Time-harmonic field excitation equivalent method based on loss and temperature distribution and related device

Abstract

The invention discloses a time-harmonic field excitation equivalent method based on loss and temperature distribution and a related device, and relates to the field of transformers, and the method comprises the steps: obtaining the first iron core total loss of a target transformer when the excitation voltage is set and the set DC bias current is injected, and taking the first iron core total loss as a target value; based on the iron core loss consistency principle, it is determined that the set excitation voltage and the set direct-current magnetic bias current are jointly equivalent to the equivalent power frequency excitation voltage without direct-current magnetic bias, and loss distribution and temperature distribution of the iron core in the target transformer are calculated in the time-harmonic field finite element simulation software according to the equivalent power frequency excitation voltage. According to the method, the set excitation voltage and the set direct current magnetic bias current under the direct current magnetic bias condition can be equivalent to the equivalent power frequency excitation voltage under the direct current magnetic bias-free condition according to the iron core loss consistency principle, so that calculation can be carried out in time-harmonic field finite element simulation software, the consumed time is shorter, and the calculation efficiency is improved. The resource consumption is lower; and the simulation calculation efficiency is greatly improved.

Description

Technical Field

[0001] The present 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 a related device. Background Art

[0002] Geomagnetic storms and unipolar asymmetric operation of DC transmission projects are the main reasons for the DC bias of transformers. DC bias will cause a sharp increase in the degree of excitation saturation, leading to asymmetry of the core flux, which in turn makes the transformer magnetic circuit unbalanced and significantly increases the leakage flux, affecting the transformer's loss, temperature rise and noise problems. In severe cases, it may even cause transformer insulation damage, causing serious faults and directly threatening the safe operation of the power system. Therefore, it is of great significance to study the impact of DC bias on the core loss distribution and temperature distribution of the transformer.

[0003] At present, in engineering design practice, the total core loss of the transformer under different excitation conditions can be obtained through an analytical calculation formula containing empirical coefficients. However, due to the core structure type and the nonlinear magnetic permeability of the silicon steel sheet, the magnetic flux density distribution at various locations on the core cross section is uneven, making it impossible to deduce the loss distribution at various locations on the core through the analytical calculation formula, and further, it is impossible to calculate the temperature distribution at various locations on the core 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 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 into corresponding time domain waveforms respectively, and used as the excitation source input 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 by transient field calculation. However, the transient field calculation method is time-consuming, computationally inefficient, and consumes a lot 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 scheme is as follows:

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

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

[0008] Taking the first core total loss as the target value, determining the equivalent power frequency excitation voltage when there is no DC bias by the set excitation voltage and the set DC bias current based on the core loss consistency principle;

[0009] The loss distribution and temperature distribution of the core in the target transformer are calculated in 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 the excitation voltage is set and the set DC bias current is injected as the first total core loss includes:

[0011] Obtaining basic parameter values ​​of the target transformer;

[0012] The pre-generated DC bias analysis method calculation program is called to calculate the first core total loss based on the basic parameter value, the set excitation voltage and the set DC bias current.

[0013] In a possible implementation, taking the first total core loss as a target value and determining, based on the core loss consistency principle, that the set excitation voltage and the set DC bias current are equivalent to an equivalent power frequency excitation voltage when there is no DC bias, 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] Calculating an absolute value of a difference between the first core total loss and the second core total loss;

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

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

[0018] If so, the initial power frequency excitation voltage is adjusted to obtain an adjusted power frequency excitation voltage, and the adjusted power frequency excitation voltage is used as the initial power frequency excitation voltage. The total core loss of the target transformer at the initial power frequency excitation voltage under the condition of no DC bias is returned until the absolute value of the difference is less than or equal to the preset threshold value, and the adjusted power frequency excitation voltage is determined 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] Determining the initial core nominal peak magnetic flux density according to the initial power frequency excitation voltage;

[0021] Obtaining a mapping curve between the peak magnetic flux density and the unit iron loss of the core;

