Improved Thermal Behavior of an Electromagnetic Linear Actuator with Different Winding Types and the Influence on the Complex Impedance

IEEE Trans. Ind. Electron.

2023

There is a need for higher specific torque electric actuators in novel direct-drive robotic applications. Since the specific torque is inherently limited by material properties, designers have to look at novel materials to push the specific torque limit further. In this article, anodised aluminium foil is considered as an alternative to enamelled copper wire in a yokeless and segmented armature axial flux machine. This machine topology has a high specific torque and is particularly suited for an anodised aluminium foil winding. The DC resistance, thermal properties and eventually the specific torque of a prototype test case machine are compared for both winding materials. A 3D thermal finite element model is used to analyse the influence of the thermal interface between winding body and housing, and the influence of the cooling performance on the specific torque. To conclude, anodised aluminium foil winding offers a higher specific torque in direct-drive yokeless and segmented armature axial flux actuators where the winding body thermal resistance is dominant in the thermal path from heat source to heat sink. It is experimentally shown that for the prototype machine, the torque per kg active stator mass increases 13% through the use of anodised aluminium foil.

Section: Introductionsupporting

confidence: 65%

Anodized Aluminum Foil Winding Axial Flux Machine for Direct-Drive Robotic Applications

IEEE Trans. Ind. Electron.

2023

“…The authors measured an equivalent thermal conductivity of 6.5 W/mK for the anodised aluminium wire sample and 2.5 W/mK for the enamelled copper wires sample. The improved thermal behaviour was also shown in a simulation study for the case of an automotive solenoid actuator in [56]. Moreover, a foil winding allows a high fill factor and exhibits superior thermal properties as was reported for copper foil windings in [47], [61].…”

Section: Concentrated Winding Tooth Coilsupporting

confidence: 58%

“…This would result in an unacceptably low fill factor when using the same insulation as used for copper foil. However, aluminiumoxide electrical insulation layers can be as thin as 3 µm [56]. • Using a foil winding in a YASA Axial Flux machine topology allows to eliminate the free space between adjacent tooth coils as illustrated in Fig.…”

Section: Concentrated Winding Tooth Coilmentioning

confidence: 99%

Anodised Aluminium Foil Winding Axial Flux Machine for (Quasi-)Direct-Drive Robotic Applications: Preliminary Design and Manufacturing

2022 12th International Electric Drives Production Conference (EDPC)

Faes

et al. 2022

Motivated by the need for higher torque density actuators in novel (quasi-)direct-drive robotics applications, a Yokeless and Segmented Armature Axial Flux Permanent Magnet Synchronous machine with anodised aluminium foil conductors instead of enamelled copper wire is considered in this work. Based on a requirements analysis of (quasi-)direct-drive actuators, a prototype axial flux machine is designed. Several design aspects are discussed keeping the application requirements in mind. It could be concluded that the combination of the machine topology and conductor material results in a high fill factor and excellent thermal properties, making it particularly promising for high torque density, low speed applications. A prototype was manufactured to demonstrate the feasibility of the design. The interconnection of aluminium foil to copper wire appeared to be challenging, two interconnection methods were tested and compared qualitatively.

“…In order to obtain more insight in the influence of using anodised aluminium foil on the torque density compared to enamelled copper wire both aspects have to be taken into account in a comparison. This was done in [21] for an automotive solenoid actuator, where it was concluded that the use of anodised aluminium foil allows to significantly increase the allowable solenoid current. Rotating electrical machines might also benefit from the use of anodised aluminium foil.…”

Section: Introductionmentioning

confidence: 99%

Performance comparison of Axial Flux PM machine with Anodised Aluminium Foil and Round Copper Wire

2022 International Conference on Electrical Machines (ICEM)

2022

In this article the electromagnetic and thermal performance of an axial flux permanent magnet machine with anodised aluminium foil as stator winding conductor material is analysed and compared to enamelled copper wire. The influence of the conductor material on the DC and AC winding losses, and the torque density is studied. Additionally, the influence of the motor housing convective heat transfer coefficient is examined. It can be concluded that the anodised aluminium foil winding offers an attractive alternative for copper wire, especially in low speed applications where the thermal resistance of the winding body is dominant in the thermal path from heat source to heat sink.