CN-121997482-A - Temperature prediction and control method, system, equipment and medium of LLC transformer

CN121997482ACN 121997482 ACN121997482 ACN 121997482ACN-121997482-A

Abstract

The invention relates to a temperature prediction and control method, a system, equipment and a medium of an LLC transformer, wherein the method comprises the steps of obtaining structural parameters and material properties of the LLC transformer, and carrying out parameterized three-dimensional modeling to obtain a transformer three-dimensional geometric model comprising complete material properties; the method comprises the steps of collecting a non-sinusoidal current waveform of an LLC transformer during working through circuit simulation, extracting key characteristic parameters of the current waveform, calculating magnetic core loss by using a IGSE formula based on the key characteristic parameters and material properties, obtaining environmental parameters of an environment where the LLC transformer is located, calculating heat transfer key parameters between the surface and air of the LLC transformer based on the environmental parameters, respectively performing steady-state thermal simulation and transient-state thermal simulation by using a three-dimensional geometric model of the transformer based on the magnetic core loss and the heat transfer key parameters to obtain temperature distribution conditions, and generating an LLC transformer temperature management strategy based on the temperature distribution conditions. Compared with the prior art, the method and the device realize more accurate transformer temperature prediction.

Inventors

ZENG PING
LI ZE
BAO WEI
ZHOU DESHENG
FENG QIAN
Lian Jiayu
LU JIAN
LI FAN
SUN TIANJIA
QIN QIN

Assignees

国网上海市电力公司

Dates

Publication Date: 20260508
Application Date: 20251217

Claims (10)