[0022] Collecting a plurality of data points according to the mapping curve, wherein the data point refers to a data point represented by a peak magnetic density and a corresponding unit iron loss, and if there is a target data point that exceeds the curve range of the mapping curve among the plurality of data points, adding the target data point to the mapping curve by a linear extrapolation method;

[0023] Obtaining an initial unit iron loss using a preset interpolation method according to the multiple data points and the initial core nominal peak magnetic flux density;

[0024] The second core total loss is determined 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 adjusting the initial power frequency excitation voltage includes:

[0027] The initial power frequency excitation voltage is increased 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, comprising:

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

[0030] A voltage equivalent module is used to determine, based on the core loss consistency principle, that the set excitation voltage and the set DC bias current are equivalent to an equivalent power frequency excitation voltage when there is no DC bias, taking the first core total loss as a target value;

[0031] The distribution simulation module is used 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.

[0032] The third aspect of the present application provides a computer program product, including computer-readable instructions. When the computer-readable instructions are executed on an electronic device, the electronic device implements the time-harmonic field excitation equivalent method based on loss and temperature distribution of the above-mentioned first aspect or any implementation of the first aspect.

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

[0034] The memory is used to store computer programs;

[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 of the above-mentioned first aspect or any implementation of the first aspect.

[0036] In a fifth aspect, the present application provides a computer storage medium, which 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 of the above-mentioned first aspect or any implementation method of the first aspect.

[0037] By means of the above technical scheme, the time-harmonic field excitation equivalent method based on loss and temperature distribution provided by the present application obtains the total core loss of the target transformer when the excitation voltage is set and the set DC bias current is injected as the first total core loss, and the first total core loss is taken as the target value. Based on the principle of consistent core loss, the set excitation voltage and the set DC bias current are determined to be equivalent to the equivalent power frequency excitation voltage when there is no DC bias. 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 the present application can, based on the principle of consistent core loss, equate the set excitation voltage and the set DC bias current under DC bias conditions to the equivalent power frequency excitation voltage under no DC bias, so that the present application can be calculated 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] The above and other features, advantages and aspects of the embodiments of the present disclosure will become more apparent with reference to the following detailed description in conjunction with the accompanying drawings. Throughout the accompanying drawings, the same or similar reference numerals represent the same or similar elements. It should be understood that the drawings are schematic and the originals and elements are not necessarily drawn to scale.

[0039] Figure 1 A schematic diagram of a system architecture provided for this application;

[0040] Figure 2 A schematic diagram of an optional hardware structure of the terminal 100 provided in this application;

[0041] Figure 3 A schematic diagram of the structure of a server 200 provided in this application;

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

[0043] Figure 5 A schematic diagram of a process for determining an equivalent power frequency excitation voltage provided in this application;

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

[0045] Figure 7 A schematic diagram of the structure of an electronic device provided in this application. DETAILED DESCRIPTION

[0046] The following describes the embodiments of the present application in conjunction with the drawings in the embodiments of the present application. The terms used in the implementation method section of the present application are only used to explain the specific embodiments of the present application, and are not intended to limit the present application.

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

[0048] The terms "first", "second", etc. in the specification and claims of the present application and the above-mentioned drawings are used to distinguish similar objects, and need not be used to describe a specific order or sequential order. It should be understood that the terms used in this way can be interchangeable under appropriate circumstances, which is only to describe the distinction mode adopted by the objects of the same attributes when describing in the embodiments of the present application. In addition, the terms "including" and "having" and any of their variations are intended to cover non-exclusive inclusions, so that the process, method, system, product or equipment comprising a series of units need not be limited to those units, but may include other units that are not clearly listed or inherent to these processes, methods, products or equipment.

[0049] See also Figure 1 , Figure 1 A schematic diagram of a system architecture is shown. The system may include a terminal 100 and a server 200. The server 200 may include one or more servers ( Figure 1 In the example, a server is included, and the server 200 can provide the method provided in the embodiment of the present application for one or more terminals.

