Analysis Method, System and Computer Equipment for Electrothermal Performance of Intelligent Power Unit

Abstract

An embodiment of the present invention discloses a method, a system, and a computer device for analyzing the electrothermal performance of an intelligent power unit. The method for analyzing the electrothermal performance of the intelligent power unit includes: establishing a DC busbar model, a DC busbar capacitor model, a driving unit model, and a power module model, and obtaining the layout of the intelligent power unit inside the inverter; building an electrothermal performance simulation model of the intelligent power unit based on the DC busbar model, the DC busbar capacitor model, the driving unit model, the power module model, and the layout, where the electrothermal performance simulation model includes an electrical performance simulation model and a thermal performance simulation model; by simulating the electrothermal performance simulation model, outputting the target design parameters of the intelligent power unit and its connection and cooling paths. The technical solution of the embodiment of the present invention can fully consider the electrical connection and physical connection relationships between the various components of the intelligent power unit, and obtain the electrothermal characteristics of the intelligent power unit closer to the actual application.

Description

Technical Field

[0001] The embodiments of the present invention relate to the technical field of electrothermal performance analysis of intelligent power units, and in particular, to a method, a system, and a computer device for analyzing the electrothermal performance of intelligent power units. Background Art

[0002] With the increasing improvement of people's living standards and the rapid development of the automotive industry, people have put forward higher requirements for the replacement speed of vehicles. As a core component of the power assembly of new energy vehicles, intelligent power units are facing higher and higher challenges.

[0003] Usually, at the initial stage of the design of intelligent power units, higher requirements are put forward based on the volume, interfaces, withstand voltage, withstand current, heat dissipation design of intelligent power units, and the long-cycle and high-cost design cycle of traditional design, trial production, testing, and optimization design, so as to achieve the requirements of integration, miniaturization, high performance, high power, and short cycle of intelligent power units, and accurately calculate and analyze the electrothermal characteristics of intelligent power units, so as to ensure the achievement of system performance and shorten the verification cycle.

[0004] Existing technologies mostly use the method of estimating the losses and heat generation of intelligent power units based on system power and efficiency as the input for heat dissipation design. However, if the estimated losses and heat generation of intelligent power units are too high, it will lead to a large design margin of the system and high system cost. Summary of the Invention

[0005] The embodiments of the present invention provide a method, a system, and a computer device for analyzing the electrothermal performance of intelligent power units, so as to fully consider the electrical connection and physical connection relationships between various components of the intelligent power unit and obtain the electrothermal characteristics of the intelligent power unit closer to actual applications.

[0006] In a first aspect, the embodiments of the present invention provide a method for analyzing the electrothermal performance of an intelligent power unit. The method for analyzing the electrothermal performance of the intelligent power unit includes:

[0007] Establish a DC busbar model, a DC busbar capacitor model, a drive unit model, and a power module model, and obtain the layout of the intelligent power unit inside the inverter;

[0008] Based on the DC busbar model, the DC busbar capacitor model, the drive unit model, the power module model, and the layout, build an electrothermal performance simulation model of the intelligent power unit. The electrothermal performance simulation model includes an electrical performance simulation model and a thermal performance simulation model;

[0009] By simulating the electrothermal performance simulation model, output the target design parameters of the intelligent power unit and its connection and cooling paths.

[0010] Further, establish a calculation model for the heat generation of the busbar and a calculation model for the heat dissipation of the busbar, and build a DC busbar model according to the heat generation calculation model of the busbar and the heat dissipation calculation model of the busbar;

[0011] Establish a calculation model for the heat generation of the busbar capacitor and a calculation model for the heat dissipation of the busbar capacitor, and build a DC busbar capacitor model according to the heat generation calculation model of the busbar capacitor and the heat dissipation calculation model of the busbar capacitor;

[0012] Build a drive unit model based on the loss data of the drive board and the target network order;

[0013] Establish a transient thermal resistance dynamic distribution model and a power thermal network model, and build a power module model according to the transient thermal resistance dynamic distribution model and the power thermal network model.

[0014] Further, build an electrothermal performance simulation model of the intelligent power unit based on the DC busbar model, the DC busbar capacitor model, the drive unit model, the power module model, and the layout method, including:

[0015] Determine the electrical performance connection relationships of the components corresponding to the electrical performance simulation model according to the layout method;

[0016] Build the electrical performance simulation model based on the electrical performance connection relationships, where the electrical performance connection relationships include the connection between the DC busbar model and the DC busbar capacitor model, the connection between the DC busbar capacitor model and the power module model, and the connection between the power module model and the drive unit model.

[0017] Further, before building the electrothermal performance simulation model of the intelligent power unit based on the DC busbar model, the DC busbar capacitor model, the drive unit model, the power module model, and the layout method, it further includes:

[0018] Establish a connector model and a cooler thermal performance model;

[0019] Build the electrothermal performance simulation model of the intelligent power unit based on the DC busbar model, the DC busbar capacitor model, the drive unit model, the power module model, and the layout method, including:

[0020] Determine the thermal performance connection relationships of the components corresponding to the thermal performance simulation model according to the layout method;

[0021] Build the thermal performance simulation model based on the thermal performance connection relationship. The thermal performance connection relationship includes that the DC busbar model is connected to the DC busbar capacitor model through the connector model, the DC busbar capacitor model is connected to the power module model through the connector model, the power module model is connected to the drive unit model, and the cooler thermal performance model is respectively connected to the DC busbar model, the DC busbar capacitor model, and the power module model.

[0022] Further, by simulating the electro-thermal performance simulation model, output the target design parameters of the intelligent power unit and its connection and cooling paths, including:

[0023] Taking the reduction of electro-thermal stress of the power module and the DC bus capacitor as the goal, simulate the electro-thermal performance simulation model based on the drive resistance, line stray inductance, thermal resistance on the heat transfer path, and the allowable voltage and current stress corresponding to the intelligent power unit.

[0024] Output the target design parameters of the intelligent power unit and its connection and cooling paths according to the simulation results obtained from the electro-thermal performance simulation model.

