A Modeling and Simulation Method for Electromagnetic Radiation of an Electric Drive System of an Electric Vehicle

Abstract

The present invention discloses a method for modeling and simulating electromagnetic radiation of an electric vehicle's electric drive system, belonging to the technical field of electromagnetic compatibility modeling and simulation of electric vehicles, and comprising the following steps: establishing a circuit model of the DC / DC system and simulating to obtain DC voltage time-domain waveform data; establishing a circuit model of the DC / AC system and simulating to obtain AC voltage time-domain waveform data; establishing a 3D electromagnetic model of the drive motor and importing the AC voltage time-domain waveform into the 3D electromagnetic model of the drive motor to simulate and obtain the radiation field; establishing a 3D electromagnetic model of the vehicle body; in the 3D electromagnetic model of the vehicle body, establishing a cable and equipment layout model and importing the radiation field; inputting the DC voltage time-domain waveform and the AC voltage time-domain waveform into the cable and equipment layout model, and obtaining the spatial electromagnetic radiation of the electric vehicle's electric drive system through field-circuit co-simulation. This method comprehensively considers the influence of the actual spatial distribution relationship among structures such as the motor, cables, and vehicle body on the spatial radiation field of the electric vehicle.

Description

Technical Field

[0001] The present invention belongs to the technical field of electromagnetic compatibility modeling and simulation of electric vehicles, and particularly relates to a method for modeling and simulating electromagnetic radiation of an electric drive system of an electric vehicle. Background Art

[0002] High-power power electronic devices are integrated in electric vehicles, such as power battery packs, DC (Direct Current) / DC converters or DC / AC (Alternating Current) inverters, drive motors, and power cables. During operation, high-power power electronic devices generate strong electromagnetic radiation, which not only affects the normal operation of various electronic devices installed in electric vehicles, but also affects human health, such as causing central nervous problems like headaches, insomnia, and arrhythmia.

[0003] These high-power power electronic devices are important electromagnetic radiation sources of electric vehicles, and among them, the motor drive system is the main electromagnetic radiation source. Due to the high voltage level of the electric drive system of electric vehicles and the high operating frequency of semiconductor devices in the electric drive system, the electromagnetic environment of the electric drive system of electric vehicles is very complex. Moreover, due to the development of electronic technology and the needs of military research such as electronic warfare and radar, more and more electronic devices are integrated into a system, and electronic devices are developing towards miniaturization and high speed. This makes an electronic system may require several or even more than a dozen antennas operating in different frequency bands to receive or transmit electronic signals. For example, in the on-vehicle antenna system of an electric vehicle, the number of antennas increases, the bandwidth increases, and the sensitivity requirement is greatly improved. However, a large number of high-voltage and high-power electronic devices are integrated in the electric drive system of electric vehicles, which causes significant electromagnetic interference to on-vehicle devices including motor controllers and affects the normal functions of on-vehicle devices. In order to better predict the impact of the electric drive system of electric vehicles on on-vehicle devices in electric vehicles, solve the electromagnetic compatibility problem of the electric drive system of electric vehicles, clarify the interference source, and provide a basis for subsequent research on the impact of electromagnetic interference of the electric drive system of electric vehicles on devices such as on-vehicle antennas, the modeling and simulation of electromagnetic radiation of the electric drive system of electric vehicles is of great significance.

