Lifetime assessment methods for electric drive power circuits, electric drive control methods and products

Abstract

This application provides a lifespan assessment method, an electric drive control method, and a product for an electric drive power circuit. The lifespan assessment method includes: monitoring target operating condition parameters of the electric drive power circuit; the electric drive power circuit is an energy transmission path connecting the power battery and the drive motor; determining temperature change information of a target part in the electric drive power circuit based on the target operating condition parameters; assessing the remaining lifespan of the target part based on the temperature change information of the target part; and determining the remaining lifespan of the electric drive power circuit based on the remaining lifespan of the target part. This application achieves online assessment of the remaining lifespan of the electric drive power circuit by determining the temperature change information of a target part in the circuit based on the monitored target operating condition parameters, and then determining the remaining lifespan of the entire circuit based on the temperature change information of the target part, thereby improving the accuracy of the lifespan assessment of the electric drive power circuit.

Description

Technical Field

[0001] This application relates to the field of electric drive technology, specifically to a life assessment method for an electric drive power circuit, an electric drive control method, and a product. Background Technology

[0002] The accuracy of life assessment for the electric drive power circuit of new energy vehicles is of great significance for ensuring driving safety. Current life assessments mainly rely on offline testing and simulation models under standard operating conditions, which cannot reflect the complex electrothermal stress impacts caused by frequent starts, rapid acceleration, and regenerative braking in actual operation, resulting in poor accuracy in current life assessments.

[0003] Improving the accuracy of life assessment for electric drive power circuits has become an urgent problem to be solved. Summary of the Invention

[0004] The main objective of this application is to propose a life assessment method, an electric drive control method, and a product for electric drive power circuits, aiming to improve the accuracy of life assessment for electric drive power circuits.

[0005] This application provides a method for assessing the lifespan of an electric drive power circuit, comprising: monitoring target operating condition parameters of the electric drive power circuit; the electric drive power circuit being an energy transmission path connecting a power battery and a drive motor; determining temperature change information of a target component in the electric drive power circuit based on the target operating condition parameters; the temperature change information being used to characterize the temperature change of the target component over time; assessing the remaining lifespan of the target component based on the temperature change information of the target component to obtain the remaining lifespan of the target component; and determining the remaining lifespan of the electric drive power circuit based on the remaining lifespan of the target component.

[0006] In one embodiment, the target location includes a DC power distribution connection node; the target operating parameters include the DC-side current and coolant temperature monitored within a time window; the time window includes an initial time and at least one target time after the initial time; determining the temperature change information of the target location in the electric drive power circuit based on the target operating parameters includes: determining the resistance loss of the DC power distribution connection node within the time window based on the DC-side current and coolant temperature monitored within the time window; for each target time within the time window, performing the following processing to obtain the temperature of the DC power distribution connection node at at least one target time: determining the temperature rise value of the DC power distribution connection node at the target time based on the resistance loss and the temperature rise value of the DC power distribution connection node at the previous time of the target time; determining the temperature of the DC power distribution connection node at the target time based on the temperature rise value of the DC power distribution connection node at the target time; wherein, the temperature change information includes the temperature of the DC power distribution connection node at the initial time and the at least one target time.

[0007] In one embodiment, determining the resistance loss of the DC power distribution connection node within the time window based on the DC-side current and coolant temperature monitored within the time window includes: determining the equivalent resistance of the DC power distribution connection node within the time window based on the coolant temperature monitored within the time window; determining the effective value of the DC current of the DC power distribution connection node within the time window based on the DC-side current monitored within the time window; and determining the resistance loss based on the equivalent resistance and the effective value of the DC current.

[0008] In one embodiment, the target location includes a bus capacitor; the target operating parameters include the DC-side current monitored within a time window, the bus capacitor casing temperature, and the switching frequency; the time window includes multiple moments; determining the temperature change information of the target location in the electric drive power circuit based on the target operating parameters includes: determining the RMS ripple value of the bus capacitor within the time window based on the DC-side current monitored within the time window; for each moment within the time window, performing the following processing to obtain the temperature of the bus capacitor at the multiple moments: determining the ripple loss of the bus capacitor at the moment based on the RMS ripple value, the bus capacitor casing temperature at the moment, and the switching frequency; determining the temperature of the bus capacitor at the moment based on the ripple loss and the bus capacitor casing temperature; wherein, the temperature change information includes the temperature of the bus capacitor at the multiple moments.

[0009] In one embodiment, determining the ripple loss of the bus capacitor at a given time based on the RMS ripple value, the bus capacitor housing temperature at that time, and the switching frequency includes: determining the equivalent resistance of the bus capacitor at that time based on the bus capacitor housing temperature and the switching frequency at that time; and determining the ripple loss based on the RMS ripple value and the equivalent resistance.

[0010] In one embodiment, the target location includes a power semiconductor device; the target operating parameters include three-phase current, switching frequency, and bus voltage monitored within a time window; the time window includes an initial time and at least one target time after the initial time; determining the temperature change information of the target location in the electric drive power circuit based on the target operating parameters includes: for each target time within the time window, performing the following processing to obtain the temperature of the power semiconductor device at the at least one target time: determining the target loss of the power semiconductor device at the target time based on the three-phase current, switching frequency, and bus voltage at the target time, and the temperature of the power semiconductor device at the previous time at the target time; determining the temperature rise of the power semiconductor device at the target time based on the target loss and the temperature rise value of the power semiconductor device at the previous time; determining the temperature of the power semiconductor device at the target time based on the temperature rise value of the power semiconductor device at the target time; wherein, the temperature change information includes the temperature of the power semiconductor device at the initial time and the at least one target time.

[0011] In one embodiment, determining the target loss of the power semiconductor device at the target time based on the three-phase current, switching frequency, bus voltage, and temperature of the power semiconductor device at the previous time at the target time includes: determining the conduction loss of the power semiconductor device at the target time based on the three-phase current and temperature of the power semiconductor device at the previous time at the target time; determining the switching loss of the power semiconductor device at the target time based on the switching frequency, bus voltage, three-phase current, and temperature of the power semiconductor device at the previous time at the target time; and determining the target loss based on the conduction loss and the switching loss.

[0012] In one embodiment, assessing the remaining lifespan of the target part based on its temperature change information to obtain the remaining lifespan of the target part includes: performing stress cycle counting analysis on the temperature change information of the target part to obtain a set of thermal stress cycles for the target part; for each thermal stress cycle in the set of thermal stress cycles, determining the lifespan loss of the target part in the thermal stress cycle based on the stress characteristic data of the target part in the thermal stress cycle; and determining the remaining lifespan of the target part based on the lifespan loss of the target part in each thermal stress cycle.

[0013] In one embodiment, the target location includes multiple locations; determining the remaining lifetime of the electric drive power circuit based on the remaining lifetime of the target location includes: comparing the remaining lifetimes of the multiple locations to determine the minimum remaining lifetime among the remaining lifetimes of the multiple locations; and determining the remaining lifetime of the electric drive power circuit based on the minimum remaining lifetime.

[0014] This application also provides an electric drive control method, comprising: obtaining the remaining lifetime of an electric drive power circuit determined by the above-described lifetime assessment method; the electric drive power circuit being an energy transmission path connecting a power battery and a drive motor; determining the target maximum allowable output power of the drive motor based on the remaining lifetime of the electric drive power circuit; and limiting the output power of the drive motor based on the target maximum allowable output power.

