 1ms timing interrupt inside the embedded controller until |V judge_out |>10V, record time t d , after dynamic compensation, T release =t d -t c -t compensation_release , which is the release time of the relay under test. The dynamic compensation time is determined by the root mean square error of the oscilloscope observation value of the pull-in release time of the same batch and the test system test value, and t compensation_close and t compensation_release , input into the human-computer interaction system, so as to obtain the real relay closing and release time after dynamic compensation, and then according to the instructions of the human-computer interaction system, reconstruct the circuit inside the dynamic response compensation time test module, reselect the object to be tested, and carry out the next round of testing, and carry out the closing and release time test on all the relays under test in turn.

[0019] Preferably, the operation of the adaptive sampling window sensor test module during the test process includes: the human-computer interaction system controls all voltage isolation relays to be disconnected through the industrial computer to isolate the contact closure reference excitation signal to prevent it from interfering with the test process; the main control system controls the current isolation relay connected in series with the circuit where the current sensor to be tested is located to be closed through the embedded controller, and the current sensor test circuit is reconstructed, and then the test personnel respectively set the error threshold δ=δ x (x=10, 30, 50, 100, 150, and δ x >0), the human-computer interaction system sends instructions to the programmable current source through the industrial computer to output I test =10A, 30A, 50A, 100A and 150A test current levels. Under a certain current output level of the programmable current source, read the secondary voltage output value of the current sensor under test, and calculate the primary current value I according to the sensor secondary conversion formula. read According to the sensor sampling waiting time adaptive algorithm based on mean square error, during the reading process, the sampling window is adjusted according to the I readThe mean square error of the sequence is adaptively moved backward until the window is I read If the mean square error of the sequence is less than the specified value, the data in the window is recorded and the current window is I read The expected value of the sequence E(I read ) as the test value of the current sensor under test, and use the reference current sensor to read the current test value I real , wait for I real Satisfy the conditions |I real -I test |<δ x , and then compare I real and E(I read ) meets the requirements, switch the current output level of the programmable current source, perform the above test operation again, complete the accuracy test of the same current sensor under test at all current levels, output the test results, and then according to the instructions of the human-computer interaction system, perform the circuit reconstruction operation inside the module, reselect the object under test, and perform the next round of testing to achieve the accuracy test of all current sensors.

[0020] Preferably, the contact resistance test module based on large current includes: the human-computer interaction system controls all voltage isolation relays to be disconnected through the industrial computer to isolate the contact closure reference excitation signal to avoid interference with the test process; the main control system controls the current isolation relay connected in series with the circuit where the current sensor to be tested is located to be closed through the embedded controller, and the current sensor test circuit is reconstructed, and then the test personnel set the error threshold δ=δ x (δ x >0, x=50, 100, 150), the human-computer interaction system sends instructions to the program-controlled current source through the industrial computer to output I test =50A, 100A and 150A test current, at a certain current output level of the programmable current source, the reference current sensor is used to read the current test value I real , wait for I real Satisfy the conditions |I real -I test |<δ x , record the data to get the real value of the loop current I real At the same time, the main control system controls the A / D differential sampling port of the embedded controller to sample and record the relay contact voltage drop V judge_out , and then sent to the human-computer interaction system, using the volt-ampere formula R=U / I to calculate R 50A , switch the current output of the programmable current source, and perform the above resistance calculation operation again to calculate R 100A and R 150A Get R Connect =(R 50A +R100A +R 150A ) / 3, after comparing with the qualified standard specified by the user, the test results are output, and then according to the instructions of the human-computer interaction system, the circuit reconstruction operation inside the contact resistance test module based on large current is carried out, the object to be tested is reselected, and the next round of testing is carried out to realize the contact resistance test of all the relays under test.

[0021] Preferably, at least two of the variable step voltage test module, the dynamic response compensation time test module, the adaptive sampling window sensor test module and the high current based contact resistance test module are used to test various performance parameters of the BDU under test.

[0022] Preferably, at least two of the variable step voltage test module, the dynamic response compensation time test module, the adaptive sampling window sensor test module and the large current based contact resistance test module are used, and the modules used contain multiple measuring points, and the circuit reconstruction can be used to select the object to be tested, and performance parameter tests can be performed on multiple components to be tested in the tested BDU.

[0023] The present invention has the beneficial effects as follows: the present invention designs an overall reconstruction circuit, and during the process of testing the BDU of a pure electric vehicle, the test circuit is automatically reconstructed according to requirements, and various functional test modules are built, thereby greatly reducing the uncertainty factors brought by manual operation to the test process, and effectively improving the test efficiency and accuracy. The test results can be used as an important reference for evaluating the performance of the BDU, and provide important technical support for ensuring the safety of the battery system of pure electric vehicles. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 It is a schematic diagram of a reconstruction circuit structure of the present invention;

[0025] Figure 2 It is a structural schematic diagram of the hybrid bus architecture of the present invention;

[0026] Figure 3 It is a circuit structure diagram of the BDU under test of the present invention;

[0027] Figure 4 It is a schematic diagram of a reconstructed circuit structure of a variable length voltage test module and a dynamic response compensation time test module of the present invention;

