Performance optimization method of mine explosion-proof frequency converter

Abstract

The application discloses a performance optimization method of a mine-used explosion-proof frequency converter, which comprises the following steps: constructing an equivalent model of a main circuit topology of the mine-used explosion-proof frequency converter; extracting a parameter set according to a geometric model of an internal device; constructing a three-dimensional digital prototype model of the mine-used explosion-proof frequency converter; analyzing electromagnetic conduction interference intensity by using the equivalent model of the main circuit topology; equivalently converting the three-dimensional digital prototype model into an antenna model of the mine-used explosion-proof frequency converter; analyzing electromagnetic radiation interference level by using the equivalent model of the main circuit topology, and optimizing the parameter set according to an analysis result; calculating power loss of the mine-used explosion-proof frequency converter according to the equivalent model of the optimized main circuit topology; introducing the power loss into the three-dimensional digital prototype model to obtain flow field data and temperature field data of the mine-used explosion-proof frequency converter; and optimizing performance parameters of a radiator. The application can more effectively optimize the performance of the mine-used explosion-proof frequency converter.

Description

Technical Field

[0001] This invention relates to the field of mining frequency converter technology, and specifically to a performance optimization method for a mining explosion-proof frequency converter. Background Technology

[0002] Explosion-proof frequency converters for mining are widely used in mining, tunneling, transportation, and ventilation, and their performance directly affects mine production and underground safety. Because of the enclosed space, the internal power devices of these converters generate significant heat during operation, and heat exchange occurs between them, leading to a significant temperature rise, reduced reliability, and susceptibility to thermal failure and degradation. Furthermore, electromagnetic interference (EMI) is a crucial indicator of the performance and reliability of explosion-proof frequency converters for mining and a key area for optimization. When EMI exceeds certain limits, unwanted electromagnetic energy can enter other sensitive equipment underground through the receiving channels of sensitive devices, such as antennas, transmission lines, power supplies, and housings. This can cause other equipment to respond to unwanted energy, resulting in erroneous actions and potentially causing safety accidents. Therefore, performance optimization of explosion-proof frequency converters for mining is of paramount importance. Summary of the Invention

[0003] The present invention aims to solve one of the technical problems existing in the prior art.

[0004] Therefore, this invention provides a comprehensive performance optimization method for explosion-proof frequency converters used in mining, which can more effectively optimize the comprehensive performance of explosion-proof frequency converters used in mining.

[0005] The technical solution adopted by this invention to solve its technical problem is: a performance optimization method for a mine explosion-proof frequency converter, comprising:

[0006] S1. Construct an equivalent model of the main circuit topology of the explosion-proof frequency converter for mining;

[0007] S2. Extract the parameter set based on the geometric model of the internal components and substitute it into the equivalent model of the main circuit topology;

[0008] S3. Combine the three-dimensional geometric models of the internal components, heat sink, and explosion-proof enclosure of the mine explosion-proof frequency converter to construct a three-dimensional digital prototype model of the mine explosion-proof frequency converter.

[0009] S4. Analyze the electromagnetic conduction interference intensity using the equivalent model of the main circuit topology, and optimize the parameter set based on the analysis results;

[0010] S5. Equivalent the three-dimensional digital prototype model to a mine explosion-proof frequency converter antenna model;

[0011] S6. Analyze the electromagnetic radiation interference level using the equivalent model of the main circuit topology, and optimize the parameter set based on the analysis results.

[0012] S7. The power loss of the explosion-proof frequency converter for mining is calculated based on the equivalent model of the optimized main circuit topology.

[0013] S8. Import the power loss into the three-dimensional digital prototype model to obtain the flow field data and temperature field data of the mine explosion-proof frequency converter; and determine whether the heat dissipation performance of the mine explosion-proof frequency converter meets the requirements; if the heat dissipation performance does not meet the requirements, optimize the performance parameters of the radiator.

