Peak current output capability identification method, system, equipment and medium

Abstract

The invention provides an output peak current capability identification method, system and device and a medium, and relates to the technical field of motor controllers, and the method comprises the steps: obtaining a power loss function of a power unit in a power module; constructing an initial junction temperature observer according to thermal resistance network nodes of the power module; acquiring peak current of the power module under different preset boundary conditions through a power module test, wherein each preset boundary condition comprises a preset value of each peak current output capability influence factor of the power module; performing test correction on the initial junction temperature observer based on the power loss function and the peak current of the power module under different preset boundary conditions to obtain a target junction temperature observer; the peak current of the power module under the real boundary condition is obtained based on the power loss function and the target junction temperature observer, the current output capacity of the motor controller can be maximized on the premise that the junction temperature of the power unit does not exceed the safety threshold value, and the performance potential of the motor controller is brought into full play.

Description

Technical Field

[0001] This application relates to the field of motor controller technology, and in particular to a method, system, device and medium for identifying output peak current capability. Background Technology

[0002] As the core component of the motor controller, the power module generates a large amount of energy loss when operating at high current and high power. The loss mainly consists of conduction loss and switching loss, which is dissipated to the outside in the form of heat energy. The heat is carried away by the coolant on the water-cooling plate. In order to prevent the power module from over-temperature failure, temperature protection is required for the power module.

[0003] The peak current capability that a motor controller can deliver is determined by the power module. Currently, most mass-produced motor controllers on the market deliver a constant peak current. This design has certain drawbacks, as it does not fully utilize the performance potential of the motor controller. For example, the lower the DC bus voltage, the lower the switching losses of the motor controller, and the current capability at low voltage is naturally higher than that at high voltage. Therefore, determining the actual current capability that the motor controller can deliver under different boundary conditions is particularly important. Summary of the Invention

[0004] In view of the shortcomings of the prior art described above, the purpose of this application is to provide a method, system, device and medium for identifying the output peak current capability, so as to solve the problem of the performance potential peak current of motor controllers in the prior art.

[0005] To achieve the above and other related objectives, this application provides a method for identifying output peak current capability, applied to a motor controller, the motor controller including a power module, the method comprising:

[0006] Obtain the power loss function of the power unit in the power module;

[0007] An initial junction temperature observer is constructed based on the thermal resistance network nodes of the power module;

[0008] The peak current of the power module under different preset boundary conditions is obtained through power module testing experiments. Each preset boundary condition includes preset values ​​of the factors affecting the peak current output capability of the power module.

[0009] The initial junction temperature observer is experimentally calibrated based on the power loss function and the peak current of the power module under different preset boundary conditions in order to obtain the target junction temperature observer.

[0010] The peak current of the power module under real boundary conditions is obtained based on the power loss function and the target junction temperature observer.

[0011] In one embodiment of this application, the power unit includes an IGBT and a freewheeling diode connected in reverse parallel with the IGBT;

[0012] The power loss function includes the switching power loss function and the conducting power loss function;

[0013] The switching power loss function includes the switching power loss function of the IGBT and the switching power loss function of the freewheeling diode.

[0014] The conduction power loss function includes the conduction power loss of the IGBT and the conduction power loss of the freewheeling diode.

[0015] In one embodiment of this application, obtaining the power loss function of the power unit in the power module includes:

[0016] Acquire the switching loss test data and conduction loss test data of the power unit under different junction temperatures, different bus voltages and different phase current values;

[0017] Based on the switching loss test data, the conduction loss test data, the switching frequency of the motor controller, the electrical frequency of the motor controller, the voltage utilization rate, and the motor power factor, the switching power loss function and the conduction power loss function of the power unit are obtained.

[0018] In one embodiment of this application, the switching power loss function and the conducting power loss function of the power unit are obtained based on the switching loss test data, the conducting loss test data, the switching frequency of the motor controller, the electrical frequency of the motor controller, the voltage utilization rate, and the motor power factor, including:

[0019] The switching energy loss function and the conducting energy loss function of the power unit are obtained based on the switching loss data and the conducting loss data.

[0020] The switching power loss function and conducting power loss function of the IGBT and diode of the power module are obtained based on the switching power loss function and conducting power loss function of the power unit, the switching frequency of the motor controller, the electrical frequency of the motor controller, the voltage utilization rate, and the motor power factor.

[0021] In one embodiment of this application, constructing an initial junction temperature observer based on the thermal resistance network nodes of the power module includes:

[0022] The thermal resistance network nodes of the power module are connected by thermal resistance and thermal capacitance to construct a thermal resistance network model. The thermal network nodes include nodes where the temperature can be directly measured by thermal sensors, nodes for junction temperature and coolant temperature that the observer needs to output.