1. A temperature prediction and control method of an LLC transformer is characterized in that the method comprises the following steps: obtaining structural parameters and material properties of an LLC transformer, and carrying out parameterized three-dimensional modeling to obtain a transformer three-dimensional geometric model comprising complete material properties; Collecting a non-sinusoidal current waveform of the LLC transformer during working through circuit simulation, extracting key characteristic parameters of the current waveform, and calculating magnetic core loss by utilizing IGSE formula based on the key characteristic parameters and material properties; Acquiring environmental parameters of the environment where the LLC transformer is located, and calculating heat transfer key parameters between the surface of the LLC transformer and air based on the environmental parameters; Based on the core loss and the heat transfer key parameters, respectively performing steady-state thermal simulation and transient thermal simulation by using a three-dimensional geometric model of the transformer to obtain temperature distribution conditions, and generating an LLC transformer temperature management strategy based on the temperature distribution conditions.
2. The method for predicting and controlling the temperature of an LLC transformer in accordance with claim 1, wherein said steady state thermal simulation is: Applying said core loss as bulk heat generation to a three-dimensional geometric model of the transformer; Determining boundary conditions based on the heat transfer key parameters and applying the boundary conditions to the three-dimensional geometric model of the transformer, wherein the heat transfer key parameters comprise natural convection heat dissipation parameters, heat transfer parameters and radiation parameters, and setting convection boundaries of the outer surface of the transformer, which is in contact with air, based on the natural convection heat dissipation parameters; And performing thermal analysis grid division on the three-dimensional geometric model of the transformer after the body heat generation rate and the boundary condition are applied, and performing steady-state heat balance calculation by using a steady-state heat simulation solver to generate a steady-state heat simulation temperature distribution condition.
3. The method for predicting and controlling the temperature of an LLC transformer in accordance with claim 1, wherein said transient thermal simulations are: setting a random initial temperature and a time-varying load curve for the three-dimensional geometric model of the transformer; For each load point in the time-varying load curve, collecting current waveform key parameters of the LLC transformer at the corresponding load point, calculating corresponding magnetic core loss, and drawing a time-varying curve based on the magnetic core loss of each load point; And applying the time change curve and boundary conditions to a three-dimensional geometric model of the transformer, calculating the complete process of the temperature change of the transformer along with time by using a solver, and obtaining the transient temperature distribution condition, wherein the boundary conditions are determined based on the heat transfer key parameters.
4. The method for predicting and controlling the temperature of an LLC transformer in accordance with claim 1, wherein said LLC transformer temperature management strategy includes a temperature monitoring strategy, an early warning strategy and a heat dissipation measure; the temperature monitoring strategy comprises a temperature monitoring position determined based on the temperature distribution condition and a key area needing key monitoring; The early warning strategy comprises multistage temperature threshold setting and trend early warning strategies; The heat dissipation measures comprise magnetic core structure optimization, heat dissipation structure optimization, improved heat dissipation air channels and an active heat dissipation control strategy, wherein the magnetic core structure optimization comprises the steps of adjusting the length of an air gap of a magnetic core, the cross section area of the magnetic core and optimizing winding arrangement, and the heat dissipation structure optimization comprises the step of increasing the number or the area of heat dissipation fins.
5. A temperature prediction and control system for an LLC transformer, the system comprising: the three-dimensional geometric model building model carries out parameterized three-dimensional modeling based on structural parameters and material properties of the LLC transformer to generate a transformer three-dimensional geometric model comprising complete material properties; The magnetic core loss calculation module collects non-sinusoidal current waveforms of the LLC transformer during working through circuit simulation, extracts key characteristic parameters of the current waveforms, and calculates magnetic core loss by utilizing IGSE formulas based on the key characteristic parameters and material properties; The heat transfer key parameter calculation module is used for calculating heat transfer key parameters between the surface of the LLC transformer and the air based on the acquired environmental parameters of the environment where the LLC transformer is positioned; and the temperature management strategy generation module is used for respectively carrying out steady-state thermal simulation and transient thermal simulation by utilizing a three-dimensional geometric model of the transformer based on the magnetic core loss and the heat transfer key parameters to obtain temperature distribution conditions, and generating an LLC transformer temperature management strategy based on the temperature distribution conditions.
6. The system according to claim 5, wherein the steady-state thermal simulation is: Applying said core loss as bulk heat generation to a three-dimensional geometric model of the transformer; Determining boundary conditions based on the heat transfer key parameters and applying the boundary conditions to the three-dimensional geometric model of the transformer, wherein the heat transfer key parameters comprise natural convection heat dissipation parameters, heat transfer parameters and radiation parameters, and setting convection boundaries of the outer surface of the transformer, which is in contact with air, based on the natural convection heat dissipation parameters; And performing thermal analysis grid division on the three-dimensional geometric model of the transformer after the body heat generation rate and the boundary condition are applied, and performing steady-state heat balance calculation by using a steady-state heat simulation solver to generate a steady-state heat simulation temperature distribution condition.
7. The system for temperature prediction and control of an LLC transformer in accordance with claim 5, wherein said transient thermal simulations are: setting a random initial temperature and a time-varying load curve for the three-dimensional geometric model of the transformer; For each load point in the time-varying load curve, collecting current waveform key parameters of the LLC transformer at the corresponding load point, calculating corresponding magnetic core loss, and drawing a time-varying curve based on the magnetic core loss of each load point; And applying the time change curve and boundary conditions to a three-dimensional geometric model of the transformer, calculating the complete process of the temperature change of the transformer along with time by using a solver, and obtaining the transient temperature distribution condition, wherein the boundary conditions are determined based on the heat transfer key parameters.
8. The system according to claim 5, wherein the LLC transformer temperature management strategy includes a temperature monitoring strategy, an early warning strategy and a heat dissipation measure; the temperature monitoring strategy comprises a temperature monitoring position determined based on the temperature distribution condition and a key area needing key monitoring; The early warning strategy comprises multistage temperature threshold setting and trend early warning strategies; The heat dissipation measures comprise magnetic core structure optimization, heat dissipation structure optimization, improved heat dissipation air channels and an active heat dissipation control strategy, wherein the magnetic core structure optimization comprises the steps of adjusting the length of an air gap of a magnetic core, the cross section area of the magnetic core and optimizing winding arrangement, and the heat dissipation structure optimization comprises the step of increasing the number or the area of heat dissipation fins.
9. An electronic device comprising a memory and a processor, the memory having stored thereon a computer program, wherein the processor, when executing the program, implements the method of any of claims 1-4.
10. A computer readable storage medium, on which a computer program is stored, characterized in that the program, when being executed by a processor, implements the method according to any one of claims 1-4.