[0004] Currently, a large number of studies on the electromagnetic compatibility of electric vehicles focus on electromagnetic noise testing, which highly relies on data measured from actual tests, is not conducive to electromagnetic compatibility prediction, and when modeling and simulating the electromagnetic radiation of the electric drive system, the influence of the actual distribution of cables, motors, and the electric vehicle shell on the radiation results is rarely considered. This makes it difficult to further predict and control the impact of electromagnetic interference from the electric drive system on other in-vehicle devices. For example, Li Xiaojie, Li Yang, Zhang Runzhe, etc. proposed a simulation method for in-vehicle electromagnetic radiation of pure electric vehicles in "Research on an Efficient Simulation Method for In-vehicle Electromagnetic Radiation of Pure Electric Vehicles". This method uses a dipole antenna to replace the actual motor model. This method cannot accurately reflect the influence of the motor radiation electric field on nearby in-vehicle devices within the near field of the motor. Liu Shaobo, Cao Zhiliang, etc. analyzed the conducted interference of the power supply and connecting cables in the in-vehicle power supply system in "Simulation and Analysis of In-vehicle Electromagnetic Radiation of Electric Vehicles", but only limited to the conducted electromagnetic interference of the power supply system, without comprehensively considering the motor and inverter devices that will generate greater interference, and without considering the influence of factors such as the spatial position of the actual cable and the vehicle shell on the simulation results. Dai Lingang, Zhang Liangli, Yan Yunbing analyzed the electromagnetic radiation characteristics of power cables of electric vehicles and their influencing factors under different driving conditions in "Simulation of Electromagnetic Radiation of Power Cables of Electric Vehicles under Driving Conditions", but this literature is only limited to the simulation analysis of the electromagnetic radiation of power cables, without considering the actual motor model connected to the three-phase cables, and without considering the influence of the actual cable spatial layout on electromagnetic radiation, and fails to accurately simulate and obtain the overall radiation characteristics of electric vehicles. The Chinese invention patent with the publication number CN 109800499A and the name of a modeling and simulation method for electromagnetic interference emission of an inverter motor drive system considered the electromagnetic interference emission simulation of an isolated motor inverter system, did not consider the influence of the vehicle shell structure on the distributed parameters of the simulation circuit, and was only limited to the electromagnetic radiation excited by three-phase cables, without comprehensively considering the influence of the spatial position distribution of structures such as the motor model and cables in the actual vehicle body on the radiation simulation results.

[0005] In summary, the existing technologies mainly have the following problems: (1) Do not comprehensively consider the main electromagnetic interference sources, interference coupling paths, and load devices of the electric drive system such as the DC / DC DC power conversion system, DC / AC inverter system, and load motor, and do not establish a complete electromagnetic radiation model of the electric drive system; (2) Do not comprehensively consider the influence of the actual spatial distribution relationship between structures such as motors, cables, and vehicle bodies on the distributed parameters of the equivalent circuit model and the spatial radiation field. Summary of the Invention

[0006] In view of this, the present invention provides a method for modeling and simulating electromagnetic radiation of an electric vehicle's electric drive system, which is used to solve the problems that a large number of studies on the electromagnetic compatibility of traditional electric vehicles do not comprehensively consider the main electromagnetic interference sources, interference coupling paths, and load devices such as the DC / DC DC power conversion system, DC / AC inverter system, and load motor of the electric drive system, do not establish a complete electromagnetic radiation model of the electric drive system, and do not comprehensively consider the influence of the actual spatial distribution relationship between structures such as motors, cables, and vehicle bodies on the distributed parameters of the equivalent circuit model and the spatial radiation field.

[0007] The present invention adopts the following technical solutions:

[0008] A method for modeling and simulating electromagnetic radiation of an electric vehicle's electric drive system includes the following steps:

[0009] Establish a DC / DC system circuit model and simulate to obtain DC voltage time-domain waveform data;

[0010] Establish a DC / AC system circuit model and simulate to obtain AC voltage time-domain waveform data;

[0011] Establish a 3D electromagnetic model of the drive motor, and import the AC voltage time-domain waveform as an excitation into the 3D electromagnetic model of the drive motor to simulate and obtain the radiation field;

[0012] Establish a 3D electromagnetic model of the vehicle body;

[0013] In the 3D electromagnetic model of the vehicle body, establish a cable and equipment layout model and import the radiation field;

[0014] Use the DC voltage time-domain waveform and the AC voltage time-domain waveform as excitations, input them into the cable and equipment layout model, and obtain the spatial electromagnetic radiation of the electric vehicle's electric drive system through field-circuit co-simulation.

[0015] Furthermore, the DC / DC system circuit model is a buck full-bridge conversion circuit simulation model based on PSpice software.

[0016] Furthermore, the buck full-bridge conversion circuit simulation model includes: a high-voltage power supply, a linear impedance stabilization network, a full-bridge circuit composed of four high-power switching tubes, a high-frequency transformer, a rectifier diode, an iron-core inductor, a capacitor, and a load circuit;

[0017] The high-voltage power supply is connected in parallel to the power supply end of the linear impedance stabilization network, the load end of the linear impedance stabilization network is connected in parallel to a capacitor, and the capacitor is connected in parallel to the input end of the full-bridge circuit and grounded. The output end of the full-bridge circuit is connected in parallel to the input end of the high-frequency transformer. The output end of the high-frequency transformer is connected in parallel to an LC circuit, and the load circuit is connected in parallel across the two ends of the capacitor of the LC circuit.