[0023] Simulations were performed based on the three-dimensional digital model of the motor controller to identify the thermal resistance and thermal capacity parameters of each thermal resistance network node in the thermal resistance network model.

[0024] The initial junction temperature observer is obtained based on the thermal resistance and thermal capacity parameters of each thermal resistance network node in the thermal resistance network model.

[0025] In one embodiment of this application, obtaining the initial junction temperature observer based on the thermal resistance and thermal capacity parameters of each thermal resistance network node in the thermal resistance network model includes:

[0026] Based on the thermal resistance and thermal capacity parameters of each thermal resistance network node in the thermal resistance network model, a state matrix, an input matrix, and an output matrix are constructed.

[0027] Based on the state matrix, input matrix, and output matrix, a first state space expression for the power module is constructed.

[0028] Based on the first state-space expression, a second state-space expression for the Luenberger junction temperature observer is constructed.

[0029] The dynamic equation of the observer estimation error is obtained by using the first state-space expression and the second state-space expression;

[0030] The observer gain matrix in the second state-space expression is solved using the pole placement method to obtain the initial junction temperature observer.

[0031] In one embodiment of this application, obtaining the peak current of the power module under real boundary conditions based on the power loss function and the target junction temperature observer includes:

[0032] Under real boundary conditions, calculate the theoretical power loss data for different phase currents based on the power loss function;

[0033] The theoretical power loss data under different phase currents are used as input to the target junction temperature observer, and the junction temperature variation trend of the power unit under different phase currents is estimated using the target junction temperature observer.

[0034] Based on the junction temperature variation trend and junction over-temperature threshold under different phase currents, the maximum phase current whose junction temperature does not exceed the junction over-temperature threshold of the power unit is determined as the peak current of the power module under the real boundary conditions.

[0035] In one embodiment of this application, the factors affecting the peak current output capability of the power module include duration, bus voltage, switching frequency, electrical frequency, coolant flow rate, coolant temperature, motor power factor, and voltage utilization rate.

[0036] In one embodiment of this application, the state variables of the initial junction temperature observer include the IGBT junction temperature, the freewheeling diode junction temperature, the sensor temperature, the coolant temperature, and the water-cooled plate temperature; the input variables include the power loss of the power unit; and the output variables include the IGBT junction temperature, the freewheeling diode junction temperature, the sensor temperature, and the coolant temperature.

[0037] In one embodiment of this application, it further includes:

[0038] Based on the peak current of the power module under different preset boundary conditions, the peak current under the actual boundary conditions is determined by interpolation; or

[0039] Based on the peak current of the power module under different preset boundary conditions, the peak current of the preset boundary condition that is close to the actual boundary condition is selected as the peak current under the actual boundary condition.

[0040] To achieve the above and other related objectives, this application also provides an output peak current capability identification system applied to a motor controller, the motor controller including a power module, the system comprising:

[0041] The loss function acquisition module is used to acquire the power loss function of the power unit in the power module;

[0042] An observer construction module is used to construct an initial junction temperature observer based on the thermal resistance network nodes of the power module.

[0043] The power module testing module is used to obtain the peak current of the power module under different preset boundary conditions through power module testing. Each preset boundary condition includes preset values ​​of the factors affecting the peak current output capability of the power module.

[0044] The observer calibration module is used to perform experimental calibration on the initial junction temperature observer based on the power loss function and the peak current of the power module under different preset boundary conditions, so as to obtain the target junction temperature observer.

[0045] A peak current identification module is used to obtain the peak current of the power module under real boundary conditions based on the power loss function and the target junction temperature observer.

[0046] To achieve the above and other related objectives, this application provides an electronic device comprising: one or more processors; and a storage device for storing one or more programs, which, when executed by the one or more processors, cause the electronic device to implement the aforementioned output peak current capability identification method.

[0047] To achieve the above and other related objectives, this application further provides a computer-readable storage medium having a computer program stored thereon, which, when executed by a computer's processor, causes the computer to perform the aforementioned output peak current capability identification method.

