This paper presents current research trends and prospects of utilizing additive manufacturing (AM) techniques to manufacture electrical machines. Modern-day machine applications require extraordinary ...performance parameters such as high power-density, integrated functionalities, improved thermal, mechanical & electromagnetic properties. AM offers a higher degree of design flexibility to achieve these performance parameters, which is impossible to realize through conventional manufacturing techniques. AM has a lot to offer in every aspect of machine fabrication, such that from size/weight reduction to the realization of complex geometric designs. However, some practical limitations of existing AM techniques restrict their utilization in large scale production industry. The introduction of three-dimensional asymmetry in machine design is an aspect that can be exploited most with the prevalent level of research in AM. In order to take one step further towards the enablement of large-scale production of AM-built electrical machines, this paper also discusses some machine types which can best utilize existing developments in the field of AM.
This paper reviews the current technologies used in high-speed electrical machines through an extensive survey of different topologies developed and built in the industry and academia for several ...applications. Developments in materials and components, including electrical steels and copper alloys, are discussed, and their impact on the machines' operating physical boundaries is investigated. The main application areas pulling the development of high-speed machines are also reviewed to better understand the typical performance requirements.
Air-Gap Convection in Rotating Electrical Machines Howey, D. A.; Childs, P. R. N.; Holmes, A. S.
IEEE transactions on industrial electronics (1982),
2012-March, 2012-03-00, 20120301, Volume:
59, Issue:
3
Journal Article
Peer reviewed
Open access
This paper reviews the convective heat transfer within the air gap of both cylindrical and disk geometry rotating electrical machines, including worked examples relevant to fractional horsepower ...electrical machines. Thermal analysis of electrical machines is important because torque density is limited by maximum temperature. Knowledge of surface convective heat transfer coefficients is necessary for accurate thermal modeling, for example, using lumped parameter models. There exists a wide body of relevant literature, but much of it has traditionally been in other application areas, dominated by mechanical engineers, such as gas turbine design. Particular attention is therefore given to the explanation of the relevant nondimensional parameters and to the presentation of measured convective heat transfer correlations for a wide variety of situations from laminar to turbulent flow at small and large gap sizes for both radial-flux and axial-flux electrical machines.
Developing a simple real-time bearing fault detection algorithm is essential for small cooling fan motors, ensuring power electronics systems and data center stability. Our study introduces a ...real-time, low-resource algorithm for microcontrollers, utilizing motor current data to detect the most common bearing faults in these applications. Notably, small motors exhibit significant current changes due to lubrication and contamination issues, unlike larger motors, where such changes are minimal. We comprehensively assess distributed bearing faults stemming from lubrication and contamination across seven motors under various conditions. These motors are tested under both no-load and fan-load scenarios at ten different speeds, with controlled aging of motor bearings. Key time-domain features, such as Root Mean Square (RMS), peak values, and crest factors of motor current, are scrutinized to create our proposed algorithm. We rigorously evaluate sensitivity, false detection scenarios, and compare our algorithm to a machine learning model. In practical experiments using the TI F280049 microcontroller, our algorithm outperforms, demanding minimal instruction cycles and memory resources. Achieving an accuracy rate exceeding 92% and consistently demonstrating an F1 score of over 90%, the algorithm is proven to be a robust and practical solution for precisely and rapidly detecting distributed bearing faults in small cooling fan motors.
In-wheel motors present a range of opportunities for innovation in electric vehicle design as the torque produced at each of two or four wheels can be controlled individually. A high-aspect ratio ...(large radius, short axial length) motor is required to fit within the wheel. Due to its location, liquid cooling of the in-wheel motor is difficult and undesirable, but a high power density is required to reduce the mass-which is particularly important as it is unsprung-and fit the space envelope. Furthermore, a high-torque density is required to eliminate the need for a gearbox. These constraints create a real challenge for the design of a machine for this application. An axial field machine using a yokeless and segmented armature (YASA) topology is designed to fit these requirements as such a machine has clear advantages when considering the high-aspect ratio. A soft magnetic composite material is utilized to carry the flux in its nonplanar path without incurring excessive losses or requiring a lamination design, which is difficult and expensive to manufacture. A novel cooling arrangement involving heat-spreading elements on each armature segment is employed to improve heat dissipation and, hence, power density. The design, analysis, manufacturing, and testing of the motor is described in this article to verify the concept against the requirements outlined earlier.
The bio-inspired algorithms are novel, modern, and efficient tools for the design of electrical machines. However, from the mathematical point of view, these problems belong to the most general ...branch of non-linear optimization problems, where these tools cannot guarantee that a global minimum is found. The numerical cost and the accuracy of these algorithms depend on the initialization of their internal parameters, which may themselves be the subject of parameter tuning according to the application. In practice, these optimization problems are even more challenging, because engineers are looking for robust designs, which are not sensitive to the tolerances and the manufacturing uncertainties. These criteria further increase these computationally expensive problems due to the additional evaluations of the goal function. The goal of this paper is to give an overview of the widely used optimization techniques in electrical machinery and to summarize the challenges and open problems in the applications of the robust design optimization and the prospects in the case of the newly emerging technologies.
This paper aims to update the review of diagnostic techniques for rotating electrical machines of different type and size. Each of the main sections of the paper is focused on a specific component of ...the machine (stator and rotor windings, magnets, bearings, airgap, load and auxiliaries, stator and rotor laminated core) and divided into subsections when the characteristics of the component are different according to the type or size of the machine. The review considers both the techniques currently applied on field for the diagnostics of the electrical machines and the novel methodologies recently proposed by the researchers in the literature.
Winding design methods have been a subject of research for many years of the past century. Many methods have been developed, each one characterized by some advantages and drawbacks. Nowadays, the ...star of slots is the most widespread design tool for electrical machine windings. In this context, this paper presents a simple and effective procedure to determine the distribution of the slot EMFs over the phases and of the winding configuration in all possible typologies of electrical machines equipped with symmetrical windings. The result of this procedure gives a Winding Distribution Table (WDT), which can be used to define coils and coil groups connections and also to simply implement winding optimizations techniques, such as zone widening, imbrication, etc. Moreover, this procedure can be easily implemented on a computer in order to perform automated winding designs for rotating electrical machines. Several examples are provided in order to validate the proposed procedure.
PDF