[0025] Further, the electro-thermal performance analysis method of the intelligent power unit further includes:

[0026] Obtain the component loss parameters of the intelligent power unit. The component loss parameters include the DC busbar model loss parameters, the DC busbar capacitor model loss parameters, the drive unit model loss parameters, and the power module model loss parameters.

[0027] Further, the electro-thermal performance analysis method of the intelligent power unit further includes:

[0028] Build an air heat transfer network model according to the air thermal conductivity and the air volume in the inverter cavity.

[0029] Build an inverter housing thermal network model according to the material, size and shape of the inverter housing.

[0030] Build the power module thermal performance model considering the coolant flow rate through the relationship curve between the coolant flow rate and the steady-state thermal resistance of the power module model and the order of the junction-to-case thermal resistance of the power module by using the state machine tool.

[0031] In a second aspect, an embodiment of the present invention further provides an electro-thermal performance analysis system for an intelligent power unit. The electro-thermal performance analysis system for the intelligent power unit includes:

[0032] A model building module, configured to build a DC busbar model, a DC busbar capacitor model, a drive unit model, and a power module model, and obtain the layout of the intelligent power unit inside the inverter.

[0033] A model building module, configured to build an electrothermal performance simulation model of the intelligent power unit based on the DC busbar model, the DC busbar capacitor model, the drive unit model, the power module model, and the layout manner, where the electrothermal performance simulation model includes an electrical performance simulation model and a thermal performance simulation model;

[0034] A result output module, configured to output target design parameters of the intelligent power unit and its connection and cooling paths by simulating the electrothermal performance simulation model.

[0035] In a third aspect, an embodiment of the present invention further provides a computer device, which includes:

[0036] One or more processors;

[0037] A storage device, configured to store multiple programs,

[0038] When at least one of the multiple programs is executed by the one or more processors, the one or more processors are caused to implement the electrothermal performance analysis method of the intelligent power unit provided in the first aspect embodiment of the present invention.

[0039] In a fourth aspect, an embodiment of the present invention further provides a computer-readable storage medium, on which a computer program is stored, and when the program is executed by a processor, the electrothermal performance analysis method of the intelligent power unit provided in the first aspect embodiment of the present invention is implemented.

[0040] The technical solution of the embodiment of the present invention is to establish a DC busbar model, a DC busbar capacitor model, a drive unit model, and a power module model, and obtain the layout manner of the intelligent power unit inside the inverter; build an electrothermal performance simulation model of the intelligent power unit based on the DC busbar model, the DC busbar capacitor model, the drive unit model, the power module model, and the layout manner, where the electrothermal performance simulation model includes an electrical performance simulation model and a thermal performance simulation model; output target design parameters of the intelligent power unit and its connection and cooling paths by simulating the electrothermal performance simulation model. This solves the problem in the prior art that the estimated loss and heat generation of the intelligent power unit are too high, resulting in a large system design margin and high system cost, so as to fully consider the electrical connection and physical connection relationships between the components of the intelligent power unit and obtain electrothermal characteristics of the intelligent power unit closer to actual applications. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] Figure 1 is a flowchart of an electrothermal performance analysis method of an intelligent power unit provided in Embodiment 1 of the present invention;

[0042] Figure 2It is a schematic structural diagram of the DC busbar model provided by an embodiment of the present invention;

[0043] Figure 3 It is a schematic structural diagram of the DC bus capacitor model provided by an embodiment of the present invention;

[0044] Figure 4 It is a schematic structural diagram of the drive unit model provided by an embodiment of the present invention;

[0045] Figure 5 It is a schematic structural diagram of the power module model provided by an embodiment of the present invention;

[0046] Figure 6 It is a schematic layout diagram of the intelligent power unit inside the inverter provided by an embodiment of the present invention;

[0047] Figure 7 It is a schematic structural diagram of the electrical performance simulation model provided by an embodiment of the present invention;

[0048] Figure 8 It is a schematic structural diagram of the connector model provided by an embodiment of the present invention;

[0049] Figure 9 It is a schematic structural diagram of the thermal performance simulation model provided by an embodiment of the present invention;

[0050] Figure 10 It is a structural diagram of an electrothermal performance analysis system of an intelligent power unit provided by Embodiment 2 of the present invention;

[0051] Figure 11 It is a schematic hardware structure diagram of a computer device provided by Embodiment 3 of the present invention. Detailed implementation manners

[0052] In order to make the objectives, technical solutions, and advantages of the present invention clearer, the following further describes the specific embodiments of the present invention in detail with reference to the accompanying drawings. It can be understood that the specific embodiments described herein are only used to explain the present invention, rather than limiting the present invention.

[0053] In addition, it should be noted that for the sake of convenience of description, only parts related to the present invention are shown in the drawings rather than all the content. Before discussing the exemplary embodiments in more detail, it should be mentioned that some exemplary embodiments are described as processes or methods depicted as flowcharts. Although the flowcharts describe the operations (or steps) as sequential processes, many of the operations can be implemented in parallel, concurrently, or simultaneously. In addition, the order of the operations can be rearranged. When the operations are completed, the process can be terminated, but there can also be additional steps not included in the drawings. The process can correspond to a method, function, procedure, subroutine, subprogram, etc.

[0054] Embodiment 1

[0055] Figure 1 The figure is a flowchart of a method for analyzing the electrothermal performance of an intelligent power unit provided in Embodiment 1 of the present invention. This embodiment is applicable to fully considering the electrical connection and physical connection relationships between the various components that make up the intelligent power unit, as well as the layout and external environment of each component in an electric vehicle on-board inverter, so that the analyzed electrothermal characteristics of the intelligent power unit are closer to the actual application situation. This method can be executed by an electrothermal performance analysis system of the intelligent power unit, and this device can be implemented in the form of software and / or hardware. The method for analyzing the electrothermal performance of the intelligent power unit specifically includes the following steps:

[0056] S110. Establish a DC busbar model, a DC busbar capacitor model, a drive unit model, and a power module model, and obtain the layout mode of the intelligent power unit inside the inverter.

