Equivalent Method for Time-Harmonic Field Excitation Based on Loss and Temperature Distribution and Related Devices

Abstract

The present application discloses a time-harmonic field excitation equivalent method based on loss and temperature distribution and related devices, which relates to the field of transformers, and includes: obtaining the total core loss of a target transformer when a set excitation voltage is applied and a set DC bias current is injected, using the total core loss as the target value, determining an equivalent power frequency excitation voltage when the set excitation voltage and the set DC bias current are equivalently converted to the case without DC bias based on the principle of consistent core loss, and calculating the loss distribution and temperature distribution of the core in the target transformer in a time-harmonic field finite element simulation software according to the equivalent power frequency excitation voltage. The present application can, based on the principle of consistent core loss, equivalently convert the set excitation voltage and the set DC bias current under the condition of DC bias into an equivalent power frequency excitation voltage without DC bias, so that the present application can be calculated in a time-harmonic field finite element simulation software, with shorter time consumption, lower resource consumption and greatly improved simulation calculation efficiency.

Description

Technical Field

[0001] This application relates to the field of transformers, and in particular to a time-harmonic field excitation equivalent method based on loss and temperature distribution and related devices. Background Art

[0002] Geomagnetic storms and the single-pole asymmetric operation of HVDC transmission projects are the main reasons for the DC bias of transformers. The DC bias will cause a sharp increase in the degree of excitation saturation, resulting in asymmetry of the core magnetic flux, and further causing the imbalance of the transformer magnetic circuit, a significant increase in leakage flux, affecting the loss, temperature rise and noise problems of the transformer. In severe cases, it may even cause damage to the transformer insulation, trigger serious faults, and directly threaten the safe operation of the power system. Therefore, it is of great significance to study the influence of DC bias on the core loss distribution and temperature distribution of transformers.

[0003] At present, in engineering design practice, the total core loss of a transformer under different excitation conditions can be obtained through an analytical calculation formula containing empirical coefficients. However, due to reasons such as the core structure type and the nonlinearity of the silicon steel sheet permeability, the magnetic flux density distribution at each part of the core cross-section is uneven, so the loss distribution at each part of the core cannot be deduced through the analytical calculation formula, and further the temperature distribution at each part of the core cannot be calculated based on the loss distribution.

[0004] In order to determine the core loss distribution and temperature distribution, it can be achieved through three-dimensional magnetic field finite element software. When the transformer is excited under DC bias conditions, the excitation source applied to the transformer is the superposition of the power frequency voltage and DC current excitation. Since the excitation source contains DC current excitation, the power frequency voltage and DC current can only be processed as corresponding time-domain waveforms respectively and input as the excitation source of the transient solver of the magnetic field finite element software. Finally, the loss distribution and temperature distribution of the transformer core under DC bias excitation conditions are obtained through the transient field calculation method. However, the transient field calculation method is time-consuming, has low calculation efficiency and consumes a large amount of hardware resources. Summary of the Invention

[0005] In view of the above problems, this application provides a time-harmonic field excitation equivalent method based on loss and temperature distribution and related devices to achieve the purpose of obtaining the core loss distribution and temperature distribution of the target transformer in the time-harmonic field finite element simulation software. The specific solutions are as follows:

[0006] The first aspect of this application provides a time-harmonic field excitation equivalent method based on loss and temperature distribution, including:

[0007] Obtain the total core loss of the target transformer when a set excitation voltage is applied and a set DC bias current is injected, as the first total core loss;

[0008] Taking the total core loss as the target value, based on the principle of consistent core loss, determine the equivalent power frequency excitation voltage when the set excitation voltage and the set DC bias current are equivalently converted to the case without DC bias;

[0009] Calculate the loss distribution and temperature distribution of the core in the target transformer in the time - harmonic field finite - element simulation software according to the equivalent power frequency excitation voltage.

[0010] In a possible implementation, obtaining the total core loss of the target transformer when a set excitation voltage is applied and a set DC bias current is injected as the first total core loss includes:

[0011] Obtain the basic parameter values of the target transformer;

[0012] Call the pre - generated DC bias analytical method calculation program to calculate the first total core loss based on the basic parameter values, the set excitation voltage, and the set DC bias current.

[0013] In a possible implementation, taking the first total core loss as the target value and determining the equivalent power frequency excitation voltage when the set excitation voltage and the set DC bias current are equivalently converted to the case without DC bias based on the principle of consistent core loss includes:

[0014] Determine the total core loss of the target transformer at the initial power frequency excitation voltage under the condition of no DC bias as the second total core loss;

[0015] Calculate the absolute value of the difference between the first total core loss and the second total core loss;

[0016] Judge whether the absolute value of the difference is greater than a preset threshold;

[0017] If not, determine the initial power frequency excitation voltage as the equivalent power frequency excitation voltage;

[0018] If so, adjust the initial power frequency excitation voltage to obtain an adjusted power frequency excitation voltage, take the adjusted power frequency excitation voltage as the initial power frequency excitation voltage, and return to determine the total core loss of the target transformer at the initial power frequency excitation voltage under the condition of no DC bias until the absolute value of the difference is less than or equal to the preset threshold, and then determine the adjusted power frequency excitation voltage as the equivalent power frequency excitation voltage.

[0019] In a possible implementation, determining the total core loss of the target transformer at the initial power frequency excitation voltage under the condition of no DC bias as the second total core loss includes:

[0020] Determine the initial core nominal peak magnetic density according to the initial power frequency excitation voltage;

[0021] Obtain the mapping curve of the peak magnetic density and the unit iron loss of the iron core;

[0022] Collect a plurality of data points according to the mapping curve, wherein the data points refer to the data points jointly represented by the peak magnetic density and the corresponding unit iron loss. If there are target data points exceeding the curve range of the mapping curve among the plurality of data points, the linear extrapolation method is used to add the target data points to the mapping curve;

[0023] Obtain the initial unit iron loss by using a preset interpolation method according to the plurality of data points and the initial nominal peak magnetic density of the iron core;

[0024] Determine the total loss of the second iron core according to the initial unit iron loss.

[0025] In a possible implementation, the preset interpolation method is one or more of a linear interpolation method, a spline interpolation method, and a polynomial interpolation method.

[0026] In a possible implementation, the adjustment of the initial power frequency excitation voltage includes:

[0027] Increase the initial power frequency excitation voltage by a preset step size.

