Electric drive test bench and method for synchronous injection of high-voltage electric stress under dynamic working conditions

Abstract

The application relates to the technical field of new energy automobile testing, and discloses a dynamic working condition high-voltage electric stress synchronous injection electric drive test bench and method, the bench contains a central control system, a dynamic working condition simulation basic platform, a multi-degree-of-freedom mechanical vibration loading system and a dynamic high-voltage electric performance comprehensive simulation and test system. The central control system comprises a PTP master clock and an EtherCAT link; a frequency conversion cabinet drives a double-power dynamometer to reproduce a vehicle driving cycle in the dynamic working condition platform, and a wet and hot bin body and a control system are matched to simulate an alternating temperature and humidity environment; a servo cylinder is installed at an electric drive suspension point to output a vibration load, and a vibration sensor collects feedback in real time; a battery simulator and a high-voltage electric performance test device are connected to a direct-current bus of a measured object, the central control system synchronously applies four-dimensional coupling loads of driving, temperature and humidity, vibration and dynamic high voltage, accurately reproduces a real vehicle transient high-voltage failure scene, and solves the problems that traditional static test working conditions are fragmented and multiple loads cannot be synchronously coupled.

Description

Technical Field

[0001] This invention relates to the field of new energy vehicle testing technology, specifically to an electric drive test bench and method for synchronous injection of high-voltage electrical stress under dynamic operating conditions. Background Technology

[0002] As high-voltage platforms for new energy vehicles are gradually upgraded to 800V and above, the power quality, electromagnetic compatibility, and operational safety issues of high-voltage systems are becoming increasingly prominent. The market frequently experiences faults such as IGBT burnout, high-voltage insulation failure, and electrical corrosion of motor bearings. Fault tracing has confirmed that these failures are all induced by non-ideal bus power supply characteristics, such as high-voltage ripple distortion and transient high-voltage impacts during vehicle operation. While the current ISO 21498-2:2024 standard sets mandatory verification requirements for voltage ripple and load dump impacts of high-voltage components, the current testing equipment and standard-specified testing methods are all static tests: the tested battery pack, motor controller, and other components are tested under shutdown or constant speed and torque conditions. This static testing mode has significant shortcomings. It cannot reproduce the dynamic superimposed ripples formed by the coupling of large current change rates and line parasitic parameters during transient driving processes such as rapid acceleration, braking, and energy recovery. It also cannot simulate the test of dynamic load dump impacts on the vehicle system protection strategy under generator-driven reverse driving conditions, resulting in insufficient fault reproduction capability.

[0003] Although the industry has launched multi-load coupling test benches that integrate road driving conditions, mechanical vibration, and temperature and humidity environments, and is gradually developing towards simulating the service environment of real vehicles, such equipment still has key shortcomings: the actual voltage fluctuation of the power battery and the transient electromagnetic interference of the high-voltage bus are not integrated as controllable variables into the dynamic test circuit; the power supply device of the test bench mostly adopts a bidirectional DC power supply with ideal smooth output, which filters out the complex harmonics and transient pulses naturally present in the high-voltage bus of the real vehicle, and the reliability results obtained from the test are too optimistic, making it difficult to expose the hidden failure of components caused by the synergistic effect of high-voltage electrical stress and mechanical and environmental loads in advance.

[0004] In summary, existing testing equipment cannot simultaneously complete the coupled verification of dynamic driving conditions, high-voltage electrical loads, mechanical vibration loads, and temperature and humidity environmental loads. The industry urgently needs an integrated coupled test bench and supporting control method that can simultaneously superimpose electrical stresses such as high-voltage ripple, load dumping, and voltage bias during the dynamic operation of the electric drive assembly, while applying mechanical loads and environmental loads. Summary of the Invention

[0005] The present invention aims to provide an electric drive test bench and method for synchronous injection of high voltage electrical stress under dynamic working conditions, so as to solve the problem that traditional static high voltage testing cannot synchronously couple multi-dimensional loads of mechanical, environmental and dynamic driving, and is difficult to reproduce the dynamic high voltage failure fault of real vehicle.

[0006] To achieve the above objectives, the present invention adopts the following technical solution: An electrically driven test bench for synchronous injection of high-voltage electrical stress under dynamic operating conditions includes: Central control system, dynamic working condition simulation platform, multi-degree-of-freedom mechanical vibration loading system, dynamic high voltage electrical performance comprehensive simulation and testing system; The central control system has a built-in PTP master clock and establishes real-time communication with the dynamic working condition simulation platform, the multi-degree-of-freedom mechanical vibration loading system, and the dynamic high-voltage electrical performance comprehensive simulation and testing system through EtherCAT communication links. The dynamic operating condition simulation platform includes dual electric dynamometers, an electric dynamometer frequency converter cabinet, a humid and hot alternating environment chamber, a humid and hot alternating environment chamber control system, and an electric drive assembly cooling system. The electric drive assembly system under test is located inside the humid and hot alternating environment chamber. The humid and hot alternating environment chamber control system is connected to the humid and hot alternating environment chamber via a humid and hot circuit medium pipeline. The humid and hot alternating environment chamber control system also communicates bidirectionally with the central control system via an EtherCAT communication link. The output cables of the electric dynamometer frequency converter cabinet are connected to the two electric dynamometers respectively. The electric dynamometer frequency converter cabinet communicates bidirectionally with the central control system via an EtherCAT communication link. The mechanical output end of the electric drive assembly system is rigidly connected to the dual electric dynamometers. The electric drive assembly cooling system is connected to the cooling circulation loop of the electric drive assembly system. The multi-degree-of-freedom mechanical vibration loading system includes several sets of servo cylinders and vibration sensors; the servo cylinders are installed at the suspension points of the electric drive assembly system, and the vibration sensors are respectively arranged on the housing of the electric drive assembly system, the output end of the servo cylinder, and the shaft end of the electric dynamometer. The vibration sensor signals are simultaneously connected to the local controller of the servo cylinder and the central control system. The dynamic high-voltage electrical performance comprehensive simulation and testing system includes a battery simulator, a high-voltage electrical performance testing device, a data acquisition unit, and an early fault diagnosis instrument. The high-voltage output terminal of the battery simulator is connected in parallel to the input terminal of the high-voltage electrical performance testing device, and the output terminal of the high-voltage electrical performance testing device is connected in series to the DC bus input terminal of the electric drive assembly system. The data acquisition unit integrates a power analyzer, a high-voltage bus voltage / current probe, and a temperature sensor, and all collected sensor signals are uniformly aggregated to the central control system. The early fault diagnosis instrument communicates with the vibration sensor and the data acquisition unit to identify early failure characteristics of components in real time. The central control system integrates a torque step pre-triggering algorithm module, a vibration and shock timing correction module, and an FPGA ripple dynamic waveform synthesis module. The torque step pre-triggering algorithm module is used to match the torque sudden change condition and pre-trigger high-pressure stress injection in advance. The vibration and shock timing correction module is used to eliminate the inherent motion jitter of the load-dropping equipment and realize the timing alignment of mechanical shock and high-pressure pulse. The FPGA ripple dynamic waveform synthesis module is used to dynamically update the ripple frequency and amplitude according to the real-time speed of the motor.

