1,720,966 research outputs found
Structural Design Evaluation of Integrated Rotor Hub and Shaft for a High-Speed Surface Mounted Radial Flux Permanent Magnet Synchronous Motor
No full textIncreasing the reliability and power density of a surface-mounted permanent magnet synchronous machine (SPMSM) is crucial due to the broader applications in the automotive and aerospace sectors. Concerns with such machines are that the overall rotating assembly experiences significant mechanical loads due to the rapid rotational speeds, making it exceptionally challenging to design the structural integrity of these components. This study's main objective is to offer a scientific justification for designing an integrated rotor hub and shaft through efficient Finite Element Modeling (FEM) and integration strategies to maximize the rotating assembly durability of a 150kW radial flux SPMSM spinning at 20,000 rpm. The optimization of integrated topology is evaluated based on a multiphysics platform, along with studies conducted on motor assembly eigen frequency. The integrated approach combining the shaft and rotor hub made of AISI 4340 solely saves 1.84kg, removing the necessity of standard components such as balancing end clamp plates, locknuts, and washers. Lower masses are proportional to lower centrifugal forces, reducing radial stress and promoting component/assembly stiffness
Rotor Durability Optimization by Means of Finite Element Multiphysics Analysis for High-Speed Surface Permanent Magnet Electric Machines
No full textTransport electrification is pushing the automotive and aerospace industries to enhance the power density of their powertrains further and further. One of the technologies currently pursued by some companies is high-speed electric motors. For instance, the new Model S Plaid motor by Tesla has a carbon-fiber wrapped IPM (Interior Permanent Magnet) rotor which can exceed 20,000rpm. The SPX88-120 made by Helix company shows a power density of about 18kW/kg at 50,000rpm. However, such high rotating speeds result is huge mechanical stresses in the entire rotating assembly, thus making the structural design of these parts extremely challenging. The primary goal of this paper is to provide a scientific rationale for the effective Finite Element Modeling (FEM) and integration strategies to maximize the rotating assembly durability of a 150kW radial flux SPMSM (surface-mounted permanent magnet synchronous motor) considered as a case-study. A non-linear simulation requires the input of a stress-strain curve and modified power law hardening study is conducted. The secondary goal of the paper is to analyze the thermal stress risers for multiphysics optimization of components. An analytical methodology to estimate the fatigue life for fully reverse cyclic loading is expressed. An extensive study on the eigen mode shape and frequency was performed to understand the dominant frequency of the system. A comparative performance study is conducted on shaft critical speeds, modal analysis, and stiffness interaction between components. Multiphysics optimization of topology is undertaken, the principal stresses in significant load-bearing components are reduced by 10 to 33%
Bearing Current Modelling and Investigation in Axial Flux Permanent Magnet Synchronous Motors for Aerospace Applications
No full textThis paper investigates the bearing current issue of the Axial Flux Permanent Magnet Synchronous Motors (AFPMSM) used in aerospace. The case-study examined in this work is an eVTOL propulsion motor. The paper focuses on calculating the various parasitic components that relate to the bearing current phenomena in the AFPMSM. The simulation work presented in this paper provides a good understanding of the bearing current phenomenon and the sensitivity of the different parameters on the bearing current. According to the authors' best knowledge, this is the first time investigating the bearing current problem in AFPMSM. The paper also proposes a model for the bearing current simulation in this machine. Once the importance of the problem had been assessed, the bearing current possibility and the different solutions to overcome this problem have been investigated. The study also shows the pros and cons of each of these suggested solutions from the electrical point of view
Investigating the Effects of PWM Currents on a High-Speed PMSM for an Aerospace Application
No full textThis paper discusses the impact of Pulse Width Modulated (PWM) current waveforms on electromagnetic losses and thermal characteristics of a high-speed PMSM designed for an aerospace application. The PWM effects are studied on a Surface Permanent Magnet Synchronous Motor (SPMSM) of 150 kW, 20000 rpm designed for an aerospace application. A 3D-Finite Element Model (FEM) of the machine is used for analysis in JMAG software. First, the machine model is studied for various electromagnetic losses using an ideal sinusoidal current waveform. These losses are used to study the thermal characteristics of the machine using Motor-CAD. The PWM currents are generated by modelling the motor drive with a 3-Level Active Neutral Point Clamped (ANPC) converter controlled by Field Oriented Control (FOC) algorithm in PSIM software. The machine losses are analyzed in FEM software by feeding the PWM current thus obtained. Using the thermal model of the machine developed in Motor-CAD, the thermal characteristics are studied. The switching frequency of the inverter is varied over a range of values to investigate its effect on the losses and thermal characteristics. Thus, this paper presents the effect of PWM current ripples on the electromagnetic losses and thermal characteristics of a high-speed machine
Multiphysics Thermo-Structural Design of the Rotor in High-Speed Permanent Magnet Machines for Aerospace Propulsion Applications
No full textHigh temperatures, thermal and mechanical stresses, rotor imbalances in high-speed Surface Permanent Magnet Synchronous machines (SPMSM) often dictates the maximum power output of the machine. Hence, a trade-off should be made between the cooling design, and machine structure stiffness, and the power rating. This work discusses the modelling and design process of the high-speed machine rotor by means of thermo-structural and modal analyses to minimize the trade-offs between the structural and thermal designs. The study discusses the design and modeling of SPMSM machine rotor thermally and structurally to achieve the highest power output of the machine while targeting rotor weight reduction. The design of the rotor shows safe operating temperatures and stress levels at the machine rated speed and power output as a result of the minimized and well-distributed thermal and mechanical stresses. A power density of 7.1 kW/kg is achieved by designing the machine within safe operating limits without using excessive safety margins