[0057] Among them, the main components of the intelligent power unit include a DC busbar, a DC bus capacitor, a drive unit, and a power module, etc. In this embodiment, for the electrothermal performance modeling and simulation analysis of the intelligent power unit, the main components of the intelligent power unit are respectively modeled, including establishing a DC busbar model, a DC busbar capacitor model, a drive unit model, and a power module model, etc.

[0058] The layout mode of the intelligent power unit inside the inverter refers to fully considering the electrical connection and physical connection relationships between the various components that make up the intelligent power unit, as well as the layout and external environment of each component in an electric vehicle on-board inverter.

[0059] The layout mode of the intelligent power unit inside the inverter can adopt the connection relationships and installation environments of the components in the existing inverter system and other layout modes. This embodiment is only for illustrative purposes and does not impose any restrictions on it. Exemplarily, the power module corresponding to the power module model can be arranged horizontally or vertically in the inverter.

[0060] Further, establishing a DC busbar model, a DC busbar capacitor model, a drive unit model, and a power module model includes: establishing a busbar heat generation calculation model and a busbar heat dissipation calculation model, and building a DC busbar model according to the busbar heat generation calculation model and the busbar heat dissipation calculation model; establishing a busbar capacitor heat generation calculation model and a busbar capacitor heat dissipation calculation model, and building a DC busbar capacitor model according to the busbar capacitor heat generation calculation model and the busbar capacitor heat dissipation calculation model; building a drive unit model according to the loss data of the drive board and the target network order; establishing a transient thermal resistance dynamic distribution model and a power thermal network model, and building a power module model according to the transient thermal resistance dynamic distribution model and the power thermal network model.

[0061] Specifically, after actually completing the 3D design and material selection of the DC busbar, the busbar parameters are extracted through Ansys Q3D software, and a DC busbar equivalent circuit model including parameters such as the equivalent resistance, capacitance, self-inductance, and mutual inductance between a single busbar and the positive and negative busbars is generated. Then, according to the heat dissipation material characteristics and external dimensions of the DC busbar, the equivalent thermal resistance of the DC busbar is calculated by the formula R th = d / kA, and then a DC busbar thermal network model is built, that is, the DC busbar model in this embodiment.

[0062] The heat generation of the DC busbar (i.e., copper busbar) is mainly determined by its own resistance and the current flowing through it, while the heat dissipation of the busbar is determined by the material of its heat dissipation source. Figure 2 is a schematic structural diagram of the DC busbar model provided by an embodiment of the present invention. Refer to Figure 2 , the DC busbar model includes a busbar heat generation calculation model 210 and a busbar heat dissipation calculation model 220. Among them, the 3 resistors R in the busbar heat generation calculation model 210 are power resistors. By applying current to them (i.e., the current flowing through the busbar extracted from each look-up table part is the electrical performance simulation model), the power loss of the busbar heat generation calculation model 210 can be output, and this power loss is used as the input in the heat dissipation model. Optionally, if the busbar in the system is in a 3-segment form, the entire DC busbar model is divided into 3 segments. The c_constant in the busbar heat dissipation calculation model 220 are all constant coefficients, which are used to calculate the thermal resistance of the DC busbar, that is, the equivalent thermal resistance of the DC busbar is calculated by the formula R th = d / kA. On this basis, in Figure 2 the DC busbar model in, in addition to the busbar heat generation calculation model 210 and the busbar heat dissipation calculation model 220, it also includes a thermal resistance-capacitance network model, which is used to simulate the heat dissipation of the DC busbar.

[0063] On the basis of the above embodiment, according to the 3D digital model of the DC bus capacitor, parameters such as the capacitance, equivalent series resistance ESR, equivalent inductance ESL, and insulation resistance of the DC bus capacitor are extracted through Ansys Q3D software, and the thermal resistance from the center of the DC bus capacitor core to the shell is simulated, and then a DC bus capacitor thermal network model is built, that is, the DC busbar capacitor model in this embodiment.

[0064] Figure 3 is a schematic structural diagram of the DC bus capacitor model provided by an embodiment of the present invention. Refer to Figure 3, the DC bus capacitor model includes a bus capacitor heat generation calculation model 310 and a bus capacitor heat dissipation calculation model. Among them, the heat generation of the bus capacitor heat generation calculation model 310 is mainly generated by two parts: one is generated by the ripple current of the capacitor and its own equivalent series resistance (that is, the lower look-up table part is the ripple current flowing through the capacitor extracted from the electrical performance simulation model, the resistor is a power resistor, and its output is the power loss of the bus capacitor heat generation calculation model 310); the other is generated by the voltage ripple across the capacitor and its equivalent parallel resistance (that is, the upper look-up table part is the ripple voltage across the capacitor extracted from the electrical performance simulation model, the resistor is a power resistor, and its output is the power loss of the bus capacitor heat generation calculation model 310). Figure 3 The part other than the bus capacitor heat generation calculation model 310 is the bus capacitor heat dissipation calculation model, that is, the thermal resistance-capacitance network, which is used to simulate the heat dissipation of the capacitor.

[0065] On the basis of the above embodiments, according to the functional requirements of the intelligent power unit for the drive unit, use the StateAMS tool of Saber software to build an electrical performance model of the drive unit based on state conversion, that is, the drive unit model in this embodiment. The drive unit model contains information such as drive resistance, stray parameters of the drive unit circuit, drive voltage, power module, and external circuit protection logic. At the same time, according to the drive unit circuit principle and the heat dissipation path of the main heating element / chip, use the finite element simulation software to extract the drive unit thermal network model. Specifically, Figure 4 is the structural schematic diagram of the drive unit model provided by the embodiment of the present invention. See Figure 4 , calculate and extract according to the loss data of the drive board through SIwave software, and generate a thermal network model of the target network order through Icepak software, and then build a drive unit model.

[0066] Based on the data sheet data of the power module, use the power electronic device modeling tool of Saber software to depict the input-output characteristics and internal parameter characteristics of the power module, and perform characteristic fitting to build an equivalent circuit electrical characteristic model of the power module. At the same time, reverse the internal structure level of the power module, and according to the system application requirements, build a multi-level thermal network model of the power module with an editable thermal network level, and then obtain the power module model in this embodiment.