[0028] Figure 5 It is a test flow chart of the variable length voltage test module of the present invention;

[0029] Figure 6 It is a test flow chart of the dynamic response compensation time test module of the present invention;

[0030] FIG. 7 ( a ) is a schematic diagram of a reconstructed circuit structure of the present invention in which the measured object is a current sensor I;

[0031] FIG7( b ) is a schematic diagram of a reconstructed circuit structure of the present invention in which the measured object is a current sensor II;

[0032] Figure 8 It is a test flow chart of the adaptive sampling window sensor test module of the present invention;

[0033] Fig. 9 It is a schematic diagram of a reconstructed circuit structure of an electric shock contact resistance test module based on a large current of the present invention;

[0034] Fig.10 The present invention is a test flow chart of a large current electric shock contact resistance test module. DETAILED DESCRIPTION

[0035] The technical solution of the present invention is further specifically described below through embodiments and in conjunction with the accompanying drawings.

[0036] The embodiment provides a pure electric vehicle BDU integrated testing system based on circuit reconstruction.

[0037] like Figure 1 As shown, the BDU integrated test equipment in the present invention includes: an industrial computer 100, an embedded controller 200, a current isolation relay group 300, a programmable current source 500, a programmable voltage source 600, a voltage isolation relay group 700 and a reference current sensor 800.

[0038] The industrial computer 100 is connected to the embedded controller 200 and the reference current sensor 800 through the first CAN bus and the second CAN bus respectively, and the connection port is COM1. The corresponding actions are coordinated during the test. The embedded controller 200 and the reference current sensor 800 collect data from the BDU under test and feed it back to the human-computer interaction system through the CAN bus network message.

[0039] The industrial computer 100 is connected to the programmable voltage source 600 via the RS485 bus, the connection port is COM2, the programmable voltage source 600 receives the network message instructions sent by the human-computer interaction system in the industrial computer 100 via the RS485 bus, outputs the corresponding voltage, and feeds back the working status and fault status of the programmable voltage source 600 itself via the RS485 bus.

[0040] The industrial computer 100 is connected to the programmable current source 500 via the RS485 bus, the connection port is COM2, the programmable current source 500 receives the network message instructions sent by the human-computer interaction system in the industrial computer 100 via the RS485 bus, outputs the corresponding current, and feeds back the working status and fault status of the programmable current source 500 itself via the RS485 bus.

[0041] The industrial computer 100 is connected to the voltage isolation relay group via the RS485 bus, the connection port is COM2, and the voltage isolation relay group 700 receives the network message instructions sent by the human-computer interaction system in the industrial computer 100 via the RS485 bus, closes and opens the relays at the corresponding positions, and feeds back the on / off status of the relays at each position.

[0042] Table 1 shows the functions included in the industrial computer 100 equipped with the human-computer interaction system.

[0043] Table 1:

[0044]

[0045] The embedded controller 200 includes multiple functional ports, including 1 CAN message receiving and transmitting port, 5 A / D differential sampling ports, 2 ground A / D sampling ports, 1 12V switch quantity (contact closure reference excitation signal) output port and 9 relay low-end drive ports.

[0046] The five pairs of A / D differential sampling ports of the embedded controller 200 include: port 1 connected to points A1 and A5 at both ends of the contact of the main negative relay 403 of the BDU under test, port 2 connected to points A2 and A6 at both ends of the contact of the fast charging relay 404 of the BDU under test, port 3 connected to points A3 and A7 at both ends of the contact of the slow charging relay 405 of the BDU under test, port 4 connected to points A4 and A8 at both ends of the contact of the main positive relay 406 and the pre-charging relay 407 (including the pre-charging resistor 408) of the BDU under test, and port 5 connected to points A9 and A10 at both ends of the output port of the programmable voltage source 600. Since the output voltage of the programmable voltage source 600 has a time delay relative to the command voltage sent by the upper computer software, the sampling ports connected to points A9 and A10 are used to detect the actual output value of the programmable voltage source.

[0047] The embedded controller 200 has two A / D ground sampling ports, wherein port 1 is connected to point A11 of the voltage output port of the current sensor II 402, and port 2 is connected to point A12 of the voltage output port of the current sensor I 401; one switching output port of the embedded controller 200 is divided into four channels connected to the parallel common end of the four relays in the voltage isolation relay group 700; five of the nine relay low-end drive ports of the embedded controller 200 are connected to the BDU under test. Points D1 to D5 of 400 are respectively connected to point D1 of the low end of the drive coil of the main negative relay 403, point D2 of the low end of the drive coil of the fast charging relay 404, point D3 of the low end of the drive coil of the slow charging relay 405, point D4 of the low end of the drive coil of the main positive relay 406, and point D5 of the low end of the drive coil of the pre-charging relay 407. The other four paths are connected to the current isolation relay group 300, which are respectively connected to point D6 of the low end of the drive coil of the main negative loop current isolation relay, point D7 of the low end of the coil of the fast charging loop current isolation relay, point D8 of the low end of the coil of the slow charging loop isolation relay, and point D9 of the low end of the drive coil of the main positive and pre-charging loop current isolation relays.