[0015] In one embodiment, determining the target maximum allowable output power of the drive motor based on the remaining lifespan of the electric drive power circuit includes: determining a first maximum allowable output power of the drive motor based on the temperature of a target location in the electric drive power circuit; determining a second maximum allowable output power of the drive motor based on the remaining lifespan of the electric drive power circuit; and determining the target maximum allowable output power based on the smaller of the first maximum allowable output power and the second maximum allowable output power.

[0016] This application also provides an electronic device, which includes a memory and a processor. The memory stores a computer program, and the processor executes the computer program to implement the above-described life assessment method or the above-described electric drive control method.

[0017] This application also provides a computer-readable storage medium storing a computer program that, when executed by a processor, implements the above-described lifetime assessment method or the above-described electric drive control method.

[0018] This application also provides a vehicle that includes the aforementioned electronic equipment.

[0019] This application provides a life assessment method, electric drive control method, and product for an electric drive power circuit. By determining the temperature change information of a target part in the circuit based on the monitored target operating parameters of the electric drive power circuit, and determining the remaining life of the entire circuit based on the temperature change information of the target part, the remaining life of the electric drive power circuit is realized online, which can improve the accuracy of life assessment of the electric drive power circuit. Attached Figure Description

[0020] Figure 1 This is a flowchart illustrating the life assessment method for an electric drive power circuit provided in an embodiment of this application.

[0021] Figure 2 This is a schematic diagram showing the selection of target components in the electric drive power circuit provided in the embodiments of this application.

[0022] Figure 3 This is a schematic flowchart of the electric drive control method provided in the embodiments of this application;

[0023] Figure 4 This is a schematic diagram showing the correspondence between remaining lifetime and maximum permissible output power provided in the embodiments of this application.

[0024] Figure 5 This is a schematic diagram of the structure of the electronic device provided in the embodiments of this application. Detailed Implementation

[0025] The technical solutions of the embodiments of this application will be clearly described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this application. All other embodiments obtained by those skilled in the art based on the embodiments of this application are within the scope of protection of this application.

[0026] The terms "first," "second," etc., used in the specification and claims of this application are used to distinguish similar objects and not to describe a specific order or sequence. It should be understood that such use of data can be interchanged where appropriate so that embodiments of this application can be implemented in orders other than those illustrated or described herein, and the objects distinguished by "first," "second," etc., are generally of the same class and the number of objects is not limited; for example, a first object can be one or more. Furthermore, in the specification and claims, "and / or" indicates at least one of the connected objects, and the digit " / " generally indicates that the preceding and following objects are in an "or" relationship.

[0027] The lifespan assessment method and electric drive control method for the electric drive power circuit provided in this application can be applied to electronic devices or the software of electronic devices. The electronic device can be a terminal or a server. In some embodiments, the terminal can be a smartphone, tablet computer, laptop computer, desktop computer, etc.; the server can be configured as an independent physical server, or as a server cluster or distributed system composed of multiple physical servers. The software can be an application that implements the lifespan assessment method or the electric drive control method for the electric drive power circuit, but is not limited to the above forms.

[0028] The life assessment method for the electric drive power circuit provided in this application will be described in detail below with reference to the accompanying drawings and specific embodiments.

[0029] Please see Figure 1 The lifetime assessment method for an electric drive power circuit provided in this application embodiment may include: Step S101: Monitor the target operating parameters of the electric drive power circuit; the electric drive power circuit is the energy transmission path connecting the power battery and the drive motor. In actual implementation, the target operating condition parameters of the electric drive power circuit can be continuously collected according to the preset monitoring cycle, and the target operating condition parameters within at least one time window can be cached. Then, for each time window, the remaining life of the electric drive power circuit can be evaluated based on the target operating condition parameters monitored within that time window.

[0030] Optionally, the target operating parameters of the electric drive power circuit can be operating parameters associated with a target part in the electric drive power circuit. Optionally, the target part can be a connection point or component in the electric drive power circuit that is sensitive to thermal stress under a specific failure mode and may fail first.

[0031] Step S102: Based on the target operating condition parameters, determine the temperature change information of the target part in the electric drive power circuit; the temperature change information is used to characterize the temperature change of the target part over time. In practical implementation, the temperature of the target component can be determined at each moment within the time window based on the target operating parameters at that moment. Then, based on the temperature of the target component at each moment within the time window, the temperature change information of the target component can be obtained. Optionally, the temperature change information can be represented as a temperature time series or a temperature time curve.

[0032] In practice, for each moment within the time window, the target operating condition parameters at that moment can be used to look up a preset table of correspondence between operating condition parameters and temperature to obtain the temperature of the target location at that moment; alternatively, the target operating condition parameters at that moment can be substituted into the preset formula of correspondence between operating condition parameters and temperature to obtain the temperature of the target location at that moment. Optionally, for the same target location, the types of target operating condition parameters are fixed at different times, but their values ​​may be different.

[0033] Step S103: Based on the temperature change information of the target part, assess the remaining lifespan of the target part to obtain the remaining lifespan of the target part; In practice, the temperature change information of the target part can be used to query the preset correspondence table between temperature change information and remaining life to obtain the remaining life of the target part; alternatively, stress cycle counting analysis can be performed on the temperature change information of the target part to obtain the remaining life of the target part. For specific implementation details, please refer to the relevant descriptions below, which will not be described here.

[0034] Step S104: Determine the remaining lifespan of the electric drive power circuit based on the remaining lifespan of the target part.

[0035] In practice, when the target part includes only one part, the remaining lifetime of the target part can be determined as the remaining lifetime of the electric drive power circuit; when the target part includes multiple parts, the remaining lifetime of the electric drive power circuit can be determined based on the minimum remaining lifetime among the remaining lifetimes of the multiple parts. For specific implementation details, please refer to the relevant descriptions below, which will not be described here.

[0036] This application embodiment determines the temperature change information of the target part in the circuit based on the monitored target operating parameters of the electric drive power circuit, and determines the remaining life of the entire circuit based on the temperature change information of the target part, thereby realizing the online assessment of the remaining life of the electric drive power circuit and improving the accuracy of the life assessment of the electric drive power circuit.

[0037] Optionally, the target location includes a DC power distribution connection node; the target operating parameters may include the DC side current and coolant temperature monitored within a time window; the time window includes the initial time and at least one target time after the initial time.

[0038] In one embodiment, determining the temperature change information of the target part in the electric drive power circuit based on the target operating condition parameters in step S102 above includes: Based on the DC-side current and coolant temperature monitored within the time window, the resistance loss of the DC power distribution connection node within the time window is determined. For each target time within the time window, the following processing is performed to obtain the temperature of the DC distribution connection node at at least one target time: Based on the resistance loss and the temperature rise value of the DC distribution connection node at the previous time of the target time, the temperature rise value of the DC distribution connection node at the target time is determined; Based on the temperature rise value of the DC distribution connection node at the target time, the temperature of the DC distribution connection node at the target time is determined. The temperature change information includes the temperature of the DC power distribution connection node at the initial moment and at least one target moment.

[0039] Optionally, the DC power distribution connection node can be an electrical connection node on the DC side power transmission path of the electric drive power circuit, used for collecting, distributing or converting DC power, and may include at least one of the main contactor, upstream connector / terminal, and DC busbar connection point (bolted / crimped / welded connection) in the electric drive power circuit.

[0040] In practice, the DC power distribution connection node's resistance loss within a time window can be obtained by querying a preset table of correspondences between the monitored DC current and coolant temperature and the resistance loss. Alternatively, the resistance loss of the DC power distribution connection node within a time window can be determined by using the equivalent resistance determined based on the monitored coolant temperature and the effective value of the DC current determined based on the monitored DC current. For specific implementation details, please refer to the relevant descriptions below, which will not be described here.

