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Influence of Single/Dual Ventilation Path on Fluid Field and Temperature Field of HVLSSR-PMSM with Air-Cooled Hybrid Ventilation Systems

Zhaobin Cao, Weili Li, Xiaochen Zhang, Yu Fan, Jianjun Zeng

2018
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Energies
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Due to the solid rotor structure, High-Voltage Line-Start Solid Rotor Permanent Magnet Synchronous Motor (HVLSSR-PMSM) operates with high rotor temperature rise. If the ventilation path cannot take the rotor heat away in time, the rotor will overheat or even may led to the thermal demagnetization for permanent magnet. Therefore, it is of great significance to study the thermal issues of HVLSSR-PMSM. In the paper, the fluid field and temperature field of a 315 kW, 6 kV HVLSSR-PMSM with
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... PMSM with air-cooled hybrid ventilation systems are investigated. Firstly, the electromagnetic analysis of the machine is done by using the finite-element method, the loss distributions then are obtained, which will be assigned as the heat source for thermal analysis. Then, the three -dimensional (3-D) fluid thermal coupled mathematical model for thermal analysis of HVLSSR-PMSM is established. The temperature field and the fluid flowing state of HVLSSR-PMSM with single ventilation path air-cooled system are investigated by using the established 3D fluid thermal coupled mathematical model. A dual ventilation path air-cooled system for HVLSSR-PMSM is proposed to reduce the operating temperature rise. Then, the temperature field and fluid field of HVLSSR-PMSM with dual ventilation system are analyzed by comparing with single ventilation system. Moreover, the temperature experiments are carried out on the machine with dual ventilation system to validate the accuracy of the established mathematical models. The results show that the proposed dual ventilation path air-cooled system can effectively improve the thermal distribution of HVLSSR-PMSM, whilst it can also reduce the working temperature rise of the machine. Scholars have done lots of research on starting and operating performance, ventilation system, and thermal problems of the permanent magnet synchronous motors. The improvements of PMSM performance have been studied in [3] [4] [5] [6] [7] [8] [9] [10] [11] , which illustrated the synchronous process and indicated the effective parameters to starting capability, such as inertia, load torque, supply voltage, rotor eddy current loss, and rotor bar size. In [12], a composite rotor structure is proposed to improve demagnetization capability of a high-speed PMSM, the performance is studied by using the fluid-thermal coupling method. The determination of pole spacer materials for a high-speed surface-mounted PMSM is made by Yuan W. in [13] , which can be used to improve the rotor temperature rise and thermal stress. Taking advantages of the small thermal resistance, the heat pipes are installed in the connection joint between stator tooth root and shaft of an outer-rotor PMSM, which is of little influence on the main magnetic path, whereas the heat generated in the windings could be transferred to the heat pipe [14] . The thermal network methods have been studied in [15, 16] , which are used to estimate the temperature of the permanent magnet motor quickly. To analyse the cause of local irreversible demagnetization, the authors performed a parameter analysis of the magnetic field based on the barrier width and magnet position considerably related to the magnetic path using the finite-element method [17] . In [18] [19] [20] , the fluid heat transfer method is used to calculate the internal fluid flowing state and the temperature distributions of each component. Although lots of achievements have been delivered by former researches, there are few cases that focus on the large solid rotor PM machines, especially those with novel air cooling system investigated via the fluid heat transfer coupled analysis. Furthermore, there is little research on the ventilation system and the thermal problem of HVLSSR-PMSM. Therefore, in this paper, the thermal performance of a 315 kW, 6 kV, 6-pole HVLSSR-PMSM is investigated. According to the physical structure of the machine and the air-cooled system, the loss distributions of the machine is analyzed by using transient electromagnetic field model. Then, the loss is assigned as the heat source for the thermal analyses. The fluid thermal coupled mathematical model is established, then the fluid flowing state and thermal field of HVLSSR-PMSM with single ventilation path is studied. In order to reduce the temperature rise of the HVLSSR-PMSM, the dual air-cooled ventilation systems are presented and the fluid field and thermal field are also investigated by comparing with that with single ventilation path. Moreover, the temperature experiments are carried out on the machine with dual ventilation system to validate the accuracy of the established mathematical models. The obtained results could provide a reliable basis for the design of new cooling system for large solid rotor PM machines, as well as the methodology. Basic Structure Description of High-Voltage Line-Start Solid Rotor Permanent Magnet Synchronous Motor (HVLSSR-PMSM) The basic design parameters of HVLSSR-PMSM are shown in Table 1 .

doi:10.3390/en11061343
fatcat:zq2juor3dvembkaal2kpquopiy