[0018] Further, the circuit model of the DC / AC system is a simulation model of a three-phase three-leg two-level inverter bridge circuit based on PSpice software.

[0019] Further, the simulation model of the three-phase three-leg two-level inverter bridge circuit includes a high-voltage power supply, a linear impedance stabilization network, a full-bridge circuit composed of six IGBTs, rectifier diodes, an IGBT control circuit, and a load circuit;

[0020] The high-voltage power supply is connected in parallel to the power supply end of the linear impedance stabilization network. The load end of the linear impedance stabilization network is connected in parallel to a capacitor, and the capacitor is connected in parallel to the three-phase three-leg two-level inverter bridge. The control end of the IGBT is connected to the IGBT control circuit. The three-phase output ends of the full-bridge circuit are star-connected to the load circuit and grounded.

[0021] Further, the IGBT control circuit includes a PWM wave generation circuit and an IGBT drive circuit composed of a square-wave source, a sine-wave source, and a comparator.

[0022] Further, the 3D electromagnetic model of the drive motor is based on CST software and is simplified and constructed according to the actual motor model;

[0023] The simplified 3D model of the drive motor includes: a stator, a rotor, a cable winding, and a motor housing;

[0024] The steps for simulating and obtaining the radiation field include the following steps:

[0025] Define discrete ports between the starting cross-section and the ending cross-section of the cable winding model, and import the time-domain waveform of the AC voltage in ASCII data format into the ExternalPort;

[0026] Select the Hexahedral TLM mode for grid division in the grid mode;

[0027] Establish an instantaneous simulation task, select the CST transient co-simulation solver, and set the FieldMonitor to select the Field source field monitor;

[0028] Generate an FSM format file after the simulation ends.

[0029] Further, the cable winding is simplified using the equivalent wire harness method.

[0030] Further, the 3D electromagnetic model of the vehicle body is simplified and established according to the actual vehicle body model, including a metal vehicle body and glass;

[0031] The cable and equipment layout model includes: a high-voltage distribution box model, a DC / AC inverter model, a DC / DC converter model, a drive motor model, a 24V battery model, an in-vehicle equipment model, a high-voltage cable model, and a low-voltage cable model;

[0032] The steps of importing the radiation field into the vehicle body 3D electromagnetic model include:

[0033] In Field Sources, in the Importfile option, import the FSM format file as the excitation field source and configure it at the position of the drive motor model to replace the drive motor model.

[0034] Furthermore, the field and circuit co-simulation includes the following steps:

[0035] Based on the CST software Cable Studio, combine the vehicle body 3D electromagnetic model, the cable and equipment layout model, and the radiation field to establish an instantaneous simulation task;

[0036] In the Cable Studio circuit-side model, import the DC voltage time-domain waveform and the AC voltage time-domain waveform in ASCII data form into the cable ports of the high-voltage cable model and the low-voltage cable model as the excitation;

[0037] Select the Hexahedra lTLM mode for the grid pattern, divide the grid, and establish an instantaneous simulation task;

[0038] Select the CST transient co-simulation solver and set the Field Monitor;

[0039] Set a Probe at the position where the electromagnetic radiation needs to be measured to obtain the electromagnetic radiation simulation results of the electric drive system space of the electric vehicle.

[0040] Beneficial effects:

[0041] (1) In this modeling and simulation method, a circuit model of the DC / DC system is established to simulate and obtain DC voltage time-domain waveform data; a circuit model of the DC / AC system is established to simulate and obtain AC voltage time-domain waveform data; a 3D electromagnetic model of the drive motor is established, and the AC voltage time-domain waveform is used as an excitation and imported into the 3D electromagnetic model of the drive motor to simulate and obtain the radiation field; a 3D electromagnetic model of the vehicle body is established; in the 3D electromagnetic model of the vehicle body, a layout model of cables and in-vehicle devices is established and the above-mentioned radiation field is imported; the DC voltage time-domain waveform and the AC voltage time-domain waveform are used as excitations and imported into the cable and device layout model, and the spatial electromagnetic radiation of the electric vehicle's electric drive system is obtained through field-circuit co-simulation. In this way, this modeling method comprehensively considers the main electromagnetic interference sources of the electric drive system such as the DC / DC DC power conversion system, the DC / AC inverter system, and the motor, establishes a radiation model of the physical motor, and comprehensively considers the influence of the actual spatial distribution relationship among the structures of the motor, cables, and vehicle body on the distributed parameters of the equivalent circuit model and the spatial radiation field, establishes a complete electromagnetic radiation model of the electric vehicle's electric drive system, and can accurately simulate and obtain the overall radiation characteristics of the electric vehicle, providing simulation design input for subsequent research on the influence of the electromagnetic interference of the electric vehicle's electric drive system on devices such as in-vehicle antennas.