[0028] The second aspect of the present application provides a time-harmonic field excitation equivalent device based on loss and temperature distribution, including:

[0029] A loss acquisition module, configured to acquire the total iron core loss of the target transformer when a set excitation voltage is applied and a set DC bias current is injected, as the first total iron core loss;

[0030] A voltage equivalent module, configured to determine the equivalent power frequency excitation voltage when the set excitation voltage and the set DC bias current are equivalently to the case without DC bias based on the principle of consistent iron core loss, with the first total iron core loss as the target value;

[0031] A distribution simulation module, configured to calculate the loss distribution and temperature distribution of the iron core in the target transformer in a time-harmonic field finite element simulation software according to the equivalent power frequency excitation voltage.

[0032] The third aspect of the present application provides a computer program product, including computer-readable instructions, which, when running on an electronic device, enable the electronic device to implement the time-harmonic field excitation equivalent method based on loss and temperature distribution in the first aspect or any implementation manner of the first aspect.

[0033] The fourth aspect of the present application provides an electronic device, including at least one processor and a memory connected to the processor, wherein:

[0034] The memory is used to store a computer program;

[0035] The processor is used to execute the computer program, so that the electronic device can implement the time - harmonic field excitation equivalent method based on loss and temperature distribution in the first aspect or any implementation manner of the first aspect.

[0036] The fifth aspect of this application provides a computer storage medium. The storage medium carries one or more computer programs. When the one or more computer programs are executed by an electronic device, the electronic device can implement the time - harmonic field excitation equivalent method based on loss and temperature distribution in the first aspect or any implementation manner of the first aspect.

[0037] By means of the above - mentioned technical solution, for the time - harmonic field excitation equivalent method based on loss and temperature distribution provided in this application, the total core loss of the target transformer when a set excitation voltage and a set DC bias current are injected is obtained as the first total core loss. Taking the first total core loss as the target value, based on the principle of consistent core loss, the equivalent power - frequency excitation voltage when the set excitation voltage and the set DC bias current are equivalently converted to the case without DC bias is determined. According to the equivalent power - frequency excitation voltage, the loss distribution and temperature distribution of the core in the target transformer are calculated in the time - harmonic field finite - element simulation software. It can be seen that this application can, based on the principle of consistent core loss, equivalently convert the set excitation voltage and the set DC bias current under the DC bias condition into the equivalent power - frequency excitation voltage without DC bias, so that this application can perform calculations in the time - harmonic field finite - element simulation software according to the equivalent power - frequency excitation voltage, which takes less time, consumes less resources and greatly improves the simulation calculation efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] Combined with the drawings and referring to the following specific implementation manners, the above - mentioned and other features, advantages and aspects of each embodiment of the present disclosure will become more obvious. Throughout the drawings, the same or similar reference numerals represent the same or similar elements. It should be understood that the drawings are schematic, and the original components and elements are not necessarily drawn to scale.

[0039] Figure 1 It is a schematic diagram of a system architecture provided by this application;

[0040] Figure 2 It is an optional hardware structure schematic diagram of the terminal 100 provided by this application;

[0041] Figure 3 It is a structure schematic diagram of a server 200 provided by this application;

[0042] Figure 4 It is a schematic flow diagram of a time - harmonic field excitation equivalent method based on loss and temperature distribution provided by this application;

[0043] Figure 5 Schematic diagram of the determination process of the equivalent power frequency excitation voltage provided by this application;

[0044] Figure 6 Schematic diagram of the structure of a time - harmonic field excitation equivalent device based on loss and temperature distribution provided by this application;

[0045] Figure 7 Schematic diagram of the structure of an electronic device provided by this application. Specific embodiments

[0046] The embodiments of this application will be described below in conjunction with the accompanying drawings in the embodiments of this application. The terms used in the embodiments part of this application are only used to explain the specific embodiments of this application, rather than intending to limit this application.

[0047] The embodiments of this application will be described below in conjunction with the accompanying drawings. Those of ordinary skill in the art will know that with the development of technology and the emergence of new scenarios, the technical solutions provided by the embodiments of this application are also applicable to similar technical problems.

[0048] The terms "first", "second", etc. in the specification, claims and above - mentioned drawings of this application are used to distinguish similar objects, and do not necessarily have to be used to describe a specific order or sequence. It should be understood that such terms can be interchanged under appropriate circumstances, which is only a way of distinguishing when describing objects with the same attributes in the embodiments of this application. In addition, the terms "including" and "having" and any variations thereof are intended to cover non - exclusive inclusion, so that a process, method, system, product or device including a series of units does not have to be limited to those units, but may include other units not clearly listed or inherent to these process, methods, products or devices.

[0049] See Figure 1 , Figure 1 shows a schematic diagram of a system architecture. The system may include a terminal 100 and a server 200. Among them, the server 200 may include one or more servers ( Figure 1 illustrated by including one server as an example), and the server 200 may provide the method provided by the embodiments of this application for one or more terminals.

[0050] Among them, an application program may be installed on the terminal 100. The above - mentioned application program and web page may provide an interface. The terminal 100 may receive relevant parameters input by the user on the interface and send the above - mentioned parameters to the server 200. The server 200 may obtain a processing result based on the received parameters and return the processing result to the terminal 100.

[0051] It should be understood that in some optional implementations, the terminal 100 can also complete the action of obtaining the processing result based on the received parameters by itself, without the cooperation of the server. The embodiments of the present application do not limit this.

[0052] Next, the product form of the terminal 100 will be described. Figure 1 in the terminal 100;

[0053] The terminal 100 in the embodiments of the present application can be a mobile phone, a tablet computer, a wearable device, a vehicle-mounted device, an augmented reality (AR) / virtual reality (VR) device, a laptop computer, an ultra-mobile personal computer (UMPC), a netbook, a personal digital assistant (PDA), etc. The embodiments of the present application do not impose any restrictions on this.

[0054] Figure 2 shows an optional hardware structure diagram of the terminal 100.

[0055] Referring to Figure 2 as shown, the terminal 100 may include a radio frequency unit 110, a memory 120, an input unit 130, a display unit 140, a camera 150 (optional), an audio circuit 160 (optional), a speaker 161 (optional), a microphone 162 (optional), a headphone jack 163 (optional), a processor 170, an external interface 180, a power supply 190, and other components. Those skilled in the art can understand that Figure 2 This is only an example of a terminal or a multifunctional device, and does not constitute a limitation on the terminal or the multifunctional device. It may include more or fewer components than those shown in the figure, or combine some components, or different components.