[0014] Furthermore, the equivalent model of the main circuit topology includes: a DC filter capacitor, a DC busbar, an AC-DC connection busbar, and an AC busbar, wherein the AC busbar contains multiple IGBT modules.

[0015] Furthermore, the parameter set of the explosion-proof frequency converter for mining is extracted, including:

[0016] Generate a behavioral model of the IGBT module to accurately describe its switching characteristics;

[0017] The parameters of resistance, capacitance, and inductance in DC filter capacitors, DC busbars, AC-DC connection busbars, and AC busbars are extracted using parameter extraction tools.

[0018] Furthermore, the explosion-proof enclosure and internal metal shell are equivalent to a surface antenna. Switching characteristic curves are applied to the IGBT module, the interference source, to establish an antenna model for the explosion-proof frequency converter in the mine. The surface antenna and the line antenna are divided using the method of moments, and the current is expanded using RWG basis functions to calculate the surface / line current and surface / line magnetic current on the antenna surface. The electromagnetic field generated by the antenna model of the explosion-proof frequency converter in space is calculated to measure the intensity of the internal and external radiated interference of the frequency converter.

[0019] Furthermore, the power loss of the explosion-proof frequency converter for mining includes: the power loss of the busbar, the power loss of the DC filter capacitor, and the power loss of the IGBT.

[0020] Furthermore, a three-dimensional geometric model of the heat sink is constructed, including:

[0021] Place the IGBT module and resistors on the substrate of the heat sink;

[0022] The temperature field distribution of the heat sink, IGBT module and resistor was characterized by ANSYS Icepak finite element method, and the heat dissipation performance of different materials, flow rates and different distances from the flow channel to the substrate was compared and analyzed.

[0023] Select the type and installation location of the cooling fan, and compare the impact of horizontal and vertical air intake and fan installation location on heat dissipation performance;

[0024] Once the heat dissipation performance meets the requirements, the final three-dimensional geometric model of the heat sink is determined.

[0025] Furthermore, assuming the temperature inside the explosion-proof chamber of the mine-use explosion-proof frequency converter is 40℃ during operation, and the temperature rise is required to not exceed 30℃, according to the principles of heat transfer, the fan flow rate to meet the heat dissipation requirements is: In the formula, Q represents the heat transferred from the heat sink to the environment per unit time, and C... p ρ represents the specific heat capacity of the cooling medium, ρ represents the density of the cooling medium, and ΔT represents the temperature rise.

[0026] Furthermore, the three-dimensional digital prototype model is divided into meshes, and material property parameters, excitation conditions, and boundary conditions are set to obtain the flow field data and temperature field data of the mine explosion-proof frequency converter.

[0027] Furthermore, the performance parameters of the radiator are optimized, including: gradually increasing the flow rate of the cooling medium to make the heat dissipation performance meet the requirements, or selecting materials with higher convective heat transfer coefficients to make the heat dissipation performance meet the requirements.

[0028] Furthermore, the boundary conditions include the convective heat transfer coefficient and the ambient temperature.

[0029] The beneficial effects of this invention are that its optimization method, combining electro-magnetic-thermal coupling for comprehensive analysis, allows for parameter extraction, field distribution, and coupling calculations across different finite element analysis software, enabling the evaluation of operating mechanisms and processes under complex environments. This method fully considers the superposition and mutual influence between physical fields, as well as the impact of parasitic effects on the operational reliability of mine explosion-proof frequency converters. Utilizing finite element analysis software, multi-physics coupling analysis can be performed directly without any modification or new development. Based on simulation results, the electrical and electromagnetic characteristics, temperature field, and flow field distribution of the mine explosion-proof frequency converter and its internal structure under operating conditions can be comprehensively characterized. This provides a feasible theoretical model and analysis method for the electro-magnetic-thermal design and performance optimization of mine explosion-proof frequency converters. Attached Figure Description

[0030] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0031] Figure 1 This is a flowchart of the optimization method of the present invention.

[0032] Figure 2 This is a schematic diagram of the equivalent model of the main circuit topology of the present invention.