[0041] Optionally, the temperature rise of the DC power distribution connection node at the initial moment can be the difference between the initial temperature of the DC power distribution connection node and the reference temperature; optionally, the reference temperature can be a preset value, and its range can be 20℃~25℃. The initial temperature of the DC power distribution connection node can be equal to the coolant temperature at that initial moment.

[0042] In practice, for the target time mentioned above, the temperature rise of the DC distribution connection node at the target time can be obtained by looking up a preset table of the correspondence between resistance loss and temperature rise at adjacent times, based on the resistance loss and the temperature rise value of the DC distribution connection node at the previous time. Alternatively, the temperature rise value of the DC distribution connection node at the target time can be calculated using formula (1). (1) in, This represents the temperature rise of the DC power distribution connection node at time k. This represents the temperature rise of the DC power distribution connection node at time k-1. Represents the thermal time constant, which is a constant; This represents thermal resistance, which is a constant. This indicates the resistance loss of a DC power distribution connection node within a time window. The above monitoring period is represented by: time k; time k-1 represents the time before the kth target time; time k-1 represents the time before the kth target time.

[0043] Next, the temperature of the DC distribution connection node at the target time can be obtained by looking up the preset table of correspondence between temperature rise and temperature using the temperature rise value of the DC distribution connection node at the target time; alternatively, the temperature of the DC distribution connection node at the target time can be calculated using formula (2): (2) in, Indicates the DC power distribution connection node at the 1st Temperature at any moment; This indicates the reference temperature mentioned above.

[0044] This embodiment of the application determines the resistance loss of a DC power distribution connection node within a time window by utilizing real-time monitored DC-side current and coolant temperature. Then, based on this resistance data, iteratively calculates the temperature rise value at each subsequent target time, starting from a known initial temperature rise value. Finally, the temperature rise value at each time is added to a reference temperature to obtain the temperature of the DC power distribution connection node at the corresponding time. This achieves real-time online estimation of the DC power distribution connection node temperature, improving the accuracy of determining the temperature change information of the DC power distribution connection node, thereby improving the accuracy of assessing the entire circuit life based on this temperature change information.

[0045] In one embodiment, determining the resistive loss of the DC power distribution connection node within a time window based on the DC-side current and coolant temperature monitored within that time window includes: Based on the coolant temperature monitored within the time window, the equivalent resistance of the DC power distribution connection node within the time window is determined. Based on the DC-side current monitored within the time window, the effective value of the DC current at the DC distribution connection node within the time window is determined. The resistance loss is determined based on the equivalent resistance and the effective value of the DC current.

[0046] In practice, the equivalent resistance of the DC power distribution connection node in the time window can be obtained by consulting a preset table of correspondence between coolant temperature and equivalent resistance based on the coolant temperature monitored within the time window; alternatively, the equivalent resistance of the DC power distribution connection node in the time window can be calculated using formula (3). (3) in, This represents the equivalent resistance of a DC power distribution connection node within a time window. The resistance value of the DC power distribution connection node at the reference temperature can be obtained from the datasheet; The resistance temperature coefficient of the DC power distribution connection node can be obtained from the datasheet; T represents the average value of the coolant temperature monitored within the time window.

[0047] Next, the DC current monitored within the time window can be used to look up the preset correspondence table between DC current and DC current effective value to obtain the DC current effective value of the DC distribution connection node within the time window; alternatively, the DC current effective value of the DC distribution connection node within the time window can be calculated using formula (4): (4) in, This represents the effective value of the DC current at the DC distribution connection node within the time window. This represents the DC-side current monitored at time x within the time window; time x represents the xth time within the time window; N represents the total number of times included in the time window.

[0048] Next, the equivalent resistance and effective value of DC current of the DC distribution connection node in the time window can be used to look up the preset correspondence table of equivalent resistance, effective value of DC current and resistance loss to obtain the resistance loss of the DC distribution connection node in the time window; or the resistance loss of the DC distribution connection node in the time window can be calculated by formula (5): (5) in, This represents the resistance loss of a DC power distribution connection node within a time window.

[0049] This application embodiment determines the resistance loss of a DC power distribution connection node within a time window by utilizing the equivalent resistance determined based on the coolant temperature monitored within the time window and the effective value of the DC current determined based on the DC side current monitored within the time window. This improves the accuracy of determining the resistance loss of the DC power distribution connection node, thereby improving the accuracy of assessing the entire circuit life based on the resistance loss.

[0050] Optionally, the target location includes the bus capacitor. Target operating parameters may include the DC-side current, bus capacitor case temperature, and switching frequency monitored within a time window. The time window may include multiple moments.

[0051] In one embodiment, determining the temperature change information of the target part in the electric drive power circuit based on the target operating condition parameters in step S102 above includes: Based on the DC-side current monitored within the time window, the effective value of the bus capacitor ripple within the time window is determined. For each moment within the time window, the following processing is performed to obtain the temperature of the bus capacitor at multiple moments: Based on the RMS ripple value, the bus capacitor casing temperature and switching frequency at that moment, the ripple loss of the bus capacitor at that moment is determined; Based on the ripple loss and the bus capacitor casing temperature at that moment, the temperature of the bus capacitor at that moment is determined. The temperature change information includes the temperature of the bus capacitor at multiple moments.

[0052] In practice, the DC-side current monitored within the time window can be used to look up the preset correspondence table between DC-side charge and ripple RMS value to obtain the bus capacitor's ripple RMS value within the time window; alternatively, the bus capacitor's ripple RMS value within the time window can be calculated using formulas (6), (7), and (8). (6) (7) (8) in, This represents the average value of the DC-side current monitored within the time window; This represents the ripple value of the bus capacitor at time x; This represents the effective value of the bus capacitor ripple within the time window.

[0053] Next, for each moment within the time window, the ripple loss of the bus capacitor at that moment can be obtained by looking up a preset table of correspondence between the RMS ripple value, bus capacitor case temperature, switching frequency, and ripple loss, using the RMS ripple value of the bus capacitor at that moment, the case temperature of the bus capacitor at that moment, and the switching frequency. Alternatively, the ripple loss of the bus capacitor at that moment can be determined by using the equivalent resistance determined based on the case temperature of the bus capacitor at that moment and the switching frequency, and the RMS ripple value of the bus capacitor at that moment. For specific implementation details, please refer to the relevant description below, which will not be described here.

[0054] Optionally, for each moment within the time window, the temperature of the bus capacitor at that moment can be the hot spot temperature of the bus capacitor at that moment, which can be used to characterize the temperature of the point with the highest temperature in the bus capacitor at that moment. In actual implementation, the hot spot temperature of the bus capacitor at that moment can be obtained by looking up a preset table of correspondence between ripple loss, bus capacitor shell temperature and hot spot temperature of the bus capacitor using the ripple loss and the bus capacitor shell temperature at that moment; or the hot spot temperature of the bus capacitor at that moment can be calculated using formula (9): (9) in, This represents the hot spot temperature of the bus capacitor at time x within the time window; Indicates bus capacitance The core-to-shell thermal resistance can be obtained from the datasheet; This represents the temperature of the bus capacitor casing at time x. This represents the ripple loss at time x.