[0048] The current isolation relay group 300 includes 4 high voltage relays, such as Figure 1 As shown in the figure, relays No. 1 to 4 are used to isolate the main negative circuit, fast charging circuit, slow charging circuit, and main positive circuit (the main positive circuit is connected in parallel with the pre-charging circuit) of the BDU under test.

[0049] The current isolation relay group 300 is used to isolate the programmable current source 500 to prevent the programmable current source from being in a non-operating state, which causes the two ends of the relay contacts in the BDU under test to be equivalent to a short-circuit state due to its infinitesimal input impedance, thereby making it impossible to determine the on / off state of the relay. The rated current of the contacts of the current isolation relay group 300 is 200A, and the rated voltage of the coil is 12V. One end of the contacts of the current isolation relay group is connected in parallel at the same point F1, connected to the positive pole of the output end of the programmable current source 500, and the other end is connected to the four circuits of the BDU 400 under test at points E1 to E4.

[0050] The programmable current source 500 is used to provide the current required for the automatic test equipment to perform the current sensor accuracy test and the relay contact resistance test. Its current output range is 0-150A, and the communication method is RS485 communication. The programmable current source 500 receives the current output command sent by the industrial computer, and feeds back the current output value and its own current fault status. The current output current fed back by the programmable current source 500 is not used as a reference value during the test process due to its low accuracy.

[0051] The programmable voltage source 600 is used to provide the specific relay driving voltage required for the automated test equipment to perform voltage testing and time testing. Its voltage output range is 0 to 30V, and the communication method is RS485 communication. Like the programmable current source 500, its feedback voltage value is not used as a test reference value.

[0052] The voltage isolation relay group 700 uses 4 relays, corresponding to Figure 1 The normally open ends of the relays are connected to points A1 to A4 respectively, and their common ends are connected in parallel to the contact closure reference excitation signal output port of the embedded controller 200. During the test, the corresponding voltage isolation relay is closed to make the on-off judgment of the specified relay under test. During the test, only the corresponding voltage isolation relay is closed, and only the contact closure reference excitation signal output port of the embedded controller 200 is introduced into the relay circuit under test. When the drive and sampling harness plug-ins of the BDU under test are connected incorrectly, the test cannot pass. The communication mode of the voltage isolation relay group 700 is RS485, and the maximum voltage it can isolate is 50VDC.

[0053] Figure 2 The figure shows the hybrid bus architecture used by the integrated test equipment in the present invention, wherein the hybrid bus includes a CAN bus and an RS485 bus. Figure 2 As shown, the programmable current source 500, the programmable voltage source 600 and the voltage isolation relay group 700 are connected to the industrial computer 100 via the RS485 bus; the reference current sensor 800, the embedded controller 200 and the industrial computer 100 are connected via the first CAN bus and the second CAN bus, wherein the embedded controller 200 and the current isolation relay group 300 are connected via the relay low-end drive port.

[0054] like Figure 3 As shown, the tested BDU 400 includes: current sensor I 401, current sensor II 402, main negative relay 403, fast charge relay 404, slow charge relay 405, main positive relay 406, pre-charge relay 407, pre-charge resistor 408, Y capacitor I 409 and Y capacitor II 410.

[0055] Table 2 shows the test items and test modules used in the integrated test equipment of the present invention.

[0056] Table 2

[0057]

[0058] like Figure 4 The illustrated embodiment is a reconstructed circuit model of a variable step voltage test module.

[0059] The embodiment is described below by taking the main negative relay 403 of the BDU 400 as an example.

[0060] To build Figure 3 In the test reconstruction circuit model shown, the human-computer interaction system in the industrial computer 100 sends instructions to the embedded controller 200 through the first CAN bus network message. After receiving the instructions, the low-end drive port of the embedded controller 200 outputs a high level to D6~D9, disconnecting all current isolation relays. The human-computer interaction system sends instructions to the voltage isolation relay group 700 through the RS485 bus, closes the No. 1 relay in the relay group, and leads the contact closure reference excitation signal output by the embedded controller 200 to the A1 connection point. After the circuit reconstruction is completed, the variable step voltage test module is built.

[0061] Figure 5 The figure shows a test flow chart of the variable step voltage test module, which provides the action flow of each component of the variable step voltage test module during the test process. The following describes this embodiment by taking the main negative relay 403 as the tested object.

[0062] First, the output of the programmable voltage source 600 is set to V drive_in =0V, the main control system outputs a low level to D1 through the embedded controller 200 to ensure that at the beginning of the test process, the voltage difference between the high and low ends of the main negative relay 403 coil is low, and the main negative relay 403 is in a disconnected state. The human-computer interaction system sends RS485 bus instructions through the industrial computer to control the programmable voltage source to use 0V as the starting voltage, and 1.5V, 1V, 0.5V, and 0.1V as the voltage climbing steps, and the voltage climbing changes every 200 milliseconds, with 1.5V cycled 2 times, 1V cycled 2 times, and 0.5V cycled 2 times. After the voltage reaches 50% of the rated pull-in voltage (6V), it cycles to 12V with a step length of 0.1V. The main control system samples the A1 and A5 points at both ends of the main negative relay 403 contact through the differential A / D sampling port of the embedded controller 200, and at the same time, the output voltage V drive_in The A9 and A10 points are sampled to obtain the real voltage V between the high and low ends of the coil drive_out During the rising process of the output voltage of the programmable voltage source 600, the main control system samples the voltage value V between the main negative relay sampling points A1 and A5 every 1 ms. judge_ou t to make a judgment, when |V judge_out |<0.1V, record the output voltage V of the programmable voltage source 600 at the current moment drive_out , V drive_out The value of is the pickup voltage of the main negative relay 403. drive_outWhen the voltage reaches 12V, if the main control system still does not determine that the relay is energized, the human-computer interaction system terminates the test and reports the test failure on the display.