[0033] Figure 3 This is a schematic diagram of the dual-pulse circuit model of the present invention.

[0034] Figure 4 This is the IGBT module start-up process curve of the present invention.

[0035] Figure 5 This is the IGBT module turn-off process curve of the present invention.

[0036] Figure 6 This is a schematic diagram of a three-dimensional digital prototype of the explosion-proof frequency converter for mining applications according to the present invention.

[0037] Figure 7 This is a cloud map showing the convective heat transfer coefficient distribution of the IGBT module substrate of the present invention.

[0038] Figure 8 This is a temperature field distribution cloud map of the explosion-proof enclosure and busbar assembly of the present invention.

[0039] Figure 9 This is a schematic diagram showing the maximum junction temperature of the IGBT module under different conditions according to the present invention.

[0040] Figure 10 This is a diagram showing the distribution of the electric field strength (near field) inside the inverter of this invention.

[0041] Figure 11 This is a near-field distribution diagram of the electric field strength on the back of the casing of the present invention.

[0042] Figure 12 This is a graph showing the distribution of field strength (near field) as a function of distance in this invention.

[0043] Figure 13 This is the far-field three-dimensional field strength distribution diagram of the present invention. Detailed Implementation

[0044] The present invention will now be described in further detail with reference to the accompanying drawings. These drawings are simplified schematic diagrams, illustrating only the basic structure of the invention, and therefore only show the components relevant to the invention.

[0045] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential," etc., indicating orientation or positional relationships, are based on the orientation or positional relationships shown in the accompanying drawings and are only for the convenience of describing the invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the invention. Furthermore, features defined with "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this invention, unless otherwise stated, "a plurality of" means two or more.

[0046] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0047] like Figure 1 As shown, the performance optimization method for the mine explosion-proof frequency converter of the present invention includes: S1, constructing an equivalent model of the main circuit topology of the mine explosion-proof frequency converter; S2, extracting a parameter set based on the geometric model of the internal components of the frequency converter, and substituting the parameter set into the equivalent model of the main circuit topology; S3, constructing a three-dimensional digital prototype model of the mine explosion-proof frequency converter by combining the three-dimensional geometric models of the internal components, heat sink, and explosion-proof enclosure of the mine explosion-proof frequency converter; S4, analyzing the electromagnetic conduction interference intensity using the equivalent model of the main circuit topology, and optimizing the parameter set based on the analysis results; S5 S6. Equivalently model the three-dimensional digital prototype model to an antenna model for a mine explosion-proof frequency converter; S7. Analyze the electromagnetic radiation interference level using the equivalent model of the main circuit topology, and optimize the parameter set based on the analysis results; S8. Calculate the power loss of the mine explosion-proof frequency converter based on the optimized equivalent model of the main circuit topology; S9. Import the power loss into the three-dimensional digital prototype model to obtain the flow field data and temperature field data of the mine explosion-proof frequency converter; and determine whether the heat dissipation performance of the mine explosion-proof frequency converter meets the requirements; if the heat dissipation performance does not meet the requirements, optimize the performance parameters of the heat sink.

[0048] The interference analysis in this invention is divided into two main parts: electromagnetic conducted interference analysis and electromagnetic radiation interference analysis. The analysis of electromagnetic conducted interference mainly relies on the equivalent model of the main circuit topology. The analysis of electromagnetic radiation interference mainly relies on the antenna model of the explosion-proof frequency converter for mining.