[0042] (2) The circuit model of the DC / DC system is a buck full-bridge conversion circuit simulation model based on PSpice software, which has a small volume and low cost.

[0043] (3) The 3D electromagnetic model of the drive motor is a 3D electromagnetic model that simplifies multiple parallel windings into a single conductor based on the equivalent wire harness method according to the actual drive motor model, avoiding the problem that the actual winding structure of the motor is quite different from the vehicle body scale, and the overly thin winding wires will occupy a large amount of computer resources, resulting in an extremely long simulation time.

[0044] (4) The 3D electromagnetic model of the vehicle body includes a metal vehicle body and glass, which is close to the vehicle body structure of the actual electric vehicle, and configures the simulated radiation field of the drive motor at the motor model in the in-vehicle device model to replace the motor model, constituting an overall simulation environment of the vehicle body, improving the simulation accuracy.

[0045] (5) The cable and device layout model includes: a high-voltage distribution box model, a DC / DC converter model, a DC / AC inverter model, a motor model, a 24V battery model, an in-vehicle device model, a high-voltage cable model, and a low-voltage cable model. The electric vehicle simulation environment composed of these devices corresponds to the actual application environment, further improving the simulation accuracy.

[0046] (6) The electric drive system and the antenna system of the electric vehicle are relatively independent. By simulating the influence of the electric drive system on the vehicle's spatial electromagnetic field, the simulated electromagnetic interference can be used as a spatial radiation source in the future to study its influence on the vehicle-mounted communication system. Description of the Drawings

[0047] Figure 1 It is the flowchart of the method provided by the embodiment of the present invention;

[0048] Figure 2 It is the circuit model diagram of the DC / DC system provided by the embodiment of the present invention;

[0049] Figure 3 is Figure 2 The time-domain voltage simulation result;

[0050] Figure 4 It is the circuit model diagram of the DC / AC system provided by the embodiment of the present invention, where Figure 4 (a) is the circuit model diagram except for the IGBT control module; Figure 4 (b) is the circuit model diagram of the IGBT control module;

[0051] Figure 5 is Figure 4 The circuit time-domain voltage simulation result, where Figure 5 (a) is the time-domain waveform diagram of the U-phase voltage, Figure 5 (b) is the time-domain waveform diagram of the V-phase voltage, Figure 5 (c) is the time-domain waveform diagram of the W-phase voltage;

[0052] Figure 6 It is the 3D model diagram of the driving motor with simplified windings for field-circuit co-simulation provided by the example of the present invention, where Figure 6 (a) is the schematic diagram of the internal structure of the driving motor, Figure 6 (b) is the enlarged model diagram of the driving motor cable winding simplified by the equivalent wire harness method;

[0053] Figure 7 It is the result diagram of the radiation electric field intensity of the probes set in the 3D electromagnetic model of the driving motor for field-circuit co-simulation provided by the example of the present invention;

[0054] Figure 8 It is the 3D electromagnetic model diagram of the vehicle body for field-circuit co-simulation provided by the example of the present invention;

[0055] Figure 9 It is the model diagram of the cable and equipment layout for field-circuit co-simulation provided by the example of the present invention;

[0056] Figure 10 (a) is the overall radiation simulation circuit diagram of the electric vehicle provided by the example of the present invention, Figure 10(b) is the result diagram of the radiation electric field intensity of the probes set in the 3D electromagnetic model of the vehicle body shell.

[0057] Among them, 1 - stator, 2 - cable winding, 3 - rotor, 4 - permanent magnet. Specific implementation manner

[0058] The following takes embodiments in conjunction with the attached drawings to elaborate on the present invention in detail.

