Vehicle hybrid power system multi-working-condition electromagnetic disturbance test method

Abstract

The invention provides a multi-working-condition electromagnetic disturbance test method for a vehicle hybrid power system, which is characterized in that a working condition test sequence is designed based on various typical system operation working conditions, and independent or correlated conduction current time domain and frequency domain tests are executed for high and low voltage wire harnesses in the system in various working conditions and working condition switching scenes. Electromagnetic disturbance characteristics, conduction coupling paths and intensity corresponding to specific working conditions can be effectively extracted by using results obtained by testing, system-level electromagnetic compatibility optimization design is performed on the basis, and the actual operation requirements of vehicles can be better met.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of electromagnetic compatibility test, and particularly relates to a cable conducted disturbance test method for a hybrid power system of a vehicle under multiple operating conditions. BACKGROUND

[0002] With the development trend of high-voltage, high-frequency and high-integration of vehicle electric drive systems and hybrid power systems, the electromagnetic compatibility (EMC) problem faced by vehicles is becoming increasingly serious. Compared with the past, the amplitude, bandwidth and coupling path complexity of conducted and radiated disturbance have significantly increased, which can easily cause communication abnormalities, sensor signal distortion and even controller failure, and it is necessary to accurately characterize and suppress the coupling disturbance between high and low voltage circuits in complex systems on vehicles. However, the existing electromagnetic compatibility test of new energy vehicles still focuses on simulation in experimental environment, and the bench and model built are often difficult to truly reflect the actual operating conditions of the vehicle electric drive system, and the experiment is mainly carried out for a single device or a specific coupling path, while ignoring the overall electromagnetic disturbance analysis of the highly integrated power system. In addition, the existing technology lacks in-depth research on the complex coupling characteristics between high and low voltage circuits on vehicles, and there are few schemes that can effectively capture the time-domain transient disturbance characteristics and low-frequency coupling characteristics of the system during dynamic operating condition switching, thereby seriously restricting the comprehensive understanding and accurate modeling of the high and low voltage coupling mechanism (especially its time-varying characteristics and low-frequency conducted path) in the system. Therefore, how to overcome the defects of the existing technology and realize the vehicle multi-condition electromagnetic disturbance test method including the coupling characteristics between high and low voltage circuits is a technical problem that needs to be solved in the field. SUMMARY

[0003] Therefore, in view of the technical problems existing in the field, the present application provides a multi-condition electromagnetic disturbance test method for a hybrid power system of a vehicle, which specifically comprises the following steps:

[0004] Step one, a test platform is built for a specific hybrid power system, including a generator, a generator controller, a drive motor, a motor controller, an electromechanical coupler, a TCU, an oil pump motor controller, a low-voltage (LV) power supply 1, a low-voltage (LV) power supply 2, a low-voltage (LV) power supply 3, a repeater, an upper computer, and high-voltage power harness (such as high-voltage DC bus, motor phase line) and low-voltage control / signal harness (such as low-voltage power line, CAN bus, resolver line, sensor harness, solenoid valve harness) required for normal work of each component; and a time-domain, frequency-domain test and analysis device for current is set;

[0005] Step two, set different operating conditions and system working states to be tested;

[0006] Step three, under the set conditions and working states, select the key high-voltage and low-voltage wire harnesses to be analyzed to perform time domain and frequency domain tests; and under the selected specific key conditions, perform corresponding time domain and frequency domain tests on the key high-voltage and low-voltage wire harnesses at the same time;

[0007] Step four, based on the test results obtained in step three, perform comparative analysis of time domain and frequency domain characteristics of the same cable conduction current under different conditions, and correlation analysis of time domain and frequency domain characteristics of high and low voltage wire harnesses under different conditions and condition switching transient; based on the analysis results, determine the electromagnetic disturbance high and low voltage coupling path characteristics and coupling strength corresponding to different conditions, and predict the interference risk that may be caused by electromagnetic disturbance high and low voltage coupling under different conditions;

[0008] Step five, based on the test and analysis results obtained in steps three and four and the risk prediction results, determine the correlation between the conduction disturbance of each component in the hybrid power system and different operating states, and perform corresponding system-level electromagnetic compatibility design optimization.