[0063] After the variable step voltage test module completes the main negative relay 403 pull-in voltage test, the main negative relay 403 release voltage test process is then performed. First, the main negative relay 403 is kept in the pull-in state, and the output voltage of the programmable voltage source 600 is set to V drive_in =12V, the human-computer interaction system sends RS485 bus instructions through the industrial computer to control the programmable voltage source to V drive_in =12V as the starting voltage, and use 1.5V, 1V, 0.5V, and 0.1V as the voltage drop step. The voltage drops every 200 milliseconds, and the voltage is cycled twice at 1.5V, twice at 1V, and twice at 0.5V. After the voltage reaches 50% (6V) of the rated pull-in voltage, it drops to 0V in steps of 0.1V. When |V judge_out |>10V, record the output voltage V of the programmable voltage source 600 at the current moment drive_out , V drive_out The value of is the release voltage of the main negative relay 403. drive_out When the voltage reaches 0V, if the main control system still does not determine that the relay is disconnected, the human-computer interaction system terminates the test and displays a test failure on the display.

[0064] Since the main positive relay 406 circuit is connected in parallel with the pre-charge relay 407 and the pre-charge resistor 408 circuit inside the tested BDU 400, when the main positive relay 406 and the pre-charge relay 407 are tested, their differential sampling points are the same pair of connection points A4 and A8.

[0065] The dynamic response compensation time test module has the same reconstructed circuit model as the variable step voltage test module. Figure 5 The time test flow chart shown is used to illustrate the embodiment by taking the main negative relay 403 as the object to be tested.

[0066] The dynamic compensation time is calculated by calculating the root mean square error between the oscilloscope observation value of the pull-in and release time of the same batch of sampling objects and the test system test value, and t compensation_close and t compensation_release , after each test is completed, dynamic time compensation is performed.

[0067] After the variable step voltage test module of the integrated test system completes the relay voltage test, the dynamic response compensation time test module performs circuit reconstruction and sets the programmable voltage source 600 to output V drive_in=12V. The main control system controls the driving coil port of the main negative relay 403 to output a low level to point D1 through the embedded controller 200. The main control system monitors V drive_out Is it greater than the measured pull-in voltage of the main negative relay 403? If the condition is met, the current time is recorded as t a , starts counting in the 1ms timer interrupt counter inside the main control system, and waits for |V judge_out |<0.1V, the counter stops counting and records the value t b , after dynamic compensation, t b -t a -t compensation_close That is, the closing time of the main negative relay 403. If the counter count exceeds the preset timeout period, the human-computer interaction system terminates the test and displays a test failure on the display.

[0068] After the dynamic response compensation time test module completes the main negative relay 403 pull-in time test, the main negative relay 403 release time test is started. The human-computer interaction system controls the programmable voltage source 600 to continuously output a 12V relay coil drive signal, and the main control system controls the drive port connected to the D1 point to output a high level through the embedded controller 200. The main control system monitors V drive_out Is it less than the release voltage of the main negative relay 403 that has been measured? If the condition is met, record the current time as t c , the 1ms timer interrupt counter of the main control system starts counting and waits for |V judge_out |>10V, the counter stops counting and records the value t d , after dynamic compensation t d -t c -t compensation_release That is, the release time of the main negative relay 403. If the counter count exceeds the preset timeout period, the human-computer interaction system terminates the test and displays a test failure on the display.

[0069] FIG7 (a) is a reconstructed circuit model of the current sensor Ⅰ 401 under test, and FIG7 (b) is a reconstructed circuit model of the current sensor Ⅱ 402 under test. Both current sensors are voltage output type sensors. FIG7 (a) and FIG7 (b) are combined to form a reconstructed circuit model of the adaptive sampling window sensor test module.

[0070] The embodiment is described below using two reconstruction circuits shown in FIG. 7 (a) and FIG. 7 (b) respectively.

[0071] FIG7 (a) shows the reconstruction circuit construction of the current sensor I401 under test by the adaptive sampling window sensor test module: First, the human-computer interaction system sends a command to the voltage isolation relay group 700 to disconnect all voltage isolation relays numbered 1 to 4. The human-computer interaction system sends a command to the main control system, and the main control system closes the main negative relay 403, fast charging relay 404, slow charging relay 405 and relays numbered 1, 2, and 3 in the current isolation relay group 300 in the tested BDU400 through the embedded controller 200. The human-computer interaction system sends a command to the programmable voltage source 600 to output a 12V relay coil drive signal to complete the reconstruction test circuit required for the current sensor I401 shown in FIG7 (a).