[0059] As Figure 1 shown, a method for modeling and simulating the electromagnetic radiation of an electric vehicle's electric drive system includes the following steps:

[0060] Establish a DC / DC system circuit model and simulate to obtain DC voltage time-domain waveform data;

[0061] Establish a DC / AC system circuit model and simulate to obtain AC voltage time-domain waveform data;

[0062] Establish a 3D electromagnetic model of the drive motor, and take the AC voltage time-domain waveform as the excitation, import it into the 3D electromagnetic model of the drive motor, and simulate to obtain the radiation field;

[0063] Establish a 3D electromagnetic model of the vehicle body shell;

[0064] In the 3D electromagnetic model of the vehicle body shell, establish a cable model and an equipment layout model, and import the above-mentioned radiation field;

[0065] Take the DC voltage time-domain waveform and the AC voltage time-domain waveform as the excitation, input them into the cable and equipment layout model, and obtain the spatial electromagnetic radiation of the electric vehicle's electric drive system through field-circuit co-simulation.

[0066] It can be understood that there are no strict step requirements among the above steps, and this embodiment is carried out according to the steps in Figure 1 . This modeling method for the electromagnetic radiation of the electric vehicle's electric drive system comprehensively considers the main electromagnetic interference sources of the electric drive system such as the DC / DC DC power conversion system, the DC / AC inverter system, and the motor, and also comprehensively considers the influence of the actual spatial distribution relationship among the structures such as the drive motor, the cable, and the vehicle body on the distributed parameters of the equivalent circuit model and the spatial radiation field, and can accurately simulate and obtain the overall radiation characteristics of the electric vehicle.

[0067] The radiation frequency band of the electric vehicle's electric drive system is 0 - 30 MHz, while medium and short wave communication is in the 2 - 40 MHz frequency band. The electromagnetic interference generated by the electric drive will affect the in-vehicle communication system. This embodiment simulates the electromagnetic radiation of the electric vehicle's electric drive system, which can provide a basis for subsequent research on the influence of the electromagnetic interference of the electric vehicle's electric drive system on the equipment in the in-vehicle communication system such as the in-vehicle antenna.

[0068] As Figure 2As shown, the above DC / DC system circuit model is a buck full-bridge conversion circuit simulation model based on PSpice software. This circuit simulation model at least includes: a high-voltage power supply, a linear impedance stabilization network (LISN), a full-bridge circuit composed of four high-power switching tubes, a high-frequency transformer, rectifier diodes, an iron-core inductor, capacitors, and a load circuit. The connection relationship of the above DC / DC system circuit model is as follows: The high-voltage power supply is connected in parallel to the power supply end of the LISN circuit. The load end of the LISN circuit is connected in parallel to a capacitor. The capacitor is connected in parallel to the input end of the full-bridge circuit and grounded. The output end of the full-bridge circuit is connected in parallel to the input end of the high-frequency transformer. The output end of the high-frequency transformer is connected in parallel to an LC circuit. The load is connected in parallel across both ends of the capacitor of the LC circuit. More specifically, among them, the value of the high-voltage power supply V1 is 600V; the capacitors C1, C2, C3, C4, C5, C6, C7, C8 are respectively 4uF, 4uF, 2nF, 2nF, 0.22uF, 0.22uF, 41pF, 1nF; the inductors L1, L2, L3, L4, L5, L6 are respectively 10uH, 10uH, 7000uH, 20uH, 20uH, 100uH, and L3, L4, and L5 form a transformer, with L3 as the primary coil and L4, L5 as the secondary coils. The resistors R1, R2, R3, R4, R5, R6, R7 are respectively 5Ω, 5Ω, 1kΩ, 50Ω, 1kΩ, 50Ω, 50Ω; the models of the transistors M1, M2, M3, M4 are all IFZH32N50; the models of the diodes D1, D2, D3, D4, D5, D6 are all DSEP8-12A; the settings of the square-wave sources V2 and V5 are: delay 0s, period 20us, rise time and fall time are both 0.2us, output voltage 0V - 5V; the settings of the square-wave sources V3 and V4 are: delay 10us, period 20us, rise time and fall time are both 0.2us, output voltage 0V - 5V; After connecting the above circuit, set the simulation task, set the simulation time to 200us, set probes between the two switching tubes of each bridge arm, and the rest are default. Run the simulation and export the simulation results in ASCII data file format to obtain the voltage time-domain simulation results as Figure 3 shown.