[0055] This application embodiment calculates the effective value of the ripple current by monitoring the DC side current, and dynamically determines the instantaneous ripple loss of the bus capacitor by combining the shell temperature and switching frequency. Using this loss as the heat source input, the hot spot temperature of the bus capacitor at different times is iteratively calculated by using the shell temperature and core-shell thermal resistance as the upward push method. This realizes the real-time online estimation of the bus capacitor temperature, which can improve the accuracy of determining the temperature change information of the bus capacitor, thereby improving the accuracy of evaluating the life of the entire circuit based on the temperature change information.

[0056] In one embodiment, determining the ripple loss of the bus capacitor at a given moment based on the RMS ripple value, the bus capacitor casing temperature at that moment, and the switching frequency includes: Based on the bus capacitor casing temperature and switching frequency at that moment, determine the equivalent resistance of the bus capacitor at that moment. Ripple loss is determined based on the RMS value of ripple and the equivalent resistance.

[0057] In practice, the bus capacitor casing temperature and switching frequency at that moment can be input into a network model that has learned the relationship between the bus capacitor casing temperature, switching frequency and equivalent resistance to obtain the equivalent resistance of the bus capacitor at that moment; alternatively, formula (10) can be used to look up the datasheet of the bus capacitor to obtain the equivalent resistance of the bus capacitor at that moment. (10) in, This represents the equivalent resistance of the bus capacitor at time x within the time window; This represents the switching frequency at time x.

[0058] Next, based on the RMS ripple value of the bus capacitor within the time window and the equivalent resistance of the bus capacitor at that moment, a preset table of correspondence between the RMS ripple value, equivalent resistance, and ripple loss can be consulted to obtain the ripple loss of the bus capacitor at that moment; alternatively, the ripple loss of the bus capacitor at that moment can be calculated using formula (11): (11) in, This represents the ripple loss of the bus capacitor at time x.

[0059] The embodiments of this application determine the equivalent resistance of the bus capacitor at a given moment based on the bus capacitor casing temperature and switching frequency; and determine the ripple loss based on the RMS ripple value and equivalent resistance. This improves the accuracy of determining the ripple loss of the bus capacitor at each moment, thereby improving the accuracy of assessing the lifetime of the entire circuit based on ripple loss.

[0060] Optionally, the target location includes power semiconductor devices. Target operating parameters may include three-phase currents, switching frequency, and bus voltage monitored within a time window; the time window may include an initial time and at least one target time after the initial time.

[0061] In one embodiment, determining the temperature change information of the target part in the electric drive power circuit based on the target operating condition parameters in step S102 above includes: For each target time point within the time window, the following processing is performed to obtain the temperature of the power semiconductor device at at least one target time point: Based on the three-phase current, switching frequency, and bus voltage at the target time point, and the temperature of the power semiconductor device at the previous time point, the target loss of the power semiconductor device at the target time point is determined; Based on the target loss and the temperature rise of the power semiconductor device at the previous time point, the temperature rise of the power semiconductor device at the target time point is determined; Based on the temperature rise of the power semiconductor device at the target time point, the temperature of the power semiconductor device at the target time point is determined. The temperature change information includes the temperature of the power semiconductor device at the initial moment and at least one target moment.

[0062] Optionally, the power semiconductor device may include at least one of an insulated gate bipolar transistor (IGBT) and a silicon carbide metal-oxide-semiconductor field-effect transistor (SIC MOSFET).

[0063] Optionally, the temperature rise of the power semiconductor device at the initial moment can be the difference between the initial temperature of the power semiconductor device and the aforementioned reference temperature. The initial temperature of the power semiconductor device can be equal to the coolant temperature at that initial moment.

[0064] In practical implementation, for the aforementioned target time, the target loss of the power semiconductor device at the target time can be obtained by looking up a preset table of correspondences between the three-phase current, switching frequency, bus voltage, and temperature of the power semiconductor device at the previous time, using the three-phase current, switching frequency, bus voltage, and temperature of the power semiconductor device at the target time. Alternatively, the conduction loss and switching loss of the power semiconductor device at the target time can be determined based on the three-phase current, switching frequency, bus voltage, and temperature of the power semiconductor device at the target time, thus obtaining the target loss of the power semiconductor device at the target time. Specific implementation details are provided below and will not be described here.

[0065] Next, the target loss of the power semiconductor device at the target time and the temperature rise of the power semiconductor device at the previous time can be used to look up the preset correspondence table between the loss and the temperature rise of the adjacent time to obtain the temperature rise of the power semiconductor device at the target time.

[0066] Optionally, the power semiconductor device can be considered as a multilayer RC network; the temperature rise of the power semiconductor device at the target time can include the temperature rise components of each RC network layer in the power semiconductor device at the target time. In actual implementation, formula (12) can also be used to calculate the temperature rise components of each RC network layer in the power semiconductor device at the target time: (12) in, This represents the temperature rise component of the i-th layer RC network in a power semiconductor device at time k. This represents the temperature rise component of the i-th layer RC network in a power semiconductor device at time k-1. This represents the target loss of the power semiconductor device at time k. This represents the thermal resistance of the i-th layer of a power semiconductor device. This represents the heat capacity of the i-th layer in a power semiconductor device. , It is a constant and can be obtained by fitting the transient thermal impedance curve provided in the power semiconductor device datasheet.

[0067] Optionally, for each moment within the time window, the temperature of the power semiconductor device at that moment can be the junction temperature of the power semiconductor device at that moment. In actual implementation, the junction temperature of the power semiconductor device at the target moment can be obtained by looking up a preset table of correspondence between temperature rise and junction temperature using the temperature rise value of the power semiconductor device at the target moment; alternatively, the junction temperature of the power semiconductor device at the target moment can be calculated using formula (13): (13) in, This represents the junction temperature of the power semiconductor device at time k. The value represents the coolant temperature at time k; M is the total number of RC network layers in the power semiconductor device, optionally M=3 or 4.

[0068] Optionally, the temperature rise component of the i-th resistive-capacitive network in the power semiconductor device at the initial moment can be the difference between the temperature of the i-th resistive-capacitive network at the initial moment and the aforementioned reference temperature. The temperature of the i-th resistive-capacitive network at the initial moment can be equal to the coolant temperature at that initial moment.

[0069] This application embodiment acquires operating parameters such as three-phase current, bus voltage, and switching frequency in real time, and dynamically calculates the target loss of the power semiconductor device at the current moment by combining the temperature state of the power semiconductor device at the previous moment. Then, using the target loss as thermal excitation, the junction temperature of the power semiconductor device at the current moment is iteratively calculated using a multi-order thermal network calculation model. This realizes real-time online estimation of the temperature of the power semiconductor device, which can improve the accuracy of determining the temperature change information of the power semiconductor device, thereby improving the accuracy of evaluating the lifetime of the entire circuit based on the temperature change information.

[0070] In one embodiment, determining the target loss of the power semiconductor device at the target time based on the three-phase current, switching frequency, bus voltage, and the temperature of the power semiconductor device at the previous time at the target time includes: Based on the three-phase current at the target time and the temperature of the power semiconductor device at the previous time, determine the conduction loss of the power semiconductor device at the target time. Based on the switching frequency, bus voltage and three-phase current at the target time, and the temperature of the power semiconductor device at the previous time, determine the switching loss of the power semiconductor device at the target time. The target loss is determined based on conduction loss and switching loss.

[0071] In practice, the three-phase current at the target time and the temperature of the power semiconductor device at the previous time can be used to look up a preset table of correspondence between the three-phase current, temperature and conduction loss, so as to obtain the conduction loss of the power semiconductor device at the target time.