[0009] Further, in step one, the test and analysis device specifically uses an oscilloscope for time domain measurement, a spectrum analyzer for frequency domain measurement, a radio frequency current probe for wideband conduction current measurement, and a large current probe for capturing low frequency transient current and high amplitude waveform; the radio frequency current probe and the large current probe are respectively clamped on the high-voltage or low-voltage cable to be tested, and are respectively connected to the oscilloscope and the spectrum analyzer.

[0010] Further, in step two, the following test conditions and working states are specifically set:

[0011] (1) system only low voltage (such as 24V system);

[0012] (2) system high voltage (such as 900V system), and drive motor controller without tube (IGBT not working);

[0013] (3) system high voltage, and drive motor controller with tube (IGBT working);

[0014] (4) drive motor idling at a specific speed (such as 1000rpm, 3000rpm, 5000rpm);

[0015] (5) drive motor running with load (such as 3000rpm, 100Nm);

[0016] (6) system only generator and oil pump motor working;

[0017] (7) drive motor, generator, oil pump motor working at the same time (joint debugging condition).

[0018] Further, the following test procedures are specifically performed in step three for each set of working conditions:

[0019] (1) Select key high-voltage and wire harnesses including high-voltage DC positive / negative lines, motor phase lines, etc., and key low-voltage wire harnesses including controller low-voltage power lines, CAN bus, sensor lines, etc.; use a large current probe and an oscilloscope to obtain the transient conduction current on the individual wire harnesses and its peak current, pulse width, rise / fall time, repetition frequency, etc. characteristic parameters; capture the transient interference caused by dynamic processes including switch action, working state switching, etc.

[0020] (2) Use a radio frequency current probe and a spectrum analyzer to obtain the conduction disturbance current spectrum characteristics of the key wire harnesses in the wide frequency band, including peak, quasi-peak, average, and harmonic amplitude, etc.

[0021] (3) Under the selected specific key working conditions, simultaneously perform the above time and frequency domain tests on the high-voltage wire harnesses and sensitive low-voltage wire harnesses including CAN bus, low-voltage power lines, etc. and record the synchronous test time.

[0022] Further, the following analysis procedures are specifically performed in step four using the test results of step three:

[0023] (1) Under different working conditions such as high-voltage on / off, no load / loaded, single machine / combined debugging, etc., compare the time domain characteristics of the same wire harnesses including transient amplitude, waveform change, etc. and the frequency domain characteristics including spectral distribution, amplitude change at specific frequency points, harmonic component change, etc.

[0024] (2) For high-voltage high-power components including drive motor controllers, generator controllers, etc. under different working conditions and working condition switching, perform the following high-low voltage correlation analysis:

[0025] ① Determine whether the specific time domain transient event (such as switch peak) appearing on the high-voltage wire harness is related in time to the abnormal transient or noise appearing on the low-voltage wire harness;

[0026] ② Determine whether the significant frequency domain disturbance component (such as a specific switch frequency harmonic, a wideband noise frequency band) appearing on the high-voltage wire harness is related in the frequency domain to the significant lifting of the disturbance amplitude of the corresponding frequency band on the low-voltage wire harness;

[0027] (3) Based on the high-low voltage correlation analysis results of steps time domain and frequency domain, determine the key coupling path characteristics of the high-voltage disturbance coupling to the low-voltage sensitive circuit, and evaluate the coupling strength using parameters including the dB value of the disturbance lifting on the low-voltage line, etc. According to the coupling path characteristics and coupling strength analysis results under different working conditions, predict the electromagnetic disturbance coupling mechanism between high and low voltage circuits under specific working conditions and the possible interference risk to the low-voltage circuit (such as communication, control signal).