[0007] The principle and advantages of this solution are as follows: In practical applications, the test bench relies on a central control system with a PTP global clock to uniformly manage the four subsystems, and can simultaneously apply dynamic driving torque, alternating temperature and humidity, multi-degree-of-freedom road vibration, and dynamic high-voltage ripple / load dump four-dimensional coupled loads. Unlike traditional static high-voltage testing equipment, it can accurately replicate the electrical stress of the real high-voltage bus under the transient conditions of rapid vehicle acceleration and energy recovery, while uniformly aligning the timing of mechanical shock, temperature and humidity changes, and high-voltage transient pulses. It can reproduce in advance in the laboratory difficult faults that frequently occur in the market, such as IGBT damage, bearing electrical corrosion, and insulation aging, which are qualified on the test bench but fail on the road test, filling the industry gap that the ISO 21498-2 standard can only verify static components and lacks system-level dynamic coupling testing. It significantly reduces the iteration cost of real vehicle road testing and the risk of high-voltage safety testing, and can also quantify the multi-stress synergistic aging acceleration rate, providing reliable data support for the optimization of electric drive high-voltage components.

[0008] Preferably, as an improvement, the high-voltage electrical performance testing equipment includes an artificial power network and a high-voltage ripple / load dump simulator. The high-voltage ripple / load dump simulator adopts an isolated DC / DC boost unit, a linear power amplifier, and a multi-stage coupling topology with a coupling transformer. The coupling transformer is connected in series to the DC bus of the electric drive assembly system under test, and an LC notch filter is connected in parallel on the primary side of the coupling transformer.

[0009] Technical benefits: The multi-level coupling topology enables the series injection of high-power, wide-bandwidth high-voltage ripple and load dump pulses, which can withstand the high-current conditions of the high-voltage main circuit and overcome the hardware bottleneck that traditional low-power signal sources cannot be connected to the vehicle-level high-voltage bus. The LC notch filter can filter out switching harmonics, avoid mutual electromagnetic interference between high-voltage stress equipment and motor controller, and ensure the stability of dynamic electrical stress waveform injection.

[0010] Preferably, as an improvement, the dual electric dynamometer driver, servo cylinder controller, high-voltage ripple / load dump simulator FPGA, humid and hot alternating environment chamber control system PLC, and data acquisition unit are all equipped with PTP slave modules, and the synchronization error between all slave modules is ≤1 microsecond.

[0011] Technical effect: Achieve microsecond-level synchronization of all devices, eliminate timing misalignment caused by independent clocks of each device, and accurately reproduce the real vehicle service scenario of multi-stress synchronous coupling.

[0012] Preferably, as an improvement, the EtherCAT communication link uses an SFP fiber optic isolation module, the high-voltage busbar and the low-voltage communication cable are laid in separate trenches with a spacing of ≥200mm, and all metal structures inside the humid and hot alternating environment chamber are grounded at a single point.

[0013] Technical effects: It reduces the strong electromagnetic interference generated by high voltage ripple and millisecond-level load dump pulses, prevents EtherCAT communication packet loss, clock drift, and sensor signal distortion, and ensures stable and reliable synchronous control and data acquisition of the entire system under strong high voltage noise environment.

[0014] Preferably, as an improvement, the FPGA ripple dynamic waveform synthesis module pre-stores three-dimensional lookup table data of the ripple amplitude-frequency characteristics obtained from actual vehicle calibration, and has a built-in second-order polynomial extrapolation algorithm unit; the ripple frequency satisfies the following formula:

[0015] In the formula To inject ripple frequency in real time, is the IGBT switching frequency of the electric drive assembly system under test, k is the harmonic order, p is the number of motor pole pairs, and n is the real-time speed of the motor; The FPGA ripple dynamic waveform synthesis module updates the DDS waveform generator based on the real-time speed and torque data sent by the central control system, and adaptively matches the ripple amplitude and frequency.

[0016] Technical effect: It solves the problem of ripple waveform update lag when the vehicle speed changes rapidly during rapid acceleration. It can adaptively adjust the ripple amplitude and frequency in milliseconds, perfectly matching the bus harmonic characteristics of dynamic migration during actual vehicle operation, and restoring the real dynamic ripple superposition effect.

[0017] Preferably, as an improvement, the execution logic of the torque step pre-triggering algorithm module includes: the central control system pre-reading the torque command sequence within a preset time window and calculating the torque change rate in real time; when the torque change rate exceeds a preset threshold, the total pre-triggering duration is calculated by superimposing communication delay, electrical response delay, and mechanical inertia delay. Before the torque step is reached The high-voltage ripple / load dump simulator sends a pre-trigger signal to the high-voltage ripple / load dump simulator FPGA after receiving the pre-trigger signal, and injects the high-voltage ripple synchronously at the torque step zero point.

[0018] Technical effects: It can predict torque step change in advance and compensate for the transmission, electrical and mechanical delays of the whole link. It can synchronously inject high voltage ripple at the zero point of torque change, greatly reduce the phase error between torque conditions and high voltage stress, solve the defect that static test cannot reproduce the dynamic ripple of transient large current coupling during rapid acceleration, and accurately simulate the bus voltage resonance peak under the acceleration conditions of real vehicles.

