Gong-kuang zidonghua (Feb 2023)
Analysis of heat dissipation performance of mine inverter based on the integrated model
Abstract
The space of the mine inverter is closed. The internal power device itself will produce a lot of heat in the operation process, which is easy to produce thermal degradation and thermal failure. In the existing research, a certain power device or a radiator of the mine inverter is analyzed independently. The heat exchange effect among the power device or the radiator is not considered. The combination with the running state of the mine inverter is not close enough. Therefore, the deviation between the heat generation and heat transfer processes and the actual situation is large. This reduces the accuracy and comprehensiveness of the heat dissipation performance analysis. In order to the above problems, taking the 630 kW/1 140 V four-quadrant mine inverter as the research object, the heat dissipation performance of the mine inverter is analyzed based on integrated model . A topological model of the main circuit of the mine inverter considering equivalent resistance is established. The electrical characteristics of the bus bar and the cable, the charge/discharge resistance, the absorption resistance, the IGBT module and the output reactor are analyzed, and the power loss is calculated. The cooling system of the inverter is optimized by forced water cooling + air cooling + natural cooling. The IGBT module and the absorption resistor are arranged on the substrate of the water-cooling radiator. The fan is configured to accelerate the heat exchange efficiency of the output reactor, and other power devices dissipate heat naturally. Based on the integrated model, the temperature field characteristics and heat transfer characteristics of the mine inverter are numerically simulated and analyzed. The correctness of the temperature field simulation based on the integrated model and the effectiveness of the heat dissipation design are verified by building the loading test platform of mineing inverter . The results show the following points. ① Under the heat transfer of conduction, convection and radiation of the internal power devices, the temperature of the flameproof enclosure is higher than the ambient temperature. The lowest temperature is 36 ℃. The temperature of the rear substrate is higher than that of the other flameproof surfaces, and the highest temperature can reach 70 ℃. The temperature of the internal components of the mine inverter is not higher than 80 ℃, which is far lower than the specified value of relevant standards. The mine inverter has good heat dissipation performance. The temperature of IGBT module is the highest, the temperature of the bus bar assembly is the second, and the temperature of the DC filter capacitor assembly is the lowest. ② The power device in the process of charging has a larger loss. But because of the short charging time, the loss will not cause severe changes in temperature. The instantaneous temperature of the power device is not more than 59 ℃. The maximum instantaneous temperature of the discharge resistance can reach 267 ℃, and the action time above 100 ℃ is 200 seconds. The high-temperature impact resistance of the trapezoidal aluminum shell resistor can meet the application scenario. It does not form a thermal stress cycle, and will not produce thermal breakdown and thermal failure. ③ The temperature of each power device tends to be stable gradually after 2-3 h. The experimental and simulation results of each calibration temperature measurement point keep good consistency in the overall trend.
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