[0072] FIG7 (b) shows the reconstruction circuit construction of the adaptive sampling window sensor test module for the current sensor II 402 under test: first, the human-computer interaction system sends a command to the voltage isolation relay group 700 to disconnect all voltage isolation relays numbered 1 to 4. The human-computer interaction system sends a command to the main control system. The main control system closes the main positive relay 406 in the BDU 400 under test and the relay numbered 4 in the current isolation relay group 300 through the embedded controller 200. The human-computer interaction system sends a command to the programmable voltage source 600 to output a 12V relay coil drive signal to complete the reconstruction test circuit required for the current sensor II 402 shown in FIG7 (b).

[0073] Figure 8 The flowchart of the current accuracy test of the current sensor is shown. The embodiment is described below with the object to be tested being the current sensor I401.

[0074] First, the adaptive sampling window sensor test module builds the reconstruction circuit of the current sensor I401 according to the embodiment of Figure 7 (a) above. The human-computer interaction system sends a command to the programmable voltage source 600 to set its voltage output 12V driving voltage, and the main control system closes the relay of the circuit where the current sensor I401 is located through the embedded controller 200. The human-computer interaction system sends a command to the programmable current source 500 to output the test current I test =10A, the embedded controller samples the secondary output voltage of the current sensor I through the differential A / D sampling port, and calculates the primary test current I according to the primary current calculation formula of the current sensor I read , generate a test sequence, and during the test, continuously calculate the I read The mean square error of the sequence is used to evaluate the fluctuation of the data in the window. If the fluctuation is large, the sampling window is moved backward in time until the sampling window moves to the window I read After the sequence is stable, the expected value of the data in the window E (I read) as the current test value of the current loop. At the same time, the human-computer interaction system reads the sampling value I of the reference current sensor through the CAN bus. real , evaluate its deviation from the set value I test =10A deviation, if it meets the user's specified deviation range δ 10 , then it is used as the real current value in the current loop, and the real current value I real The current test value E (I read ) is sent to the human-computer interaction system, which compares the current sampling value of the current sensor Ⅰ401 to be tested with the real current reference value. After completing the test of the current level of 10A, the I test =The accuracy test is carried out under the current level conditions of 30A, 50A, 100A, and 150A, and the test conclusion is finally given.

[0075] After the integrated test system completes the current sensor accuracy test, the relay contact resistance test is performed using the high current based contact resistance test module.

[0076] Fig. 9 The figure shows a reconstructed circuit model of a contact resistance test module based on a large current. The embodiment is described below by taking the main negative relay 403 of the BDU 400 as an example.

[0077] To build Fig. 9 In the reconstructed circuit model of the contact resistance test module based on large current shown, the human-computer interaction system sends a network message to the main control system through the CAN bus, controls the low-end drive port of the embedded controller 200 to be grounded, outputs a low level to points D1 and D6, closes the main negative relay 403 and the relay numbered 1 in the current isolation relay group 300, and forms a complete test loop. The human-computer interaction system sends an instruction to the voltage isolation relay group 700 through the RS485 bus, disconnects all relays in the relay group, isolates the contact closure reference excitation signal from the sampling line, and completes the reconstructed circuit model of the contact resistance test module based on large current.

[0078] Fig.10 The figure shows a test action flow chart of the contact resistance test module based on large current. This embodiment provides the actions of each structure in the test process. The main negative relay 403 is used as the test object to illustrate this embodiment.

[0079] First, the human-computer interaction system sends a CAN message instruction through the industrial computer 100 to set the output of the programmable voltage source 600 to V drive_in=12V, the main control system outputs a low level to the D1 point through the embedded controller 200 to ensure that the main negative relay 403 is in a closed state at the beginning of the test process.

[0080] The human-computer interaction system sends instructions to control the programmable current source 500 to output the test current I test =50A, using the sampling window adaptive algorithm, the real current I in the loop is read through the reference current sensor 800 real_50 , and then the voltage V at both ends of the main negative relay 403 contacts is collected by the embedded controller 200 at the same time judge_out_50 In the same way, I test =100A, 150A current level test, get data I real_100 , V judge_out_100 and I real_150 , V judge_out_150 , the test is sent to the human-machine interaction system via the CAN bus. The human-machine interaction system then uses the following formula to calculate the contact resistance of the main negative relay 403:

[0081]

[0082] After the contact resistance value is calculated, the human-computer interaction system completes data recording.

[0083] Finally, it should be pointed out that the above embodiments are only representative examples of the present invention. Obviously, the present invention is not limited to the above embodiments, and there are many variations. Any simple modification, equivalent changes and modifications made to the above embodiments based on the technical essence of the present invention should be considered to belong to the protection scope of the present invention.