[0056] The input unit 130 can be used to receive input numerical or character information, and generate key signal inputs related to the user settings and function controls of the portable multifunctional device. Specifically, the input unit 130 can include a touch screen 131 (optional) and / or other input devices 132. The touch screen 131 can collect touch operations of the user thereon or nearby (such as operations of the user using any suitable object such as a finger, a joint, a stylus, etc. on or near the touch screen), and drive corresponding connection devices according to a preset program. The touch screen can detect the touch action of the user on the touch screen, convert the touch action into a touch signal and send it to the processor 170, and can receive and execute commands sent by the processor 170; the touch signal at least includes contact coordinate information. The touch screen 131 can provide an input interface and an output interface between the terminal 100 and the user. In addition, multiple types such as resistive, capacitive, infrared, and surface acoustic wave can be used to implement the touch screen. In addition to the touch screen 131, the input unit 130 can also include other input devices. Specifically, the other input devices 132 can include, but are not limited to, one or more of a physical keyboard, function keys (such as volume control keys, switch keys, etc.), a trackball, a mouse, a joystick, etc.

[0057] Among them, the input device 132 can receive input data and so on.

[0058] The display unit 140 can be used to display information input by the user or information provided to the user, various menus of the terminal 100, an interactive interface, file display, and / or the playback of any multimedia file.

[0059] The memory 120 can be used to store instructions and data. The memory 120 mainly includes a storage instruction area and a storage data area. The storage data area can store various data, such as multimedia files, texts, etc.; the storage instruction area can store software units such as an operating system, applications, instructions required for at least one function, or their subsets or extended sets. It can also include a non-volatile random access memory; it provides the processor 170 with management of hardware, software, and data resources in the computing processing device, supports control software and applications. It is also used for the storage of multimedia files, and the storage of running programs and applications.

[0060] The processor 170 is the control center of the terminal 100, connecting various parts of the entire terminal 100 through various interfaces and circuits. By running or executing instructions stored in the memory 120 and calling data stored in the memory 120, it performs various functions of the terminal 100 and processes data, thereby exercising overall control over the terminal device. Optionally, the processor 170 may include one or more processing units; preferably, the processor 170 may integrate an application processor and a modem processor. Among them, the application processor mainly processes the operating system, user interface, application programs, etc., and the modem processor mainly processes wireless communication. It can be understood that the above-mentioned modem processor may not be integrated into the processor 170 either. In some embodiments, the processor and the memory may be implemented on a single chip, and in some embodiments, they may also be separately implemented on independent chips. The processor 170 can also be used to generate corresponding operation control signals, send them to corresponding components of the computing and processing device, read and process data in the software, especially read and process the data and programs in the memory 120, so that each functional module therein executes corresponding functions, thereby controlling the corresponding components to act according to the requirements of the instructions.

[0061] Among them, the memory 120 can be used to store software codes related to the time-harmonic field excitation equivalent method based on loss and temperature distribution. The processor 170 can execute the steps of the time-harmonic field excitation equivalent method based on loss and temperature distribution, and can also schedule other units (such as the above-mentioned input unit 130 and display unit 140) to implement corresponding functions.

[0062] The radio frequency unit 110 (optional) can be used for receiving and transmitting information or signals during a call. For example, after receiving the downlink information from the base station, it is sent to the processor 170 for processing; in addition, the uplink data designed is sent to the base station. Generally, the RF circuit includes but is not limited to an antenna, at least one amplifier, a transceiver, a coupler, a low noise amplifier (LNA), a duplexer, etc. In addition, the radio frequency unit 110 can also communicate with network devices and other devices through wireless communication. This wireless communication can use any communication standard or protocol, including but not limited to Global System of Mobile Communication (GSM), General Packet Radio Service (GPRS), Code Division Multiple Access (CDMA), Wideband Code Division Multiple Access (WCDMA), Long Term Evolution (LTE), email, Short Messaging Service (SMS), etc.

[0063] Wherein, in the embodiment of the present application, the radio frequency unit 110 can send data to the server 200 and receive the processing result sent by the server 200.

[0064] It should be understood that the radio frequency unit 110 is optional and can be replaced by other communication interfaces, such as a network interface.

[0065] The terminal 100 further includes a power supply 190 (such as a battery) for powering each component. Preferably, the power supply can be logically connected to the processor 170 through a power management system, so as to implement functions such as management of charging, discharging, and power consumption management through the power management system.

[0066] The terminal 100 further includes an external interface 180. This external interface can be a standard Micro USB interface or a multi-pin connector, and can be used to connect the terminal 100 to other devices for communication, or can be used to connect a charger to charge the terminal 100.

[0067] Although not shown, the terminal 100 may further include a flash, a Wireless Fidelity (WiFi) module, a Bluetooth module, sensors with different functions, etc., which will not be elaborated here. Some or all of the methods described below can be applied to the terminal 100 as Figure 2 shown.

[0068] Next, the product form of the server 200 will be described. Figure 1 The product form of the server 200 in Figure 1 ;

[0069] Figure 3 A schematic structural diagram of a server 200 is provided, as Figure 3 shown. The server 200 includes a bus 201, a processor 202, a communication interface 203, and a memory 204. The processor 202, the memory 204, and the communication interface 203 communicate with each other through the bus 201.

[0070] The bus 201 can be a Peripheral Component Interconnect (PCI) bus or an Extended Industry Standard Architecture (EISA) bus, etc. The bus can be divided into an address bus, a data bus, a control bus, etc. For the sake of convenience in representation, Figure 3 only a thick line is used to represent it in Figure 3 , but it does not mean that there is only one bus or one type of bus.

[0071] The processor 202 can be any one or more of a Central Processing Unit (CPU), a Graphics Processing Unit (GPU), a Micro Processor (MP), or a Digital Signal Processor (DSP), etc.

[0072] The memory 204 can include volatile memory, such as Random Access Memory (RAM). The memory 204 can also include non-volatile memory, such as Read-Only Memory (ROM), flash memory, a Hard Disk Drive (HDD), or a Solid State Drive (SSD).