[0028] The multi-condition electromagnetic interference testing method for vehicle hybrid power systems provided by the present invention designs a test sequence based on various typical system operating conditions, and performs individual or related time-domain and frequency-domain tests on the high and low voltage wiring harnesses in the system under various operating conditions and operating condition switching scenarios. The test results can effectively extract the electromagnetic interference characteristics, conducted coupling paths and strengths corresponding to specific operating conditions. Based on this, system-level electromagnetic compatibility optimization design can be carried out, which can better meet the actual operating needs of vehicles. Attached Figure Description

[0029] Figure 1 This is a diagram showing the optional connection structure of the high-voltage wiring harness in the test platform constructed in the method provided by this invention;

[0030] Figure 2 This is a diagram showing the optional connection structure of the low-voltage wiring harness in the test platform built in the method provided by the present invention. Detailed Implementation

[0031] The technical solution of the present invention will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0032] The multi-condition electromagnetic interference testing method for automotive hybrid power systems provided by this invention specifically includes the following steps:

[0033] Step 1: Build a test platform for the specific hybrid power system, including: generator, generator controller, drive motor, motor controller, electromechanical coupler, electromechanical transmission controller (TCU), oil pump motor controller, low-voltage (LV) power supply 1, low-voltage (LV) power supply 2, low-voltage (LV) power supply 3, repeater, host computer, and high-voltage power harnesses (such as high-voltage DC bus, motor phase lines) and low-voltage control / signal harnesses (such as low-voltage power lines, CAN bus, resolver cable, sensor harness, solenoid valve harness) required for the normal operation of each component; and set up time-domain and frequency-domain current testing and analysis devices. Figure 1 , 2 The diagram shows a high-voltage and low-voltage wiring harness connection structure constructed based on an example of the present invention;

[0034] Step 2: Set the different operating conditions and system working status to be tested;

[0035] Step 3: Under each set operating condition and working state, select the key high-voltage harness and low-voltage harness to be analyzed and perform time-domain and frequency-domain tests respectively; and, under a specific key operating condition, simultaneously perform the corresponding time-domain and frequency-domain tests on the key high-voltage harness and low-voltage harness.

[0036] Step four, based on the test results obtained in step three, the time domain and frequency domain characteristics of the same cable conduction current under different conditions are compared and analyzed, and the time domain and frequency domain characteristics of the high and low voltage wire harness current under different conditions and the switching transient are analyzed. Based on the analysis results, the electromagnetic disturbance high and low voltage coupling path characteristics and coupling strength corresponding to different conditions are determined, and the interference risk caused by electromagnetic disturbance high and low voltage coupling under different conditions is predicted;

[0037] Step five, based on the test and analysis results obtained in steps three and four and the risk prediction results, the correlation between each component in the hybrid power system and the conduction disturbance under different operating conditions is determined, and the corresponding system-level electromagnetic compatibility design optimization is carried out.

[0038] In a preferred embodiment of the present application, the test and analysis device in step one specifically uses an oscilloscope for time domain measurement, a spectrum analyzer for frequency domain measurement, a radio frequency current probe for wideband conduction current measurement, and a large current probe for capturing low frequency transient current and high amplitude waveform; The radio frequency current probe and the large current probe are respectively clamped on the high voltage or low voltage cable to be tested, and are respectively connected to the oscilloscope and the spectrum analyzer.

[0039] In a preferred embodiment of the present application, the following test conditions and working conditions are specifically set in step two:

[0040] (1) The system is only low voltage (such as 24V system);

[0041] (2) The system is high voltage (such as 900V system), and the drive motor controller is not open tube (IGBT is not working);

[0042] (3) The system is high voltage, and the drive motor controller is open tube (IGBT is working);

[0043] (4) The drive motor is idling at a specific speed (such as 1000rpm, 3000rpm, 5000rpm);

[0044] (5) The drive motor is running with load (such as 3000rpm, 100Nm);

[0045] (6) The system only generator and oil pump motor work;

[0046] (7) The drive motor, generator and oil pump motor work at the same time (joint debugging condition).