[0072] Alternatively, when the power semiconductor device includes an IGBT, formula (14) can also be used to calculate the conduction loss of the IGBT at the target time: (14) in, This represents the conduction loss of the IGBT at time k; The three-phase phase currents based on time k The determined equivalent load current; Indicates that IGBT is in the first stage The temperature at any given moment; The saturation voltage drop of the IGBT at time k can be represented by... and Consult the voltage in the device datasheet. The current curve table is obtained by interpolation; This represents the duty cycle and is a known state variable of the motor controller.

[0073] Alternatively, when the power semiconductor device includes a SiC MOSFET, formula (15) can also be used to calculate the conduction loss of the SiC MOSFET at the target time: (15) in, This represents the conduction loss of the SiC MOSFET at time k. The on-resistance of a SiC MOSFET at time k can be represented by... Consult the resistor datasheet. Temperature curves are obtained through interpolation.

[0074] In practice, the switching frequency, bus voltage, three-phase current, and temperature of the power semiconductor device at the target time can be used to look up a preset table of correspondences between switching frequency, bus voltage, three-phase current, temperature, and switching losses to obtain the switching losses of the power semiconductor device at the target time. Alternatively, the switching losses of the power semiconductor device at the target time can be calculated using formula (16): (16) in, This represents the switching loss of the power semiconductor device at time k. This represents the bus voltage at time k; These represent the single turn-on, turn-off, and diode reverse recovery energy, respectively, which can be based on... You can find this information by consulting the device datasheet or double-pulse test report.

[0075] Next, the target loss of the power semiconductor device at the target time can be calculated using formula (17): (17) in, It can be or In actual implementation, it can also be done in By multiplying the sum by a coefficient, the target loss of the power semiconductor device at the target time can be obtained.

[0076] This application embodiment collects operating parameters such as three-phase current, bus voltage, and switching frequency at the target time, and introduces the temperature of the power semiconductor device at the previous time as feedback. It independently determines the conduction loss, which is strongly correlated with current and temperature, and the switching loss, which is correlated with voltage, current, switching frequency, and temperature. It fully considers the different physical mechanisms of each component of the loss and their coupling relationship with the thermal state, which can improve the accuracy of determining the conduction loss and switching loss of the power semiconductor device at each time. This can improve the accuracy of evaluating the lifetime of the entire circuit based on conduction loss and switching loss.

[0077] Optionally, the target location includes the stator winding of the drive motor. Target operating condition parameters may include the temperature of the stator winding of the drive motor monitored within a time window, which may include multiple moments. Temperature change information of the stator winding of the drive motor may include the temperature of the stator winding of the drive motor at multiple moments.

[0078] In actual implementation, since the stator winding of the drive motor has a large thermal inertia and a built-in temperature sensor, the temperature of the stator winding of the drive motor at multiple moments can be directly collected by the temperature sensor.

[0079] Alternatively, for each moment, the temperature of the stator winding of the drive motor at that moment can be determined using formula (18): (18) in, This indicates that the stator winding of the drive motor is in the... Temperature at any moment; This indicates that the temperature sensor embedded in the stator winding of the drive motor collects data on the stator winding of the drive motor at the [missing information - likely a specific temperature value]. The temperature at any given time can be read from the drive motor side via a hard-wired signal.

[0080] This application embodiment determines the temperature change information of the stator winding of the drive motor by using the real-time sampling value of the temperature sensor embedded in the stator winding of the drive motor. This can improve the efficiency and accuracy of determining the temperature change information of the stator winding of the drive motor, thereby improving the efficiency and accuracy of evaluating the life of the entire circuit based on the temperature change information.

[0081] In one embodiment, step S103 above: assessing the remaining lifespan of the target part based on the temperature change information of the target part, and obtaining the remaining lifespan of the target part, includes: Stress cycle counting analysis is performed on the temperature change information of the target part to obtain the thermal stress cycle set of the target part; For each thermal stress cycle in the thermal stress cycle set, the life loss of the target part in the thermal stress cycle is determined based on the stress characteristic data of the target part in the thermal stress cycle. The remaining lifespan of the target part is determined based on the life loss of the target part in each thermal stress cycle.

[0082] In practice, at least one of rainflow counting and peak counting can be used to perform stress cycle counting analysis on the temperature change information of the target part to obtain the thermal stress cycle set of the target part; the thermal stress cycle set can include multiple thermal stress cycles and stress characteristic data of each thermal stress cycle.

[0083] Optionally, for each thermal stress cycle, the stress characteristic data of the thermal stress cycle may include the temperature swing, average temperature, and number of cycles. In actual implementation, the life loss of the target part during the thermal stress cycle can be obtained by querying a preset correspondence table between stress characteristic data and life loss based on the stress characteristic data of the target part during the thermal stress cycle; alternatively, the stress characteristic data of the target part during the thermal stress cycle can be input into the life prediction model to obtain the life loss of the target part during the thermal stress cycle; then, the life loss of the target part in each thermal stress cycle can be accumulated to obtain the cumulative life loss of the target part within the time window; finally, the cumulative life loss can be subtracted from the life of the target part to obtain the remaining life of the target part.

[0084] Optionally, the aforementioned temperature change information can be represented as a temperature time series. In actual implementation, before performing stress cycle counting analysis on the temperature change information of the target location to obtain the thermal stress cycle set of the target location, the temperature time series of the target location can be preprocessed as follows to remove non-reversal points: Traverse the temperature time series, and if a value is between two consecutive values ​​(i.e., the middle temperature point in a monotonically rising or falling process), then discard it. Forming a peak-valley sequence: Retaining only local maxima (peaks) and local minima (valleys) to reconstruct a new peak-valley sequence. .

[0085] Next, a sliding window mechanism can be used to analyze the peak-valley sequence. Perform iterative scanning, with the following logic: (a) Taking points: in the sequence Take four consecutive adjacent points in sequence, and denote them as follows: (corresponding to the sequence) ); (b) Amplitude calculation: Calculate intermediate range:

[0086] Calculate the left-side range:

[0087] Calculate the right-side range:

[0088] (c) Closure determination: If the conditions are met and (That is, the fluctuation range in the middle is included by the fluctuation ranges on both sides), then the line segment is determined. This forms a closed temperature cycle. Record the characteristic parameters of this cycle: temperature swing. average temperature Number of loops .

[0089] (d) Extraction and splicing: If it is determined to be a closed cycle: move the point... and points From sequence Permanently delete from the middle. Remaining points. and Adjacent points will be automatically joined together to form a new sequence with subsequent points E and F. Steps (a) to (c) above will be repeated for the new sequence. If a non-closed cycle is determined: all points are retained, and the pointer is moved one position to the right (i.e., the next group is taken). Continue with steps (a) to (c) above.

[0090] (e) Final output: Each closed loop identified from the temperature time series is determined as a thermal stress cycle, and a set of stress cycles is output. p represents the total number of thermal stress cycles identified from the temperature time series.

[0091] In practice, for each thermal stress cycle, the life loss of the target part in that thermal stress cycle is calculated using formulas (19) and (20): (19) (20) in, This indicates the number of cycles that the material can withstand under a specific stress; A and m represent the material fatigue coefficients. Indicates activation energy; Represents the Boltzmann constant; Kelvin represents absolute temperature. The value of q ranges from 1 to p.

[0092] Next, the remaining lifespan of the target part can be calculated using formulas (21), (22), and (23): (twenty one) (twenty two) (twenty three) in, This indicates the cumulative lifespan loss of the target component within the time window; This indicates the cumulative lifespan loss of the target component before the time window; L represents the cumulative lifespan loss of the target part after the time window; L represents the remaining lifespan of the target part.