[0049] like Figure 2 As shown, the equivalent model of the main circuit topology includes: a DC filter capacitor, a DC busbar, an AC-DC connection busbar, and an AC busbar, wherein the AC busbar contains multiple IGBT modules. U dc Where C is the DC bus voltage, C is the DC filter capacitor, and R is the DC bus voltage. C L is the equivalent resistance of a DC capacitor. C R is the stray inductance of the DC filter capacitor. INV1+ R INV2+ R INV1- R INV1- R represents the equivalent resistance of the positive and negative terminals of the DC bus, respectively. U+ R UV+ R VW+ R U- R UV- R VW- R represents the equivalent resistance of the positive and negative terminals of the AC-DC busbar, respectively. k++ R k-～ The equivalent resistances R of the positive and negative terminals of the upper arms of the U-phase, V-phase, and W-phase AC busbars are respectively. k～+ R k-- The equivalent resistances of the positive and negative terminals of the lower bridge arms of the U-phase, V-phase, and W-phase AC busbars are respectively, L INV1+ L INV2+ L INV1- L INV1- The stray inductances of the positive and negative terminals of the DC bus, L U+ L UV+ L VW+ L U- L UV- L VW- The stray inductances of the positive and negative terminals of the AC-DC busbar are respectively, L k++ L k-～ The stray inductances of the positive and negative terminals of the upper bridge arms of the U-phase, V-phase, and W-phase AC busbars are respectively, L k～+ L k-- These are the stray inductances of the positive and negative terminals of the lower bridge arms of the U-phase, V-phase, and W-phase AC busbars, respectively.

[0050] In step S2, a parameter set is extracted based on the geometric model of the internal components of the frequency converter. This includes: generating a behavioral model of the IGBT module to accurately describe its switching characteristics; and using a parameter extraction tool to extract the resistance, capacitance, and inductance parameters of the DC filter capacitor, DC busbar, AC-DC connection busbar, and AC busbar. The proposed parameter set consists of electromagnetic field-related parameters. Stray inductances in power electronic equipment include stray inductances from the DC filter capacitor, busbar stray inductance and resistance, and stray inductances from switching device leads and connecting bolts. Among these, the busbar stray inductance is the primary factor affecting the switching characteristics and power loss of the IGBT module. This method generates a behavioral model of the IGBT module to more accurately understand its switching characteristics.

[0051] For example, the behavioral modeling of an IGBT module includes: based on the device datasheet parameters and combined with the transfer characteristic curves, output characteristic curves, and freewheeling diode characteristic curves, a behavioral model of the FZ800R33KF2C IGBT module is built using ANSYS Simplorer. After the model is built, a dual-pulse circuit model is then built using ANSYS Simplorer, and a dual-pulse experimental platform is set up to verify the correctness of the behavioral model. Figure 3 As shown, when only the AC busbar is connected, the bus voltage is adjusted to 1100V, 1300V, 1500V, and 1700V respectively. The turn-on and turn-off waveforms of the IGBT module are measured using a Rogowski coil, oscilloscope, and current clamp. The peak voltage comparison results between the simulated and experimental waveforms are shown in Table 1. According to Table 1, the simulated and experimental waveforms maintain a high degree of consistency in trend. The established IGBT behavior model can accurately reflect the switching characteristics of the IGBT and has high simulation accuracy, making it usable.

[0052] Table 3

[0053]

[0054]

[0055] The switching characteristics of IGBT modules act as a crucial link between electric and magnetic fields.

[0056] For example, the intensity of electromagnetic conducted interference (EMI) can be analyzed by connecting a standard LISN probe in series in the equivalent model of the main circuit topology and performing time-domain and frequency-domain analyses on differential-mode and common-mode interference to obtain the intensity of ESI. If the intensity of ESI is too high, it can be suppressed. Suppression measures for ESI include: optimizing the internal structure of power devices to reduce stray inductance, using a multi-level topology with stronger harmonic suppression capabilities, connecting filter devices in series in the main circuit, or connecting absorption circuits in parallel across the IGBT module.