Claims

1. A pure electric vehicle BDU integrated test system based on circuit reconstruction, characterized in that: The integrated test system is based on a set of overall reconfiguration test circuits. During the test process, the system can realize online reconfiguration operations in two dimensions by reusing different electrical components and changing electrical connections. The two dimensions are reconfiguration between multiple test modules according to different test item requirements and reconfiguration within a single test module according to different test object requirements. The test module includes at least one of a variable step voltage test module, a dynamic response compensation time test module, an adaptive sampling window sensor test module and a contact resistance test module based on a large current. The test module also includes a main control system and a human-computer interaction system. The variable step voltage test module and the dynamic response compensation time test module reuse a set of hardware systems, which are connected to both ends of the driving coil and the main contacts of the relay in the tested BDU. The adaptive sampling window sensor test module and the contact resistance test module based on a large current reuse a set of hardware systems, except for the connection to the driving coil of the relay in the tested BDU. In addition to the two ends of the coil and the main contact, it is also connected to the external high-voltage interface of the BDU under test to form a closed-loop test circuit; the main control system and the human-computer interaction system are connected to each test module, and the main control system is used to coordinate the reconstruction operation of the two dimensions and the operation of each component during the test process; the human-computer interaction system is used to send reconstruction instructions and receive the original test data sent by each test module through the hybrid bus, promote the test process and the analysis, storage and interface display of the test data, and realize the integrated test of the relay pull-in release voltage, relay pull-in release time, current sensor accuracy and relay contact resistance of the BDU of the pure electric vehicle; The electrical components of the overall reconstruction test circuit include an industrial computer, an embedded controller, a voltage isolation relay group, a current isolation relay group, a programmable voltage source, a programmable current source and a reference current sensor; The industrial computer is equipped with human-computer interaction system software, and is connected to the embedded controller, the voltage isolation relay group, the programmable voltage source, the programmable current source and the reference current sensor through a hybrid bus, and is used to coordinate the actions of the electrical components during the operation of the test system, and complete the online reconstruction operation between and within the test modules; The embedded controller is equipped with a main control system, which is connected to the CAN bus of the industrial computer, the relay coil drive port of the current isolation relay group, the relay coil drive port of the BDU under test, the 12V switch signal, the differential A / D sampling port and the ground A / D sampling port, and is used to receive network message instructions sent by the industrial computer, and control the current isolation relay group and the relay carried by the BDU under test; the differential A / D sampling port is connected to the two ends of the main contact of the BDU under test and the output end of the program-controlled voltage source, and performs A / D sampling on the relay-related voltage signal of the BDU under test; The ground A / D sampling port is connected to the secondary side output ports of the current sensor I and the current sensor II of the BDU under test, and the secondary side output voltages of the current sensor I and the current sensor II in the BDU under test are sampled; The current isolation relay group, whose main contacts are connected in series between the programmable current source and the external high-voltage output port of the BDU under test, and whose driving coil is connected to the embedded controller, is used to control the on-off of the main circuit in the test process and cooperate to complete the reconstruction operation. The closing and opening of the relays in the current isolation relay group are controlled by the embedded controller; A programmable current source, whose output port is connected in series between the current isolation relay group and the external high-voltage output port of the BDU under test, and whose communication interface is connected to the industrial computer through the RS485 bus, is used to provide the current excitation signal required for the BDU loop test under test during the test process. The output current of the programmable current source is controlled by the command of the industrial computer; A program-controlled voltage source, whose output port is connected to the relay drive coil in the BDU under test, and whose communication interface is connected to the industrial computer through the RS485 bus, is used to provide the voltage signal required for the BDU relay test during the test process, and the output voltage of the program-controlled voltage source is controlled by the command of the industrial computer; The voltage isolation relay group, whose contacts are connected in series between the switch output port of the embedded system and the main contacts of the BDU under test, and whose communication interface is connected to the industrial computer through the RS485 bus, is used for circuit reconstruction operation in the test process. The closing and opening of the relays in the voltage isolation relay group are controlled by the industrial computer; The reference current sensor is used to measure the real current value in the circuit under test. It is connected to the industrial computer and sends the current value at the collection point to the industrial computer through the CAN bus. The human-computer interaction system coordinates the electrical components to implement the reconstruction operations between and within the modules during the test.

2. According to claim 1, a pure electric vehicle BDU integrated test system based on circuit reconstruction is characterized in that: The overall reconstruction test circuit adopts a hybrid bus architecture design, the hybrid bus includes a first CAN bus, a second CAN bus, and an RS485 bus, the first CAN bus is connected between the industrial computer and the embedded controller, and is used to transmit the reconstruction instructions sent by the human-computer interaction system carried by the industrial computer and the test data sent by the embedded system; The second CAN bus is connected between the industrial computer and the reference current sensor, and is used for the industrial computer to read the bus current value sent by the reference current sensor; The RS485 bus is connected between the industrial computer, the voltage isolation relay group, the programmable voltage source and the programmable current source. The industrial computer sends the on-off control instructions of the voltage isolation relay group and reads the on-off status information of its relays. The industrial computer sends the output control instructions of the programmable voltage source and the programmable current source. The hybrid bus realizes the interaction of control instructions and status information of the overall reconstruction test circuit during the reconstruction operation and test process.