[0067] Figure 5 is the structural schematic diagram of the power module model provided by the embodiment of the present invention. See Figure 5 , the power module model includes a relationship model 510 between thermal resistance and coolant flow rate, a transient thermal resistance dynamic distribution model 520, and a power thermal network model. Figure 5The part other than the thermal resistance and coolant flow relationship model 510 and the transient thermal resistance dynamic distribution model 520 in it is the power thermal network model. The specific working principle of the power module model is that after the coolant flow and temperature are input externally, the junction temperature of the power module can be calculated and fed back to the electrical performance simulation model.

[0068] Optionally, the power module model includes, but is not limited to, insulated gate bipolar transistor IGBT, metal-oxide-semiconductor field-effect transistor MOSFET, integrated gate-commutated thyristor IGCT, freewheeling diode DIODE, etc.

[0069] It should be noted that the heat dissipation method of the power module is not limited to liquid cooling, and can also be forced air cooling or natural cooling, etc. This embodiment does not make any restrictions on this.

[0070] In this embodiment, for the DC busbar model, DC busbar capacitor model, drive unit model, and power module model, each component model aims at the dynamic characteristic parameters of the intelligent power unit and the results of the double-pulse test, and by analyzing the key parameters and parameter sensitivities that affect the accuracy of the intelligent power unit, the parameters of each component model are iteratively optimized to obtain high-precision component models.

[0071] S120. Build the electrothermal performance simulation model of the intelligent power unit based on the DC busbar model, the DC busbar capacitor model, the drive unit model, the power module model, and the layout method. The electrothermal performance simulation model includes an electrical performance simulation model and a thermal performance simulation model.

[0072] The intelligent power unit is the heat source of the system. Figure 6 This is the layout schematic diagram of the intelligent power unit provided by the embodiment of the present invention inside the inverter. Refer to Figure 6 , the heat dissipation paths of the main components of the intelligent power unit inside the inverter are as follows: The main heat dissipation path of the power module is forced liquid cooling at the bottom of the module; the main heat dissipation path of the DC busbar capacitor is heat dissipation by attaching to the inverter housing and heat conduction through the connector to the power module; the main heat dissipation path of the DC busbar is heat conduction through the connector to the DC busbar capacitor; the main heat dissipation path of the drive unit is heat conduction through connection with the power module. At the same time, the main components of the above intelligent power unit all conduct heat through the air inside the inverter and dissipate heat through the inverter box.

[0073] In this embodiment, through the layout of the main components of the intelligent power unit in the inverter and the connection relationship between the main components, the electrothermal performance simulation model of the intelligent power unit is built, that is, the electrical performance simulation model and the thermal performance simulation model are obtained.

[0074] Further, an electrothermal performance simulation model of the intelligent power unit is built based on the DC busbar model, the DC busbar capacitor model, the drive unit model, the power module model, and the layout method, including: determining the electrical performance connection relationships of the components corresponding to the electrical performance simulation model according to the layout method; building the electrical performance simulation model based on the electrical performance connection relationships, where the electrical performance connection relationships include the connection between the DC busbar model and the DC busbar capacitor model, the connection between the DC busbar capacitor model and the power module model, and the connection between the power module model and the drive unit model.

[0075] Figure 7 FIG. is a schematic structural diagram of the electrical performance simulation model provided by an embodiment of the present invention. Refer to Figure 7 , the electrical performance simulation model is respectively connected to the input end of the control algorithm and the motor. The control algorithm is used to input simulation analysis parameters into the electrical performance simulation model. The motor can be a permanent magnet synchronous motor (PMSM) or other motors, and this embodiment does not limit this. It can be understood that the electrical performance simulation model is also connected to a power supply, and the power supply is used to supply power to the electrical performance simulation model.

[0076] Further, before building the electrothermal performance simulation model of the intelligent power unit based on the DC busbar model, the DC busbar capacitor model, the drive unit model, the power module model, and the layout method, it further includes:

[0077] Building a connector model and a cooler thermal performance model;

[0078] Building the electrothermal performance simulation model of the intelligent power unit based on the DC busbar model, the DC busbar capacitor model, the drive unit model, the power module model, and the layout method, including:

[0079] Determining the thermal performance connection relationships of the components corresponding to the thermal performance simulation model according to the layout method;

[0080] Building the thermal performance simulation model based on the thermal performance connection relationships, where the thermal performance connection relationships include the connection between the DC busbar model and the DC busbar capacitor model through the connector model, the connection between the DC busbar capacitor model and the power module model through the connector model, the connection between the power module model and the drive unit model, and the cooler thermal performance model is respectively connected to the DC busbar model, the DC busbar capacitor model, and the power module model.

[0081] Among them, the connector and the cooler are the main media for heat transfer between the various components of the intelligent power unit. In this embodiment, a thermal network model of the connector and the cooler is built according to the forms and materials of the connector and the cooler, that is, a connector model and a thermal performance model of the cooler are established.

[0082] Figure 8 It is a schematic structural diagram of the connector model provided by the embodiment of the present invention. Figure 8 It is a schematic entity structure diagram of the connector model. Taking bolt connection as an example, a heat transfer network model based on the bolt material and size is built, that is, the connector model is obtained.

[0083] Figure 9 It is a schematic structural diagram of the thermal performance simulation model provided by the embodiment of the present invention. Refer to Figure 9 The connector model is used to connect the DC bus bar model and the DC bus bar capacitor model, and to connect the DC bus bar capacitor model and the power module model.

[0084] It can be understood that the thermal performance simulation model is respectively connected to the input end of the control algorithm and the motor. The control algorithm is used to input simulation analysis parameters into the thermal performance simulation model. The motor can be a permanent magnet synchronous motor PMSM or other motors, and this embodiment does not limit this. It can be understood that the thermal performance simulation model is also connected to the power supply, and the power supply is used to supply power to the thermal performance simulation model.