[0048] As described above, the output peak current capability identification method, system, device, and medium of this application have the following beneficial effects:

[0049] This application includes obtaining the power loss function of the power unit in the power module; constructing an initial junction temperature observer based on the thermal resistance network nodes of the power module; obtaining the peak current of the power module under different preset boundary conditions through power module testing experiments, each preset boundary condition including preset values ​​of the factors affecting the peak current output capability of the power module; experimentally correcting the initial junction temperature observer based on the power loss function and the peak current of the power module under different preset boundary conditions to obtain a target junction temperature observer; obtaining the peak current of the power module under real boundary conditions based on the power loss function and the target junction temperature observer, thereby maximizing the output current capability of the motor controller and fully utilizing the performance potential of the motor controller while ensuring that the junction temperature of the power unit does not exceed the safety threshold. Attached Figure Description

[0050] Figure 1 The diagram shows a flowchart illustrating the output peak current capability identification method provided in this application embodiment;

[0051] Figure 2 The diagram shown is a block diagram of a state observer provided in an embodiment of this application.

[0052] Figure 3 The diagram shows the factors affecting peak current output capability as provided in the embodiments of this application.

[0053] Figure 4 The diagram shown is a structural block diagram of an output peak current capability identification system provided in an embodiment of this application.

[0054] Figure 5 The diagram shown is a structural schematic of an electronic device according to an embodiment of this application. Detailed Implementation

[0055] The following specific examples illustrate the implementation of this application. Those skilled in the art can easily understand other advantages and effects of this application from the content disclosed in this specification. This application can also be implemented or applied through other different specific embodiments, and various details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of this application. It should be noted that, unless otherwise specified, the following embodiments and features in the embodiments can be combined with each other.

[0056] It should be noted that the illustrations provided in the following embodiments are only schematic representations of the basic concept of this application. Therefore, the drawings only show the components related to this application and are not drawn according to the actual number, shape and size of the components in the actual implementation. In the actual implementation, the form, quantity and proportion of each component can be arbitrarily changed, and the layout of the components may also be more complex.

[0057] In the following description, numerous details are explored to provide a more thorough explanation of embodiments of the present application. However, it will be apparent to those skilled in the art that embodiments of the present application may be practiced without these specific details. In other embodiments, well-known structures and devices are shown in block diagram form rather than in detail to avoid obscuring embodiments of the present application.

[0058] Please see Figure 1 This application provides a method for identifying peak output current capability, applied to a motor controller, which includes a power module, and includes steps S10-S50. The motor controller can be an automotive motor controller or a motor controller from other industrial fields.

[0059] The following will combine Figure 1 The technical solution of this application will be described in detail below.

[0060] Step S10: Obtain the power loss function of the power unit in the power module.

[0061] In this application, when obtaining the power loss function of the power unit in the power module, the switching loss test data and conduction loss test data of the power unit under different junction temperatures, different bus voltages and different phase current values ​​can be obtained first; then, based on the switching loss test data, the conduction loss test data, the switching frequency of the motor controller, the electrical frequency of the motor controller, the voltage utilization rate, and the motor power factor, the switching power loss function and the conduction power loss function of the power unit can be obtained.

[0062] Based on the switching loss test data, the conduction loss test data, the switching frequency of the motor controller, the electrical frequency of the motor controller, the voltage utilization rate, and the motor power factor, the switching power loss function and the conduction power loss function of the power unit can be obtained. First, the switching energy loss function and the conduction energy loss function of the power unit can be obtained based on the switching loss data and the conduction loss data. Then, based on the switching energy loss function and the conduction energy loss function of the power unit, the switching frequency of the motor controller, the electrical frequency of the motor controller, the voltage utilization rate, and the motor power factor, the switching power loss function and the conduction power loss function of the IGBT and diode of the power module can be obtained.

[0063] A power unit typically includes an IGBT and a freewheeling diode, which is connected in anti-parallel to the IGBT. Power loss is composed of the switching losses and conduction losses of the IGBT and diode; therefore, the power loss function includes a switching power loss function and a conduction power loss function. Specifically, the switching power loss function includes the switching power loss function of the IGBT and the switching power loss function of the freewheeling diode; the conduction power loss function includes the conduction power loss of the IGBT and the conduction power loss of the freewheeling diode. It is understood that in other embodiments, the power unit may also be composed of a MOSFET and a body diode.

[0064] Specifically, different junction temperatures T can be obtained through switch testing. j The switching loss data of IGBT and Diode under different bus voltages U and different phase currents i were used to fit the switching loss function relationship. The switching loss of IGBT mainly consists of turn-on loss and turn-off loss, while the switching loss of Diode mainly consists of reverse recovery loss.

[0065] E IGBT-switch =f(U,T) j ,i)

[0066] E Diode-switch =f(U,T) j ,i)

[0067] In the formula: E IGBT-switch E represents the switching energy loss function of an IGBT. Diode-switch This represents the switching energy loss function of the Diode, where U is the motor controller bus voltage, and T is the voltage value. j is the junction temperature value (because the IGBT and Diode are together, the junction temperature can be approximately equal), and i is the phase current value.