[0073] Among them, the memory 204 can be used to store software codes related to the time-harmonic field excitation equivalent method based on loss and temperature distribution. The processor 202 can execute the steps of the time-harmonic field excitation equivalent method based on loss and temperature distribution of the chip, or can also schedule other units to achieve the corresponding functions.

[0074] It should be understood that the above terminal 100 and server 200 can be centralized or distributed devices, and the processors in the above terminal 100 and server 200 (such as processor 170 and processor 202) can be hardware circuits (such as Application Specific Integrated Circuit (ASIC), Field-Programmable Gate Array (FPGA), general-purpose processor, DSP, microprocessor or microcontroller, etc.), or a combination of these hardware circuits. For example, the processor can be a hardware system with the function of executing instructions, such as CPU, DSP, etc., or a hardware system without the function of executing instructions, such as ASIC, FPGA, etc., or a combination of the above hardware system without the function of executing instructions and the hardware system with the function of executing instructions.

[0075] This application provides a method for equivalent excitation of a time-harmonic field based on loss and temperature distribution. The method for equivalent excitation of a time-harmonic field based on loss and temperature distribution in the embodiments of this application will be introduced in detail below with reference to the accompanying drawings.

[0076] Refer to Figure 4 , Figure 4 which is a schematic flowchart of a method for equivalent excitation of a time-harmonic field based on loss and temperature distribution provided by an embodiment of this application. The method may include:

[0077] Step S401: Obtain the total core loss of the target transformer when a set excitation voltage is applied and a set DC bias current is injected, as the first total core loss.

[0078] DC bias means that there is a certain DC component in the excitation current of the target transformer, resulting in the excitation source applied to the target transformer including not only the set excitation voltage (the set excitation voltage is the voltage at the power frequency), but also the set DC bias current. Here, the target transformer refers to the transformer object studied in this application; the set DC bias current refers to the actual DC bias current of the target transformer under the DC bias condition. For example, when the target transformer is under the 1A DC bias condition, the set DC bias current is 1A; the set excitation voltage refers to the actual excitation voltage of the target transformer under the DC bias condition. For example, the set excitation voltage is the actual excitation voltage of the target transformer when it is under the 1A DC bias condition.

[0079] In order to efficiently determine the loss distribution and temperature distribution of the iron core of a transformer under DC bias conditions, the inventors of this case conducted in-depth research and found that when the total iron core loss under DC bias conditions is the same as the total iron core loss without DC bias, the loss distribution and temperature distribution of the iron core are also basically the same. Based on this, the inventors of this case thought that the equivalent of the power frequency voltage could be carried out according to the principle of consistent iron core loss.

[0080] Therefore, first, obtain the total iron core loss of the iron core of the target transformer under the dual excitation of the set excitation voltage and the set DC bias current through this embodiment. For the convenience of subsequent description, the total iron core loss obtained here is denoted as the first total iron core loss.

[0081] The above-mentioned principle of consistent iron core loss means that when the target transformer is under DC bias conditions, the total iron core loss of its iron core when injecting the set DC bias current under the set excitation voltage is the same as the total iron core loss of the iron core of the target transformer without DC bias when under the equivalent power frequency excitation voltage.

[0082] Step S402: Take the first total iron core loss as the target value, and based on the principle of consistent iron core loss, determine the equivalent power frequency excitation voltage when the set excitation voltage and the set DC bias current are jointly equivalent to the case without DC bias.

[0083] That is, this embodiment can, based on the principle of consistent iron core loss, take the first total iron core loss as the target value of voltage iteration, and jointly equivalent the set excitation voltage and the set DC bias current to the equivalent power frequency excitation voltage without DC bias. Here, the equivalent power frequency excitation voltage refers to the equivalent excitation voltage at the power frequency.

[0084] Step S403: Calculate the loss distribution and temperature distribution of the iron core in the target transformer in the time-harmonic field finite element simulation software according to the equivalent power frequency excitation voltage.

[0085] Specifically, this step can use the equivalent power frequency excitation voltage as the excitation source of the time-harmonic field solver in the time-harmonic field finite element simulation software to calculate the loss distribution and temperature distribution of the iron core based on the time-harmonic field solver.

[0086] The time - harmonic field excitation equivalent method based on loss and temperature distribution provided by this application obtains the total core loss of the target transformer when a set excitation voltage is applied and a set DC bias current is injected, which is used as the first total core loss. Taking the first total core loss as the target value, based on the principle of consistent core loss, the equivalent power - frequency excitation voltage when the set excitation voltage and the set DC bias current are jointly equivalent to the case without DC bias is determined. According to the equivalent power - frequency excitation voltage, the loss distribution and temperature distribution of the core in the target transformer are calculated in the time - harmonic field finite - element simulation software. It can be seen that this application can, based on the principle of consistent core loss, equivalent the set excitation voltage and the set DC bias current under DC - bias conditions to the equivalent power - frequency excitation voltage without DC bias, enabling this application to perform calculations in the time - harmonic field finite - element simulation software according to the equivalent power - frequency excitation voltage, with shorter time consumption, lower resource consumption, and greatly improved simulation calculation efficiency.

[0087] To make those skilled in the art better understand this application, the following provides a detailed introduction to steps S401 - S403 above.

[0088] In some embodiments of this application, the process of "obtaining the total core loss of the target transformer when a set excitation voltage is applied and a set DC bias current is injected, which is used as the first total core loss" above is introduced.

[0089] In one possible implementation, this embodiment can use an iron - loss tester and / or a measurement method to measure the total core loss of the target transformer when a set excitation voltage is applied and a set DC bias current is injected.

[0090] In another possible implementation, this embodiment can obtain the basic parameter values of the target transformer, and then call a pre - generated DC - bias analytical method calculation program to calculate the first total core loss based on the basic parameter values, the set excitation voltage, and the set DC bias current.

[0091] For example, the basic parameter values of the target transformer are as follows: the number of turns N of the excitation coil is 706, the cross - sectional area S of the core is 11594.99 cm², the core window height is 2410 mm, the core diameter is 1265 mm, the frequency is 50 Hz, the transformer load loss (rated) is 1248675 W, the transformer impedance (rated) is 14%, and so on.

[0092] It should be noted that the above basic parameter values are only examples and do not limit this application.

[0093] For the convenience of subsequent introduction, the set excitation voltage is denoted as , the set DC bias current is denoted as , and the first total core loss is denoted as .