[0047] In a preferred embodiment of the present application, the following test processes are specifically performed in step three for each set condition:

[0048] (1) Select the key high-voltage and wire harnesses including high-voltage DC positive / negative lines, motor phase lines, etc., and the key low-voltage wire harnesses including controller low-voltage power lines, CAN bus, sensor lines, etc.; use a large-current probe and an oscilloscope to obtain the transient conduction current on the individual wire harness and its peak current, pulse width, rise / fall time, repetition frequency, etc. characteristic parameters; capture the transient interference caused by the dynamic process including switch action, working state switching, etc.

[0049] (2) Use a radio frequency current probe and a spectrum analyzer to obtain the conduction disturbance current spectrum characteristics of the key wire harnesses in a wide frequency band, including peak, quasi-peak, average, and harmonic amplitude, etc.

[0050] (3) Under selected specific key working conditions, simultaneously perform the above time domain and frequency domain tests on the high-voltage wire harnesses and sensitive low-voltage wire harnesses including CAN bus, low-voltage power lines, etc. and record the synchronous test time.

[0051] In one preferred embodiment of the present application, the test results of step three are used in step four to perform the following analysis process:

[0052] (1) Under different working conditions such as high-voltage on / off, no load / loaded, single machine / combined debugging, etc., compare the time domain characteristics of the same wire harness including transient amplitude, waveform change, etc. and the frequency domain characteristics including spectrum distribution, amplitude change at specific frequency points, harmonic component change, etc.

[0053] (2) For high-voltage high-power components including motor controller, generator controller, etc. under different working conditions and working condition switching, perform the following high-low voltage correlation analysis:

[0054] ① Determine whether the specific time domain transient event (such as switch peak) appearing on the high-voltage wire harness is related in time to the abnormal transient or noise appearing on the low-voltage wire harness;

[0055] ② Determine whether the significant frequency domain disturbance component (such as a specific switch frequency harmonic, a wideband noise frequency band) appearing on the high-voltage wire harness is related in the frequency domain to the significant lifting of the disturbance amplitude of the corresponding frequency band on the low-voltage wire harness;

[0056] (3) Based on the high-low voltage correlation analysis results of steps time domain and frequency domain, determine the key coupling path characteristics of the high-voltage disturbance coupling to the low-voltage sensitive circuit, and evaluate the coupling strength using parameters including the dB value of the disturbance lifting on the low-voltage line, etc. According to the coupling path characteristics and coupling strength analysis results under different working conditions, predict the electromagnetic disturbance coupling mechanism between the high-low voltage circuits under specific working conditions and the possible interference risk to the low-voltage circuit (such as communication, control signal).

[0057] It should be understood that the size of the serial number of each step in the embodiments of the present application does not mean the order of execution, and the execution order of each process should be determined according to its function and inherent logic, and should not constitute any limitation on the implementation process of the embodiments of the present application.

[0058] Although embodiments of the present application have been shown and described, it will be understood by those of ordinary skill in the art that various changes, modifications, substitutions and alterations can be made thereto without departing from the principles and spirit of the present application, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A multi-condition electromagnetic interference test method for automotive hybrid power systems, characterized in that: Specifically, the following steps are included: Step 1: Build a test platform for a specific hybrid power system, including: generator, generator controller, drive motor, motor controller, electromechanical coupler, electromechanical transmission controller, oil pump motor controller, low-voltage power supply, low-voltage power supply, repeater, host computer, and high-voltage power harnesses and low-voltage control and signal harnesses required for the normal operation of each component; and set up time-domain and frequency-domain current testing and analysis devices. Step 2: Set the different operating conditions and system working status to be tested; Step 3: Under each set operating condition and working state, select the key high-voltage harness and low-voltage harness to be analyzed and perform time-domain and frequency-domain tests respectively; and, under a specific key operating condition, simultaneously perform the corresponding time-domain and frequency-domain tests on the key high-voltage harness and low-voltage harness. Step 4: Based on the test results obtained in Step 3, perform comparative analysis of the time-domain and frequency-domain characteristics of the conduction current of the same cable under different operating conditions, as well as correlation analysis of the time-domain and frequency-domain characteristics of the high- and low-voltage harness current at the moment of switching between different operating conditions. Based on these analysis results, the characteristics and coupling strength of the electromagnetic interference high- and low-voltage coupling paths corresponding to different operating conditions are determined, and the interference risks that may be caused by electromagnetic interference high- and low-voltage coupling under different operating conditions are predicted. Step 5: Based on the test and analysis results and risk prediction results obtained in Steps 3 and 4, determine the correlation between each component in the hybrid power system and conducted interference under different operating conditions, and perform corresponding system-level electromagnetic compatibility design optimization.