[0068] Switching losses occur only during the switching process, which is very short and has no relation to the duty cycle. Therefore, switching losses are unrelated to the modulation (also known as voltage utilization) and power factor of SVPWM.

[0069] The switching power loss function relationship between IGBT and Diode under SVMWM modulation is as follows:

[0070] P sw,IGBT =f(U,T) j ,i,f sw ,f EI )

[0071] P sw,Diode =f(U,T) j ,i,f sw ,f EI )

[0072] In the formula: P sw,IGBT P represents the switching power loss function of the IGBT. sw,Diode Let f represent the switching power loss function of a diode. sw f represents the switching frequency of the motor controller. EI This indicates the electrical frequency of the motor controller.

[0073] Different junction temperatures T can be obtained through continuity testing. j The on-state voltage drop data of IGBT and Diode under different bus voltages U and different phase currents i were obtained, and fitting or linear interpolation was performed to obtain the junction temperature T at different junction temperatures. j The conduction loss data of IGBT and Diode under different bus voltages U and different phase currents i were fitted to obtain the following conduction loss function relationship:

[0074] E IGBT-cond =f(U,T) j ,i)

[0075] E Diode-cond =f(U,T) j ,i)

[0076] In the formula: E IGBT-cond E represents the on-state energy loss function of an IGBT. Diode-switch This represents the conduction energy loss function of the diode, where U is the motor controller bus voltage, and T is the voltage value. j is the junction temperature value, and i is the phase current value.

[0077] The on-loss function relationship between IGBT and Diode under SVPWM modulation is as follows:

[0078]

[0079]

[0080] In the formula: P cond,IGBT P represents the on-state power loss function of the IGBT. cond,Diode This represents the conduction power loss function of the diode, where m is the voltage utilization rate. The power factor.

[0081] It should be noted that, under other modulation methods, the switching loss function and conduction loss function of IGBT and Diode can also be obtained using similar methods.

[0082] Step S20: Construct an initial junction temperature observer based on the thermal resistance network nodes of the power module.

[0083] In this application, an initial junction temperature observer is constructed based on the thermal resistance network nodes of the power module. Each thermal resistance network node of the power module can be connected via thermal resistance and thermal capacitance to construct a thermal resistance network model. The thermal network nodes include nodes where thermal sensors can directly measure temperature, nodes for outputting junction temperature, coolant temperature, and other relevant temperature measurement nodes. Thermal simulation is performed based on the three-dimensional digital model of the motor controller to identify the thermal resistance and thermal capacitance parameters of each thermal resistance network node in the thermal resistance network model, which are used as coefficients for constructing the junction temperature observer. The initial junction temperature observer is obtained based on the thermal resistance and thermal capacitance parameters of each thermal resistance network node in the thermal resistance network model.

[0084] In this application, as Figure 2 As shown, obtaining the initial junction temperature observer based on the thermal resistance and thermal capacity parameters of each thermal resistance network node in the thermal resistance network model may further include:

[0085] Based on the thermal resistance and thermal capacity parameters of each thermal resistance network node in the thermal resistance network model, a state matrix A, an input matrix B, and an output matrix C are constructed.

[0086] Based on the state matrix A, input matrix B, and output matrix C, construct the first state space expression of the power module:

[0087]

[0088] In the formula: x represents state variables, including IGBT junction temperature, freewheeling diode junction temperature, sensor temperature, coolant temperature, water-cooled plate temperature, etc. Let x represent the first derivative, u represent the input quantity, including the power loss of the power unit; and y represent the output quantity, including the IGBT junction temperature, the freewheeling diode junction temperature, the sensor temperature, and the coolant temperature.

[0089] Based on the first state-space expression, construct the second state-space expression for the Luenberger junction temperature observer:

[0090]

[0091] In the formula: This represents the estimated value of the state variable. express The first derivative; This represents an estimated value of the output quantity;

[0092] The dynamic equation for the observer estimation error is obtained by using the first state-space expression and the second state-space expression:

[0093]

[0094] In the formula: L represents the estimation error, and L is the observer gain matrix.

[0095] To ensure that the error between the state observer and the original system approaches zero, the eigenvalues ​​of (A-LC) need to have negative real parts. The observer gain matrix L in the second state-space expression can be solved by the pole placement method to obtain the initial junction temperature observer.

[0096] Steps S30 and S40: Obtain the peak current of the power module under different preset boundary conditions through power module testing. Each preset boundary condition includes preset values ​​of the factors affecting the peak current output capability of the power module. Based on the power loss function and the peak current of the power module under different preset boundary conditions, perform experimental correction on the initial junction temperature observer to obtain the target junction temperature observer.