[0057] For example, the power loss of a mine-use explosion-proof frequency converter includes: the power loss of the busbar, the power loss of the DC filter capacitor, and the power loss of the IGBT. ANSYS Q3D simulation is used to obtain the electromagnetic field intensity distribution cloud map of the busbar and the equivalent resistance versus frequency curve. Then, ANSYS Simplore simulation is used to obtain the current curve flowing through the busbar. Finally, the formula is used... Calculate the power loss of the busbar, where I RMS The current represents the effective value, and R represents the equivalent resistance. The DC filter capacitors in the inverter / rectifier unit each consist of two capacitors connected in parallel, each with a capacitance of 2.3mF and an equivalent resistance of 1.2mΩ. The ripple current of a single DC filter capacitor within one fundamental cycle is obtained using ANSYS Simplore simulation, and then combined with the formula... The power loss of the DC filter capacitor can be calculated. Based on the IGBT's behavioral model, the IGBT switching characteristic curve under full-load conditions can be obtained using ANSYS Simplorer (e.g., ...). Figure 4 and Figure 5 As shown), where u ce For collector-emitter voltage, I c Using the base current as an integral over the IGBT switching characteristic curve and taking a single pulse period, the power loss of the IGBT module can be obtained.

[0058] The power loss of the explosion-proof frequency converter for mining can be used as an excitation condition for subsequent flow field and temperature field data solving, and it is the hub connecting the electric field with the flow field and temperature field.

[0059] The performance of explosion-proof frequency converters used in mining is also closely related to heat dissipation. To comprehensively evaluate the heat dissipation performance of explosion-proof frequency converters used in mining, this invention establishes a three-dimensional digital prototype model of the explosion-proof frequency converter (e.g., Figure 6 (As shown). The 3D digital prototype model includes components such as heat sinks, explosion-proof enclosures, sheet metal parts, controllers, filters, and sensors. In other words, the 3D digital prototype model contains all the components of a mining explosion-proof frequency converter, facilitating a comprehensive and accurate analysis of its heat dissipation performance.

[0060] The 3D digital prototype model was meshed, and material property parameters, excitation conditions, and boundary conditions were set to obtain the flow field and temperature field data of the mine explosion-proof frequency converter. In the mine explosion-proof frequency converter, the gaseous or liquid medium forms a flow field under heat, which also serves a heat dissipation function. Therefore, the flow field and temperature field are tightly coupled bidirectionally, and this bidirectional coupling calculation can be completed independently by fluid dynamics software. The boundary conditions include the convective heat transfer coefficient and the ambient temperature. The heat dissipation effect of the water-cooled radiator is equivalent to convective heat transfer. The ambient air temperature is set to 30℃, and the cooling water flow rate is 30L / min. The convective heat transfer coefficient distribution cloud map of the IGBT module substrate is obtained using ANSYS Fluent simulation (e.g., ...). Figure 7 As shown in the figure, the minimum convective heat transfer coefficient at the bottom of the IGBT module is 1200 W / (m²·℃). Therefore, considering extreme heat dissipation conditions, this value is used as the convective heat transfer coefficient for fatigue failure analysis of the IGBT module. A finite element model of the mine explosion-proof frequency converter is established using ANSYS Icepak, and the power losses of the IGBT module, various busbars, and other devices are substituted into the finite element model. The ambient air temperature is set to 30℃, and the temperature field distribution cloud map of the explosion-proof enclosure and busbar assembly (as shown in the figure) is obtained. Figure 8 As shown in the figure, due to the conduction, convection, and radiation heat transfer of the internal power devices, the actual ambient temperature of the IGBT module is higher than that of the explosion-proof cavity and the outside air temperature. Near the IGBT module, the AC busbar has the highest temperature, reaching 67℃. Therefore, considering extreme operating conditions, this value is used as the ambient temperature for IGBT module bond wire fault analysis.

[0061] For example, the construction of the three-dimensional geometric model of the heat sink includes: placing the IGBT module and resistor on the heat sink substrate; using ANSYS Icepak finite element method to characterize the temperature field distribution of the heat sink, IGBT module, and resistor, and comparing and analyzing the heat dissipation performance of different materials, flow rates, and different distances from the flow channel to the substrate; selecting the type of cooling fan and the installation position of the cooling fan, and using ANSYS Maxwell and ANSYS Icepak to perform electromagnetic field coupling simulation analysis, comparing the impact of lateral and longitudinal air intake and fan installation position on heat dissipation performance; when the heat dissipation performance meets the requirements, determining the final three-dimensional geometric model of the heat sink.

