دانلود رایگان مقاله نرم افزار تحقیق حرارتی سیستم خنک سازی هوا دراینورتر سه سطح NPC

ABSTRACT

During the process of cooling system design, the traditional method is calculating power losses of power devices, building thermal model of power devices, establishing system structure model, and making thermal analysis. While, the ideal assumptions and complex equivalent models in traditional methods bring in large error and the analysis of whole system model reduces the effectiveness of cooling system design for complicated high-power inverters. In this paper, the power losses of power devices in NPC (Neutral-Point-Clamped) three-level inverter based on SVPWM(Space Vector Pulse Width Modulation) was calculated firstly; the input power and cooling power of each power module block were analyzed, and the cooling power of each block supplied by cooling fan was obtained to figure out the cooling fan parameters. The designed forced-air cooling system was proved by finite element simulation. Finally, the temperature rise experiment was carried out on a 1 MW NPC threelevel inverter, and the results proved the effectiveness and feasibility of the proposed method.

5. Conclusions

A method based on analysis of single power module block for cooling system design of NPC three-level inverter was put forward. It has completed power loss calculation of power module block, theory calculation of heat-sink parameter, characteristic parameters calculation of cooling fan, and finally cooling fan selection. The power loss calculation of power devices and thermal model building of power module block were finished separately, but the analysis was made under the combination of the two modules to avoid these ideal assumptions in traditional algorithms, such as absolute smooth in contact surface and absolute excellent contact. The method proposed in this paper has a much higher accuracy compared with the traditional ones. Through finite element simulation, the power module block was analyzed. The effectiveness and feasibility of the proposed method was proved by experiment.