[0019] Preferably, as an improvement, the working logic of the vibration and impact timing correction module is as follows: when the servo cylinder outputs a mechanical impact load, the vibration sensor collects the acceleration peak hardware interrupt signal and feeds it back to the central control system. After receiving the hardware interrupt signal, the central control system immediately triggers the high-voltage load throwing simulator to output a transient high-voltage pulse to counteract the inherent action jitter of the internal relay of the load throwing simulator.

[0020] Technical effect: By using the vibration peak hardware interrupt signal to synchronously trigger the load release pulse, the inherent action jitter of the load release relay is offset, and the timing error of mechanical impact and high voltage transient overvoltage pulse is controlled within a very small range. It can freely match the synchronous / offset coupling conditions of vibration and high voltage peak, and reproduce the real failure scenario of energy recovery interruption and road impact superimposed dual severe stress.

[0021] Preferably, as an improvement, the data acquisition unit has a sampling rate of not less than 1MHz, and all acquisition channels are synchronously bound to a global PTP timestamp.

[0022] Technical benefits: It enables synchronous acquisition of multi-channel data, and afterwards, the timing and phase relationships of various load signals can be accurately verified through cross-correlation algorithms. It can also fully trace the device degradation process corresponding to transient high-pressure impact and vibration peak values, ensuring the accuracy of failure mechanism analysis data.

[0023] Preferably, as an improvement, the high-voltage power flow connection relationship is as follows: the high-voltage output terminal of the battery simulator is connected in parallel to the input terminal of the high-voltage electrical performance testing equipment; the output terminal of the high-voltage electrical performance testing equipment is connected in series to the DC bus input terminal of the electric drive assembly system under test; and the AC output terminal of the electric drive assembly system under test is connected to the mechanical shaft of the dual electric dynamometer.

[0024] Technical benefits: The series arrangement of high-voltage power flow allows dynamic high-voltage stress to be directly superimposed on the main DC bus of the electric drive assembly. The bidirectional power link can fully simulate the full operating conditions of battery discharge drive and electric drive reverse drag power generation feedback, truly restoring the energy flow characteristics of the vehicle's high-voltage circuit, and avoiding the bus operating condition distortion problem caused by traditional parallel small signal injection.

[0025] An electric drive test method for synchronous injection of high-voltage electrical stress under dynamic operating conditions, performed using the aforementioned electric drive test bench for synchronous injection of high-voltage electrical stress under dynamic operating conditions, includes: S1, Bench Assembly and Wiring Setup: Fix the electric drive assembly system under test inside the humid and hot alternating environment chamber, and complete the mechanical connection of the dual electric dynamometers, torque and speed sensors, and couplings; assemble the servo cylinders to the corresponding suspension points of the electric drive assembly system under test, and install vibration sensors and temperature sensors; complete the series connection of the battery simulator, high-voltage electrical performance testing equipment, and the DC bus of the electric drive assembly system under test according to the high-voltage power flow sequence; install broadband high-voltage probes and current clamps on the DC bus and connect them to the data acquisition unit; establish EtherCAT communication links between the central control system and each subsystem; S2, Test parameter calibration configuration: Import standard WLTC driving cycle road spectrum into the central control system; calibrate dynamic ripple amplitude-frequency envelope, load dump trigger condition, and peak voltage based on actual vehicle data; import actual vehicle road load spectrum to generate servo cylinder random vibration PSD curve; configure temperature and humidity cycle change program for the humid and hot alternating environment chamber control system; input multi-level fault alarm thresholds for bus ripple, vibration acceleration, insulation resistance, and IGBT case temperature; import ripple amplitude-frequency characteristic three-dimensional lookup table data into the FPGA ripple dynamic waveform synthesis module; S3, Global Clock Synchronization Calibration: Start the central control system PTP master clock to automatically complete the clock alignment of all slave devices, including dual electric dynamometers, servo cylinder controllers, high-voltage ripple / load dump simulator FPGA, humid heat alternating environment chamber control system PLC, electric dynamometer frequency converter cabinet, and data acquisition unit. S4, Four-dimensional load synchronous coupling loading: The central control system synchronously issues multiple sets of control commands for parallel execution. S41, through the frequency converter cabinet of the electric dynamometer, drives the dual dynamometers to run the standard driving cycle, and reproduces the dynamic torque and speed conditions of the whole vehicle driving, coasting, and energy recovery. S42, through the heat and humidity control system, regulates the chamber and applies alternating temperature and humidity environmental loads; S43 drives the multi-servo cylinder to output spectrum vibration, applying multi-degree-of-freedom mechanical impact to the electric drive suspension point; S44 dynamically matches and injects high-voltage ripple into the bus based on the real-time speed and torque of the motor using an FPGA algorithm; pre-triggered stress is applied when torque changes suddenly; and high-voltage pulses are synchronously output in combination with vibration peak interruption signals during reverse power generation to achieve precise timing coupling of power generation, vibration, and transient overvoltage. S5, Synchronous Data Acquisition and Online Fault Monitoring: The data acquisition unit synchronously acquires electrical, mechanical, and temperature sensor data across all dimensions and binds them to a global PTP timestamp; S6, Durability Cyclic Operation and Failure Quantification Analysis: Continuously run a four-dimensional coupled durability cycle, export all test data after the cycle ends, and compare and analyze the device failure characteristics of static tests. Attached Figure Description

[0026] Figure 1 This is a schematic diagram of the structure of an electrically driven test bench for synchronous injection of high-voltage electrical stress under dynamic operating conditions.

[0027] The reference numerals in the accompanying drawings include: 1. Humidity and heat alternating environment chamber body; 2. Electric drive assembly system; 3. Electric dynamometer; 4. Servo cylinder; 5. Vibration sensor; 6. High voltage electrical performance testing equipment; 7. Battery simulator; 8. Central control system; 9. Data acquisition unit; 10. Electric drive assembly cooling system; 11. Humidity and heat alternating environment chamber control system; 12. Early fault diagnosis instrument; 13. Electric dynamometer frequency converter cabinet; 14. Temperature sensor. Detailed Implementation

[0028] The following detailed description illustrates the specific implementation method: The electric drive test bench for synchronous injection of high voltage electrical stress under dynamic working conditions includes: a central control system 8, a dynamic working condition simulation base platform, a multi-degree-of-freedom mechanical vibration loading system, and a dynamic high voltage electrical performance comprehensive simulation and testing system.