2. The method as described in claim 1, characterized in that: In step one, the testing and analysis apparatus specifically uses an oscilloscope for time-domain measurements, a spectrum analyzer for frequency-domain measurements, an RF current probe for broadband conducted current measurements, and a high-current probe for capturing low-frequency transient currents and high-amplitude waveforms. The RF current probe and the high-current probe are respectively clamped onto the high-voltage or low-voltage cable under test and connected to the oscilloscope and the spectrum analyzer respectively.

3. The method as described in claim 1, characterized in that: Step two involves setting the following test conditions and operating status: (1) The system is only supplied with low voltage; (2) The system is under high voltage and the drive motor controller is not open; (3) The system is under high voltage and the drive motor controller is open; (4) The drive motor idles at a specific speed; (5) The drive motor operates under load; (6) Only the generator and oil pump motor operate in the system; (7) Joint commissioning condition where the drive motor, generator and oil pump motor work simultaneously.

4. The method as described in claim 1, characterized in that: Step three involves performing the following test procedures for each set of operating conditions: (1) Select key high voltage and wiring harnesses including high voltage DC positive / negative lines and motor phase lines, as well as key low voltage wiring harnesses including controller low voltage power supply lines, CAN bus and sensor lines; use a high current probe and oscilloscope to obtain transient conduction current and its peak current, pulse width, rise / fall time and repetition frequency characteristic parameters on individual wiring harnesses; capture transient interference caused by dynamic processes including switching action and working state switching; (2) Use an RF current probe and a spectrum analyzer to obtain the conducted disturbance current spectrum characteristics of the key harness in a wide bandwidth, including peak, quasi-peak, average and harmonic amplitudes. (3) Under the selected specific critical operating conditions, the above time domain and frequency domain tests were performed simultaneously on the high voltage harness and the sensitive low voltage harness including the CAN bus and low voltage power line, and the synchronous test time was recorded.

5. The method as described in claim 1, characterized in that: Step four utilizes the test results from step three to perform the following analysis process: (1) Under different operating conditions including high voltage switching, no-load / load, single unit / joint commissioning, compare the time domain characteristics of the same harness including transient amplitude and waveform changes, as well as the frequency domain characteristics including spectrum distribution, amplitude changes at specific frequency points, and harmonic component changes. (2) Perform the following high-low voltage correlation analysis on high-voltage, high-power components, including drive motor controllers and generator controllers, under different operating conditions and during instantaneous switching between operating conditions: ① Determine whether a specific time-domain transient event occurring on a high-voltage line harness is temporally correlated with an abnormal transient or noise occurring on a low-voltage line harness; ② Determine whether the significant frequency domain interference components appearing on the high-voltage line harness are correlated in the frequency domain with the significant increase in the interference amplitude of the corresponding frequency band on the low-voltage line harness; (3) Based on the time-domain and frequency-domain correlation analysis results of high and low voltage, the key coupling path characteristics of high voltage interference coupled to low voltage sensitive circuit are determined, and the coupling strength is evaluated using parameters including the dB value of interference rise on the low voltage line. Based on the coupling path characteristics and coupling strength analysis results under different operating conditions, the electromagnetic interference coupling mechanism between high and low voltage circuits under specific operating conditions and the interference risk that it may cause to low voltage circuits are predicted.

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