[0050] Among them, an application can be installed on the terminal 100, and the above application and web page can provide an interface. The terminal 100 can receive relevant parameters entered by the user on the interface and send the above parameters to the server 200. The server 200 can obtain processing results based on the received parameters and return the processing results 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, and the embodiments of the present application are not limited to this.

[0052] Next describe Figure 1 The product form of the mid-terminal 100;

[0053] The terminal 100 in the embodiment 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., and the embodiment of the present application does not impose any restrictions on this.

[0054] Figure 2 An optional hardware structure diagram of the terminal 100 is shown.

[0055] refer 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), an earphone jack 163 (optional), a processor 170, an external interface 180, a power supply 190 and other components. Those skilled in the art will appreciate that Figure 2 These are merely examples of terminals or multi-function devices and do not constitute limitations on the terminals or multi-function devices, which may include more or fewer components than those shown in the figures, or combinations of certain components, or different components.

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

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

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

[0059] The memory 120 can be used to store instructions and data. The memory 120 can mainly include an instruction storage area and a data storage area. The data storage area can store various data, such as multimedia files, texts, etc.; the instruction storage area can store software units such as operating systems, applications, instructions required for at least one function, or their subsets and extensions. It can also include a non-volatile random access memory; provide the processor 170 with hardware, software and data resources including management of computing and processing equipment, and support 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. It uses various interfaces and lines to connect various parts of the entire terminal 100. By running or executing instructions stored in the memory 120 and calling data stored in the memory 120, it executes various functions of the terminal 100 and processes data, thereby controlling the terminal device as a whole. Optionally, the processor 170 may include one or more processing units; preferably, the processor 170 may integrate an application processor and a modem processor, wherein the application processor mainly processes the operating system, user interface and application program, and the modem processor mainly processes wireless communication. It is understandable that the above-mentioned modem processor may not be integrated into the processor 170. In some embodiments, the processor and the memory may be implemented on a single chip, and in some embodiments, they may also be implemented separately on separate chips. The processor 170 may 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 data and programs in the memory 120, so that each functional module therein performs 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 the display unit 140) to achieve corresponding functions.

[0062] The radio frequency unit 110 (optional) can be used for receiving and sending information or receiving and sending signals during a call, for example, after receiving the downlink information of the base station, it is sent to the processor 170 for processing; in addition, the designed uplink data 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 (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. The wireless communication can use any communication standard or protocol, including but not limited to Global System of Mobile Communication (Global System of Mobile Communication, GSM), General Packet Radio Service (General Packet Radio Service, GPRS), Code Division Multiple Access (Code Division Multiple Access, CDMA), Wideband Code Division Multiple Access (Wideband Code Division Multiple Access, WCDMA), Long Term Evolution (Long Term Evolution, LTE), email, Short Messaging Service (SMS), etc.

[0063] In this embodiment of the present application, the RF unit 110 can send data to the server 200 and receive processing results 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 port.

[0065] The terminal 100 also includes a power supply 190 (such as a battery) for supplying power to various components. Preferably, the power supply can be logically connected to the processor 170 through a power management system, so that the power management system can manage functions such as charging, discharging, and power consumption.

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

[0067] Although not shown, the terminal 100 may also include a flashlight, a wireless fidelity (WiFi) module, a Bluetooth module, sensors with different functions, etc., which are not described in detail here. Some or all of the methods described below may be applied in the following embodiments. Figure 2 In the terminal 100 shown.

[0068] Next describe Figure 1 The product form of the server 200;

[0069] Figure 3 A schematic diagram of the structure of a server 200 is provided, such as Figure 3 As 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 via the bus 201.

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

[0071] The processor 202 may be any one or more of a central processing unit (CPU), a graphics processing unit (GPU), a microprocessor (MP), or a digital signal processor (DSP).

[0072] The memory 204 may include a volatile memory, such as a random access memory (RAM). The memory 204 may also include a non-volatile memory, such as a read-only memory (ROM), a 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, and can also schedule other units to implement corresponding functions.