[0062] For example, setting the ambient temperature to 30℃, using copper T2 and steel Q235, with a cooling water flow rate of 10–30 L / min and a channel-to-substrate distance of 4 mm–8 mm, the maximum junction temperature of the IGBT module under different conditions is as follows: Figure 9As shown, under the same conditions, copper T2 has better heat dissipation performance than steel Q235, but steel Q235 has better pressure resistance than copper T2, and copper T2 has higher material and processing costs. To achieve the same heat dissipation performance, the cooling water flow rate needs to be increased and the distance from the flow channel to the substrate needs to be reduced. Given that the design requires the IGBT module and absorption resistor to have a maximum junction temperature of 75℃, a cooling water flow rate of 30L / min and a flow channel distance of 4mm can be selected.

[0063] Assuming the temperature inside the explosion-proof chamber of the mine-use explosion-proof frequency converter is 40℃ during operation, and the required temperature rise is no more than 30℃, according to the principles of heat transfer, the fan flow rate to meet the heat dissipation requirements is: In the formula, Q represents the heat transferred from the heat sink to the environment per unit time, and C... p ρ represents the specific heat capacity of the cooling medium, ρ represents the density of the cooling medium, and ΔT represents the temperature rise. Before optimization, a rough flow rate value can be set based on the fan flow rate formula, and then gradually optimized. Optimization of the radiator performance parameters includes: gradually increasing the flow rate parameter of the cooling medium to meet the heat dissipation requirements, or selecting materials with higher convective heat transfer coefficients to meet the heat dissipation requirements. Electromagnetic conduction strength and temperature rise judgments should be performed according to industry or company standards.

[0064] For example, a three-dimensional digital prototype model can be equivalent to an antenna model of a mine explosion-proof frequency converter. The explosion-proof enclosure and internal metal shell are equivalent to a surface antenna. Switching characteristic curves are applied to the IGBT module, the interference source, to establish the antenna model of the mine explosion-proof frequency converter. The surface antenna and linear antenna are subdivided using the method of moments, and the current is expanded using RWG basis functions to calculate the surface / linear current and surface / linear magnetic current on the antenna surface (surface current corresponds to surface magnetic current, and linear current corresponds to linear magnetic current). The electromagnetic field generated by the mine explosion-proof frequency converter antenna model in space is calculated to measure the intensity of internal and external radiated interference of the frequency converter.

[0065] The waveform of the IGBT module voltage amplitude in the frequency domain was obtained through Fourier transform, and the voltage amplitude at each frequency point was added to the antenna model as the feed power supply. Based on the constructed antenna model, the ground was set as an ideal conductor, and the electric field intensity radiated into space under normal operating conditions of the mine explosion-proof frequency converter was calculated. Excitation frequencies of 0.1MHz, 0.5MHz, 1MHz, and 20MHz were used, and the calculation results of electromagnetic radiation interference were analyzed from both near-field and far-field perspectives.