[0029] The central control system 8 incorporates a PTP precision time protocol master clock (hereinafter referred to as the PTP master clock) conforming to the IEEE 1588 standard, with an accuracy better than ±100 nanoseconds. The central control system 8 establishes real-time communication with the dynamic operating condition simulation platform, the multi-degree-of-freedom mechanical vibration loading system, and the dynamic high-voltage electrical performance comprehensive simulation and testing system via EtherCAT communication links. It uniformly issues control commands for operating conditions, vibration, temperature and humidity, high-voltage electrical stress, etc., and uniformly receives multi-dimensional sensor data, achieving microsecond-level clock synchronization across all devices. The EtherCAT communication link uses an SFP fiber optic isolation module.

[0030] The dynamic operating condition simulation platform is used to simulate the vehicle's road driving conditions (speed, torque commands) and provides a controllable temperature and humidity environment background. The dynamic operating condition simulation platform includes dual electric dynamometers 3, electric dynamometer frequency converter cabinet 13, humid and hot alternating environment chamber body 1, humid and hot alternating environment chamber control system 11, and electric drive assembly cooling system 10.

[0031] The main body 1 of the humid heat alternating environment chamber is a sealed chamber with explosion-proof function. The electric drive assembly system 2 (including motor and inverter) under test is arranged inside the main body 1. The control system 11 of the humid heat alternating environment chamber integrates a PLC controller, a temperature and humidity acquisition board, and a temperature and humidity execution drive module. The control system 11 is connected to the main body 1 of the humid heat alternating environment chamber through a humid heat circuit medium pipeline to realize the circulation and delivery of hot and cold air and humidified water vapor to regulate the temperature and humidity field inside the chamber. The control system 11 of the humid heat alternating environment chamber also communicates bidirectionally with the central control system 8 through an EtherCAT communication link to receive temperature and humidity cycle program instructions and transmit back the temperature and humidity inside the chamber and equipment fault signals.

[0032] The electric dynamometer frequency converter cabinet 13 has a built-in rectifier feedback unit and a dual-channel drive frequency converter. Three-phase power grid energy is connected to the electric dynamometer frequency converter cabinet 13. The two inverter output power cables in the cabinet are connected to two electric dynamometers 3 respectively, realizing four-quadrant drive of electric dynamometers 3 and energy feedback of generated power to the grid. The electric dynamometer frequency converter cabinet 13 communicates bidirectionally with the central control system 8 through the EtherCAT communication link, receives dynamic speed and torque condition commands, and uploads real-time torque, speed, winding temperature, and fault alarm data of electric dynamometers 3. The two electric dynamometers 3 are rigidly connected to both ends of the electric drive assembly system 2 through torque and speed sensors and couplings in a mechanical connection manner, which is used to simulate the dynamic torque and speed conditions of vehicle drive and energy recovery. The electric drive assembly cooling system 10 is connected in a closed loop with the water-cooled / oil-cooled flow channel inside the electric drive assembly system 2 through the cooling circuit, replicating the heat dissipation boundary of the real vehicle.

[0033] The multi-degree-of-freedom mechanical vibration loading system is used to reproduce the mechanical load spectrum collected from real roads, simulating the physical stress on the housing, connectors, and internal structure of the electric drive assembly system 2 caused by road bumps and rapid acceleration / deceleration. The multi-degree-of-freedom mechanical vibration loading system includes several sets of servo cylinders 4 and vibration sensors 5. In this embodiment, there are four servo cylinders 4. The servo cylinders 4 (servo hydraulic / electric cylinder vibration system) are mechanically connected to the four suspension points of the electric drive assembly system 2 to reproduce random vibrations and instantaneous impact loads on the real vehicle road surface. The vibration sensors 5 (accelerometers) are respectively installed on the housing of the electric drive assembly system 2, the output end of the servo cylinders 4, and the shaft end of the electric dynamometer 3. The collected vibration sensor signals are simultaneously connected to the local controller of the servo cylinders 4 and the central control system 8.

[0034] The dynamic high-voltage electrical performance comprehensive simulation and testing system includes a battery simulator 7, a high-voltage electrical performance testing device 6, a data acquisition unit 9, and an early fault diagnosis instrument 12.

[0035] The battery simulator 7 includes a programmable bidirectional DC power supply with bias function and a real / simulated battery pack. The programmable bidirectional DC power supply is used to simulate the voltage platform changes and power bias conditions of the vehicle power battery under different SOC states. The real / simulated battery pack serves as the energy supply source and feedback energy absorber of the test circuit. The battery simulator 7 as a whole simulates the complete charge and discharge characteristics of the vehicle power battery.

[0036] The high-voltage electrical performance testing equipment 6 includes an artificial power network and a high-voltage ripple / load dump simulator. The high-voltage ripple / load dump simulator has high-bandwidth power amplifier characteristics and can be connected in series or parallel to the high-voltage DC bus, enabling the synchronous superposition of dynamic ripple and millisecond-level load dump transient high-voltage pulses on the main high-voltage bus. Traditional ripple generators are mostly low-power signal sources (<1A), which cannot be directly injected into the high-voltage bus. In this embodiment, a multi-stage coupling topology is adopted: first, an isolated DC / DC boost unit is used to increase the bus voltage, then it is modulated by a linear power amplifier, and finally connected in series to the main bus through a coupling transformer. This topology can achieve ripple injection with a peak current of up to 200A within the DC~500kHz range without affecting the normal operation of the main circuit. To suppress mutual interference between the power amplifier and the motor controller, an LC notch filter is connected in parallel on the primary side of the coupling transformer to filter out the second harmonic of the switching frequency. Millisecond-level 800V-level load dump transient high-voltage pulses are generated, solving the hardware bottleneck that traditional low-power ripple sources cannot adapt to high-voltage, high-power main circuits.