[0069] As Figure 4As shown, the above-mentioned DC / AC system circuit model is a three-phase three-leg two-level inverter bridge circuit simulation model based on PSpice software, which at least includes: a high-voltage power supply, a linear impedance stabilization network (LISN), a full-bridge circuit composed of six insulated gate bipolar transistors (IGBTs), rectifier diodes, an IGBT control circuit, and a load circuit; the connection relationship of the above-mentioned DC / DC system circuit model is: the high-voltage power supply is connected in parallel to the power supply end of the LISN circuit, the load end of the LISN circuit is connected in parallel to a capacitor, the capacitor is connected in parallel to the three-phase three-leg two-level inverter bridge, the IGBT control end is connected to the IGBT control circuit, and the three-phase output ends of the full-bridge circuit are star-connected to the load and grounded. The above-mentioned IGBT control circuit includes: a PWM wave generation circuit composed of a square-wave source, a sine-wave source and a comparator, and an IGBT drive circuit in two parts.

[0070] The main circuit model of the three-phase three-leg two-level inverter bridge circuit is as Figure 4 (a) shown, where the power supplies V2 and V3 are set to 300V, and the capacitors C1, C2, C3, C4, C5, C6, C7 are 8uF, 8uF, 0.25uF, 0.25uF, 20pF, 12pF, 12pF respectively; the inductors L1, L2, L3, L4, L5 are 20uH, 20uH, 600uH, 600uH, 600uH respectively; the resistors R3, R4, R5, R8, R28, R29 are 1kΩ, 50Ω, 1kΩ, 50Ω, 27mΩ, 27mΩ respectively; and the unlabeled resistors in the figure are all 200Ω; the models of the IGBT tubes Z1, Z2, Z3, Z4, Z5, Z6 are all APT25GF100BN, and the diodes D1, D2, D3, D4, D5, D6 are all ideal diodes.

[0071] Each IGBT in the main circuit is controlled by the IGBT control circuit, and the IGBT control circuit model is as Figure 4 (b) shown, where the parameters of the sine-wave source V27 are: frequency 9kHz, amplitude 5V; the parameters of the square-wave source V28 are: delay 0s, period 11us, rise time and fall time are both 5us, output voltage 0V - 10V; the model of the comparator U20 is UA318, and it is driven by two 15V power supplies; the resistors R49, R48, R10 are all 1kΩ; the model of the drive element is MCT62; the triodes Q7, Q8 and the diode D10 are all ideal devices. After connecting the circuit, set the simulation task, set the simulation time to 1000us, set probes at the three-phase star load, and the rest are default, and run the simulation. Export the simulation results in ASCII data file format to obtain the voltage time-domain simulation results as Figure 5 shown, where Figure 5 (a) is the voltage waveform of phase U, Figure 5 (b) is the voltage waveform of phase V, Figure 5(c) is the W-phase voltage waveform.

[0072] The above-mentioned 3D electromagnetic model of the drive motor is as Figure 6 (a) shows, including: stator 1, cable winding 2, rotor 3, permanent magnet 4 and a housing (not shown). The dimensions refer to a physical motor: the outer diameter of the rotor 3 is about 400 mm, the length is about 1200 mm, the outer diameter of the stator 1 is about 600 mm, and the length is about 900 mm; the length, width and height of the motor housing are about 650 mm, 650 mm and 900 mm respectively. This 3D electromagnetic model of the drive motor is simplified and constructed based on the actual motor model using the CST software. The equivalent wire harness method is used to simplify the multiple parallel windings of the cable winding 2 in the 3D electromagnetic model of the drive motor into a single conductor. More specifically, the cable winding 2 is a thin copper column with a diameter of 1 mm wound around the stator teeth after being simplified based on the equivalent wire harness method, as specifically shown in Figure 6 (b).

[0073] Define discrete ports between the starting cross-section and the ending cross-section of the cable winding 2 of the drive motor. Import the obtained three-phase voltage in ASCII data form into the ExternalPort as the excitation. The solution frequency is set to 0 - 30 MHz. The mesh mode is selected as the Hexahedral TLM mode. Reasonably divide the mesh, establish an instantaneous simulation task, and select the CST transient co-simulation solver. Define an electric field probe above the drive motor, with the position (0, 1000, 0), and define Field Monitors, with the type of field-source, and the range is 0 - 30 MHz. Run the motor radiation simulation task to obtain the field monitor output as an FSM format field source file. The electric field intensity at the probe is as Figure 7 shown.