[0066] Near-field analysis: To analyze the distribution of electromagnetic interference inside the frequency converter, three near-field calculation areas are set inside the frequency converter, and the coordinate positions corresponding to the model are respectively: (X=0, -200<Y<200, 0<Z<190), (-150<X<150, -200<Y<200, Z=121.7), (-150<X<150, -200<Y<200, Z=54.2). Then the electric field intensity at typical frequency points of these three positions is calculated, Figure 10 the field strength distribution diagrams at frequency points of 0.1MHz, 0.5MHz, 1MHz and 20MHz are listed. From Figure 10 it can be seen from the internal field strength distribution of the 4 frequency points that the field strength distribution is all limited inside the frequency converter casing, and the casing plays a good shielding role. The field strength between the laminated busbar of the inverter at each frequency point and the heat sink is the largest, followed by the inlet and outlet cables, various components and internal connecting wires, which are significantly higher than other positions. Since the heat sink of the inverter is installed on the back of the casing, the interference here is relatively serious. Therefore, a near-field calculation area is specially set at a position 2cm away from the back of the casing, and the calculation structure is as shown in Figure 11 . The electric field intensity at the installation position of the heat sink is relatively large in the field strength distribution at each frequency point. And with the increase of frequency, the proportion of high field strength distribution at the position of the incoming cable increases gradually, so the electromagnetic interference of the cable is more serious at high frequency. In terms of value, from the perspective of the maximum field strength at each frequency point, the field strength decreases with the increase of frequency. To further study the change of field strength at the heat sink position with the calculation distance, a calculation point is set every 0.5m, and the field strength distribution at a distance of 0-10m is calculated, as shown in Figure 12 , from Figure 12 it can be seen that the electric field intensity at each frequency point gradually decreases with the increase of distance. The electric field intensity decreases the fastest within 0 to 0.5m, and the field strength curve gradually tends to be gentle after 0.5m, and the field strength at frequency points of 0.1MHz, 0.3MHz and 0.5MHz tends to be consistent. According to the provisions of *GB17626.6 Electromagnetic Compatibility Testing and Measurement Technology*, the radio interference limit for frequencies of 0.15 to 80MHz is 1V / m (about 120dBμV / m), and all frequency points outside 0.5m meet this limit.

[0067] Far-field analysis: To study the propagation law of electromagnetic interference to the distance, the far field at each typical frequency point is calculated, Figure 13 the three-dimensional far-field field strength distribution diagrams at frequency points of 0.1MHz, 0.5MHz, 1MHz, 5MHz, 10MHz and 20MHz are shown. It can be seen from the far-field distribution diagram that frequency points lower than 1MHz propagate uniformly in a波纹 shape around the top of the frequency converter as the center. After the 5MHz frequency point, the far-field distribution is no longer uniform, and the number of lobes gradually increases. The far-field lobes at 10MHz and 20MHz frequency points mainly propagate above the incoming cable. The field strength value is small, and the interference to the distance is not obvious.

[0068] In summary, the optimization method of this invention, combining electro-magnetic-thermal coupling analysis, can perform parameter extraction, field distribution, and coupling calculations for multiphysics field analysis across different finite element analysis software, completing the evaluation of operating mechanisms and processes under complex environments. This method fully considers the superposition and mutual influence between physical fields, as well as the impact of parasitic effects on the operational reliability of mine explosion-proof frequency converters. Utilizing finite element analysis software, multiphysics field coupling analysis can be performed directly without any modification or new development. Based on simulation results, the electrical and electromagnetic characteristics, temperature field, and flow field distribution of the mine explosion-proof frequency converter and its internal structural components under operating conditions can be comprehensively characterized. This provides a feasible theoretical model and analysis method for the electro-magnetic-thermal design and performance optimization of mine explosion-proof frequency converters.

[0069] Based on the above-described preferred embodiments of the present invention, and through the foregoing description, those skilled in the art can make various changes and modifications without departing from the inventive concept. The technical scope of this invention is not limited to the contents of the specification, but must be determined by the scope of the claims.

Claims

1. A method for performance optimization of a mine explosion-proof frequency converter, characterized in that, include: S1. Construct an equivalent model of the main circuit topology of the explosion-proof frequency converter for mining; S2. Extract the parameter set based on the geometric model of the internal components of the frequency converter, and substitute the parameter set into the equivalent model of the main circuit topology; S3. Combine the three-dimensional geometric models of the internal components, heat sink, and explosion-proof enclosure of the mine explosion-proof frequency converter to construct a three-dimensional digital prototype model of the mine explosion-proof frequency converter; S4. Analyze the electromagnetic conduction interference intensity using the equivalent model of the main circuit topology, and optimize the parameter set based on the analysis results; S5. Equivalent the three-dimensional digital prototype model to a mine explosion-proof frequency converter antenna model; S6. Analyze the electromagnetic radiation interference level using the equivalent model of the main circuit topology, and optimize the parameter set based on the analysis results. S7. The power loss of the explosion-proof frequency converter for mining is calculated based on the equivalent model of the optimized main circuit topology. S8. Import the power loss into the three-dimensional digital prototype model to obtain the flow field data and temperature field data of the mine explosion-proof frequency converter; and determine whether the heat dissipation performance of the mine explosion-proof frequency converter meets the requirements; if the heat dissipation performance does not meet the requirements, optimize the performance parameters of the radiator.