[0037] The power flow connection is as follows: the high voltage output terminal of the battery simulator 7 is connected in parallel to the input terminal of the artificial power network, the output terminal of the artificial power network is connected in series with the high voltage ripple / load dump simulator, the output terminal of the high voltage ripple / load dump simulator is connected in series with the DC bus input terminal of the electric drive assembly system 2 under test, and the AC power terminal of the electric drive assembly system 2 under test is mechanically connected to the dual electric dynamometer 3 to simulate the full working conditions of drive discharge and energy recovery power generation.

[0038] The data acquisition unit 9 integrates a high-voltage bus voltage / current probe, a dynamometer torque and speed sensor, an environmental chamber temperature and humidity sensor, and a power analyzer, etc., to simultaneously collect multi-dimensional sensing signals of electrical, temperature, and mechanical dimensions. The data is packaged and uploaded to the central control system 8, and the dynamic ripple component of the bus is monitored in real time through the high-voltage bus voltage / current probe and the power analyzer.

[0039] The early fault diagnostic instrument 12 establishes signal communication links with the vibration sensor 5 and the data acquisition unit 9, respectively, for real-time analysis of signal characteristics and identification of early failure characteristics of power devices, bearings, insulation and other devices.

[0040] The central control system 8 is connected to the driver of the dual electric dynamometer 3 via EtherCAT bus to transmit speed / torque commands, to the controller of the servo cylinder 4 to transmit displacement / force commands, to the FPGA controller of the high-voltage electrical performance testing equipment 6 to transmit trigger signals (ripple frequency, amplitude, waveform parameters and load dump), to the humid and hot alternating environment chamber control system 11 to transmit temperature and humidity setpoints, and to the data acquisition unit 9 to start synchronous acquisition and reception.

[0041] The central control system 8 integrates a torque step pre-triggering algorithm module, a vibration and shock timing correction module, and an FPGA ripple dynamic waveform synthesis module. The torque step pre-triggering algorithm module is used to match the torque sudden change condition and pre-trigger high-pressure stress injection in advance. The vibration and shock timing correction module is used to eliminate the inherent motion jitter of the load-dropping equipment and realize the timing alignment of mechanical shock and high-pressure pulse. The FPGA ripple dynamic waveform synthesis module is used to dynamically update the ripple frequency and amplitude according to the real-time speed of the motor. The test bench is synchronously controlled by a unified clock to realize the synchronous superposition of four-dimensional loads of dynamic driving conditions, alternating temperature and humidity, multi-degree-of-freedom mechanical vibration, and dynamic high-pressure electrical stress of the electric drive assembly system under test 2.

[0042] To ensure that the time base error between electrical stress, mechanical vibration, and dynamic operating conditions is less than 1 microsecond, the dual electric dynamometer 3 driver, servo cylinder 4 controller, high-voltage ripple / load dump simulator FPGA, humid heat alternating environment chamber control system 11 PLC, and data acquisition unit 9 are all equipped with PTP slave modules, which are automatically aligned through the EtherCAT distributed clock (DC) mechanism, and the synchronization error between all slave modules is ≤1 microsecond.

[0043] Because ripple injection and load dumping generate strong electromagnetic noise, EtherCAT communication cables use double-shielded twisted-pair cables, and all slave devices are connected to the central control system 8 via fiber optic isolation (SFP modules); otherwise, packet loss will occur, leading to synchronization failure. In this embodiment, through on-site debugging, the low-voltage communication cables and high-voltage busbars are routed in separate channels with a spacing of ≥200mm, and all metal structures within the humid and hot alternating environment chamber 1 are grounded at a single point.

[0044] To address the phase synchronization issue between ripple injection and torque step, a torque step pre-triggering algorithm module is executed. The execution logic includes: the central control system 8 pre-reads the torque command sequence within a preset time window (e.g., the next 50ms) and calculates the torque change rate in real time. When the rate of change of torque When the torque exceeds a preset threshold (e.g., 500 Nm / s), a torque step is determined to occur. The required advance time is calculated based on the known delays of the dynamometer system, such as communication delays. Electrical response delay Mechanical inertia delay Calculate the total pre-trigger duration The central control system 8 operates before the torque step reaches its limit. A pre-trigger signal is sent to the high-voltage ripple / load dump simulator FPGA. After receiving the pre-trigger signal, the high-voltage ripple / load dump simulator FPGA synthesizes the target waveform in advance and injects ripple voltage synchronously at the zero-crossing point of the torque step through a hardware counter, with the phase error controlled within ±2° (@10kHz).

[0045] The working logic of the vibration and impact timing correction module is as follows: When the servo cylinder 4 outputs a mechanical impact load, the vibration sensor 5 collects the acceleration peak hardware interrupt signal and feeds it back to the central control system 8. After receiving the hardware interrupt signal, the central control system 8 immediately triggers the high-voltage load dumping simulator to output a transient high-voltage pulse, which cancels the inherent ±0.5ms action jitter of the relay inside the load dumping simulator. The timing error between the voltage peak and the mechanical vibration and impact peak is controlled within ±100μs. It supports the configuration of voltage peak and vibration and impact synchronous or offset 90° coupling conditions, which solves the problem of misalignment between the timing of the load dumping pulse and the road vibration and impact and the inability to reproduce the real coupling failure.

[0046] The FPGA ripple dynamic waveform synthesis module pre-stores three-dimensional lookup table data of the ripple amplitude-frequency characteristics obtained from the actual vehicle calibration, and has a built-in second-order polynomial extrapolation algorithm unit; the ripple frequency satisfies the following formula:

[0047] In the formula To inject ripple frequency in real time, The switching frequency of the 2IGBTs in the electric drive assembly system under test is given by , k is the harmonic order, p is the number of motor pole pairs, and n is the real-time motor speed. A three-dimensional lookup table of the amplitude-frequency characteristics of the ripple under different operating conditions is extracted through real-vehicle data acquisition or high-fidelity simulation and stored in the central control system 8. During online operation, the central control system 8 reads the current speed and torque in real time, quickly obtains the ripple parameters to be injected through interpolation, and updates the FPGA's DDS synthesizer within milliseconds to adaptively match the ripple amplitude and frequency. When the motor speed change rate is high (e.g., rapid acceleration > 5000 rpm / s), the ripple frequency changes extremely rapidly, and ordinary software lookup tables cannot meet the update rate. This embodiment implements a second-order polynomial extrapolation algorithm within the FPGA to predict the ripple frequency of the next cycle based on the speed change trend of the previous three cycles, synthesizing the waveform in advance and effectively solving the lag problem.