3. According to claim 1, a pure electric vehicle BDU integrated test system based on circuit reconstruction is characterized in that: The electrical components of the hardware system reused by the variable step voltage test module and the dynamic response compensation time test module include an industrial computer, an embedded controller, a voltage isolation relay group and a programmable voltage source. The human-computer interaction system carried by the industrial computer sends circuit reconstruction instructions and test instructions to the main control system of the embedded controller through the first CAN bus. The main control system operates the embedded controller to output relay coil drive signals, contact closure reference excitation signals and collects the voltage difference between the two ends of the main contacts of the corresponding relay under test; the human-computer interaction system sends instructions to the voltage isolation relay group through the RS485 bus, closes the corresponding relay in the group, and is used to introduce the contact closure reference excitation signal to one end of the main contact of the current relay under test, and other relays in the group remain in the disconnected state, isolating the contact closure reference excitation signals of each circuit to realize the fool-proof test of the BDU relay under test; the human-computer interaction system sends instructions to the programmable voltage source through the RS485 bus to control its output voltage to change according to the instructions.

4. According to claim 1, a pure electric vehicle BDU integrated test system based on circuit reconstruction is characterized in that: The electrical components of the hardware system reused by the adaptive sampling window sensor test module and the contact resistance test module based on large current include an industrial computer, an embedded controller, a current isolation relay group, a programmable current source, a programmable voltage source, a voltage isolation relay group and a reference current sensor. The human-computer interaction system carried by the industrial computer sends the circuit reconstruction instruction and the test instruction to the main control system of the embedded controller through the first CAN bus. The main control system operates the embedded controller to output the relay coil drive signal, the contact closure reference excitation signal and the voltage difference between the two ends of the main contact of the corresponding relay under test; the human-computer interaction system transmits the circuit reconstruction instruction and the test instruction to the main control system of the embedded controller through the RS485 bus. Send instructions to the voltage isolation relay group to close the corresponding relay in the group, which is used to introduce the contact closure reference excitation signal to one end of the main contact of the relay under test. Other relays in the group remain in the disconnected state, and the contact closure reference excitation signals of each circuit are isolated to achieve foolproof testing of the BDU relay under test; the human-computer interaction system sends instructions to the programmable voltage source through the RS485 bus to control its output voltage to change according to the instructions; the human-computer interaction system also sends instructions to the programmable current source through the RS485 bus to control its output voltage to change according to the instructions, and reads the bus current value fed back to the bus by the reference current sensor through the first CAN bus; The current isolation relay group is controlled by the embedded system, and the current isolation relay of the circuit under test is connected to form a closed-loop test circuit.

5. According to the circuit reconstruction-based BDU integrated test system for pure electric vehicles according to claim 1, it is characterized in that: The operation of the variable step voltage test module during the test process includes: the human-computer interaction system controls the corresponding relay in the voltage isolation relay group connected to the relay coil under test in the BDU to be in a closed state through the industrial control computer, and provides a V connected to point M for judging whether the relay is closed. judge_in =12V contact closure reference excitation signal, the main control system samples the two ends of the relay under test through the A / D sampling port A1~A8 of the embedded controller to obtain V diff1 , use the A / D sampling port to sample the output ports A9 and A10 of the programmable voltage source to obtain V judge_out The human-computer interaction system controls the programmable voltage source to output V drive_in =0V, making the relay under test in the disconnected state. The human-computer interaction system sends RS485 bus instructions through the industrial computer to control the program-controlled voltage source to use 0V as the starting voltage, and use 1.5V, 1V, 0.5V, and 0.1V as the voltage climbing step. The voltage is increased every 200 milliseconds, and 1.5V is cycled twice, 1V is cycled twice, and 0.5V is cycled twice. After the voltage reaches 50% of the rated pull-in voltage, that is, 6V, it is cycled to 12V with a step of 0.1V until the port connected to A1~A8 samples |V judge_out |<0.1V, record the output voltage V of the programmable voltage source collected by the ports connected to points A9 and A10 at this time drive_out , and at the same time stop the rising operation of the programmable voltage source output voltage, V close =V drive_out The pull-in voltage is V. After the pull-in voltage test is completed, the human-computer interaction system sends RS485 bus instructions through the industrial computer to control the program-controlled voltage source to V drive_in =12V is the starting voltage, and the voltage is decreased in steps of 1.5V, 1V, 0.5V, and 0.1V respectively. The voltage is decreased every 200 milliseconds, and 1.5V is cycled twice, 1V is cycled twice, and 0.5V is cycled twice. When the voltage reaches 50% of the rated pull-in voltage, that is, 6V, it is cycled down to 0V in steps of 0.1V until the ports connected to A1~A8 are sampled and |V judge_out |>10V, record the output voltage V of the programmable voltage source collected by the port connected to points A9 to A10 at this time drive_out , V release =V drive_out That is the release voltage of the relay under test. After completing the pull-in release voltage test of the current relay under test, the variable step voltage test module reconstructs the circuit inside the module according to the instructions of the human-computer interaction system, reselects the object under test, and performs the next round of testing, and performs the pull-in release voltage test on all the relays under test in turn.