Description

Temperature prediction and control method, system, equipment and medium of LLC transformer Technical Field The invention relates to the technical field of power electronics, in particular to a temperature prediction and control method, a system, equipment and a medium of an LLC transformer. Background The LLC resonant converter can realize high-efficiency energy conversion due to excellent resonance characteristics, and can maintain good current and voltage stability under a wide range of input voltage and load conditions, so that the LLC resonant converter is widely applied in the power electronics field. As power electronics evolve towards higher power densities, the LLC resonant converter heats up more and more significantly when operated at high power. The transformer is used as a core component for energy transfer in the LLC resonant converter and bears larger power, and the temperature rise problem is particularly remarkable. And the performance of the magnetic material is extremely sensitive to the working temperature, for example, the magnetic permeability of the magnetic material shows a complex change trend of increasing and then decreasing along with the temperature rise, and the magnetic permeability rapidly decreases after reaching a certain peak value, and finally tends to 0 under the high-temperature condition, and the temperature corresponding to the maximum magnetic permeability of most magnetic materials is only about 20 ℃ different from the temperature when the magnetic permeability of the magnetic materials decreases to zero. If the temperature rise of the magnetic core in the LLC resonant converter is controlled improperly, the magnetic core may be reduced sharply due to the magnetic permeability, causing a series of problems such as reduced magnetic circuit performance, increased magnetic core loss, deviation of LLC resonant characteristics from design values, and the like, and further causing the functional failure of the whole converter system. In addition, the saturation magnetic flux density of the magnetic material is also obviously affected by temperature, and decreases along with the temperature rise, when the magnetic material enters a magnetic saturation state, the problems of waveform distortion, current overload, and aggravation of heat loss of a magnetic core are caused due to the obvious decrease of magnetic permeability. Meanwhile, temperature has an important influence on the loss characteristics of the magnetic material, and the loss of the magnetic core material mainly comprises hysteresis loss and eddy current loss, and the loss acts on the magnetic core in the form of heat, so that the temperature rise problem is further aggravated. When the loss and the temperature rise of the magnetic core are overlarge, the performance of the material can be obviously affected, the magnetic permeability is reduced, the saturation magnetic flux density is reduced, malignant circulation between the loss and the temperature rise can be possibly caused, and the performance and the stability of the magnetic material are weakened. The loss of the core material exhibits a complex change with increasing temperature, i.e., the loss may decrease slightly at the initial stage of the temperature increase, but then the loss increases significantly with further temperature increase. Therefore, it is indispensable to consider the magnetic effect when analyzing the temperature of the transformer, for example, chinese patent application CN119918353a provides a method for calculating the temperature of the transformer tank using electromagnetic induction heating, which introduces the electromagnetic field principle in the process of temperature solving, but still has the following problems that it calculates eddy current and joule heat based on the electromagnetic induction principle, but does not consider the characteristic that the current waveform in the LLC resonant converter is non-sinusoidal, and the accuracy is low under such waveform by adopting the conventional loss calculation method, resulting in larger magnetic core loss prediction deviation, thereby affecting the accuracy of temperature prediction. Therefore, how to realize more accurate magnetic core loss prediction and thus more accurate temperature prediction is a technical problem to be solved. Disclosure of Invention The invention aims to overcome the defects of the prior art and provide a temperature prediction and control method, a system, equipment and a medium of an LLC transformer, and aims to realize accurate prediction of the temperature of the LLC resonant converter transformer by means of accurate modeling, simulation analysis, experimental verification and the like, and accordingly, an effective temperature management strategy is formulated, so that the operation of the transformer in a normal working temperature range is ensured, and the stability and reliability of the transformer are improved. The aim of the invention