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![Core losses of Vacoflux 48 with a lamination of 0.1 mm between 50 Hz and 2000 Hz In [10] material properties were analyzed. Now, in terms of iron losses, a further material comparison emphasizes the superiority of Vacoflux 48 over a soft magnetic composite (SMC) material (Somaloy)](profile/Hans-Christian-Lahne/publication/287201607/figure/fig3/AS:667841141432339@1536237144670/Core-losses-of-Vacoflux-48-with-a-lamination-of-01-mm-between-50-Hz-and-2000-Hz-In-10.png)
Core losses of Vacoflux 48 with a lamination of 0.1 mm between 50 Hz and 2000 Hz In [10] material properties were analyzed. Now, in terms of iron losses, a further material comparison emphasizes the superiority of Vacoflux 48 over a soft magnetic composite (SMC) material (Somaloy)
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In this paper design aspects of high-speed electrical machines are discussed. Analytical calculations dealing with issues of volume and weight are presented. Furthermore, machine design parameters are analyzed. The main target is the design of a turbo generator for usage in aircraft. To improve reliability, a six-phase electrical machine is introdu...
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Superconducting electric machines have shown potential for significant increase in power density, making them attractive for size and weight sensitive applications such as offshore wind generation, marine propulsion, and hybrid-electric aircraft propulsion. Superconductors exhibit no loss under dc conditions, though ac current and field produce con...
Citations
... In mechanical aspects, the required rated torque T can be calculated according to [22] as: T = P/2πn, with the rated power P and the rated speed n. The required volume can be calculated by using Esson's law [23]: D 2 si L = P/Cn, where D si is the stator inner diameter, D si = 2r so +2δ, utilization factor C dependent on the machine type and various other variables such as the cooling system and size of the machine [24]. The minimum rotor diameter D min can be calculated based on the torque transmission requirement as described by the following equation: D min = 2 J p τ /T , with the polar moment of inertia J p . ...
... The free-free modal analysis is implemented on two rotors, and the specific test method has been explained in [23]. The tested results of the rotor spectrum are shown in Fig. 16. ...
High-speed electrical machines have become more and more popular applications driven by electric vehicles and all-electric aircraft. Their design usually requires a high level of integration, including loss, thermal, cooling, and mechanical aspects. This article makes a comprehensive overview of the multidiscipline design method of high-speed permanent magnet (HSPM) machines. A 4-kW machine with the flexible rotor operating above the first bending critical speed is presented, and a 30-kW machine is also developed with consideration of the multidisciplinary design process for contrast. The constraint and the mechanism in the overview are investigated to clarify the influence of different design variables on the rotor structure and performance. Finally, two machines are fabricated and tested, and the values are compared with theoretical results.
... The analytical schemes of the calculation of the loss as presented in [2] [6] can be taken as a first step to approach FEM analysis. Taking into consideration the high frequency in bearingless motor drives the core material losses should be investigated [9] II. BEARINGLESS MOTOR STRUCTURE AND MAIN PRINCIPLES ...
... The main advantage of high-speed machines is the minimization of weight and size in a direct comparison to conventionally designed machines. In many papers information about high-speed machines such as measurements, simulations, prototypes and comparisons of machine types suitable for the high-speed range can be found [1]- [11]. But there are material investigations as well. ...
... In [10] and [11] models of a high-speed induction machine (1M) in the desired performance range are presented. The 1M provides a good reliability. ...
... In [11] the crucial pros and cons of a six-phase system, consisting of two independent (i.e., two isolated neutral points) three-phase windings, are described. The phase shift between the two winding systems is 30°. ...
... Moghaddam assumes in [10] that at this HS value, the temperature rise could be the limiting factor of the machine. Limits lie at about 20 A/mm² or even greater values up to 30 A/mm² according to [39] when using cooling liquids like water, oil or glycol [38]. Cooling and thermal aspects will be covered in a following paper. ...
... The work done on reducing skin effects and proximity effects can be found in various sources, e.g., in [39]. According to [40], skin-and-proximity effects are shown to be controllable. ...
This paper presents and discusses the state of the art in high-speed electrical machines. It is connected to a project in which there is a challenge to design a high-speed turbo generator with a rated speed of 50000 rpm and a continuous power of 700 kW for usage in aircraft. For this reason, typical electrical machines are compared in order to examine their advantages and disadvantages in identifying the best topology and in fulfilling given requirements. Finally, FEM results provide an indication of the feasibility of fulfilling project requirements.
... Moghaddam assumes in [10] that at this HS value, the temperature rise could be the limiting factor of the machine. Limits lie at about 20 A/mm² or even greater values up to 30 A/mm² according to [39] when using cooling liquids like water, oil or glycol [38]. Cooling and thermal aspects will be covered in a following paper. ...
... The work done on reducing skin effects and proximity effects can be found in various sources, e.g., in [39]. According to [40], skin-and-proximity effects are shown to be controllable. ...
This paper presents and discusses the state of the art in high-speed electrical machines. It is connected to a project in which there is a challenge to design a high-speed turbo generator with a rated speed of 50000 rpm and a continuous power of 700 kW for usage in aircraft. For this reason, typical electrical machines are compared in order to examine their advantages and disadvantages in identifying the best topology and in fulfilling given requirements. Finally, FEM results provide an indication of the feasibility of fulfilling project requirements.
Efficiency improvement that can be provided by the high-speed rotating equipment becomes a concern for designers nowadays. Since the high-speed rotating machinery was capable of rotating at very near to critical speed, the accurate estimation of critical speed needs to be considered. This paper investigated the effect of torsional element towards critical speed of high-speed rotating shaft system for pinned-pinned (P-P), clamped-free (C-F) and clamped-free (C-F) boundaries condition. The Nelson’s finite element model that considers the torsional effect was developed for formulating the finite element (FE) model. This FE model was used to derive Mathieu-Hill’s equation and then solved by applying the Bolotin’s theory. From the solution, the Campbell’s diagram of the high-speed shaft was plotted. It was found that torsional motion has significant effect on the critical speed for different boundary conditions. The difference between critical speed of 4DOF and 5DOF models can be as high as 6.91 %.
Monitoring of the rotor temperature is very important for both control and protection of induction machines. Temperature sensors are usually avoided due to additional wiring. Although the best precision is achieved by test-signal-based methods, they are rarely used due to a high torque ripple. The ripple is negligible in cases where inherent PWM voltage component is used as the test signal. In this paper, a novel temperature estimation method is devised, robust against the PWM delays, signal acquisition delays and phase errors in high frequency voltage and current components. Opposed to previous solutions where temperature is calculated based on the real part of the impedance, the presented method is based on the absolute value of the impedance at the PWM frequencies. The temperature is calculated from the change of the input impedance. Proposed method for temperature estimation was tested on an experimental setup which uses an inverter with sine modulated output voltages and an induction servo motor.