[0048] It also includes an electric drive test method for synchronous injection of high-voltage electrical stress under dynamic operating conditions, which is performed using the electric drive test bench for synchronous injection of high-voltage electrical stress under dynamic operating conditions. This method is used to achieve synchronous coupling verification of four-dimensional loads in electrical, mechanical, environmental, and driving conditions, and includes the following steps: S1, Bench Assembly and Wiring Setup: Fix the electric drive assembly system 2 under test inside the humid and hot alternating environment chamber 1, and complete the mechanical connection of the dual electric dynamometers 3, torque and speed sensors, and couplings; assemble the four servo cylinders 4 to the four suspension points of the electric drive assembly system 2 under test, and install vibration sensors 5 and temperature sensors 14; complete the series connection of the programmable bidirectional DC power supply, artificial power network, high-voltage ripple / load dump simulator, and DC bus of the electric drive assembly under test according to the high-voltage power flow sequence; install broadband high-voltage probes and current clamps (bandwidth ≥ 100MHz) on the DC bus and connect them to the data acquisition unit 9; establish fiber optic EtherCAT communication links between the central control system 8 and each subsystem, complete the single-point grounding of the bench metal structure, and lay high and low voltage cables in separate trenches; connect the electric drive assembly cooling system 10 to the cooling channel of the electric drive assembly under test.

[0049] S2, Test Parameter Calibration Configuration: Import the standard WLTC driving cycle road spectrum (e.g., the first 800 seconds of the WLTC operating condition) into the central control system 8, including segments such as rapid acceleration, constant speed, coasting, and energy recovery. Based on the typical ripple amplitude-frequency characteristics in Annex A of ISO 21498-2, and combined with real vehicle data, calibrate the dynamic ripple amplitude-frequency envelope, load dump trigger condition, and peak voltage, such as... ,in =10kHz, The amplitude varies with the rotational speed from 0 to 200 Hz. The load dumping trigger condition is set to occur at the moment of energy recovery interruption (i.e., the instant the torque command jumps from a negative value to 0), with the peak load dumping voltage set to 800V and a rise time of 2μs. The actual vehicle road load spectrum is imported to generate a random vibration PSD curve for servo cylinder 4, with a frequency range of 5-200Hz and a total root mean square acceleration of 1.5g. The ambient temperature (e.g., 25℃) and humidity (e.g., 50%RH) of the environmental chamber are set. A temperature and humidity cycle change program (e.g., 25℃→40℃→25℃) is configured for the alternating humidity and heat environmental chamber control system 11; multi-level fault alarm thresholds for bus ripple, vibration acceleration, insulation resistance, and IGBT case temperature are entered; and ripple amplitude-frequency characteristic three-dimensional lookup table data is imported into the FPGA ripple dynamic waveform synthesis module, etc.

[0050] S3, Global Clock Synchronization Calibration: Start the central control system 8PTP master clock, automatically complete the clock alignment of all slave devices including dual electric dynamometer 3, servo cylinder 4 controller, high voltage ripple / load dump simulator FPGA, humid heat alternating environment chamber control system 11 PLC, electric dynamometer frequency converter cabinet 13, and data acquisition unit 9, verify the full channel synchronization error ≤1μs, and eliminate local clock deviation of multiple devices.

[0051] S4, Four-dimensional load synchronous coupling loading: The central control system synchronously issues multiple sets of control commands for parallel execution: S41 controls the frequency converter cabinet 13 of the electric dynamometer to drive the dual electric dynamometers 3 to output continuous dynamic speed and torque according to the standard driving cycle, simulating the full driving conditions of the whole vehicle, including rapid acceleration, constant speed, coasting, and energy recovery.

[0052] S42, the control system 11 of the humidity and heat alternating environment chamber drives the body 1 of the humidity and heat alternating environment chamber to switch the temperature and humidity according to the preset program and continuously apply the alternating humidity and heat environment load.

[0053] S43 controls four servo cylinders to output the random vibration load spectrum of the road surface, and synchronously applies multi-degree-of-freedom mechanical vibration stress to the suspension point of the electric drive assembly under test.

[0054] S44 reads the motor speed and torque signals in real time, and dynamically updates the high-voltage ripple frequency and amplitude through the FPGA second-order polynomial extrapolation algorithm, continuously injecting dynamic matching ripple into the DC bus of the electric drive assembly under test. When the torque change rate exceeds the preset threshold and a torque step change is detected, a pre-trigger signal is issued in advance through the torque step pre-trigger algorithm. Under the energy recovery reverse drag condition, combined with the impact peak hardware interrupt signal output by the vibration sensor 5, the high-voltage load dump simulator is synchronously triggered to output a millisecond-level transient high-voltage pulse, realizing the precise timing coupling of the three: power generation reverse drag, mechanical impact, and high-voltage overvoltage pulse.

[0055] The load dumping coupling verification condition specifically includes: the central control system 8 controls the electric dynamometer frequency converter cabinet 13 to drive the dual electric dynamometer 3 to reverse pull the electric drive assembly under test into the power generation energy recovery state, synchronously controlling the servo cylinder 4 to output instantaneous impact vibration load, and then synchronously triggering the high-voltage load dumping simulator to output millisecond-level transient high-voltage pulses through the vibration impact timing correction module, to test the avalanche withstand capability of the inverter SiC power module and the overvoltage protection strategy of the bus capacitor, and solve the defect that the static test bench cannot verify the high-voltage transient impact protection capability under dynamic power generation conditions.

[0056] S5. Synchronous Data Acquisition and Online Fault Monitoring: The data acquisition unit 9 synchronously acquires electrical, mechanical, and temperature sensor data at a sampling rate of ≥1MHz and binds it to a global PTP timestamp; the early fault diagnostic instrument 12 analyzes vibration, current, and insulation signal characteristics in real time. When parameters exceed preset thresholds, it automatically stores fault timing data and triggers bench alarms and shutdown protection; for example, the peak-to-peak value of DC bus voltage ripple is normally ≤50V, but an alarm occurs at ≥80V; the vibration acceleration of the motor bearing is normally ≤0.5g, but an alarm occurs at ≥1.0g; the insulation resistance is normally ≥10MΩ, but an alarm occurs at ≤1MΩ; the IGBT module case temperature is normally ≤85℃, but an alarm occurs at ≥100℃.