6. According to the circuit reconstruction-based BDU integrated test system for pure electric vehicles according to claim 1, it is characterized in that: The operation of the dynamic response compensation time test module during the test process includes: the human-computer interaction system controls the voltage isolation relay group through the industrial computer to connect the corresponding relay connected to the relay coil under test to a closed state, and provides a V connected to the M point for judging whether the relay is closed. judge_in =12V contact closure sampling excitation signal, the main control system samples the two ends of the relay under test through the A / D sampling port A1~A8 of the embedded controller to obtain V judge_out , use the A / D sampling ports A9 and A10 to sample the output port of the programmable voltage source to obtain V drive_out The human-computer interaction system controls the programmable voltage source to output V drive_in =0V, so that the relay under test is in the disconnected state. During the test, the human-computer interaction system controls the program-controlled voltage source to output V judge_in =12V, the programmable voltage source V is collected at the ports connected to points A9 and A10. judge_out >V close , that is, when the relay is energized, record the time t a The main control system starts timing through the 1ms timing interrupt inside the embedded controller until |V judge_out |<0.1V, record time t b , and then after dynamic compensation, the interval time T close =t b -t a -t compensation_close , which is the closing time of the relay under test. After completing the closing time test, the human-computer interaction system controls the programmable voltage source to output 0V through the industrial computer, and collects the programmable voltage source V at the port connected to point A9 and point A10. out2 <V release , that is, when the relay releases the voltage, record the time t c The main control system starts timing through the 1ms timing interrupt inside the embedded controller until |V judge_out |>10V, record time t d , after dynamic compensation, T release =t d -t c -t compensation_release , which is the release time of the relay under test. The dynamic compensation time is determined by the root mean square error of the oscilloscope observation value of the pull-in release time of the same batch and the test system test value, and t compensation_close and t compensation_release , input into the human-computer interaction system, so as to obtain the real relay closing and release time after dynamic compensation, and then according to the instructions of the human-computer interaction system, reconstruct the circuit inside the dynamic response compensation time test module, reselect the object to be tested, and carry out the next round of testing, and carry out the closing and release time test on all the relays under test in turn.

7. According to claim 1, a pure electric vehicle BDU integrated test system based on circuit reconstruction is characterized in that: The operation of the adaptive sampling window sensor test module during the test process includes: the human-computer interaction system controls all voltage isolation relays to be disconnected through the industrial computer to isolate the contact closure reference excitation signal to prevent it from interfering with the test process; the main control system controls the current isolation relay connected in series with the circuit where the current sensor to be tested is located to be closed through the embedded controller, and the current sensor test circuit is reconstructed, and then the test personnel set the error threshold δ=δ x (x=10, 30, 50, 100, 150, and δ x >0), the human-computer interaction system sends instructions to the programmable current source through the industrial computer to output I test =10A, 30A, 50A, 100A and 150A test current levels. Under a certain current output level of the programmable current source, read the secondary voltage output value of the current sensor under test, and calculate the primary current value I according to the sensor secondary conversion formula. read According to the sensor sampling waiting time adaptive algorithm based on mean square error, during the reading process, the sampling window is adjusted according to the I read The mean square error of the sequence is adaptively moved backward until the window is I read If the mean square error of the sequence is less than the specified value, the data in the window is recorded and the current window is I read The expected value of the sequence E(I read ) as the test value of the current sensor under test, and use the reference current sensor to read the current test value I real , wait for I real Satisfy the conditions |I real -I test |<δ x , and then compare I real and E(I read ) meets the requirements, switch the current output level of the programmable current source, perform the above test operation again, complete the accuracy test of the same current sensor under test at all current levels, output the test results, and then according to the instructions of the human-computer interaction system, perform the circuit reconstruction operation inside the module, reselect the object under test, and perform the next round of testing to achieve the accuracy test of all current sensors.

8. According to claim 1, a pure electric vehicle BDU integrated test system based on circuit reconstruction is characterized in that: The contact resistance test module based on large current includes the following steps during the test process: the human-computer interaction system controls all voltage isolation relays to be disconnected through the industrial computer to isolate the contact closure reference excitation signal to prevent it from interfering with the test process; the main control system controls the current isolation relay connected in series with the circuit where the current sensor to be tested is located to be closed through the embedded controller to reconstruct the current sensor test circuit, and then the test personnel set the error threshold δ=δ x (δ x >0, x=50, 100, 150), the human-computer interaction system sends instructions to the program-controlled current source through the industrial computer to output I test =50A, 100A and 150A test current, at a certain current output level of the programmable current source, the reference current sensor is used to read the current test value I real , wait for I real Satisfy the conditions |I real -I test |<δ x , record the data to get the real value of the loop current I real At the same time, the main control system controls the A / D differential sampling port of the embedded controller to sample and record the relay contact voltage drop V judge_out , and then sent to the human-computer interaction system, using the volt-ampere formula R=U / I to calculate R 50A , switch the current output of the programmable current source, and perform the above resistance calculation operation again to calculate R 100A and R 150A Get R Connect =(R 50A +R 100A +R 150A ) / 3, after comparing with the qualified standard specified by the user, the test results are output, and then according to the instructions of the human-computer interaction system, the circuit reconstruction operation inside the contact resistance test module based on large current is carried out, the object to be tested is reselected, and the next round of testing is carried out to realize the contact resistance test of all the relays under test.

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