[0093] This application embodiment obtains a set of thermal stress cycles for the target location by performing stress cycle counting analysis on the temperature change information of the target location; and for each thermal stress cycle in the set of thermal stress cycles, the lifetime loss of the target location in the thermal stress cycle is determined based on the stress characteristic data of the target location in the thermal stress cycle; and the remaining lifetime of the target location is determined based on the lifetime loss of the target location in each thermal stress cycle. This can achieve accurate prediction of the remaining lifetime of the target location, thereby improving the accuracy of assessing the remaining lifetime of the entire circuit based on the remaining lifetime of the target location.

[0094] Optionally, the aforementioned target locations include multiple locations. Considering that under dynamic operating conditions such as frequent starts, rapid acceleration, and regenerative braking, the primary and secondary relationships of thermal stress in different sections of the electric drive power circuit will dynamically shift, in order to improve the accuracy of the electric drive power circuit's life assessment, in practical implementation, the electric drive power circuit can be divided into multiple sections, and at least one representative location in each section can be selected as the target location, forming a life assessment framework covering the entire power circuit from the power battery to the drive motor end. This ensures that life loss caused by thermal stress under any operating condition can be monitored, thereby achieving an accurate assessment of the electric drive power circuit's life.

[0095] In one embodiment, S104 above: determining the remaining lifetime of the electric drive power circuit based on the remaining lifetime of the target location includes: The remaining lifetimes of multiple parts are compared to determine the minimum remaining lifetime among them. The remaining lifetime of the electric drive power circuit is determined based on the minimum remaining lifetime.

[0096] In practical implementation, the remaining lifetimes of multiple components can be compared, and the minimum remaining lifetime among these components can be determined as the minimum remaining lifetime. This minimum remaining lifetime can then be directly determined as the remaining lifetime of the electric drive power circuit. Alternatively, further calculations can be performed based on the minimum remaining lifetime to obtain the remaining lifetime of the electric drive power circuit. Alternatively, for each segment of the electric drive power circuit, the remaining lifetimes of each component within that segment can be compared first, and the minimum remaining lifetime of each component can be determined as the minimum remaining lifetime of that segment. Then, the minimum remaining lifetimes of each segment can be compared, and the minimum of the minimum remaining lifetimes of all segments can be determined as the remaining lifetime of the electric drive power circuit.

[0097] This application embodiment determines the minimum remaining life by comparing the remaining life of multiple parts; and determines the remaining life of the electric drive power circuit based on the minimum remaining life, which can improve the accuracy of the life assessment of the electric drive power circuit.

[0098] like Figure 2 As shown, the above-mentioned electric drive power circuit can be the power circuit of the vehicle drive system: starting from the output end of the power battery, passing through the high-voltage distribution box and the main contactor to the motor controller (also known as the inverter), and then to the stator winding of the drive motor (also known as the motor stator winding) – a complete energy transmission path.

[0099] In actual implementation, it can be based on physical location. Figure 2 The power circuit shown is divided into three sections, and at least two parts in each section can be selected as target parts (also known as lifetime targets): (1) Battery and upstream power distribution section Z1: The lifespan objects may include the main contactor and upstream connectors / terminals. The main aging form is aging caused by heat generation due to the increase in contact resistance / connection resistance with aging.

[0100] (2) DC power section Z2 inside the motor controller: The lifespan objects may include bus capacitors and DC bus connection points. The main failure modes are increased equivalent resistance of capacitors, overheating of hot spots leading to capacity decay, and aging caused by heat generation due to increased resistance of connection points.

[0101] (3) Inverter output and motor section Z3: The lifespan objects may include power semiconductor devices and motor stator windings. The main aging forms are junction temperature cycling leading to package fatigue and winding insulation aging under temperature / thermal cycling.

[0102] Please see Figure 3 This application also provides an electric drive control method, which may include: Step S201: Obtain the remaining lifespan of the electric drive power circuit determined by the above lifespan assessment method; the electric drive power circuit is the energy transmission path connecting the power battery and the drive motor. Step S202: Determine the target maximum allowable output power of the drive motor based on the remaining life of the electric drive power circuit; Step S203: Limit the output power of the drive motor based on the target maximum allowable output power.

[0103] In practical implementation, the target maximum allowable output power corresponding to the remaining lifespan of the electric drive power circuit can be determined based on a preset correspondence between the remaining lifespan and the maximum allowable output power. Alternatively, the target maximum allowable output power of the drive motor can be comprehensively determined based on the remaining lifespan of the electric drive power circuit, combined with a preset motor control strategy related to at least one of the parameters of temperature, current, and voltage. Specific implementation details are provided below and will not be described here. Next, the actual output power of the drive motor can be limited to be less than or equal to the target maximum allowable output power.

[0104] This application embodiment determines the target maximum allowable output power of the drive motor based on the remaining lifespan of the electric drive power circuit; and limits the output power of the drive motor based on the target maximum allowable output power. This enables dynamic power envelope management of the drive motor, which means that the output power of the drive motor can be actively and dynamically adjusted based on the remaining lifespan of the entire power circuit. This not only enables instantaneous safety protection, but also makes the lifespan consumption of the power circuit more balanced under actual dynamic operating conditions, thereby extending the overall service life of the electric drive power circuit.

[0105] In one embodiment, determining the target maximum allowable output power of the drive motor based on the remaining lifespan of the electric drive power circuit includes: Based on the temperature of the target part in the electric drive power circuit, determine the first maximum allowable output power of the drive motor; Based on the remaining lifespan of the electric drive power circuit, determine the second maximum allowable output power of the drive motor; The target maximum allowable output power is determined based on the smaller of the first maximum allowable output power and the second maximum allowable output power.

[0106] In practical implementation, a first maximum allowable output power corresponding to the temperature of the target part can be determined based on a preset temperature-related drive motor control strategy. A second maximum allowable output power corresponding to the remaining lifespan of the electric drive power circuit can be determined based on a preset relationship between remaining lifespan and maximum allowable output power. Then, the first and second maximum allowable output powers can be compared, and the smaller value is determined as the target maximum allowable output power of the drive motor.

[0107] Optionally, the aforementioned preset remaining lifespan With maximum allowable output power The correspondence can be as follows: Figure 4 As shown: During the time interval 0 to t1 ≥L1, then ; During the time interval t1~t2, L2 < <L1, then ; In the time period after t2, ≤L2, then ; in, > .

[0108] Optionally, when the electric drive power circuit is the same as the power circuit in the vehicle, L1, L2, , and Different configurations can be made based on the warranty mileage target (such as 300,000 kilometers or 600,000 kilometers) of different vehicle models and the reliability level of components.

[0109] Optionally, the value of L1 can be 0.2 to 0.3 times the maximum lifespan of the electric drive power circuit, and the value of L2 can be 0.05 to 0.1 times the maximum lifespan of the electric drive power circuit. L2 < <L1 can characterize the devices in the circuit entering the aging period, and the aging rate can be slowed down by the power limitation mentioned above; ≤L can represent that the device in the circuit is close to failure. The power limit and output maintenance prompts mentioned above can ensure that the vehicle can safely leave the road or go to the repair shop, avoiding sudden disaster failure.

[0110] This application embodiment determines the first maximum allowable output power of the drive motor based on the temperature of the target location; determines the second maximum allowable output power of the drive motor based on the remaining lifespan of the electric drive power circuit; and determines the target maximum allowable output power based on the smaller of the first maximum allowable output power and the second maximum allowable output power. This enables the parallel execution of multiple power limits, which not only prevents transient overheating of the target location in the circuit and achieves instantaneous thermal safety protection, but also makes the lifespan consumption of the power circuit more balanced under actual dynamic operating conditions, thereby extending the overall lifespan of the electric drive power circuit.