[0097] The initial junction temperature observer constructed based on thermal resistance network nodes has a coefficient matrix obtained through thermal simulation, which has limited accuracy. It is necessary to obtain the peak current of the power module under different preset boundary conditions through power module testing experiments, and then test and correct the coefficient matrix of the initial junction temperature observer accordingly to ensure the accuracy of the junction temperature observer.

[0098] like Figure 3 As shown in this application, the factors affecting the peak current output capability of the power module may include, for example, duration, bus voltage, switching frequency, electrical frequency, coolant flow rate, coolant temperature, motor power factor, voltage utilization rate, etc.

[0099] In this application, the power module testing includes dummy load current testing and motor bench torque control mode testing. The dummy load current testing simulates the motor's state using inductors, while the motor bench testing involves testing the controller and motor together. By testing under various influencing factors such as duration, DC bus voltage, controller switching frequency, controller electrical frequency, coolant flow rate, coolant temperature, motor power factor, and voltage utilization, the parameters of the thermal resistance network model are verified. Through cross-referencing between experiments and simulations, the simulated temperature results are made close to the measured temperature results, meeting the error requirements. Table 1 shows an example of typical values ​​for the factors affecting peak current output capability. Table 2 shows the peak current output capability of the motor controller obtained from experiments under different preset boundary conditions by changing a single variable based on the typical values ​​of the factors affecting peak current output capability in Table 1.

[0100] Table 1 Typical values ​​of factors affecting peak current output capability

[0101] Duration bus voltage Switching frequency electrical frequency Coolant flow rate Coolant temperature Motor power factor Voltage utilization 10s 350V 10kHz 50Hz 8L / min 65℃ 0.75 1

[0102] Table 2. Peak Current Output Capability of Controller under Different Boundary Conditions

[0103] Duration bus voltage Switching frequency electrical frequency Coolant flow rate Coolant temperature Motor power factor Voltage utilization Peak current 10s 350V 10kHz 50Hz 8L / min 65℃ 0.75 1 xxx 4s 350V 10kHz 50Hz 8L / min 65℃ 0.75 1 xxx 15s 350V 10kHz 50Hz 8L / min 65℃ 0.75 1 xxx 30s 350V 10kHz 50Hz 8L / min 65℃ 0.75 1 xxx 10s 200V 10kHz 50Hz 8L / min 65℃ 0.75 1 xxx 10s 250V 10kHz 50Hz 8L / min 65℃ 0.75 1 xxx 10s 300V 10kHz 50Hz 8L / min 65℃ 0.75 1 xxx 10s 400V 10kHz 50Hz 8L / min 65℃ 0.75 1 xxx 10s 350V 5kHz 50Hz 8L / min 65℃ 0.75 1 xxx 10s 350V 6kHz 50Hz 8L / min 65℃ 0.75 1 xxx 10s 350V 8kHz 50Hz 8L / min 65℃ 0.75 1 xxx 10s 350V 9kHz 50Hz 8L / min 65℃ 0.75 1 xxx 10s 350V 10kHz 10Hz 8L / min 65℃ 0.75 1 xxx 10s 350V 10kHz 30Hz 8L / min 65℃ 0.75 1 xxx 10s 350V 10kHz 70Hz 8L / min 65℃ 0.75 1 xxx 10s 350V 10kHz 100Hz 8L / min 65℃ 0.75 1 xxx 10s 350V 10kHz 50Hz 2L / min 65℃ 0.75 1 xxx 10s 350V 10kHz 50Hz 4L / min 65℃ 0.75 1 xxx 10s 350V 10kHz 50Hz 5L / min 65℃ 0.75 1 xxx 10s 350V 10kHz 50Hz 6L / min 65℃ 0.75 1 xxx 10s 350V 10kHz 50Hz 8L / min 0℃ 0.75 1 xxx 10s 350V 10kHz 50Hz 8L / min 20℃ 0.75 1 xxx 10s 350V 10kHz 50Hz 8L / min 40℃ 0.75 1 xxx 10s 350V 10kHz 50Hz 8L / min 80℃ 0.75 1 xxx 10s 350V 10kHz 50Hz 8L / min 65℃ -1 1 xxx 10s 350V 10kHz 50Hz 8L / min 65℃ -0.5 1 xxx 10s 350V 10kHz 50Hz 8L / min 65℃ 1 1 xxx 10s 350V 10kHz 50Hz 8L / min 65℃ 0.5 1 xxx 10s 350V 10kHz 50Hz 8L / min 65℃ 0.75 -1 xxx 10s 350V 10kHz 50Hz 8L / min 65℃ 0.75 -0.5 xxx 10s 350V 10kHz 50Hz 8L / min 65℃ 0.75 1 xxx 10s 350V 10kHz 50Hz 8L / min 65℃ 0.75 0.5 xxx xxx xxx xxx xxx xxx xxx xxx xxx xxx xxx xxx xxx xxx xxx xxx xxx xxx xxx

[0104] S50. Obtain the peak current of the power module under real boundary conditions based on the power loss function and the target junction temperature observer.