[0085] S130. By simulating the electro-thermal performance simulation model, output the target design parameters of the intelligent power unit and its connection and cooling paths.

[0086] On the basis of the above embodiment, by simulating the electro-thermal performance simulation model, output the target design parameters of the intelligent power unit and its connection and cooling paths, including: aiming at the reduction of the electro-thermal stress of the power module and the DC bus capacitor, simulating the electro-thermal performance simulation model based on the drive resistance, the line stray inductance, the thermal resistance on the heat transfer path, and the allowable voltage and current stress corresponding to the intelligent power unit; outputting the target design parameters of the intelligent power unit and its connection and cooling paths according to the simulation results obtained from the electro-thermal performance simulation model.

[0087] Specifically, aiming at reducing the electrothermal stress of the power module and the DC bus capacitor, the drive resistance is scanned and simulated with a fixed step of 0.5 Ω to obtain the optimal switching speed of the power unit, so that the voltage stress and its high-frequency radiation energy of the power module are within an acceptable range. At the same time, the loss of the power module is also within an acceptable range, and the electrothermal performance of the power module reaches a balance, thereby selecting the optimal switching resistance value; the stray inductance of the circuit is scanned and simulated with a fixed step of 1 nH, and when the voltage stress at both ends of the power module is relatively small, the stray inductance value that can be achieved by the structural design is selected as the design target value of the equivalent series inductance of the DC bus bar and the DC bus capacitor. Thus, when designing the DC bus bar and the DC bus capacitor, the influence of the external circuit on the voltage stress of the power module can be reduced. It can be understood that the stray inductance of the circuit not only includes the equivalent series inductance of the DC bus bar and the DC bus capacitor, but also includes the stray inductance of the drive unit, the lead inductance of the power module, etc.; the thermal resistance on the heat transfer path is scanned and simulated with a fixed step of 0.1 Ω, and considering the structural and cost feasibility, the optimal heat dissipation path is designed and the most suitable heat dissipation material is selected. On the other hand, through simulation, the highest phase voltage and phase current that the intelligent power unit can output are obtained within the maximum voltage and current stress ranges allowed for each component of the intelligent power unit and within the switching frequency range allowed by the control algorithm. The technical solution of this embodiment finally guides the electrothermal performance analysis and design of the intelligent power unit through the method of modeling and simulation, and the order of the thermal network model of each component of the power module can be adjusted according to the actual application and computing resources.

[0088] Based on the above embodiments, the component loss parameters of the intelligent power unit are obtained, and the component loss parameters include the DC bus bar model loss parameter, the DC bus capacitor model loss parameter, the drive unit model loss parameter, and the power module model loss parameter.

[0089] Specifically, in the process of analyzing the electrothermal characteristics of the intelligent power unit, in addition to the above models, it also includes an electrothermal performance test program compiled according to the electrothermal performance test conditions of the intelligent power unit, that is, the above control algorithm, which is used for extracting the component loss parameters of the intelligent power unit.

[0090] The power module model loss parameter is equal to the sum of the insulated gate bipolar transistor IGBT loss and the freewheeling diode DIODE loss, and the insulated gate bipolar transistor IGBT and the freewheeling diode DIODE losses are respectively composed of the conduction loss generated by the saturation voltage drop during conduction and the sum of the switching losses during switching. That is:

[0091] P module =P igbt +P diode

[0092] P igbt =Pcond_igbt +P sw_igbt

[0093] P cond_igbt = d * Vcesat * Ic

[0094] P sw_igbt = f sw (E on + E off )

[0095] P diode = P cond_diode + P sw_diode

[0096] P cond_diode = (1 - d)V f I f

[0097] P sw_diode = f sw E rec

[0098] Among them, P module is the loss parameter of the power module model; P igbt is the loss of the insulated gate bipolar transistor IGBT; P diode is the loss of the freewheeling diode DIODE;

[0099] The loss parameter of the DC bus bar model is mainly determined by the effective value of the current flowing through the bus bar and the equivalent impedance of the bus bar. Among them, the effective value of the current is obtained through the electrical performance test program of the intelligent power unit, and the equivalent impedance is extracted through Ansys Q3D software. The loss parameter of the DC bus bar model is calculated by the following formula:

[0100] P DC_bus = i rms 2 r equ

[0101] Among them, is the loss parameter of the DC bus bar model; i rms is the effective value of the current; r equ is the equivalent impedance.

[0102] The loss parameter of the DC bus bar capacitor model is mainly composed of two parts. One part is generated by the effective value of the ripple current flowing through the capacitor and the equivalent series resistance ESR of the capacitor, and the other part is generated by the terminal voltage of the DC bus bar capacitor and the insulation resistance of the capacitor. Among them, the effective value of the capacitor ripple current and the terminal voltage of the capacitor are obtained through the electrical performance test program of the intelligent power unit, and the equivalent series resistance and the insulation resistance are obtained through the capacitor body simulation. Specifically, the loss parameter of the DC bus bar capacitor model is calculated by the following formula:

[0103] P capacitor = i rms 2 esr + U DC 2 / R iso

[0104] Among them, P capacitor is the loss parameter of the DC bus capacitor model; i fms is the effective value of the capacitor ripple current; esr is the equivalent series resistance of the capacitor; U DC is the capacitor terminal voltage; R iso is the insulation resistance.

[0105] Based on the above embodiments, the method for analyzing the electrothermal performance of the intelligent power unit further includes: building an air heat transfer network model according to the air thermal conductivity and the air volume in the inverter cavity; building an inverter housing thermal network model according to the material, size and shape of the inverter housing; building a power module thermal performance model considering the coolant flow rate through the relationship curve between the coolant flow rate and the steady-state thermal resistance of the power module model and the state machine tool and the order of the junction-to-case thermal resistance of the power module.