[0074] It should be understood that the above-mentioned terminal 100 and server 200 can be centralized or distributed devices, and the processors in the above-mentioned terminal 100 and server 200 (such as processor 170 and processor 202) can be hardware circuits (such as application-specific integrated circuits (ASIC), field-programmable gate arrays (FPGA), general-purpose processors, DSPs, microprocessors or microcontrollers, etc.), or a combination of these hardware circuits. For example, the processor can be a hardware system with an instruction execution function, such as a CPU, DSP, etc., or a hardware system without an instruction execution function, such as an ASIC, FPGA, etc., or a combination of the above-mentioned hardware systems without an instruction execution function and hardware systems with an instruction execution function.

[0075] The present application provides a time-harmonic field excitation equivalent method based on loss and temperature distribution. The time-harmonic field excitation equivalent method based on loss and temperature distribution of the embodiment of the present application is described in detail below with reference to the accompanying drawings.

[0076] Reference Figure 4 , Figure 4 A schematic flow chart of a time-harmonic field excitation equivalent method based on loss and temperature distribution provided in an embodiment of the present application, the method may include:

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

[0078] DC bias refers to the presence of a certain DC component in the excitation current of the target transformer, which results 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, if 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 under the 1A DC bias condition.

[0079] In order to efficiently determine the loss distribution and temperature distribution of the core of the transformer under DC bias conditions, the inventor of this case conducted in-depth research and found that when the total core loss under DC bias conditions is consistent with the total core loss without DC bias, the core loss distribution and temperature distribution are also basically consistent. Based on this, the inventor of this case thought that the power frequency voltage can be equivalent based on the principle of consistent core loss.

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

[0081] The above-mentioned core loss consistency principle means that when the target transformer is under DC bias conditions, the total core loss of its core when a set DC bias current is injected under a set excitation voltage is consistent with the total core loss of the target transformer core at an equivalent power frequency excitation voltage when there is no DC bias.

[0082] Step S402: Taking the first core total loss as the target value, based on the core loss consistency principle, determine that the set excitation voltage and the set DC bias current are equivalent to an equivalent power frequency excitation voltage when there is no DC bias.

[0083] That is, based on the core loss consistency principle, this embodiment can use the first core total loss as the target value of voltage iteration, and set the excitation voltage and the set DC bias current to be equivalent to the equivalent power frequency excitation voltage when there is no 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 core in the target transformer in time-harmonic field finite element simulation software according to the equivalent power frequency excitation voltage.

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

[0086] The time-harmonic field excitation equivalence method based on loss and temperature distribution provided in the present application obtains the total core loss of the target transformer when the excitation voltage is set and the set DC bias current is injected as the first total core loss, and the first total core loss is taken as the target value. Based on the principle of consistent core loss, the set excitation voltage and the set DC bias current are determined to be equivalent to the equivalent power frequency excitation voltage when there is no DC bias. 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 the present application can, based on the principle of consistent core loss, equate the set excitation voltage and the set DC bias current under the DC bias condition to the equivalent power frequency excitation voltage under the DC bias condition, so that the present application can be calculated 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.

[0087] In order to enable those skilled in the art to better understand the present application, the above steps S401 to S403 are described in detail below.

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

[0089] In a possible implementation, this embodiment may use an iron loss tester and / or a measurement method to measure the total core loss of the target transformer when the excitation voltage is set and the 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 total loss of the first core based on the basic parameter values, set excitation voltage and set DC bias current.

[0091] For example, the basic parameter values ​​of the target transformer are as follows: the number of turns of the excitation coil N is 706, the core cross-sectional area S 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 are not intended to limit the present application.

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

[0094] Of course, there may be other ways to implement the process of obtaining the total loss of the first core, which is not limited in this application.

[0095] Next, this embodiment can use step S402 to "take the first core total loss as the target value, and determine the equivalent power frequency excitation voltage when there is no DC bias based on the core loss consistency principle when the set excitation voltage and the set DC bias current are equivalent."