[0057] S6. Durability Cyclic Operation and Failure Quantitative Analysis: A four-dimensional coupled durability cycle was continuously run for hundreds of hours, equivalent to 100,000 kilometers of accelerated aging in a real vehicle, with a shutdown inspection every 10 hours during the cycle. After the cycle, all test data were exported, and ripple spectrum waterfall plots, bearing vibration envelope spectra, and insulation impedance attenuation curves were plotted. The failure characteristics of the components were compared with those obtained from the static ISO 21498-2 component test and this dynamic coupling test. The aging acceleration factor of the combined effect of dynamic high-voltage electrical stress, mechanical, and environmental loads was quantified, and a high-voltage system reliability verification report and component optimization and improvement schemes were output. For example, in this embodiment, comparing the static ISO 21498-2 test results with the results of this dynamic coupling test revealed that: dynamic ripple superposition caused an additional 12°C increase in bus capacitor temperature rise and a 15% increase in ESR; after coupled vibration and load dumping, obvious electro-corrosion micropores appeared in the bearings (not observed in the static test); the insulation impedance decrease rate was 2.5 times faster than in the static test. A test report was generated, and optimization suggestions were proposed, such as increasing the bus capacitor capacity, using conductive grease bearings, and optimizing the switching frequency.

[0058] The above descriptions are merely embodiments of the present invention, and common knowledge such as specific technical solutions and / or characteristics are not described in detail here. It should be noted that those skilled in the art can make various modifications and improvements without departing from the technical solutions of the present invention, and these should also be considered within the scope of protection of the present invention. These modifications and improvements will not affect the effectiveness of the implementation of the present invention or the practicality of the patent. The scope of protection claimed in this application should be determined by the content of its claims, and the specific embodiments described in the specification can be used to interpret the content of the claims.

Claims

1. An electrically driven test bench for synchronous injection of high-voltage electrical stress under dynamic operating conditions, characterized in that: include: Central control system, dynamic working condition simulation platform, multi-degree-of-freedom mechanical vibration loading system, dynamic high voltage electrical performance comprehensive simulation and testing system; The central control system has a built-in PTP master clock and establishes real-time communication with the dynamic working condition simulation platform, the multi-degree-of-freedom mechanical vibration loading system, and the dynamic high-voltage electrical performance comprehensive simulation and testing system through EtherCAT communication links. The dynamic operating condition simulation platform includes dual electric dynamometers, an electric dynamometer frequency converter cabinet, a humid and hot alternating environment chamber, a humid and hot alternating environment chamber control system, and an electric drive assembly cooling system. The electric drive assembly system under test is located inside the humid and hot alternating environment chamber. The humid and hot alternating environment chamber control system is connected to the humid and hot alternating environment chamber via a humid and hot circuit medium pipeline. The humid and hot alternating environment chamber control system also communicates bidirectionally with the central control system via an EtherCAT communication link. The output cables of the electric dynamometer frequency converter cabinet are connected to the two electric dynamometers respectively. The electric dynamometer frequency converter cabinet communicates bidirectionally with the central control system via an EtherCAT communication link. The mechanical output end of the electric drive assembly system is rigidly connected to the dual electric dynamometers. The electric drive assembly cooling system is connected to the cooling circulation loop of the electric drive assembly system. The multi-degree-of-freedom mechanical vibration loading system includes several sets of servo cylinders and vibration sensors; the servo cylinders are installed at the suspension points of the electric drive assembly system, and the vibration sensors are respectively arranged on the housing of the electric drive assembly system, the output end of the servo cylinder, and the shaft end of the electric dynamometer. The vibration sensor signals are simultaneously connected to the local controller of the servo cylinder and the central control system. The dynamic high-voltage electrical performance comprehensive simulation and testing system includes a battery simulator, a high-voltage electrical performance testing device, a data acquisition unit, and an early fault diagnosis instrument. The high-voltage output terminal of the battery simulator is connected in parallel to the input terminal of the high-voltage electrical performance testing device, and the output terminal of the high-voltage electrical performance testing device is connected in series to the DC bus input terminal of the electric drive assembly system. The data acquisition unit integrates a power analyzer, a high-voltage bus voltage / current probe, and a temperature sensor, and all collected sensor signals are uniformly aggregated to the central control system. The early fault diagnosis instrument communicates with the vibration sensor and the data acquisition unit to identify early failure characteristics of components in real time. The central control system integrates a torque step pre-triggering algorithm module, a vibration and shock timing correction module, and an FPGA ripple dynamic waveform synthesis module. The torque step pre-triggering algorithm module is used to match the torque sudden change condition and pre-trigger high-pressure stress injection in advance. The vibration and shock timing correction module is used to eliminate the inherent motion jitter of the load-dropping equipment and realize the timing alignment of mechanical shock and high-pressure pulse. The FPGA ripple dynamic waveform synthesis module is used to dynamically update the ripple frequency and amplitude according to the real-time speed of the motor.

2. The electrically driven test bench for synchronous injection of high-voltage electrical stress under dynamic working conditions as described in claim 1, characterized in that: The high-voltage electrical performance testing equipment includes an artificial power network and a high-voltage ripple / load dump simulator. The high-voltage ripple / load dump simulator adopts an isolated DC / DC boost unit, a linear power amplifier, and a multi-stage coupling topology with a coupling transformer. The coupling transformer is connected in series to the DC bus of the electric drive assembly system under test, and an LC notch filter is connected in parallel on the primary side of the coupling transformer.

3. The electrically driven test bench for synchronous injection of high-voltage electrical stress under dynamic working conditions as described in claim 1, characterized in that: The dual electric dynamometer driver, servo cylinder controller, high-voltage ripple / load dump simulator FPGA, humid and hot alternating environment chamber control system PLC, and data acquisition unit are all equipped with PTP slave modules, and the synchronization error between all slave modules is ≤1 microsecond.