[0106] Specifically, building an air heat transfer network model according to the air thermal conductivity and the air volume in the inverter cavity, that is, the air heat transfer network model; building an inverter housing thermal network model according to the material, size and shape of the inverter housing; obtaining the relationship curve between the coolant flow rate and the steady-state thermal resistance of the power module through the power module sample test, and based on the state machine tool and the order of the junction-to-case thermal resistance of the power module, dynamically allocate the thermal resistance between the connections of each structure of the module under the condition of ensuring the accuracy of the steady-state thermal resistance used, and build a power module thermal performance model considering the coolant flow rate, that is, the power module thermal performance model considering the coolant flow rate.

[0107] The technical solution of the embodiment of the present invention, by establishing a DC bus model, a DC bus capacitor model, a drive unit model and a power module model, and obtaining the layout method of the intelligent power unit inside the inverter; building the electrothermal performance simulation model of the intelligent power unit based on the DC bus model, the DC bus capacitor model, the drive unit model, the power module model and the layout method, the electrothermal performance simulation model includes an electrical performance simulation model and a thermal performance simulation model; by simulating the electrothermal performance simulation model, output the target design parameters of the intelligent power unit and its connection and cooling path. Solve the problem that the loss and heat generation of the intelligent power unit estimated by the prior art are too high, resulting in a large system design margin and high system cost, so as to fully consider the electrical connection and physical connection relationship between the components of the intelligent power unit and obtain the electrothermal characteristics of the intelligent power unit closer to the actual application.

[0108] Embodiment 2

[0109] Figure 10 The figure is a structural diagram of an electrothermal performance analysis system for an intelligent power unit provided in Embodiment 2 of the present invention. This embodiment is applicable to fully considering the electrical connection and physical connection relationships between the various components that make up the intelligent power unit, as well as the layout and external environment of these components in an electric vehicle on-board inverter, so that the electrothermal characteristics of the analyzed intelligent power unit are closer to the actual application situation.

[0110] As Figure 10 shown, the electrothermal performance analysis system of the intelligent power unit includes: a model establishment module 1010, a model construction module 1020, and a result output module 1030, where:

[0111] The model establishment module 1010 is used to establish a DC busbar model, a DC busbar capacitor model, a drive unit model, and a power module model, and obtain the layout method of the intelligent power unit inside the inverter;

[0112] The model construction module 1020 is used to build an electrothermal performance simulation model of the intelligent power unit based on the DC busbar model, the DC busbar capacitor model, the drive unit model, the power module model, and the layout method. The electrothermal performance simulation model includes an electrical performance simulation model and a thermal performance simulation model;

[0113] The result output module 1030 is used to output the target design parameters of the intelligent power unit and its connection and cooling paths by simulating the electrothermal performance simulation model.

[0114] The electrothermal performance analysis system of the intelligent power unit in this embodiment establishes a DC busbar model, a DC busbar capacitor model, a drive unit model, and a power module model, and obtains the layout method of the intelligent power unit inside the inverter; builds an electrothermal performance simulation model of the intelligent power unit based on the DC busbar model, the DC busbar capacitor model, the drive unit model, the power module model, and the layout method. The electrothermal performance simulation model includes an electrical performance simulation model and a thermal performance simulation model; outputs the target design parameters of the intelligent power unit and its connection and cooling paths by simulating the electrothermal performance simulation model. It solves the problem that the loss and heat generation of the intelligent power unit estimated by the existing technology are on the high side, resulting in a large system design margin and high system cost, so as to fully consider the electrical connection and physical connection relationships between the various components of the intelligent power unit and obtain electrothermal characteristics of the intelligent power unit closer to the actual application.

[0115] Based on the above embodiments, the model establishment module 1010 is specifically used for:

[0116] Establish a busbar heat generation calculation model and a busbar heat dissipation calculation model, and build a DC busbar model according to the busbar heat generation calculation model and the busbar heat dissipation calculation model;

[0117] Establish a busbar capacitor heat generation calculation model and a busbar capacitor heat dissipation calculation model, and build a DC busbar capacitor model according to the busbar capacitor heat generation calculation model and the busbar capacitor heat dissipation calculation model;

[0118] Build a drive unit model according to the loss data of the drive board and the target network order;

[0119] Establish a transient thermal resistance dynamic distribution model and a power thermal network model, and build a power module model according to the transient thermal resistance dynamic distribution model and the power thermal network model.

[0120] Based on the above embodiments, the model building module 1020 includes:

[0121] An electrical performance connection relationship determination unit for determining the electrical performance connection relationships of the components corresponding to the electrical performance simulation model according to the layout;

[0122] An electrical performance simulation model building unit for building the electrical performance simulation model based on the electrical performance connection relationships, where the electrical performance connection relationships include the connection between the DC busbar model and the DC busbar capacitor model, the connection between the DC busbar capacitor model and the power module model, and the connection between the power module model and the drive unit model.

[0123] Based on the above embodiments, the electrothermal performance analysis system of the intelligent power unit further includes:

[0124] A connector model establishment module for establishing a connector model and a cooler thermal performance model;

[0125] The model building module 1020 includes:

[0126] A thermal performance connection relationship determination unit for determining the thermal performance connection relationships of the components corresponding to the thermal performance simulation model according to the layout;

[0127] A thermal performance simulation model building unit for building the thermal performance simulation model based on the thermal performance connection relationships, where the thermal performance connection relationships include the connection between the DC busbar model and the DC busbar capacitor model through the connector model, the connection between the DC busbar capacitor model and the power module model through the connector model, the connection between the power module model and the drive unit model, and the connection of the cooler thermal performance model with the DC busbar model, the DC busbar capacitor model, and the power module model respectively.

[0128] Based on the above embodiments, the result output module 1030 includes:

[0129] An electrothermal performance simulation model simulation unit, configured to simulate the electrothermal performance simulation model with the goal of reducing the electrothermal stress of the power module and the DC bus capacitor, based on the drive resistance, the line stray inductance, the thermal resistance on the heat transfer path, and the allowable voltage and current stress corresponding to the intelligent power unit.

[0130] A result output unit, configured to output the target design parameters of the intelligent power unit and its connection and cooling path according to the simulation result obtained from the electrothermal performance simulation model.