[0094] Of course, there can be other implementation manners for the process of obtaining the total core loss of the first core, and the present application does not make any limitation thereto.

[0095] Next, in this embodiment, step S402 can be performed: "Taking the total core loss of the first core as the target value, and determining the equivalent power frequency excitation voltage when the set excitation voltage and the set DC bias current are equivalently converted to the case without DC bias based on the principle of consistent core loss."

[0096] Optionally, the process of step S402 can include: determining the total core loss of the target transformer under the condition of no DC bias at the initial power frequency excitation voltage as the second core total loss, calculating the absolute value of the difference between the first core total loss and the second core total loss, determining whether the absolute value of the difference is greater than a preset threshold. If not, the initial power frequency excitation voltage is determined as the equivalent power frequency excitation voltage. If so, the initial power frequency excitation voltage is adjusted to obtain the adjusted power frequency excitation voltage, taking the adjusted power frequency excitation voltage as the initial power frequency excitation voltage, and returning to determine the total core loss of the target transformer under the condition of no DC bias at the initial power frequency excitation voltage until the absolute value of the difference is less than or equal to the preset threshold, and then determining the adjusted power frequency excitation voltage as the equivalent power frequency excitation voltage.

[0097] Specifically, as shown in step S4021 of Figure 5 , in this embodiment, the total core loss of the target transformer under a single excitation of the initial power frequency excitation voltage without DC bias can be determined. For the purpose of distinction from the foregoing, the total core loss determined here is denoted as the second core total loss. .

[0098] Optionally, the initial power frequency excitation voltage can be an empirical value at the power frequency determined according to the basic parameter values of the target transformer, denoted as hereinafter. Of course, the initial power frequency excitation voltage can also be a value at any specified power frequency, and the present application does not make any limitation thereto.

[0099] Optionally, the process of "determining the total core loss of the target transformer under the condition of no DC bias at the initial power frequency excitation voltage as the second core total loss" can include: determining the initial core nominal peak magnetic density according to the initial power frequency excitation voltage, obtaining the mapping curve between the peak magnetic density of the core and the unit iron loss, collecting a plurality of data points based on the mapping curve, where the data points refer to the data points represented by the peak magnetic density B and the corresponding unit iron loss P. If there are target data points exceeding the curve range of the mapping curve among the plurality of data points, the linear extrapolation method is used to add the target data points to the mapping curve, and based on the plurality of data points and the initial core nominal peak magnetic density, the preset interpolation method is used to obtain the initial unit iron loss, and the second core total loss is determined according to the initial unit iron loss.

[0100] Optionally, the process of "determining the initial nominal peak magnetic density of the iron core based on the initial power frequency excitation voltage" may include: obtaining the rated operating frequency of the target transformer, the number of turns of the excitation coil of the target transformer, and the effective cross-sectional area of the iron core column of the target transformer, and based on the rated operating frequency of the standard transformer, the number of turns of the excitation coil of the target transformer, the effective cross-sectional area of the iron core column of the target transformer, and the initial power frequency excitation voltage, calculating the initial nominal peak magnetic density of the iron core using the following formula (1).

[0101] Formula (1);

[0102] Wherein, represents the rated operating frequency of the target transformer, with the unit of hertz (Hz); represents the number of turns of the excitation coil of the target transformer, with the unit of turn; represents the effective cross-sectional area of the iron core column of the target transformer, with the unit of square meter ( ) represents the initial power frequency excitation voltage, with the unit of volt (V); represents the initial nominal peak magnetic density of the iron core, with the unit of tesla (T).

[0103] Optionally, the process of "obtaining the mapping curve of the peak magnetic density and the unit iron loss of the iron core" may include: querying the mapping curve of the peak magnetic density and the unit iron loss according to the grade of silicon steel sheet used for the iron core of the target transformer.

[0104] It should be noted that the grade of silicon steel sheet usually only contains the mapping curve, but does not provide the representation function of the mapping curve. Therefore, it is impossible to directly substitute the representation function to obtain the initial unit iron loss corresponding to the initial nominal peak magnetic density of the iron core. In order to obtain the initial unit iron loss, in this embodiment, multiple data points can be collected based on the mapping curve. Here, the data point refers to the data point jointly represented by the peak magnetic density B and the corresponding unit iron loss P.

[0105] It should be understood that there may be a situation where the data points to be collected exceed the curve range of the mapping curve. For example, the peak magnetic density B corresponding to the data points to be collected exceeds the peak magnetic density range in the mapping curve. For the sake of convenience of description, the data points exceeding the curve range of the mapping curve are denoted as target data points. Since the target data points are not on the mapping curve, they cannot be directly collected through the mapping curve. Optionally, in this embodiment, a linear extrapolation method can be used to add the target data points to the mapping curve.

[0106] Here, the linear extrapolation method, also known as the linear trend extrapolation method, is a method for predicting or estimating new data points based on the linear relationship between existing data points. This method assumes that things change at a constant growth rate over time. Therefore, in a coordinate graph with time as the abscissa, the change of things is close to a straight line. Based on this straight line, the future change of things can be inferred.

[0107] Next, in this embodiment, the initial specific iron loss can be obtained according to multiple data points and the initial nominal peak magnetic density of the iron core by using a preset interpolation method, as shown in the following formula (2).

[0108] Formula (2);

[0109] Wherein, represents the initial specific iron loss, with the unit of W / kg; B and P represent the data points collected based on the mapping curve, represents the above-mentioned preset interpolation method, represents the interpolation operation.

[0110] Optionally, the above interpolation method can be one or more of the linear interpolation method, the spline interpolation method, and the polynomial interpolation method.

[0111] Among them, the linear interpolation method is a simple and commonly used interpolation technique. This method assumes that the data change between two known points is linear, and thus the value of unknown data points can be estimated or predicted based on the linear relationship.

[0112] The spline interpolation method is an interpolation method commonly used in numerical analysis and computer graphics. It estimates or predicts the value of unknown data points by constructing a smooth curve (or called a spline) between known data points.

[0113] The polynomial interpolation method is an important technique in numerical analysis. It uses polynomial functions to approximate known data points, thereby constructing a polynomial that can exactly pass through these points.

[0114] Of course, the above interpolation method can also be others, and the present application does not make specific limitations.

[0115] After determining the initial specific iron loss through the above process, in this embodiment, the total iron loss of the second iron core can be determined according to the initial specific iron loss, as shown in the following formula (3).