[0105] In this application, obtaining the peak current of the power module under real boundary conditions based on the power loss function and the target junction temperature observer may further include:

[0106] Under real boundary conditions, calculate the theoretical power loss data for different phase currents based on the power loss function;

[0107] The theoretical power loss data under different phase currents are used as input to the target junction temperature observer, and the junction temperature variation trend of the power unit under different phase currents is estimated using the target junction temperature observer.

[0108] Based on the junction temperature variation trend and junction over-temperature threshold under different phase currents, the maximum phase current at which the junction temperature of the power unit does not exceed the junction over-temperature threshold is determined, and this is used as the peak current of the power module under the real boundary conditions. This maximizes the output current capability of the motor controller and fully utilizes the performance potential of the motor controller while ensuring that the junction temperature of the power unit does not exceed the safety threshold.

[0109] It should be noted that the peak current capability identification method of this application can also be based on the peak current capability obtained by the test under different preset boundary conditions of the controller output in step S30, i.e., Table 2, and the peak current of the motor controller under real boundary conditions can be identified by looking up the table.

[0110] For cases where a single variable is changed, the peak current of the power module under the actual boundary conditions can be determined by interpolation based on the peak current of the power module under different preset boundary conditions. It should be noted that the selection of the interpolation method requires fitting analysis based on a large amount of experimental data from test operating points to determine which interpolation method better reflects the actual capability of the power module.

[0111] For situations where a single variable or multiple variables are changed, the peak current of the power module under the actual boundary conditions can be selected based on the peak current of the power module under different preset boundary conditions, with the peak current of the preset boundary conditions being more stringent than the actual boundary conditions.

[0112] Please refer to 4. This application also provides an output peak current capability identification system for a motor controller, including a loss function acquisition module 111, an observer construction module 112, a power module testing module 113, an observer correction module 114, and a peak current identification module 115.

[0113] The loss function acquisition module 111 is used to acquire the power loss function of the power unit in the power module.

[0114] Observer construction module 112 is used to construct an initial junction temperature observer based on the thermal resistance network nodes of the power module;

[0115] The power module test module 113 is used to obtain the peak current of the power module under different preset boundary conditions through power module testing. Each preset boundary condition includes preset values ​​of the factors affecting the peak current output capability of the power module.

[0116] The observer correction module 114 is used to perform experimental correction on the initial junction temperature observer based on the power loss function and the peak current of the power module under different preset boundary conditions, so as to obtain the target junction temperature observer.

[0117] Peak current identification module 115 is used to obtain the peak current of the power module under real boundary conditions based on the power loss function and the target junction temperature observer;

[0118] The lookup table current identification module 116 is used to determine the peak current under the real boundary conditions by interpolation based on the peak current of the power module under different preset boundary conditions; or to select the peak current of the preset boundary conditions that are close to the real boundary conditions as the peak current under the real boundary conditions based on the peak current of the power module under different preset boundary conditions.

[0119] It should be noted that the output peak current capability identification system 11 provided in the above embodiments and the output peak current capability identification method provided in the above embodiments belong to the same concept. The specific operation methods of each module and unit have been described in detail in the method embodiments and will not be repeated here. In practical applications, the output peak current capability identification system 11 provided in the above embodiments can be assigned to different functional modules as needed, that is, the internal structure of the device can be divided into different functional modules to complete all or part of the functions described above. This is not a limitation here.

[0120] Please see Figure 5 The electronic device 1 may include a memory 12, a processor 13 and a bus, and may also include a computer program stored in the memory 12 and executable on the processor 13, such as an output peak current capability identification program.

[0121] The memory 12 includes at least one type of readable storage medium, such as flash memory, portable hard drive, multimedia card, card-type memory (e.g., SD or DX memory), magnetic memory, magnetic disk, optical disk, etc. In some embodiments, the memory 12 can be an internal storage unit of the electronic device 1, such as a portable hard drive. In other embodiments, the memory 12 can be an external storage device of the electronic device 1, such as a plug-in portable hard drive, smart media card (SMC), secure digital (SD) card, flash card, etc., equipped on the electronic device 1. Furthermore, the memory 12 can include both internal and external storage units of the electronic device 1. The memory 12 can be used not only to store application software and various types of data installed on the electronic device 1, such as codes for identifying peak current output capabilities, but also to temporarily store data that has been output or will be output.