Cooling System Design of a High-Speed Radial-Flux Permanent Magnet Machine for Aerospace Propulsion Applications
No full textLoad constraints in aerospace propulsion applications are driving great attention towards research and development of high-speed electric machines. A major focus area for such machines is a cooling system that is reliable and efficient. In this work the cooling system of a high-speed radial-flux surface-mount permanent magnet synchronous motor is presented. The method of modeling the motor and investigating the cooling performance is detailed. The cooling system of the stator of the baseline design consists of encapsulation on the end windings, a cooling duct on the bearings and a cooling jacket housing on the stator laminations. The rotor is cooled by air forced convection by a fan mounted on the shaft. The effect of various design parameters, like coolant flow rate and potting material, on the temperature of the stator and end windings is investigated. The cooling effect obtained by inserting an additional coolant-carrying tube in close proximity to the high heat-generating parts, is also studied
Low Resistance Heat Paths Application to Electric Machines Rotor Cooling
No full textThermal non-uniformities in electric machines manifested as local hotspots and high temperature gradients, pose significant risks to machine safety, leading to heightened thermal stresses and an increased likelihood of component failures. In this research, a newly developed 150 kW high-speed machine exhibited significant thermal imbalances, leading to hot spots near bearing seats. To mitigate these challenges, the paper proposes the use of integrated low-resistance heat paths in the steel rotor, replacing traditional void entities with lightweight, highly conductive materials such as aluminum or copper. Computational Fluid Dynamics (CFD) simulations demonstrate the effectiveness of an aluminum insert, resulting in a significant 47°C reduction in maximum shaft temperature and improved thermal uniformity. Structural analysis guides the optimization of fit parameters, defining a transition fit for maximum stress within yield strength. This comprehensive approach offers a strategic solution for enhancing rotor thermal management in high-speed electrical machines
Numerical Investigation of Different Jet Impingement Configurations for Thermally Unbalanced Power Modules in Aerospace Traction Inverters
No full textThermal management of power electronic inverters becomes a critical necessity for high density aerospace applications. Proper thermal management techniques can push the rated power of such power inverters. Jet impingement is one of the optimistic techniques that possesses superior heat transfer characteristics, which can be an advanced assist for power inverters cooling innovation. This paper proposes different jet impingement configurations to provide a thermal management solution for thermally unbalanced power modules used in 1 MVA, 3-level ANPC inverter, by performing computational fluid dynamics simulations to analyze the thermal and hydraulic characteristics. The optimal design target is to decrease the temperature difference between the unbalanced switches to enhance the overall reliability and lifetime of the power module while simultaneously reducing the pressure drop. With the optimized design among all the proposals, the minimum temperature difference is 24 °C between the power module switches, while the pressure drop reached 12 kPa for the optimal jet configuration
Design of a Cylindrical Jet Impingement Cooling System for High-Power Common-Mode Choke in Aerospace Applications
No full textWith the increasing demand for efficient, power-dense, and reliable power systems in aerospace applications, the thermal management of high-power electronic components has become a critical challenge. High-power common-mode chokes, essential components for electromagnetic interference (EMI) suppression, generate significant heat during operation, necessitating effective cooling techniques to maintain optimal performance and prolong their lifespan. This paper presents the design of a novel cylindrical jet impingement cooling system specifically tailored for high-power common-mode chokes in aerospace applications. The proposed cooling system leverages the advantages of jet impingement cooling to achieve enhanced heat transfer and temperature uniformity across the magnetic core as well as the bus bar while offering a competitive mass reduction compared to similar devices. A cylindrical configuration is chosen to accommodate the geometric constraints of the magnetic core and bus bar configuration used in such applications. Mathematical modelling in partnership with computational fluid dynamics (CFD) simulations is employed to evaluate the thermal as well as pressure drop performance of the system
Design and Characterization of Bus Bars for 1-MVA Three-Level ANPC Inverters in Aerospace Applications
No full textBus bars play a crucial role in connecting components and are widely utilized in high-power inverters. Efforts have been made in the past to reduce the stray inductance of bus bars. In the case of multilevel inverters, which involve more complex commutation loops than their two-level counterparts, the physical layout and parasitic parameters of bus bars are particularly important. Furthermore, for novel and more demanding applications such as aerospace, bus bars need to be designed to be lightweight while ensuring a partial discharge (PD)-free insulation performance. Given the challenging cooling condition in aerospace applications, the thermal design and cooling performance of bus bars also warrant considerable attention. This article presents a comprehensive design approach of a laminated bus bar for a 1.5-kV 1-MVA three-level active neutral-point-clamped (ANPC) inverter for electrified aircraft propulsion. With the proposed design methodologies, 29.4- and 48.8-nH inductance for short and long commutation loops, PD-free insulation, and satisfactory thermal performance are achieved with an only 1.77-kg layout. Experimental results confirm that the efficiency of the 1-MVA ANPC inverter can reach 98.97% under half-load conditions with the designed bus bar
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