[0116] Formula (3);

[0117] Wherein, represents the total iron loss of the second iron core; represents the process coefficient of the target transformer core. Optionally, the process coefficient is a dimensionless value with a value range between 1.05 and 1.3; represents the total weight of the target transformer core sheets, with the unit of kilogram (kg).

[0118] such as Figure 5 in step S4022, in this embodiment, the total loss of the first iron core can be calculated and the total loss of the second iron core The absolute value of the difference, that is .

[0119] Next, as Figure 5 shown, it can be determined based on step S4023 whether the absolute value of the above difference is greater than a preset threshold.

[0120] As introduced in the previous description of the principle of consistent iron core loss, if the absolute value of the above difference is less than or equal to the preset threshold, it indicates that the previous initial power frequency excitation voltage can be equivalent to the set excitation voltage and the set DC bias current. Then, the initial power frequency excitation voltage Figure 5 can be determined as the equivalent power frequency excitation voltage without DC bias according to the steps shown in

[0121] On the contrary, if the absolute value of the above interpolation is greater than the preset threshold, it means that the previous initial power frequency excitation voltage cannot be completely equivalent to the set excitation voltage and the set DC bias current. Then, as in Figure 5 step S4024, the initial power frequency excitation voltage needs to be adjusted to obtain the adjusted power frequency excitation voltage . Then, calculate the total loss of the second iron core corresponding to the adjusted power frequency excitation voltage . The calculation process can refer to the introduction in step S4021, that is, replace the previous initial power frequency excitation voltage with the adjusted power frequency excitation voltage . Then, according to step S4022, compare the calculated total loss of the second iron core (that is the total loss of the second iron core corresponding to ) with the total loss of the first iron core , that is, calculate the new absolute value of the difference , and so on, until step S4023 determines that the absolute value of the difference Figure 5 is less than or equal to the above preset threshold, and then according to the steps shown in ​Determined as the equivalent power frequency excitation voltage .

[0122] Optionally, the process of "adjusting the initial power frequency excitation voltage" may include: increasing the initial power frequency excitation voltage by a preset step. For example, if the preset step is 10, then .

[0123] Optionally, the process of "judging whether the absolute value of the difference is greater than the preset threshold" may include: if the following formula (4) holds, it is determined that the absolute value of the difference is less than or equal to the preset threshold; if the following formula (4) does not hold, it is determined that the absolute value of the difference is greater than the preset threshold.

[0124] Formula (4).

[0125] It should be noted that 0.1% in the above formula (4) is only an example. In addition, other values can also be used, and the present application does not make specific limitations.

[0126] In the above process, in this embodiment, the excitation voltage under the equivalent power frequency and non-biased magnetic condition is calculated based on the principle of consistent core loss , and the total second core loss generated by the core of the target transformer under the excitation of this excitation voltage (that is the corresponding total second core loss) and the total first core loss under the biased magnetic condition have a deviation of less than 0.1%. Therefore, from the perspective of loss equivalence, it can be considered that the total second core loss under the excitation of the power frequency non-biased magnetic voltage , is the same as the total first core loss under the dual excitation of the set excitation voltage and the specified biased magnetic current .

[0127] Then, this embodiment can use the equivalent power frequency excitation voltage as the excitation source of the time-harmonic field solver in the time-harmonic field finite element simulation software, and then perform equivalent calculations of the core loss distribution and temperature rise distribution of the target transformer under the DC biased magnetic condition based on this time-harmonic field solver.

[0128] In summary, this embodiment provides a method for equivalent excitation in calculating the core loss and temperature distribution of a time-harmonic field finite element transformer under DC biased magnetic conditions. First, obtain the total first core loss of the target transformer under the set excitation voltage and the set DC biased magnetic current , and then, based on the principle of consistent core loss, with As the target value of the equivalent iteration, by changing the power frequency excitation voltage of the target transformer under the condition of no DC bias current, the excitation voltage Relationship with the total core loss of the second core Iterative calculation is carried out between them, and the condition for the end of the iteration is And The deviation between is less than or equal to 0.1%. At this time, The corresponding Is the required equivalent core loss Equivalent power frequency excitation voltage under the condition . Finally, the obtained Is used as the excitation source of the time-harmonic magnetic field solver of the magnetic field finite element software, and the equivalent calculations of the core loss distribution and temperature rise distribution under the DC bias condition of the target transformer are carried out.

[0129] Through the above excitation source equivalent method, the problem that originally needed to be solved by the transient field, which consumes a large amount of time and resources, is transformed into a time-harmonic field calculation problem with short time consumption and low resource consumption, greatly improving the calculation efficiency and providing strong support for the efficient design of the target transformer.

[0130] The above introduces a time-harmonic field excitation equivalent method based on loss and temperature distribution provided by the embodiments of the present application. Next, the device for implementing the above time-harmonic field excitation equivalent method based on loss and temperature distribution will be introduced.

[0131] Please refer to Figure 6 , Figure 6 Is a schematic structural diagram of a time-harmonic field excitation equivalent device provided by the embodiments of the present application. As Figure 6 Shown, the device may include:

[0132] A loss acquisition module 501, configured to acquire the total core loss of the target transformer when a set excitation voltage is applied and a set DC bias current is injected, as the first total core loss;

[0133] A voltage equivalent module 502, configured to use the first total core loss as the target value, and determine the equivalent power frequency excitation voltage when the set excitation voltage and the set DC bias current are equivalently combined to the case without DC bias based on the principle of consistent core loss;

[0134] A distribution simulation module 503, configured to calculate the loss distribution and temperature distribution of the core in the target transformer in the time-harmonic field finite element simulation software according to the equivalent power frequency excitation voltage.

[0135] In a possible implementation, the above loss acquisition module may include: a basic parameter value acquisition module and a first loss calculation module.

[0136] Among them, the basic parameter value acquisition module is used to acquire the basic parameter values of the target transformer;

[0137] The first loss calculation module is used to call the pre-generated calculation program of the DC bias analysis method to calculate the total core loss of the first core based on the basic parameter values, the set excitation voltage, and the set DC bias current.

[0138] In a possible implementation, the above voltage equivalent module may include: a second loss calculation module, a deviation calculation module, a deviation comparison module, a first voltage determination module, and a second voltage determination module.