[0074] The 3D electromagnetic model of the drive motor is a 3D electromagnetic model that simplifies multiple parallel cable windings into a single conductor based on the equivalent wire harness method. It separately models and simulates the radiation of the drive motor, extracts the radiation field as the field source and imports it into the vehicle body, and jointly simulates with structures such as cables and the vehicle shell, avoiding the problems that the actual cable winding structure of the motor and the vehicle body scale differ greatly, and the overly thin winding wires will occupy a large amount of computer resources, resulting in an extremely long simulation time.

[0075] As Figure 8 shown, the above-mentioned 3D electromagnetic model of the vehicle shell is simplified and established based on the actual electric vehicle body model using the CST software, including: the metal vehicle shell, glass and tires, which is close to the actual electric vehicle body structure, constituting an overall simulation environment for the vehicle body and improving the simulation accuracy.

[0076] As Figure 9As shown, the above cable and equipment layout model is a 3D electromagnetic model simplified based on CST Cable Studio according to the actual cable and equipment layout in an electric vehicle. The cable and equipment layout model includes: a high-voltage distribution box model, a DC / AC inverter model, a DC / DC converter model, a drive motor model, a 24V battery model, an in-vehicle equipment model (the in-vehicle equipment refers to in-vehicle equipment such as a sensor distribution box. In this embodiment, the in-vehicle equipment does not include an antenna), a high-voltage cable model, and a low-voltage cable model. Among them, the DC / DC converter model is a cube-shaped housing with a FR4 dielectric board placed inside. Wires are laid on the dielectric board, and a DC voltage time-domain waveform excitation is added to the wires to equivalently represent the electromagnetic interference generated by the switching tube jump of the DC / DC converter.

[0077] The obtained radiation field source above is an FSM format file. In Field Sources, in the Import file option, import the FSM format file as the excitation field source to replace the drive motor model in the cable and equipment layout model. Use the above-obtained time-domain voltage waveform as the excitation and input it into the high-voltage cable model and the low-voltage cable model in the above cable and equipment layout model. Through field-circuit co-simulation, the spatial radiation result is obtained. Figure 10 (a) shows the overall radiation simulation circuit diagram of the electric vehicle.

[0078] Specifically, the above field-circuit co-simulation is based on the CST software Cable Studio, and an instantaneous simulation task is established by combining the above vehicle body 3D electromagnetic model, cable and equipment layout model, and radiation field. According to the actual situation, in the Cable Studio circuit-side model, import the DC voltage time-domain waveform and AC voltage time-domain waveform in ASCII data form into the cable ports of the high-voltage cable model and the low-voltage cable model as the excitation. Select the Hexahedra lTLM mode for the grid mode, reasonably divide the grid, establish an instantaneous simulation task, select the CST transient co-simulation for the solver, and set the Field Monitor. Set a probe Probe at the position of the point to be observed to obtain the electromagnetic radiation simulation of the electric drive system space of the electric vehicle. In this embodiment, the electromagnetic radiation simulation result is as shown in Figure 10 (b).