[0131] Based on the above embodiments, the electrothermal performance analysis system of the intelligent power unit further includes:

[0132] A loss parameter acquisition module, configured to acquire the component loss parameters of the intelligent power unit, where the component loss parameters include the DC bus bar model loss parameter, the DC bus capacitor model loss parameter, the drive unit model loss parameter, and the power module model loss parameter.

[0133] Based on the above embodiments, the electrothermal performance analysis system of the intelligent power unit further includes:

[0134] An air heat transfer network model building module, configured to build an air heat transfer network model according to the air thermal conductivity and the air volume in the inverter cavity.

[0135] An inverter housing thermal network model building module, configured to build an inverter housing thermal network model according to the material, size, and shape of the inverter housing.

[0136] A power module thermal performance model building module considering the coolant flow rate, configured to build the power module thermal performance model considering the coolant flow rate through the relationship curve between the coolant flow rate and the steady-state thermal resistance of the power module model and the state machine tool and the junction-to-case thermal resistance order of the power module.

[0137] The electrothermal performance analysis system of the intelligent power unit provided by the above embodiments can execute the electrothermal performance analysis method of the intelligent power unit provided by any embodiment of the present invention, and has the corresponding function modules and beneficial effects for executing the electrothermal performance analysis method of the intelligent power unit.

[0138] Embodiment 3

[0139] Figure 11 It is a schematic structural diagram of a computer device provided by Embodiment 3 of the present invention, as Figure 11As shown in the figure, the computer device includes a processor 1110, a memory 1120, an input device 1130, and an output device 1140; the number of processors 1110 in the computer device can be one or more, Figure 11 In this example, one processor 1110 is taken as an example; the processor 1110, the memory 1120, the input device 1130, and the output device 1140 in the computer device can be connected through a bus or other means, Figure 11 In this example, connection through a bus is taken as an example.

[0140] The memory 1120, as a computer-readable storage medium, can be used to store software programs, computer-executable programs, and modules, such as program instructions / modules corresponding to the electrothermal performance analysis method of the intelligent power unit in the embodiments of the present invention (for example, the model establishment module 1010, the model construction module 1020, and the result output module 1030 in the electrothermal performance analysis device of the intelligent power unit). The processor 1110 executes various functional applications and data processing of the computer device by running the software programs, instructions, and modules stored in the memory 1120, that is, implements the above-mentioned electrothermal performance analysis method of the intelligent power unit.

[0141] The memory 1120 mainly includes a program storage area and a data storage area. Among them, the program storage area can store an operating system and application programs required for at least one function; the data storage area can store data created according to the use of the terminal, etc. In addition, the memory 1120 can include high-speed random access memory, and can also include non-volatile memory, such as at least one disk storage device, a flash memory device, or other non-volatile solid-state storage devices. In some instances, the memory 1120 can further include a memory remotely set relative to the processor 1110, and these remote memories can be connected to the computer device through a network. Examples of the above network include but are not limited to the Internet, an enterprise intranet, a local area network, a mobile communication network, and their combinations.

[0142] The input device 1130 can be used to receive input digital or character information, and generate key signal inputs related to the user settings and function control of the computer device. The output device 1140 can include a display device such as a display screen.

[0143] Embodiment Four

[0144] Embodiment Four of the present invention further provides a storage medium containing computer-executable instructions, and the computer-executable instructions are used to execute an electrothermal performance analysis method of an intelligent power unit when executed by a computer processor. The electrothermal performance analysis method of the intelligent power unit includes:

[0145] Establish a DC bus bar model, a DC bus bar capacitor model, a drive unit model, and a power module model, and obtain the layout of the intelligent power unit inside the inverter;

[0146] Based on the DC bus bar model, the DC bus bar capacitor model, the drive unit model, the power module model, and the layout, build an electrothermal performance simulation model of the intelligent power unit, where the electrothermal performance simulation model includes an electrical performance simulation model and a thermal performance simulation model;

[0147] By simulating the electrothermal performance simulation model, output the target design parameters of the intelligent power unit and its connection and cooling paths.

[0148] Of course, for a storage medium containing computer-executable instructions provided by an embodiment of the present invention, the computer-executable instructions are not limited to the method operations described above, and can also execute related operations in the electrothermal performance analysis method of the intelligent power unit provided by any embodiment of the present invention.

[0149] From the above description of the embodiments, those skilled in the art can clearly understand that the present invention can be implemented by means of software and necessary general-purpose hardware. Of course, it can also be implemented by hardware, but in many cases the former is a better implementation method. Based on such an understanding, the technical solution of the present invention, in essence, or the part that contributes to the prior art, can be embodied in the form of a software product. This computer software product can be stored in a computer-readable storage medium, such as a floppy disk, a read-only memory (ROM), a random access memory (RAM), a flash memory (FLASH), a hard disk, or an optical disc of a computer, and includes several instructions for causing a computer device (which can be a personal computer, a server, or a network device, etc.) to execute the methods described in various embodiments of the present invention.

[0150] It should be noted that in the embodiments of the above electrothermal performance analysis device of the intelligent power unit, the included units and modules are only divided according to functional logic, but are not limited to the above division, as long as the corresponding functions can be realized; in addition, the specific names of the functional units are only for the convenience of mutual distinction and do not limit the protection scope of the present invention.

[0151] Note that the above is only the preferred embodiment of the present invention and the technical principles applied. Those skilled in the art will understand that the present invention is not limited to the specific embodiments described herein. Various obvious changes, re-adjustments and substitutions can be made by those skilled in the art without departing from the protection scope of the present invention. Therefore, although the present invention has been described in detail through the above embodiments, the present invention is not limited to the above embodiments. Without departing from the concept of the present invention, more other equivalent embodiments can be included, and the scope of the present invention is determined by the scope of the appended claims.