[0139] Among them, the second loss calculation module is used to determine the total core loss of the target transformer under the condition of no DC bias at the initial power frequency excitation voltage as the total core loss of the second core;

[0140] The deviation calculation module is used to calculate the absolute value of the difference between the total core loss of the first core and the total core loss of the second core;

[0141] The deviation comparison module is used to determine whether the absolute value of the difference is greater than a preset threshold;

[0142] The first voltage determination module is used to determine the initial power frequency excitation voltage as the equivalent power frequency excitation voltage when the judgment result of the deviation comparison module is negative;

[0143] The second voltage determination module is used to adjust the initial power frequency excitation voltage to obtain the adjusted power frequency excitation voltage when the judgment result of the deviation comparison module is positive, take the adjusted power frequency excitation voltage as the initial power frequency excitation voltage, and return to the second loss calculation module. Until the judgment result of the deviation comparison module is negative, the adjusted power frequency excitation voltage is determined as the equivalent power frequency excitation voltage.

[0144] In a possible implementation, the above second loss calculation module may include: a peak magnetic density determination module, a mapping curve acquisition module, a data point acquisition module, a unit iron loss determination module, and an iron loss determination module.

[0145] Among them, the peak magnetic density determination module is used to determine the initial core nominal peak magnetic density according to the initial power frequency excitation voltage;

[0146] The mapping curve acquisition module is used to acquire the mapping curve of the peak magnetic density and the unit iron loss of the core;

[0147] The data point acquisition module is used to collect multiple data points based on the mapping curve. Among them, the data point refers to the data point jointly represented by the peak magnetic density and the corresponding unit iron loss. If there is a target data point that exceeds the curve range of the mapping curve among the multiple data points, the linear extrapolation method is used to add the target data point to the mapping curve;

[0148] The unit iron loss determination module is configured to obtain the initial unit iron loss by using a preset interpolation method based on multiple data points and the initial core nominal peak magnetic density.

[0149] The iron loss determination module is configured to determine the total core loss of the second core according to the initial unit iron loss.

[0150] In a possible implementation, the preset interpolation method in the above unit iron loss determination module is one or more of a linear interpolation method, a spline interpolation method, and a polynomial interpolation method.

[0151] In a possible implementation, when adjusting the initial power frequency excitation voltage, the above second voltage determination module can specifically be used to: increase the initial power frequency excitation voltage by a preset step size.

[0152] The time - harmonic field excitation equivalent device based on loss and temperature distribution provided by the embodiments of the present application corresponds to the time - harmonic field excitation equivalent method based on loss and temperature distribution provided above. For details, reference can be made to the above introduction and will not be elaborated here.

[0153] Embodiments of the present application also provide an electronic device. Refer to Figure 7 As shown, it shows a schematic structural diagram of an electronic device suitable for implementing the electronic device in the embodiments of the present application. The electronic device in the embodiments of the present application may include, but is not limited to, fixed terminals such as mobile phones, laptop computers, PDAs (Personal Digital Assistants), PADs (Tablet Computers), desktop computers, and the like. Figure 7 The electronic device shown is only an example and should not impose any limitations on the functions and usage scope of the embodiments of the present application.

[0154] As Figure 7 shown, the electronic device may include a processing device (such as a central processing unit, a graphics processing unit, etc.) 601, which can perform various appropriate actions and processes according to the program stored in the read - only memory (ROM) 602 or the program loaded from the storage device 608 into the random access memory (RAM) 603. When the electronic device is powered on, various programs and data required for the operation of the electronic device are also stored in the RAM 603. The processing device 601, the ROM 602, and the RAM 603 are connected to each other through a bus 604. The input / output (I / O) interface 605 is also connected to the bus 604.

[0155] Typically, the following devices can be connected to the I / O interface 605: input devices 606 including, for example, a touch screen, a touchpad, a keyboard, a mouse, a camera, a microphone, an accelerometer, a gyroscope, etc.; output devices 607 including, for example, a liquid crystal display (LCD), a speaker, a vibrator, etc.; storage devices 608 including, for example, a memory card, a hard disk, etc.; and a communication device 609. The communication device 609 can allow the electronic device to communicate with other devices wirelessly or wiredly to exchange data. Although Figure 7 an electronic device with various devices is shown, it should be understood that it is not required to implement or have all the shown devices. Instead, more or fewer devices can be implemented or had.

[0156] An embodiment of the present application also provides a computer program product including computer-readable instructions. When the computer-readable instructions run on an electronic device, the electronic device is enabled to implement any one of the time-harmonic field excitation equivalence methods based on loss and temperature distribution provided by the embodiments of the present application.

[0157] An embodiment of the present application also provides a computer-readable storage medium carrying one or more computer programs. When the one or more computer programs are executed by an electronic device, the electronic device can be enabled to implement any one of the time-harmonic field excitation equivalence methods based on loss and temperature distribution provided by the embodiments of the present application.

[0158] In addition, it should be noted that the device embodiments described above are merely illustrative. The units described as separate components may or may not be physically separated, and the components shown as units may or may not be physical units, that is, they may be located in one place or distributed to multiple network units. Some or all of the modules can be selected according to actual needs to achieve the purpose of the solution of this embodiment. In addition, in the drawings of the device embodiments provided in the present application, the connection relationship between modules indicates that they have a communication connection, which can be specifically implemented as one or more communication buses or signal lines.

[0159] Through the description of the above embodiments, those skilled in the art can clearly understand that this application can be implemented by means of software plus necessary general hardware. Of course, it can also be implemented by dedicated hardware including application-specific integrated circuits, dedicated CPUs, dedicated memories, dedicated components, etc. Generally, functions completed by computer programs can be easily implemented by corresponding hardware, and the specific hardware structures for implementing the same function can also be diverse, such as analog circuits, digital circuits, or dedicated circuits, etc. However, for this application, in more cases, software program implementation is a better embodiment. Based on such an understanding, the technical solution of this application, in essence, or the part that makes a contribution to the prior art, can be embodied in the form of a software product. This computer software product is stored in a readable storage medium, such as a floppy disk, USB flash drive, mobile hard disk, ROM, RAM, magnetic disk, or optical disc of a computer, etc., and includes several instructions to enable a computer device (which can be a personal computer, training device, or network device, etc.) to execute the methods described in various embodiments of this application.