[0111] The electric drive power life assessment method provided in this application divides the electric drive power circuit into multiple segments and selects life-related objects within each segment, forming a life assessment framework covering the entire power circuit from the power battery to the drive motor. This allows for accurate assessment of the remaining life of the entire circuit. Furthermore, the target operating parameters used in this application, such as DC-side current, coolant temperature, bus capacitor casing temperature, switching frequency, three-phase current, and bus voltage, are all in-service operating data of the circuit. This not only enables online assessment of the remaining life of the electric drive power circuit but also allows these operating parameters to be directly obtained through the motor controller without the need for additional hardware sensors. This allows for direct integration into mass-produced motor controllers, offering significant advantages such as low implementation cost and ease of large-scale deployment. Furthermore, the electric drive control method provided in this application embodiment can calculate the maximum allowable power under different duration scales based on the remaining lifespan of the entire circuit, thereby forming a power envelope curve that changes with the lifespan state and realizing dynamic power envelope management. In addition, by treating the remaining lifespan of the circuit as an independent constraint of power envelope management and constraining it in parallel with protection conditions such as instantaneous temperature and current, not only can instantaneous safety protection be realized, but the lifespan consumption of the power circuit can also be made more balanced under actual dynamic operating conditions, thereby extending the overall service life of the electric drive power circuit.

[0112] This application also provides a life assessment device for an electric drive power circuit, which can implement the above-mentioned life assessment method for the electric drive power circuit. The device may include a monitoring module, a temperature module, a first life module, and a second life module.

[0113] The monitoring module can be used to monitor the target operating parameters of the electric drive power circuit; the electric drive power circuit is the energy transmission path connecting the power battery and the drive motor. The temperature module can be used to determine the temperature change information of the target part in the electric drive power circuit based on the target operating condition parameters; the temperature change information is used to characterize the temperature change of the target part over time. The first lifetime module can be used to assess the remaining lifetime of the target part based on the temperature change information of the target part, and obtain the remaining lifetime of the target part. The second lifetime module can be used to determine the remaining lifetime of the electric drive power circuit based on the remaining lifetime of the target location.

[0114] The electric drive power circuit lifetime assessment device provided in this application embodiment can realize all the steps of the above-described electric drive power circuit lifetime assessment method embodiment and achieve the same technical effect. To avoid repetition, it will not be described again here.

[0115] This application also provides an electric drive control device that can implement the above-described electric drive control method. The device may include an acquisition module, a power determination module, and a power limiting module.

[0116] The acquisition module can be used to acquire the remaining lifespan of the electric drive power circuit determined by the above-mentioned lifespan assessment method; the electric drive power circuit is the energy transmission path connecting the power battery and the drive motor. The power determination module can be used to determine the target maximum allowable output power of the drive motor based on the remaining life of the electric drive power circuit; The power limiting module can be used to limit the output power of the drive motor based on the target maximum allowable output power.

[0117] The electric drive control device provided in this application embodiment can implement all the steps of the above-described electric drive control method embodiment and achieve the same technical effect. To avoid repetition, it will not be described again here.

[0118] This application also provides an electronic device, including a processor and a memory. The memory stores a program or instructions that can run on the processor. When the program or instructions are executed by the processor, they implement the steps in the above-described embodiments of the electric drive power circuit lifetime assessment method or the above-described electric drive control method, and can achieve the same technical effect. To avoid repetition, they will not be described again here.

[0119] Figure 5 To illustrate the hardware structure of the electronic device according to the embodiments of this application, the electronic device includes: The processor 501 can be implemented using a general-purpose central processing unit (CPU), microprocessor, application specific integrated circuit (ASIC), or one or more integrated circuits, and is used to execute relevant programs to implement the technical solutions provided in the embodiments of this application. The memory 502 can be implemented as a read-only memory (ROM), static storage device, dynamic storage device, or random access memory (RAM). The memory 502 can store the operating system and other application programs. When the technical solutions provided in the embodiments of this specification are implemented through software or firmware, the relevant program code is stored in the memory 502 and is called and executed by the processor 501 to execute the life assessment method of the electric drive power circuit or the electric drive control method of the embodiments of this application. The input / output interface 503 is used to implement information input and output; The communication interface 504 is used to enable communication and interaction between this electronic device and other devices. Communication can be achieved through wired means (such as USB, network cable, etc.) or wireless means (such as mobile network, WIFI, Bluetooth, etc.). Bus 505 transmits information between various components of an electronic device (e.g., processor 501, memory 502, input / output interface 503, and communication interface 504); The processor 501, memory 502, input / output interface 503, and communication interface 504 are connected to each other within the electronic device via bus 505.

[0120] The electronic device provided in this application embodiment can implement the various steps of the above-described electric drive power circuit life assessment method embodiment or the above-described electric drive control method embodiment, and can achieve the same technical effect. To avoid repetition, it will not be described again here.

[0121] This application also provides a computer-readable storage medium storing a program or instructions. When the program or instructions are executed by a processor, they implement the steps of the above-described embodiments of the electric drive power circuit lifetime assessment method or the above-described embodiments of the electric drive control method, and achieve the same technical effect. To avoid repetition, they will not be described again here.

[0122] The processor is the processor in the electronic device described in the above embodiments. The computer-readable storage medium includes computer-readable storage media such as computer read-only memory (ROM), random access memory (RAM), magnetic disk, or optical disk.

[0123] This application also provides a vehicle including the aforementioned electronic device. This vehicle, through the aforementioned electronic device, can implement the various steps in the embodiments of the above-described electric drive power circuit life assessment method or the above-described electric drive control method, and can achieve the same technical effects. To avoid repetition, further details are omitted here.

[0124] This application also provides a chip, which includes a processor and a communication interface. The communication interface and the processor are coupled. The processor is used to run programs or instructions to implement the various steps of the above-described electric drive power circuit lifetime assessment method embodiment or the above-described electric drive control method embodiment, and can achieve the same technical effect. To avoid repetition, it will not be described again here.

[0125] It should be understood that the chip mentioned in the embodiments of this application may also be referred to as a system-on-a-chip, system chip, chip system, or system-on-a-chip, etc.

[0126] This application provides a computer program product stored in a storage medium. The program product is executed by at least one processor to implement the steps of the above-described electric drive power circuit life assessment method embodiment or the above-described electric drive control method embodiment, and can achieve the same technical effect. To avoid repetition, it will not be described again here.

[0127] It should be noted that, in this document, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not delete other identical elements present in the process, method, article, or apparatus that includes that element. Furthermore, it should be noted that the scope of the methods and apparatuses in the embodiments of this application is not limited to performing functions in the order shown or discussed, but may also include performing functions substantially simultaneously or in the reverse order, depending on the functions involved. For example, the described methods may be performed in a different order than described, and various steps may be added, omitted, or combined. Additionally, features described with reference to certain examples may be combined in other examples.

[0128] Through the above description of the embodiments, those skilled in the art can clearly understand that the methods of the above embodiments can be implemented by means of software plus necessary general-purpose hardware platforms. Of course, they can also be implemented by hardware, but in many cases the former is a better implementation method. Based on this understanding, the technical solution of this application, in essence, or the part that contributes to the prior art, can be embodied in the form of a computer software product. This computer software product is stored in a storage medium (such as ROM / RAM, magnetic disk, optical disk) and includes several instructions to cause a terminal (which may be a mobile phone, computer, server, or network device, etc.) to execute the methods of the various embodiments of this application.