[0122] In some embodiments, the processor 13 may be composed of integrated circuits, such as a single packaged integrated circuit or multiple integrated circuits with the same or different functions, including combinations of one or more central processing units (CPUs), microprocessors, digital processing chips, graphics processors, and various control chips. The processor 13 is the control unit of the electronic device 1, connecting various components of the electronic device 1 via various interfaces and lines. It executes programs or modules stored in the memory 12 (e.g., output peak current capability identification programs) and calls data stored in the memory 12 to perform various functions and process data of the electronic device 1.

[0123] The processor 13 executes the operating system of the electronic device 1 and various installed applications. The processor 13 executes the applications to implement the steps in the above-described method for identifying output peak current capability.

[0124] For example, the computer program may be divided into one or more modules, which are stored in the memory 12 and executed by the processor 13 to complete this application. The one or more modules may be a series of computer program instruction segments capable of performing specific functions, which describe the execution process of the computer program in the electronic device 1. For example, the computer program may be divided into unit modules of the output peak current capability identification system 11.

[0125] The integrated unit implemented as a software functional module described above can be stored in a computer-readable storage medium, which can be non-volatile or volatile. The software functional module, stored in the storage medium, includes several instructions to cause a computer device (which may be a personal computer, computer equipment, or network device, etc.) or processor to execute some functions of the output peak current capability identification method described in the various embodiments of this application.

[0126] In summary, this application discloses a method, system, device, and medium for identifying peak output current capability. The method includes: acquiring the power loss function of the power unit in the power module; constructing an initial junction temperature observer based on the thermal resistance network nodes of the power module; obtaining the peak current of the power module under different preset boundary conditions through power module testing, where each preset boundary condition includes preset values ​​for various factors influencing the peak current output capability of the power module; experimentally correcting the initial junction temperature observer based on the power loss function and the peak current of the power module under different preset boundary conditions to obtain a target junction temperature observer; and obtaining the peak current of the power module under actual boundary conditions based on the power loss function and the target junction temperature observer. This allows for maximizing the output current capability of the motor controller while ensuring that the junction temperature of the power unit does not exceed a safe threshold, thus fully realizing the performance potential of the motor controller. Therefore, this application effectively overcomes various shortcomings of the prior art and has high industrial applicability.

[0127] The above embodiments are merely illustrative of the principles and effects of this application and are not intended to limit this application. Any person skilled in the art can modify or alter the above embodiments without departing from the spirit and scope of this application. Therefore, all equivalent modifications or alterations made by those skilled in the art without departing from the spirit and technical concept disclosed in this application should still be covered by the claims of this application.

Claims

1. A method for identifying peak current capability, characterized in that, Applied to a motor controller, the motor controller including a power module, the method includes: Obtain the power loss function of the power unit in the power module; An initial junction temperature observer is constructed based on the thermal resistance network nodes of the power module; The peak current of the power module is obtained under different preset boundary conditions through power module testing experiments. Each preset boundary condition includes preset values ​​of the factors affecting the peak current output capability of the power module. The initial junction temperature observer is experimentally calibrated based on the power loss function and the peak current of the power module under different preset boundary conditions in order to obtain the target junction temperature observer. The peak current of the power module under real boundary conditions is obtained based on the power loss function and the target junction temperature observer.

2. The peak current capability identification method according to claim 1, characterized in that, The power unit includes an IGBT and a freewheeling diode connected in reverse parallel with the IGBT; The power loss function includes the switching power loss function and the conducting power loss function; The switching power loss function includes the switching power loss function of the IGBT and the switching power loss function of the freewheeling diode. The conduction power loss function includes the conduction power loss of the IGBT and the conduction power loss of the freewheeling diode.

3. The peak current capability identification method according to claim 1, characterized in that, Obtaining the power loss function of the power unit in the power module includes: Acquire the switching loss test data and conduction loss test data of the power unit under different junction temperatures, different bus voltages and different phase current values; Based on the switching loss test data, the conduction loss test data, the switching frequency of the motor controller, the electrical frequency of the motor controller, the voltage utilization rate, and the motor power factor, the switching power loss function and the conduction power loss function of the power unit are obtained.