[0096] Optionally, the process of step S402 may include: 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, 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 value, if not, determining the initial power frequency excitation voltage as an equivalent power frequency excitation voltage, if so, adjusting the initial power frequency excitation voltage to obtain an adjusted power frequency excitation voltage, using the adjusted power frequency excitation voltage as the initial power frequency excitation voltage, returning 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 value, determining the adjusted power frequency excitation voltage as the equivalent power frequency excitation voltage.

[0097] For details, see Figure 5 As shown in step S4021, this embodiment can determine the total core loss of the target transformer under the single excitation of the initial power frequency excitation voltage when there is no DC bias. In order to distinguish it from the previous text, the total core loss determined here is recorded as the second total core loss .

[0098] Optionally, the initial power frequency excitation voltage may be an empirical value at the power frequency determined according to the basic parameter value of the target transformer, hereinafter referred to as Of course, the initial power frequency excitation voltage may also be a value at any specified power frequency, and this application does not limit it.

[0099] Optionally, the process of "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" may include: determining the initial nominal peak magnetic flux density of the core according to the initial power frequency excitation voltage, obtaining a mapping curve of the peak magnetic flux density of the core and the unit iron loss, collecting multiple data points according to the mapping curve, where the data point refers to the data point jointly represented by the peak magnetic flux density B and the corresponding unit iron loss P, if there is a target data point among the multiple data points that exceeds the curve range of the mapping curve, then a linear extrapolation method is used to add the target data point to the mapping curve, and based on the multiple data points and the initial nominal peak magnetic flux density of the core, a preset interpolation method is used to obtain the initial unit iron loss, and the second total core loss is determined based on the initial unit iron loss.

[0100] Optionally, the above-mentioned process of "determining the initial core nominal peak magnetic flux density 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 target transformer excitation coil and the effective cross-sectional area of ​​the target transformer core column, and based on the rated operating frequency of the target transformer, the number of turns of the target transformer excitation coil, the effective cross-sectional area of ​​the target transformer core column, and the initial power frequency excitation voltage, using the following formula (1) to calculate the initial core nominal peak magnetic flux density.

[0101] Formula (1);

[0102] in, Indicates the rated operating frequency of the target transformer, in Hertz (Hz); Indicates the number of turns of the exciting coil of the target transformer, in turns; Indicates the effective cross-sectional area of ​​the target transformer core, in square meters ( ); Indicates the initial power frequency excitation voltage, in volts (V); It represents the initial core nominal peak magnetic flux density, in Tesla (T).

[0103] Optionally, the above process of "obtaining a mapping curve between the peak magnetic flux density and unit iron loss of the core" may include: querying and obtaining a mapping curve between the peak magnetic flux density and unit iron loss according to the brand of silicon steel sheets used in the core of the target transformer.

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

[0105] It should be understood that there may be a situation where the data point to be collected exceeds the curve range of the mapping curve. For example, the peak magnetic density B corresponding to the data point to be collected exceeds the peak magnetic density range in the mapping curve. For the convenience of description, the data point that exceeds the curve range of the mapping curve is recorded as the target data point. Since the target data point is not on the mapping curve, it cannot be directly collected through the mapping curve. Optionally, in this embodiment, the linear extrapolation method can be used to add the target data point 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, so in a coordinate graph with time as the horizontal axis, the change of things is close to a straight line, and based on this straight line, the future changes of things can be inferred.

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

[0108] Formula (2);

[0109] in, represents the initial unit iron loss in W / kg; B and P represent the data points collected based on the mapping curve. represents the above preset interpolation method, Represents an interpolation operation.

[0110] Optionally, the interpolation method may be one or more of a linear interpolation method, a spline interpolation method and a 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, so the value of the unknown data point can be estimated or predicted based on the linear relationship.

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

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

[0114] Of course, the above interpolation method may also be other methods, which are not specifically limited in this application.

[0115] After the initial unit iron loss is determined through the above process, the present embodiment can determine the second core total loss according to the initial unit iron loss, as shown in the following formula (3).