4. The electrically driven test bench for synchronous injection of high-voltage electrical stress under dynamic working conditions as described in claim 3, characterized in that: The EtherCAT communication link uses SFP fiber optic isolation modules. The high-voltage busbar and low-voltage communication cable are laid in separate trenches with a spacing of ≥200mm. All metal structures inside the humid and hot alternating environment chamber are grounded at a single point.

5. The electrically driven test bench for synchronous injection of high-voltage electrical stress under dynamic working conditions as described in claim 1, characterized in that: The FPGA ripple dynamic waveform synthesis module pre-stores three-dimensional lookup table data of the ripple amplitude-frequency characteristics obtained from the actual vehicle calibration, and has a built-in second-order polynomial extrapolation algorithm unit; the ripple frequency satisfies the following formula: In the formula To inject ripple frequency in real time, is the IGBT switching frequency of the electric drive assembly system under test, k is the harmonic order, p is the number of motor pole pairs, and n is the real-time speed of the motor; The FPGA ripple dynamic waveform synthesis module updates the DDS waveform generator based on the real-time speed and torque data sent by the central control system, and adaptively matches the ripple amplitude and frequency.

6. The electrically driven test bench for synchronous injection of high-voltage electrical stress under dynamic working conditions as described in claim 1, characterized in that: The execution logic of the torque step pre-triggering algorithm module includes: the central control system pre-reads the torque command sequence within a preset time window and calculates the torque change rate in real time; when the torque change rate exceeds a preset threshold, communication delay, electrical response delay, and mechanical inertia delay are added to calculate the total pre-triggering duration. Before the torque step is reached The high-voltage ripple / load dump simulator sends a pre-trigger signal to the high-voltage ripple / load dump simulator FPGA after receiving the pre-trigger signal, and injects the high-voltage ripple synchronously at the torque step zero point.

7. The electrically driven test bench for synchronous injection of high-voltage electrical stress under dynamic working conditions as described in claim 1, characterized in that: The working logic of the vibration and impact timing correction module is as follows: when the servo cylinder outputs mechanical impact load, the vibration sensor collects the acceleration peak hardware interrupt signal and feeds it back to the central control system. After receiving the hardware interrupt signal, the central control system immediately triggers the high-voltage load throwing simulator to output transient high-voltage pulses to offset the inherent action jitter of the internal relay of the load throwing simulator.

8. The electrically driven test bench for synchronous injection of high-voltage electrical stress under dynamic working conditions as described in claim 1, characterized in that: The data acquisition unit has a sampling rate of no less than 1MHz, and all acquisition channels are synchronously bound to a global PTP timestamp.

9. The electrically driven test bench and method for synchronous injection of high-voltage electrical stress under dynamic working conditions as described in claim 1, characterized in that: The high-voltage power flow connection is as follows: the high-voltage output terminal of the battery simulator is connected in parallel to the input terminal of the high-voltage electrical performance testing equipment; the output terminal of the high-voltage electrical performance testing equipment is connected in series to the DC bus input terminal of the electric drive assembly system under test; and the AC output terminal of the electric drive assembly system under test is connected to the mechanical shaft of the dual electric dynamometer.

10. An electrically driven testing method for synchronous injection of high-voltage electrical stress under dynamic operating conditions, characterized in that: The test is performed using an electrically driven test bench for synchronous injection of high-voltage electrical stress under dynamic operating conditions as described in any one of claims 1-9, comprising: S1, Bench Assembly and Wiring Setup: Fix the electric drive assembly system under test inside the humid and hot alternating environment chamber, and complete the mechanical connection of the dual electric dynamometers, torque and speed sensors, and couplings; assemble the servo cylinders to the corresponding suspension points of the electric drive assembly system under test, and install vibration sensors and temperature sensors; complete the series connection of the battery simulator, high-voltage electrical performance testing equipment, and the DC bus of the electric drive assembly system under test according to the high-voltage power flow sequence; install broadband high-voltage probes and current clamps on the DC bus and connect them to the data acquisition unit; establish EtherCAT communication links between the central control system and each subsystem; S2, Test parameter calibration configuration: Import standard WLTC driving cycle road spectrum into the central control system; calibrate dynamic ripple amplitude-frequency envelope, load dump trigger condition, and peak voltage based on actual vehicle data; import actual vehicle road load spectrum to generate servo cylinder random vibration PSD curve; configure temperature and humidity cycle change program for the humid and hot alternating environment chamber control system; input multi-level fault alarm thresholds for bus ripple, vibration acceleration, insulation resistance, and IGBT case temperature; import ripple amplitude-frequency characteristic three-dimensional lookup table data into the FPGA ripple dynamic waveform synthesis module; S3, Global Clock Synchronization Calibration: Start the central control system PTP master clock to automatically complete the clock alignment of all slave devices, including dual electric dynamometers, servo cylinder controllers, high-voltage ripple / load dump simulator FPGA, humid heat alternating environment chamber control system PLC, electric dynamometer frequency converter cabinet, and data acquisition unit. S4, Four-dimensional load synchronous coupling loading: The central control system synchronously issues multiple sets of control commands for parallel execution. S41, through the frequency converter cabinet of the electric dynamometer, drives the dual dynamometers to run the standard driving cycle, and reproduces the dynamic torque and speed conditions of the whole vehicle driving, coasting, and energy recovery. S42, through the heat and humidity control system, regulates the chamber and applies alternating temperature and humidity environmental loads; S43 drives the multi-servo cylinder to output spectrum vibration, applying multi-degree-of-freedom mechanical impact to the electric drive suspension point; S44 dynamically matches and injects high-voltage ripple into the bus based on the real-time speed and torque of the motor using an FPGA algorithm; pre-triggered stress is applied when torque changes suddenly; and high-voltage pulses are synchronously output in combination with vibration peak interruption signals during reverse power generation to achieve precise timing coupling of power generation, vibration, and transient overvoltage. S5, Synchronous Data Acquisition and Online Fault Monitoring: The data acquisition unit synchronously acquires electrical, mechanical, and temperature sensor data across all dimensions and binds them to a global PTP timestamp; S6, Durability Cyclic Operation and Failure Quantification Analysis: Continuously run a four-dimensional coupled durability cycle, export all test data after the cycle ends, and compare and analyze the device failure characteristics of static tests.

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