4. The peak current capability identification method according to claim 3, characterized in that, Based on the switching loss test data, the conduction loss test data, the switching frequency of the motor controller, the electrical frequency of the motor controller, the voltage utilization rate, and the motor power factor, the switching power loss function and the conduction power loss function of the power unit are obtained, including: The switching energy loss function and the conducting energy loss function of the power unit are obtained based on the switching loss data and the conducting loss data. The switching power loss function and conducting power loss function of the IGBT and diode of the power module are obtained based on the switching power loss function and conducting power loss function of the power unit, the switching frequency of the motor controller, the electrical frequency of the motor controller, the voltage utilization rate, and the motor power factor.

5. The peak current capability identification method according to claim 1, characterized in that, Constructing an initial junction temperature observer based on the thermal resistance network nodes of the power module includes: The thermal resistance network nodes of the power module are connected by thermal resistance and thermal capacitance to construct a thermal resistance network model. The thermal network nodes include nodes where the temperature can be directly measured by thermal sensors, nodes for junction temperature and coolant temperature that the observer needs to output. Simulations were performed based on the three-dimensional digital model of the motor controller to identify the thermal resistance and thermal capacity parameters of each thermal resistance network node in the thermal resistance network model. The initial junction temperature observer is obtained based on the thermal resistance and thermal capacity parameters of each thermal resistance network node in the thermal resistance network model.

6. The peak current capability identification method according to claim 5, characterized in that, The initial junction temperature observer is obtained based on the thermal resistance and thermal capacity parameters of each node in the thermal resistance network model, including: Based on the thermal resistance and thermal capacity parameters of each thermal resistance network node in the thermal resistance network model, a state matrix, an input matrix, and an output matrix are constructed. Based on the state matrix, input matrix, and output matrix, a first state space expression for the power module is constructed. Based on the first state-space expression, a second state-space expression for the Luenberger junction temperature observer is constructed. The dynamic equation of the observer estimation error is obtained by using the first state-space expression and the second state-space expression; The observer gain matrix in the second state-space expression is solved using the pole placement method to obtain the initial junction temperature observer.

7. The peak current capability identification method according to claim 1, characterized in that, The peak current of the power module under real boundary conditions is obtained based on the power loss function and the target junction temperature observer, including: Under real boundary conditions, calculate theoretical power loss data for different phase currents based on the power loss function. The theoretical power loss data under different phase currents are used as input to the target junction temperature observer, and the junction temperature variation trend of the power unit under different phase currents is estimated using the target junction temperature observer. Based on the junction temperature variation trend and junction over-temperature threshold under different phase currents, the maximum phase current whose junction temperature does not exceed the junction over-temperature threshold of the power unit is determined as the peak current of the power module under the real boundary conditions.

8. The peak current capability identification method according to claim 1, characterized in that, Factors affecting the peak current output capability of the power module include duration, bus voltage, switching frequency, electrical frequency, coolant flow rate, coolant temperature, motor power factor, and voltage utilization rate.

9. The peak current capability identification method according to claim 1, characterized in that, The state variables of the initial junction temperature observer include IGBT junction temperature, freewheeling diode junction temperature, sensor temperature, coolant temperature, and water-cooled plate temperature. The input variables include the power loss of the power unit. The output variables include IGBT junction temperature, freewheeling diode junction temperature, sensor temperature, and coolant temperature.

10. The peak current capability identification method according to claim 1, characterized in that, Also includes: Based on the peak current of the power module under different preset boundary conditions, the peak current under the actual boundary conditions is determined by interpolation. or Based on the peak current of the power module under different preset boundary conditions, the peak current of the preset boundary condition that is close to the actual boundary condition is selected as the peak current under the actual boundary condition.

11. A peak current output capability identification system, characterized in that, Applied to a motor controller, the motor controller including a power module, the system includes: The loss function acquisition module is used to acquire the power loss function of the power unit in the power module; An observer construction module is used to construct an initial junction temperature observer based on the thermal resistance network nodes of the power module. The power module testing module is used to obtain the peak current of the power module under different preset boundary conditions through power module testing. Each preset boundary condition includes preset values ​​of the factors affecting the peak current output capability of the power module. The observer calibration module is used to perform experimental calibration on the initial junction temperature observer based on the power loss function and the peak current of the power module under different preset boundary conditions, so as to obtain the target junction temperature observer. A peak current identification module is used to obtain the peak current of the power module under real boundary conditions based on the power loss function and the target junction temperature observer.

12. An electronic device, characterized in that: The electronic device includes: One or more processors; A storage device for storing one or more programs, which, when executed by the one or more processors, cause the electronic device to implement the output peak current capability identification method as described in any one of claims 1 to 10.

13. A computer-readable storage medium, characterized in that, It stores a computer program that, when executed by the computer's processor, causes the computer to perform the output peak current capability identification method according to any one of claims 1 to 10.

Images