Electromagnetic field analysis and cooling system design for high power switched reluctance motor

Abstract

Purpose The electromagnetic field and cooling system of a high power switched reluctance motor (SRM) are studied numerically. The geometry of the motor and its main components are established using a computer-aided design software in the actual size. This study aims to evaluate the resulting thermal losses using the electromagnetic analysis of the motor. Design/methodology/approach In the electromagnetic analysis, the Joule’s loss in the copper wires of the coil windings and the iron losses (the eddy currents loss and the hysteresis loss) are considered. The flow and heat transfer model for the thermal analysis of the motor including the conduction in solid parts and convection in the fluid part is introduced. The magnetic losses are imported into the thermal analysis model in the form of internal heat generation in motor components. Several cooling system approaches were introduced, such as natural convection cooling, natural convection cooling with various types of fins over the motor casing, forced conviction air-cooled cooling system using a mounted fan, casing surface with and without heat sinks, liquid-cooled cooling system using the water in a channel shell and a hybrid air-cooled and liquid-cooled cooling system. Findings The results of the electromagnetics analysis show that the low rotational speed of the motor induces higher currents in coil windings, which in turn, it causes higher copper losses in SRM coil windings. For higher rotational speed of SRM, the core loss is higher than the copper loss is in SRM due to the higher frequency. An air-cooled cooling system is used for cooling of SRM. The results reveal when the rotational speed is at 4,000 rpm, the coil loss would be at the maximum value. Therefore, the coil temperature is about 197.9°C, which is higher than the tolerated standard temperature insulation material. Hence, the air-cooled system cannot reduce the temperature to the safe temperature limitation of the motor and guarantee the safe operation of SRM. Thus, a hybrid system of both air-cooled and liquid-cooled cooling system with mounting fins at the outer surface of the casing is proposed. The hybrid system with the liquid flow of Re = 1,500 provides a cooling power capable of safe operation of the motor at 117.2°C, which is adequate for standard insulation material grade E. Originality/value The electromagnetic field and cooling system of a high power SRM in the presence of a mounted fan at the rear of the motor are analyzed. The thermal analysis is performed for both of the air-cooled and liquid-cooled cooling systems to meet the cooling demands of the motor for the first time.

Research Progress of Enhanced Thermal Evacuation and Cooling Technology for High-Speed Motors

“…Husain et al [43] found that a single U-shaped arrangement of permanent magnets was more effective in cooling the rotor. For improving the convection transfer efficiency of a stator and rotor, Yan et al [44] added a fan to the main shaft and enlarged the grille area, as illustrated in Figure 13. For convective heat transfer in the motor gap, improving the gas flow state in the gap is a very important parameter, which is affected by the flow rate, gap size, etc.…”

“…Husain et al [43] found that a single U-shaped arrangement of permanent magnets was more effective in cooling the rotor. For improving the convection transfer efficiency of a stator and rotor, Yan et al [44] added a fan to the main shaft and enlarged the grille area, as illustrated in Figure 13.…”

Advancement of Liquid Immersion Cooling for Data Centers

“…In addition, research has also pointed out the impact of surface modification on two-phase immersion cooling technology. Surface modification technology can further enhance phase change heat transfer in the cooling system and improve the thermal conductivity efficiency of the system [13]. Meanwhile, studies on the heat transfer characteristics of natural and forced convection have also shown that these systems perform well in single-phase immersion cooling applications in data centers.…”

A novel solar‐powered master‐slave electric motor‐based energy‐saving and cooling approach for the motors of conveyor system

“…Rated Speed = 5300 rpm Rated Torque = 70 Nm Yan et al 10 (2019) Type = SRM Hybrid cooling system of both air-cooled and liquid-cooled system A maximum coil winding temperature drop of 17.7% was obtained for the liquid flow of Reynolds number (Re) = 500. The higher liquid flow rate of Re = 1500 was also used, whereas the air cooling was only helpful when the motor speed was higher than 4000 rpm.…”