Claims

1. A method for analyzing the electrothermal performance of an intelligent power unit, characterized in that, Including: Establish a DC busbar model, a DC busbar capacitor model, a drive unit model, and a power module model, and obtain the layout of the intelligent power unit inside the inverter. Among them, the layout is determined by fully considering the electrical connection and physical connection relationships between the components that make up the intelligent power unit, and the layout of each component in the vehicle-mounted inverter of the electric vehicle and the external environment; Based on the DC busbar model, the DC busbar capacitor model, the drive unit model, the power module model, and the layout, build the electrothermal performance simulation model of the intelligent power unit. The electrothermal performance simulation model includes an electrical performance simulation model and a thermal performance simulation model; Among them, building the electrothermal performance simulation model of the intelligent power unit based on the DC busbar model, the DC busbar capacitor model, the drive unit model, the power module model, and the layout includes: determining the electrical performance connection relationships of the components corresponding to the electrical performance simulation model according to the layout; building the electrical performance simulation model based on the electrical performance connection relationships. The electrical performance connection relationships include the connection between the DC busbar model and the DC busbar capacitor model, the connection between the DC busbar capacitor model and the power module model, and the connection between the power module model and the drive unit model; By simulating the electrothermal performance simulation model, output the target design parameters of the intelligent power unit and its connection and cooling paths.

2. The method for analyzing the electrothermal performance of the intelligent power unit according to claim 1, wherein Establishing a DC busbar model, a DC busbar capacitor model, a drive unit model, and a power module model includes: Establish a busbar heat generation calculation model and a busbar heat dissipation calculation model, and build a DC busbar model according to the busbar heat generation calculation model and the busbar heat dissipation calculation model; Establish a busbar capacitor heat generation calculation model and a busbar capacitor heat dissipation calculation model, and build a DC busbar capacitor model according to the busbar capacitor heat generation calculation model and the busbar capacitor heat dissipation calculation model; Build a drive unit model according to the loss data of the drive board and the target network order; Establish a transient thermal resistance dynamic distribution model and a power thermal network model, and build a power module model according to the transient thermal resistance dynamic distribution model and the power thermal network model.

3. The method for analyzing the electrothermal performance of the intelligent power unit according to claim 1, characterized in that Before building the electrothermal performance simulation model of the intelligent power unit based on the DC busbar model, the DC busbar capacitor model, the drive unit model, the power module model, and the layout, it also includes: Establish a connector model and a cooler thermal performance model; Building the electrothermal performance simulation model of the intelligent power unit based on the DC busbar model, the DC busbar capacitor model, the drive unit model, the power module model, and the layout includes: Determine the thermal performance connection relationships of the components corresponding to the thermal performance simulation model according to the layout; Based on the thermal performance connection relationship, the thermal performance simulation model is built. The thermal performance connection relationship includes that the DC busbar model is connected to the DC busbar capacitor model through the connector model, the DC busbar capacitor model is connected to the power module model through the connector model, the power module model is connected to the drive unit model, and the cooler thermal performance model is respectively connected to the DC busbar model, the DC busbar capacitor model and the power module model.

4. The method for analyzing the electrothermal performance of the intelligent power unit according to claim 1, characterized in that, By simulating the electro-thermal performance simulation model, the target design parameters of the intelligent power unit and its connection and cooling paths are output, including: Taking the reduction of the electro-thermal stress of the power module and the DC bus capacitor as the goal, the electro-thermal performance simulation model is simulated based on the drive resistance, the line stray inductance, the thermal resistance on the heat transfer path, and the allowable voltage and current stress corresponding to the intelligent power unit. According to the simulation results obtained from the electro-thermal performance simulation model, the target design parameters of the intelligent power unit and its connection and cooling paths are output.

5. The method for analyzing the electrothermal performance of the intelligent power unit according to claim 1, characterized in that, The electro-thermal performance analysis method of the intelligent power unit further includes: Obtaining the component loss parameters of the intelligent power unit, where the component loss parameters include the DC busbar model loss parameters, the DC busbar capacitor model loss parameters, the drive unit model loss parameters and the power module model loss parameters.

6. The method for analyzing the electrothermal performance of the intelligent power unit according to claim 1, characterized in that, The electro-thermal performance analysis method of the intelligent power unit further includes: Building an air heat transfer network model according to the air thermal conductivity and the air volume in the inverter cavity; Building an inverter housing thermal network model according to the material, size and shape of the inverter housing; Building a power module thermal performance model considering the coolant flow rate through the relationship curve between the coolant flow rate and the steady-state thermal resistance of the power module model and the state machine tool and the order of the junction-to-case thermal resistance of the power module.

7. An electrothermal performance analysis system for an intelligent power unit, characterized in that, Including: A model establishment module for establishing a DC busbar model, a DC busbar capacitor model, a drive unit model and a power module model, and obtaining the layout mode of the intelligent power unit inside the inverter, where the layout mode is determined by fully considering the electrical connection and physical connection relationships between the components constituting the intelligent power unit, and the layout of each component in the electric vehicle on-board inverter and the external environment; The model building module is used to build the electrothermal performance simulation model of the intelligent power unit based on the DC busbar model, the DC busbar capacitor model, the drive unit model, the power module model and the layout method. The electrothermal performance simulation model includes an electrical performance simulation model and a thermal performance simulation model. Among them, building the electrothermal performance simulation model of the intelligent power unit based on the DC busbar model, the DC busbar capacitor model, the drive unit model, the power module model and the layout method is specifically used for: determining the electrical performance connection relationships of the components corresponding to the electrical performance simulation model according to the layout method; building the electrical performance simulation model based on the electrical performance connection relationships, and the electrical performance connection relationships include the connection between the DC busbar model and the DC busbar capacitor model, the connection between the DC busbar capacitor model and the power module model, and the connection between the power module model and the drive unit model. The result output module is used to output the target design parameters, their connections and cooling paths of the intelligent power unit by simulating the electrothermal performance simulation model.

8. A computer device, characterized in that, The computer device includes: One or more processors; A storage device for storing one or more programs; When the one or more programs are executed by the one or more processors, the one or more processors implement the electrothermal performance analysis method of the intelligent power unit as described in any one of claims 1-6.

9. A computer-readable storage medium having a computer program stored thereon, characterized in that, When the program is executed by the processor, it implements the electrothermal performance analysis method of the intelligent power unit as described in any one of claims 1-6.

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