| With the rapid development of the power electronic technology, the energy-saving and secure requirements of the mining equipment and electric drive system are increasing day by day, Ac-variable-frequency regulating speed technology as an important energy-saving technology is widely accepted. In the coal mine production process, inverter is used more and more widely for its excellent energy-saving effect and the performance of speed adjustment. However, the electric equipments of coal mine underground use must be explosion-proof, comparing the advantages and disadvantages of various explosion-proof types, flameproof inverter arises at the historic moment, all electronic components are installed in the flameproof shell, while electronic components power loss serious influence the use of inverter.In view of the cooling effect and dewing problems appear on flameproof water-cooling inverter, it is necessary to analysis the process of cooling inverter heatexchange, temperature difference and its influence factor, so as to guide design water-cooling control system of flameproof water-cooling inverter.First of all, the total power components loss of 1140V/100KW flameproof water-cooling inverter is calculated by analysis of main circuit structure, thermal path of loss heat is detailedly analyzed,the main heatexchange process is forced convection, and with a heat conduction and radiation, the heat transfer process is coupled solid, liquid and gas by three heat transfer foems. In the whole cooling process, the flameproof shell interior air temperature field distribution is important influenced by cooling water temperature, flow and environmental temperature.Secondly, the heat dissipation model of flameproof water-cooling inverter is established,the heatexchange is numerically simulated by computational fluid simulation software FLUENT, obtained contours of the heat dissipation model temperature field, cooling water temperature field, flameproof shell internal air temperature field and the temperature distribution curves of key parts under the certain temperatures different flow and certain flow different temperature,compared and analyzed cooling effect influence of cooling water flow and temperature. The numerical simulation results indicate that, with cooling water velocity increasing, temperature of the heat dissipation model decreases; the best cooling effect of this model water velocity is V=0.4m/s, velocity continue to increase and temperature decrease slowly. The influence of cooling water inlet temperature to thermal model temperature field is linear, the lower temperature of cooling water the better cooling effect.Obtained the low temperature distribution areas and dewing zones under different conditions.Then, summarizes the temperature and humidity change rule of flameproof water-cooling inverter working environment climate. And then analyzes the mechanism of the dewing of air, temperature below the dewpoint temperature will appear the dewing phenomenon, low temperature or large flow of the cooling water will lead to large temperature difference and appear dew. When this model in the mine air temperature t=20℃, relative humidityφ=80%, the internal air relative humidity field and dewing area are analyzed under different temperature and cooling water flow, appear to effectively cooling and does not produce the cooling water condensation best inlet velocity V=0.27 m/s and temperature t=286.5 K.Finally, cooling water flow controlling temperature difference of flameproof water-cooling inverter is analyzed, temperature control flow is proposed, and use Matlab Fuzzy Logic Toolbox to designe Fuzzy controller, through the control system block diagram simulation compared the Fuzzy controller and PID controller outputs curves, the results show that the Fuzzy controller with good dynamic and static performance, can easily control the flameproof water-cooling inverter internal temperature.
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