2. The performance optimization method for the explosion-proof frequency converter for mining as described in claim 1, characterized in that, The equivalent model of the main circuit topology includes: a DC filter capacitor, a DC busbar, an AC-DC connection busbar, and an AC busbar, wherein the AC busbar contains multiple IGBT modules.

3. The performance optimization method for the explosion-proof frequency converter for mining as described in claim 2, characterized in that, The parameter set is extracted based on the geometric model of the internal components of the frequency converter, including: Generate a behavioral model of the IGBT module to accurately describe its switching characteristics; The parameter extraction tool was used to extract the resistance, capacitance, and inductance parameters of the DC filter capacitor, DC busbar, AC-DC connection busbar, and AC busbar. The power loss of explosion-proof frequency converters used in mining includes: power loss of the busbar, power loss of the DC filter capacitor, and power loss of the IGBT.

4. The performance optimization method for a mine explosion-proof frequency converter as described in claim 1, characterized in that, The explosion-proof enclosure and internal metal shell are equivalent to a surface antenna. Switching characteristic curves are applied to the IGBT module, the interference source, to establish an antenna model for the explosion-proof frequency converter in mining. The surface antenna and line antenna are divided using the method of moments, and the current is expanded using RWG basis functions to calculate the surface / line current and surface / line magnetic current on the antenna surface. The electromagnetic field generated by the antenna model of the explosion-proof frequency converter in space is calculated to measure the intensity of electromagnetic radiation interference inside and outside the frequency converter.

5. The performance optimization method for the explosion-proof frequency converter for mining as described in claim 3, characterized in that, The process of constructing the three-dimensional geometric model of the heat sink includes: Place the IGBT module and resistors on the substrate of the heat sink; The temperature field distribution of the heat sink, IGBT module and resistor was characterized by ANSYS Icepak finite element method, and the heat dissipation performance of different materials, flow rates and different distances from the flow channel to the substrate was compared and analyzed. Select the type and installation location of the cooling fan, and compare the impact of horizontal and vertical air intake and fan installation location on heat dissipation performance; Once the heat dissipation performance meets the requirements, the final three-dimensional geometric model of the heat sink is determined.

6. The performance optimization method for a mine explosion-proof frequency converter as described in claim 5, characterized in that, Assuming the temperature inside the explosion-proof chamber of the mine-use explosion-proof frequency converter is 40℃ during operation, and the required temperature rise is no more than 30℃, according to the principles of heat transfer, the fan flow rate to meet the heat dissipation requirements is: In the formula, Q represents the heat transferred from the heat sink to the environment per unit time, and C... p ρ represents the specific heat capacity of the cooling medium, ρ represents the density of the cooling medium, and ΔT represents the temperature rise.

7. The performance optimization method for a mine explosion-proof frequency converter as described in claim 1, characterized in that, The three-dimensional digital prototype model is divided into meshes, and material property parameters, excitation conditions and boundary conditions are set to obtain the flow field data and temperature field data of the explosion-proof frequency converter for mining.

8. The performance optimization method for a mine explosion-proof frequency converter as described in claim 1, characterized in that, Optimize the performance parameters of the radiator, including: gradually increasing the flow rate of the cooling medium to make the heat dissipation performance meet the requirements, or selecting materials with a higher convective heat transfer coefficient to make the heat dissipation performance meet the requirements.

9. The performance optimization method for a mine explosion-proof frequency converter as described in claim 7, characterized in that, The boundary conditions include the convective heat transfer coefficient and the ambient temperature.

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