[0116] Formula (3);

[0117] in, represents the total loss of the second core; The process coefficient of the target transformer core is optional and is a dimensionless value ranging from 1.05 to 1.3; Indicates the total weight of the target transformer core sheets in kilograms (kg).

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

[0119] Then, if Figure 5 As shown, the absolute value of the difference can be determined based on step S4023. Is it greater than the preset threshold?

[0120] As described in the previous article on the principle of core loss consistency, if the absolute value of the above difference Less than or equal to the preset threshold, indicating that the initial power frequency excitation voltage It is equivalent to setting the excitation voltage and setting the DC bias current. Then, Figure 5 Step S4025 shows that the initial power frequency excitation voltage Determine the equivalent industrial frequency excitation voltage when there is no DC bias.

[0121] On the contrary, if the above interpolation absolute value is greater than the preset threshold, it means that the initial power frequency excitation voltage It is not completely equivalent to setting the excitation voltage and setting the DC bias current. Figure 5 Step S4024 requires the initial power frequency excitation voltage Adjust to obtain the adjusted power frequency excitation voltage , and then calculate the adjusted power frequency excitation voltage The corresponding second core total loss, the calculation process can refer to the introduction in step S4021, that is, the adjusted power frequency excitation voltage Replace the initial power frequency excitation voltage in the previous text Then, according to step S4022, the calculated total loss of the second core is (Right now The corresponding second core total loss) and the first core total loss Compare, that is, calculate the new absolute value of the difference , and so on, until step S4023 determines the absolute value of the difference When it is less than or equal to the above preset threshold, Figure 5 Step S4025 is to adjust the power frequency excitation voltage obtained by the last adjustment. Determined as the equivalent power frequency excitation voltage .

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

[0123] Optionally, the above process of "determining whether the absolute value of the difference is greater than a preset threshold" may include: if the following formula (4) holds true, determining that the absolute value of the difference is less than or equal to the preset threshold; if the following formula (4) does not hold true, determining 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 to this, other values ​​may also be used, and this application does not specifically limit this.

[0126] In the above process, this embodiment calculates the excitation voltage under the condition of equivalent power frequency and no bias magnetism based on the principle of consistent core loss. , at which the excitation voltage The total second core loss generated by the core of the target transformer under the excitation (Right now The corresponding total loss of the second core) and the total loss of the first core under the biased magnetic condition The deviation between them is less than 0.1%, so from the perspective of loss equivalence, it can be considered that there is no bias magnetic voltage at the power frequency. Total loss of the second core under excitation , and set the excitation voltage And the specified bias current Total loss of the first core under double excitation are consistent.

[0127] Then, in this embodiment, the equivalent power frequency excitation voltage can be set to It is used as the excitation source of the time-harmonic field solver in the time-harmonic field finite element simulation software, and then based on the time-harmonic field solver, equivalent calculations of the core loss distribution and temperature rise distribution of the target transformer under DC bias conditions are performed.

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

[0129] Through the above-mentioned excitation source equivalent method, the problem that originally required the use of transient field solutions that consumed a lot of time and resources was transformed into a time-harmonic field calculation problem that takes less time and consumes less resources, which greatly improves the calculation efficiency and provides 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 an embodiment of the present application. The following will introduce a device for executing the above-mentioned time-harmonic field excitation equivalent method based on loss and temperature distribution.

[0131] See also Figure 6 , Figure 6 This is a schematic diagram of the structure of a time-harmonic field excitation equivalent device based on loss and temperature distribution provided in an embodiment of the present application. Figure 6 As shown, the device may include:

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

[0133] The voltage equivalent module 502 is used to determine the equivalent power frequency excitation voltage when there is no DC bias by setting the excitation voltage and the DC bias current together based on the core loss consistency principle, taking the first core total loss as the target value;

[0134] The distribution simulation module 503 is used 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 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 obtain the basic parameter value of the target transformer;

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

[0138] In a possible implementation, the 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] The second loss calculation module is used to 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;

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

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

[0142] A first voltage determination module, configured to determine the initial power frequency excitation voltage as an equivalent power frequency excitation voltage when the determination 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 yes, and use 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.