[0160] In the above embodiments, it can be implemented in whole or in part by software, hardware, firmware, or any combination thereof. When implemented using software, it can be implemented in whole or in part in the form of a computer program product.

[0161] The computer program product includes one or more computer instructions. When the computer program instructions are loaded and executed on a computer, the processes or functions described in the embodiments of this application are generated in whole or in part. The computer can be a general-purpose computer, a dedicated computer, a computer network, or other programmable devices. The computer instructions can be stored in a computer-readable storage medium, or transmitted from one computer-readable storage medium to another computer-readable storage medium. For example, the computer instructions can be transmitted from a website, computer, training device, or data center to another website, computer, training device, or data center in a wired (such as coaxial cable, optical fiber, digital subscriber line (DSL)) or wireless (such as infrared, wireless, microwave, etc.) manner. The computer-readable storage medium can be any available medium that a computer can store, or a data storage device such as a training device or data center that includes one or more integrated available media. The available medium can be a magnetic medium (such as a floppy disk, hard disk, magnetic tape), an optical medium (such as a DVD), or a semiconductor medium (such as a solid-state drive (SSD)).

Claims

1. A time-harmonic field excitation equivalent method based on loss and temperature distribution, characterized in that Including: Obtaining the total core loss of the target transformer when a set excitation voltage is applied and a set DC bias current is injected, as the first total core loss; Determining the total core loss of the target transformer under the condition of no DC bias at the initial power frequency excitation voltage, as the second total core loss; Calculating the absolute value of the difference between the first total core loss and the second total core loss; Judging whether the absolute value of the difference is greater than a preset threshold; If not, determining the initial power frequency excitation voltage as the equivalent power frequency excitation voltage; If so, adjusting the initial power frequency excitation voltage to obtain an adjusted power frequency excitation voltage, taking the adjusted power frequency excitation voltage as the initial power frequency excitation voltage, and returning to determine the total core loss of the target transformer under the condition of no DC bias at the initial power frequency excitation voltage until the absolute value of the difference is less than or equal to the preset threshold, and then determining the adjusted power frequency excitation voltage as the equivalent power frequency excitation voltage; Calculating the loss distribution and temperature distribution of the core in the target transformer in the time-harmonic field finite element simulation software according to the equivalent power frequency excitation voltage.

2. The time-harmonic field excitation equivalent method based on loss and temperature distribution according to claim 1, wherein The obtaining the total core loss of the target transformer when a set excitation voltage is applied and a set DC bias current is injected, as the first total core loss, includes: Obtaining the basic parameter values of the target transformer; Invoking a pre-generated DC bias analytical method calculation program to calculate the first total core loss based on the basic parameter values, the set excitation voltage, and the set DC bias current.

3. The equivalent method for time-harmonic field excitation based on loss and temperature distribution according to claim 1, wherein The determining the total core loss of the target transformer under the condition of no DC bias at the initial power frequency excitation voltage, as the second total core loss, includes: Determining the initial core nominal peak magnetic density according to the initial power frequency excitation voltage; Obtaining the mapping curve between the peak magnetic density and the unit core loss of the core; Collecting a plurality of data points according to the mapping curve, where the data point refers to the data point jointly represented by the peak magnetic density and the corresponding unit core loss. If there is a target data point in the plurality of data points that exceeds the curve range of the mapping curve, the linear extrapolation method is used to add the target data point to the mapping curve; Obtaining the initial unit core loss by using a preset interpolation method according to the plurality of data points and the initial core nominal peak magnetic density; Determining the second total core loss according to the initial unit core loss.

4. The equivalent method of time-harmonic field excitation based on loss and temperature distribution according to claim 3, wherein The preset interpolation method is one or more of the linear interpolation method, the spline interpolation method, and the polynomial interpolation method.

5. The equivalent method for time-harmonic field excitation based on loss and temperature distribution according to claim 1, characterized in that The adjusting the initial power frequency excitation voltage includes: Increasing the initial power frequency excitation voltage by a preset step size.

6. A time-harmonic field excitation equivalent device based on loss and temperature distribution, characterized in that, Including: A loss acquisition module for obtaining the total core loss of the target transformer when a set excitation voltage is applied and a set DC bias current is injected, as the first total core loss; A voltage equivalence module for determining the equivalent power frequency excitation voltage when the set excitation voltage and the set DC bias current are equivalently converted to the case of no DC bias based on the principle of consistent core loss with the first total core loss as the target value; A distribution simulation module for calculating the loss distribution and temperature distribution of the iron core in the target transformer in a time-harmonic field finite element simulation software according to the equivalent power frequency excitation voltage; The voltage equivalent module specifically includes: a second loss calculation module, a deviation calculation module, a deviation comparison module, a first voltage determination module, and a second voltage determination module; The second loss calculation module is used to determine the total iron core loss of the target transformer under the condition of no DC bias at the initial power frequency excitation voltage as the second total iron core loss; The deviation calculation module is used to calculate the absolute value of the difference between the first total iron core loss and the second total iron core loss; The deviation comparison module is used to determine whether the absolute value of the difference is greater than a preset threshold; The first voltage determination module is used to determine the initial power frequency excitation voltage as the equivalent power frequency excitation voltage when the judgment result of the deviation comparison module is no; The second voltage determination module is used to adjust the initial power frequency excitation voltage to obtain an adjusted power frequency excitation voltage when the judgment result of the deviation comparison module is yes, take the adjusted power frequency excitation voltage as the initial power frequency excitation voltage, and return to the second loss calculation module until the judgment result of the deviation comparison module is no, and determine the adjusted power frequency excitation voltage as the equivalent power frequency excitation voltage.

7. A computer program product, characterized in that, It includes computer-readable instructions that, when the computer-readable instructions run on an electronic device, enable the electronic device to implement the time-harmonic field excitation equivalent method based on loss and temperature distribution as described in any one of claims 1 to 5.

8. An electronic device, characterized in that, It includes at least one processor and a memory connected to the processor, wherein: The memory is used to store a computer program; The processor is used to execute the computer program so that the electronic device can implement the time-harmonic field excitation equivalent method based on loss and temperature distribution as described in any one of claims 1 to 5.

9. A computer storage medium, characterized in that, The storage medium carries one or more computer programs that, when the one or more computer programs are executed by an electronic device, can enable the electronic device to implement the time-harmonic field excitation equivalent method based on loss and temperature distribution as described in any one of claims 1 to 5.

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