[0079] In summary, the above is only a preferred embodiment of the present invention and is not used to limit the protection scope of the present invention. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A method for modeling and simulating electromagnetic radiation of an electric drive system for an electric vehicle, characterized in that, Including the following steps: Establish a DC / DC system circuit model and simulate to obtain DC voltage time-domain waveform data; Establish a DC / AC system circuit model and simulate to obtain AC voltage time-domain waveform data; Establish a 3D electromagnetic model of the drive motor, import the AC voltage time-domain waveform as an excitation into the 3D electromagnetic model of the drive motor, and simulate to obtain the radiation field; Establish a 3D electromagnetic model of the vehicle body shell; In the 3D electromagnetic model of the vehicle body shell, establish a cable and equipment layout model and import the radiation field; Use the DC voltage time-domain waveform and the AC voltage time-domain waveform as excitations, input them into the cable and equipment layout model, and obtain the spatial electromagnetic radiation of the electric vehicle's electric drive system through field-circuit co-simulation; The DC / DC system circuit model is a buck full-bridge conversion circuit simulation model based on PSpice software; The buck full-bridge conversion circuit simulation model includes: a high-voltage power supply, a linear impedance stabilization network, a full-bridge circuit composed of four high-power switching tubes, a high-frequency transformer, a rectifier diode, an iron-core inductor, a capacitor, and a load circuit; The high-voltage power supply is connected in parallel to the power supply end of the linear impedance stabilization network, the load end of the linear impedance stabilization network is connected in parallel to the capacitor, and the capacitor is connected in parallel to the input end of the full-bridge circuit composed of four high-power switching tubes and grounded. The output end of the full-bridge circuit is connected in parallel to the input end of the high-frequency transformer. The output end of the high-frequency transformer is connected in parallel to an LC circuit, and the load circuit is connected in parallel across the capacitor in the LC circuit; The 3D electromagnetic model of the drive motor is based on CST software and is simplified and constructed according to the actual motor model; The simplified 3D electromagnetic model of the drive motor includes: a stator, a rotor, a cable winding, and a machine shell; The steps for simulating to obtain the radiation field include the following steps: Define discrete ports between the starting cross-section and the ending cross-section of the cable winding, and import the AC voltage time-domain waveform into the External Port in ASCII data format; Select the Hexahedral TLM mode for grid division in the grid mode; Establish an instantaneous simulation task, select the CST transient co-simulation solver, and set the FieldMonitor, and select the Field source field monitor; Generate an FSM format file after the simulation ends.

2. The electromagnetic radiation modeling and simulation method for an electric vehicle electric drive system according to claim 1, characterized in that, The DC / AC system circuit model is a three-phase three-leg two-level inverter bridge circuit simulation model based on PSpice software.

3. The electromagnetic radiation modeling and simulation method for an electric vehicle electric drive system according to claim 2, wherein The three-phase three-leg two-level inverter bridge circuit simulation model includes a high-voltage power supply, a linear impedance stabilization network, a full-bridge circuit composed of six IGBTs, a rectifier diode, an IGBT control circuit, and a load circuit; The high-voltage power supply is connected in parallel to the power supply end of the linear impedance stabilization network, the load end of the linear impedance stabilization network is connected in parallel to a capacitor, the capacitor is connected in parallel to the three-phase three-leg two-level inverter bridge, the IGBT control terminal is connected to the IGBT control circuit, and the three-phase output ends of the full-bridge circuit are star-connected to the load circuit and grounded.

4. The electromagnetic radiation modeling and simulation method for an electric vehicle electric drive system according to claim 3, characterized in that The IGBT control circuit includes a PWM wave generation circuit composed of a square wave source, a sine wave source, and a comparator, and an IGBT drive circuit.

5. The electromagnetic radiation modeling and simulation method for the electric drive system of an electric vehicle according to claim 1, characterized in that The cable winding is simplified by the equivalent wire harness method.

6. A method for electromagnetic radiation modeling and simulation of an electric drive system of an electric vehicle according to any one of claims 1 to 5, characterized in that, The 3D electromagnetic model of the vehicle body is simplified and established according to the actual vehicle body model, including a metal vehicle body and glass; The cable and equipment layout model includes: a high-voltage distribution box model, a DC / AC inverter model, a DC / DC converter model, a drive motor model, a 24V battery model, an in-vehicle equipment model, a high-voltage cable model, and a low-voltage cable model; The steps of importing the radiation field into the 3D electromagnetic model of the vehicle body include: In Field Sources, in the Import file option, import the FSM format file as the excitation field source and configure it at the position of the drive motor model to replace the drive motor model.

7. A method for modeling and simulating electromagnetic radiation of an electric drive system of an electric vehicle according to claim 6, characterized in that, The field-line co-simulation includes the following steps: Based on the CST software Cable Studio, combine the 3D electromagnetic model of the vehicle body, the cable and equipment layout model, and the radiation field to establish an instantaneous simulation task; In the Cable Studio circuit-side model, import the DC voltage time-domain waveform and the AC voltage time-domain waveform in ASCII data form into the cable ports of the high-voltage cable model and the low-voltage cable model as excitation; Select the Hexahedral TLM mode for the mesh mode, divide the mesh, and establish an instantaneous simulation task; Select the CST transient co-simulation for the solver and set the Field Monitor; Set a Probe at the position where the electromagnetic radiation needs to be measured to obtain the electromagnetic radiation simulation results of the electric drive system space of the electric vehicle.

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