[0144] In a possible implementation, the 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] The peak magnetic flux density determination module is used to determine the initial core nominal peak magnetic flux density according to the initial power frequency excitation voltage;

[0146] A mapping curve acquisition module is used to obtain a mapping curve between the peak magnetic density and the unit iron loss of the core;

[0147] A data point acquisition module is used to collect multiple data points according to the mapping curve, wherein the data point refers to a data point 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, a linear extrapolation method is used to add the target data point to the mapping curve;

[0148] A unit iron loss determination module is used to obtain an initial unit iron loss using a preset interpolation method based on multiple data points and an initial core nominal peak magnetic flux density;

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

[0150] In a possible implementation, the preset interpolation method in the above-mentioned 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 the second voltage determination module adjusts the initial power frequency excitation voltage, it can be specifically 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 in the embodiment of the present application corresponds to the time-harmonic field excitation equivalent method based on loss and temperature distribution provided in the previous text. For details, please refer to the previous introduction and will not be repeated here.

[0153] The present application also provides an electronic device in an embodiment. Figure 7 As shown, it shows a schematic diagram of the structure of an electronic device suitable for implementing the embodiment of the present application. The electronic device in the embodiment of the present application may include but is not limited to fixed terminals such as mobile phones, laptops, PDAs (personal digital assistants), PADs (tablet computers), desktop computers, etc. Figure 7 The electronic device shown is merely an example and should not bring any limitation to the functions and scope of use of the embodiments of the present application.

[0154] like Figure 7 As shown, the electronic device may include a processing device (e.g., a central processing unit, a graphics processing unit, etc.) 601, which can perform various appropriate actions and processes according to a program stored in a read-only memory (ROM) 602 or a program loaded from a storage device 608 to a 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 via a bus 604. An input / output (I / O) interface 605 is also connected to the bus 604.

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

[0156] An embodiment of the present application also provides a computer program product including computer-readable instructions. When the computer-readable instructions are executed on an electronic device, the electronic device implements any time-harmonic field excitation equivalent method based on loss and temperature distribution provided in the embodiment of the present application.

[0157] A computer-readable storage medium is also provided in an embodiment of the present application. 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 any time-harmonic field excitation equivalent method based on loss and temperature distribution provided in an embodiment of the present application.

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

[0159] Through the description of the above implementation mode, the technicians in the field can clearly understand that the present application can be implemented by means of software plus necessary general hardware, and of course, it can also be implemented by special hardware including special integrated circuits, special CPUs, special memories, special components, etc. In general, all functions completed by computer programs can be easily implemented by corresponding hardware, and the specific hardware structure used to implement the same function can also be various, such as analog circuits, digital circuits or special circuits. However, for the present application, software program implementation is a better implementation mode in more cases. Based on such an understanding, the technical solution of the present application is essentially or the part that contributes to the prior art can be embodied in the form of a software product, which is stored in a readable storage medium, such as a computer floppy disk, a U disk, a mobile hard disk, a ROM, a RAM, a disk or an optical disk, etc., including a number of instructions to enable a computer device (which can be a personal computer, a training device, or a network device, etc.) to execute the methods described in each embodiment of the present application.

[0160] In the above embodiments, all or part of the embodiments may be implemented by software, hardware, firmware or any combination thereof. When implemented by software, all or part of the embodiments may be implemented 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 process or function described in the embodiment of the present application is generated in whole or in part. The computer may be a general-purpose computer, a special-purpose computer, a computer network, or other programmable devices. The computer instructions may 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 may be transmitted from a website site, a computer, a training device, or a data center by wired (e.g., coaxial cable, optical fiber, digital subscriber line (DSL)) or wireless (e.g., infrared, wireless, microwave, etc.) mode to another website site, computer, training device, or data center. The computer-readable storage medium may be any available medium that a computer can store or a data storage device such as a training device, a data center, etc. that includes one or more available media integrations. The available medium may be a magnetic medium, (e.g., a floppy disk, a hard disk, a tape), an optical medium (e.g., a DVD), or a semiconductor medium (e.g., a solid-state drive (SSD)), etc.