[0129] The embodiments of this application have been described above with reference to the accompanying drawings. However, this application is not limited to the specific embodiments described above. The specific embodiments described above are merely illustrative and not restrictive. Those skilled in the art can make many other forms under the guidance of this application without departing from the spirit and scope of the claims, and all of these forms are within the protection scope of this application.

Claims

1. A method for assessing the lifetime of an electrically driven power circuit, characterized in that, include: Monitor the target operating parameters of the electric drive power circuit; the electric drive power circuit is the energy transmission path connecting the power battery and the drive motor. Based on the target operating parameters, the temperature change information of the target part in the electric drive power circuit is determined; the temperature change information is used to characterize the temperature change of the target part over time. Based on the temperature change information of the target part, the remaining lifespan of the target part is evaluated to obtain the remaining lifespan of the target part; The remaining lifespan of the electric drive power circuit is determined based on the remaining lifespan of the target part.

2. The life assessment method as described in claim 1, characterized in that, The target location includes a DC power distribution connection node; the target operating parameters include the DC side current and coolant temperature monitored within a time window; the time window includes an initial time and at least one target time after the initial time; The step of determining the temperature change information of the target part in the electric drive power circuit based on the target operating condition parameters includes: Based on the DC-side current and coolant temperature monitored within the time window, the resistance loss of the DC power distribution connection node within the time window is determined. For each target time within the time window, the following processing is performed to obtain the temperature of the DC distribution connection node at at least one target time: based on the resistance loss and the temperature rise value of the DC distribution connection node at the previous time of the target time, the temperature rise value of the DC distribution connection node at the target time is determined; based on the temperature rise value of the DC distribution connection node at the target time, the temperature of the DC distribution connection node at the target time is determined. The temperature change information includes the temperature of the DC power distribution connection node at the initial time and at the at least one target time.

3. The life assessment method as described in claim 2, characterized in that, The determination of the resistance loss of the DC power distribution connection node within the time window, based on the DC-side current and coolant temperature monitored within the time window, includes: Based on the coolant temperature monitored within the time window, the equivalent resistance of the DC power distribution connection node within the time window is determined. Based on the DC-side current monitored within the time window, the effective value of the DC current at the DC distribution connection node within the time window is determined. The resistance loss is determined based on the equivalent resistance and the effective value of the DC current.

4. The life assessment method as described in claim 1, characterized in that, The target location includes the bus capacitor; the target operating parameters include the DC-side current, bus capacitor casing temperature, and switching frequency monitored within a time window; the time window includes multiple moments. The step of determining the temperature change information of the target part in the electric drive power circuit based on the target operating condition parameters includes: Based on the DC-side current monitored within the time window, the effective value of the bus capacitor's ripple within the time window is determined. For each moment within the time window, the following processing is performed to obtain the temperature of the bus capacitor at each of the multiple moments: based on the RMS ripple value, the bus capacitor casing temperature at each moment, and the switching frequency, the ripple loss of the bus capacitor at each moment is determined; based on the ripple loss at each moment and the bus capacitor casing temperature, the temperature of the bus capacitor at each moment is determined. The temperature change information includes the temperature of the bus capacitor at multiple times.

5. The life assessment method as described in claim 4, characterized in that, The determination of the ripple loss of the bus capacitor at a given time, based on the RMS ripple value and the bus capacitor casing temperature and switching frequency at that time, includes: Based on the bus capacitor casing temperature and switching frequency at the specified time, determine the equivalent resistance of the bus capacitor at that time. The ripple loss is determined based on the RMS value of the ripple and the equivalent resistance.

6. The life assessment method as described in claim 1, characterized in that, The target location includes power semiconductor devices; the target operating parameters include three-phase current, switching frequency, and bus voltage monitored within a time window; the time window includes an initial time and at least one target time after the initial time; The step of determining the temperature change information of the target part in the electric drive power circuit based on the target operating condition parameters includes: For each target time within the time window, the following processing is performed to obtain the temperature of the power semiconductor device at at least one target time: Based on the three-phase current, switching frequency, and bus voltage at the target time, and the temperature of the power semiconductor device at the previous time, the target loss of the power semiconductor device at the target time is determined; based on the target loss and the temperature rise of the power semiconductor device at the previous time, the temperature rise of the power semiconductor device at the target time is determined; based on the temperature rise of the power semiconductor device at the target time, the temperature of the power semiconductor device at the target time is determined. The temperature change information includes the temperature of the power semiconductor device at the initial time and at the at least one target time.

7. The life assessment method as described in claim 6, characterized in that, The determination of the target loss of the power semiconductor device at the target time, based on the three-phase current, switching frequency, bus voltage at the target time, and the temperature of the power semiconductor device at the previous time, includes: Based on the three-phase current at the target time and the temperature of the power semiconductor device at the previous time, the conduction loss of the power semiconductor device at the target time is determined. Based on the switching frequency, bus voltage and three-phase current at the target time, and the temperature of the power semiconductor device at the previous time, the switching loss of the power semiconductor device at the target time is determined. The target loss is determined based on the conduction loss and the switching loss.

8. The life assessment method as described in claim 1, characterized in that, The process of assessing the remaining lifetime of the target part based on the temperature change information of the target part, and obtaining the remaining lifetime of the target part, includes: Stress cycle counting analysis is performed on the temperature change information of the target location to obtain the thermal stress cycle set of the target location. For each thermal stress cycle in the set of thermal stress cycles, the life loss of the target part in the thermal stress cycle is determined based on the stress characteristic data of the target part in the thermal stress cycle. The remaining lifespan of the target part is determined based on the lifespan loss of the target part in each thermal stress cycle.

9. The life assessment method as described in claim 1, characterized in that, The target area includes multiple areas; Determining the remaining lifetime of the electric drive power circuit based on the remaining lifetime of the target location includes: The remaining lifetimes of the plurality of parts are compared to determine the minimum remaining lifetime among the plurality of parts; The remaining lifetime of the electric drive power circuit is determined based on the minimum remaining lifetime.

10. An electric drive control method, characterized in that, include: Obtain the remaining lifetime of the electric drive power circuit as determined by the lifetime assessment method as described in any one of claims 1-9; the electric drive power circuit is an energy transmission path connecting the power battery and the drive motor. Based on the remaining lifespan of the electric drive power circuit, determine the target maximum allowable output power of the drive motor; The output power of the drive motor is limited based on the target maximum allowable output power.

11. The electric drive control method as described in claim 10, characterized in that, Determining the target maximum allowable output power of the drive motor based on the remaining lifespan of the electric drive power circuit includes: Based on the temperature of the target location in the electric drive power circuit, the first maximum allowable output power of the drive motor is determined; Based on the remaining lifespan of the electric drive power circuit, determine the second maximum allowable output power of the drive motor; The target maximum allowable output power is determined based on the smaller of the first maximum allowable output power and the second maximum allowable output power.

12. An electronic device, characterized in that, The electronic device includes a memory and a processor, the memory storing a computer program, and the processor executing the computer program to implement the life assessment method as described in any one of claims 1 to 9, or the electric drive control method as described in any one of claims 10-11.

13. A computer-readable storage medium storing a computer program, characterized in that, When the computer program is executed by the processor, it implements the life assessment method as described in any one of claims 1 to 9, or the electric drive control method as described in any one of claims 10-11.

14. A vehicle, characterized in that, The vehicle includes the electronic equipment as described in claim 12.

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