Claims

1. A time-harmonic field excitation equivalent method based on loss and temperature distribution, characterized in that: include: Obtaining the total core loss of the target transformer when the excitation voltage is set and the set DC bias current is injected as the first total core loss; Taking the first core total loss as the target value, determining the equivalent power frequency excitation voltage when there is no DC bias by the set excitation voltage and the set DC bias current based on the core loss consistency principle; The loss distribution and temperature distribution of the core in the target transformer are calculated in 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 is characterized in that: The step of obtaining the total core loss of the target transformer when the excitation voltage is set and the set DC bias current is injected as the first total core loss includes: Obtaining basic parameter values ​​of the target transformer; The pre-generated DC bias analysis method calculation program is called to calculate the first core total loss based on the basic parameter value, the set excitation voltage and the set DC bias current.

3. The time-harmonic field excitation equivalent method based on loss and temperature distribution according to claim 1 is characterized in that: The method of taking the first core total 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 equivalent to no DC bias current based on the core loss consistency principle includes: 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; Calculating an absolute value of a difference between the first core total loss and the second core total loss; Determine 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, the initial power frequency excitation voltage is adjusted to obtain an adjusted power frequency excitation voltage, and the adjusted power frequency excitation voltage is used as the initial power frequency excitation voltage. The total core loss of the target transformer at the initial power frequency excitation voltage under the condition of no DC bias is returned until the absolute value of the difference is less than or equal to the preset threshold value, and the adjusted power frequency excitation voltage is determined as the equivalent power frequency excitation voltage.

4. The time-harmonic field excitation equivalent method based on loss and temperature distribution according to claim 3 is characterized in that: The determining of 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: Determining the initial core nominal peak magnetic flux density according to the initial power frequency excitation voltage; Obtaining a mapping curve between the peak magnetic flux density and the unit iron loss of the core; Collecting a plurality of data points according to the mapping curve, wherein the data point refers to a data point represented by a peak magnetic density and a corresponding unit iron loss, and if there is a target data point that exceeds the curve range of the mapping curve among the plurality of data points, adding the target data point to the mapping curve by a linear extrapolation method; Obtaining an initial unit iron loss using a preset interpolation method according to the multiple data points and the initial core nominal peak magnetic flux density; The second core total loss is determined according to the initial unit iron loss.

5. The time-harmonic field excitation equivalent method based on loss and temperature distribution according to claim 4 is characterized in that: The preset interpolation method is one or more of a linear interpolation method, a spline interpolation method and a polynomial interpolation method.

6. The time-harmonic field excitation equivalent method based on loss and temperature distribution according to claim 3 is characterized in that: The step of adjusting the initial power frequency excitation voltage comprises: The initial power frequency excitation voltage is increased by a preset step size.

7. A time-harmonic field excitation equivalent device based on loss and temperature distribution, characterized in that: include: A loss acquisition module, used to acquire the total core loss of the target transformer when the excitation voltage is set and the set DC bias current is injected, as the first total core loss; A voltage equivalent module is used to determine, based on the core loss consistency principle, that the set excitation voltage and the set DC bias current are equivalent to an equivalent power frequency excitation voltage when there is no DC bias, taking the first core total loss as a target value; The distribution simulation module is used 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.

8. A computer program product, characterized in that The method comprises computer-readable instructions, which, when executed on an electronic device, enable the electronic device to implement the time-harmonic field excitation equivalent method based on loss and temperature distribution as claimed in any one of claims 1 to 6.

9. An electronic device, characterized in that: The method comprises at least one processor and a memory connected to the processor, wherein: The memory is used to store computer programs; 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 6.

10. A computer storage medium, characterized in that: The storage medium carries one or more computer programs, which, when executed by 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 6.

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