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Minimization of Electric Heating of the Traction Induction Machine Rotor

South Ural State University-Elena Nikiforova, Victor Smolin
University of Michigan-Sergey Gladyshev
  • Technical Paper
  • 2020-01-0562
To be published on 2020-04-14 by SAE International in United States
The article solves the problem of reducing electric power losses of the traction induction machine rotor to prevent its overheating in nominal and high-load modes. Electric losses of the rotor power are optimized by the stabilization of the main magnetic flow of the electric machine at a nominal level with the amplitude-frequency control in a wide range of speeds and increased loads. The quasi-independent excitation of the induction machine allows us to increase the rigidity of mechanical characteristics, decrease the rotor slip at nominal loads and overloads and significantly decrease electrical losses in the rotor as compared to other control methods. The article considers the technology of converting the power of individual phases into a single energy flow using a three-phase electric machine equivalent circuit and obtaining an energy model in the form of equations of instantaneous active and reactive power balance. The quasi-independent excitation of the induction machine is performed according to the model by stabilizing the current of the magnetizing branch using the algorithms to control the voltage amplitude, synchronous frequency and electromagnetic…
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Searching for Optimal Solutions for Motor Performance Design

Honda R&D Co.,Ltd.-Yuko Miyabe, Masahito Kakema, Toshihiro Saito
  • Technical Paper
  • 2020-01-0460
To be published on 2020-04-14 by SAE International in United States
Because strength and the torque/rotational speed characteristic play a considerable role in determining the maximum speed and the acceleration force of a vehicle, they have been taken up as optimization issues. By contrast, loss and torque ripple have not necessarily been focused on in the initial search for optimal solutions. They are both linked to efficiency, comfortability, and the cost of development of the cooling system and supporting structures, however, it is necessary to reduce both parameters. For this reason, it is important to search for the Pareto front for strength, the torque/rotational speed characteristic, loss, and torque ripple at the initial stage of design. The strength constraint was set that von Mises stress in the rotor core in relation to the centrifugal force load at maximum speed would not exceed the breaking strength of a standard electromagnetic steel sheet material. The torque/rotational speed characteristic employed the maximum torque for each rotational speed when maximum torque per ampere control and field weakening control are applied, with consideration of maximum input voltage and current. Maximum torque…
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Virtual Method for Simulating Driveline Launch Shudder for Solid Axle Suspension Architecture Vehicles

FCA Engineering India Pvt., Ltd.-Dhanasekar Venkatesan
FCA US LLC-Abhishek Paul, Kevin Thomson
  • Technical Paper
  • 2020-01-1271
To be published on 2020-04-14 by SAE International in United States
Driveline launch shudder is a second-order vibration phenomenon excited by the driveline system in vehicles. It is experienced as low frequency tactile vibrations at the vehicle seat track and is further deteriorated by a high torque demand from the engine. These vibrations are unwanted and affect the vehicle ride quality. A virtual method has been developed in ADAMS/Car to simulate the driveline launch shudder event for solid axle suspension architecture vehicles. Detailed modeling of the full vehicle system with appropriate boundary conditions has been presented. The simulated driveline launch shudder event has been quantified in the form of axle windup and accelerations at the driveline pinion, center bearing and seat track locations. A physical test correlation case study has been performed to validate the developed virtual method. This virtual method is also successfully applied to provide a driveline launch shudder mitigation enabler to improve vehicle ride performance.
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A New Flux weakening control strategy for IPMSM(Interior Permanent Magnet Synchronous Machine) in Automotive Applications

CATARC-Zhihong Liu, Lei Zhang, Denggao Huang, Erxi Liu, Zhongwen Zhu, Xu Wang
  • Technical Paper
  • 2020-01-0466
To be published on 2020-04-14 by SAE International in United States
As one of the core components of electric vehicles(EV), the drive motor system has a significant impact on the EV operation performance. The interior permanent magnet synchronous motor (IPMSM) has a wide range of applications in EV, due to its high efficiency, high power density, high torque current and wide speed range. In the field of EV, motor control system is required to have a high operating range. IPMSM operates at constant torque mode below rated speed and constant power mode above rated speed. The back electromotive force(Back-EMF) generated by the rotor in the constant power mode causes the inverter output voltage to saturate. Therefore, it is necessary to ensure that the controller is still operating in the linear region by applying a flux weakening(FW) current to the stator. This paper propose an optimal FW path control strategy based on a state space consisting of a direct-axis current and a cross-axis current, bounded by maximum torque per ampere (MTPA), maximum current curve, and a maximum torque per voltage (MTPV) curve. The approach is founded on…
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Helicopter Transmissions, A Brief Overview of

Boeing Co.-Patrick R. Darmstadt, Mark Robuck
  • Technical Paper
  • 2020-01-0437
To be published on 2020-04-14 by SAE International in United States
Transmission and drivelines as they apply to helicopters are discussed including history, common configurations, and typical, industry design philosophies. A brief history of transmission used in helicopter applications is provided, including an emphasis on the flight critical nature of transmissions and drivelines in helicopter applications and how the helicopter transmission has evolved over their 100 years of service. Common helicopter drivelines are discussed for a variety of helicopter configurations (single main rotor, tandem rotor, and tilt rotor, among others), touching on typical shaft speed and horsepower ranges. Finally, typical helicopter transmission design practices are discussed for gear, bearing, and lubrication systems.
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Conjugate Heat Transfer CFD Analysis of an Oil Cooled Automotive Electrical Motor

General Motors LLC-Jeff Schlautman, Xiaofeng Yang, Srihari Gangaraj
Simerics, Inc.-Deming Wang
  • Technical Paper
  • 2020-01-0168
To be published on 2020-04-14 by SAE International in United States
This study brings to forefront the analysis capability of CFD for the oil-cooling of an Electric-Motor (E-Motor) powering an automobile. With the rapid increase in electrically powered vehicle, there is an increasing need in the CFD modeling community to perform virtual simulations of the E-Motors to determine the viability of the designs and their performance capabilities. The thermal predictions are extremely vital as they have tremendous impact on the design, spacing and sizes of these motors. In this paper, with the Simerics, Inc. software, Simerics-MP+®, a complete three dimensional CFD with conjugate heat transfer CHT model of an Electric Motor, including all the important parts like the windings, rotor and stator laminate, endrings etc. is created. The multiphase Volume of Fluid (VOF) approach is used to model the oil flow inside this motor. Two parts of the oil flow, rotor and stator flow, both are simulated, and the net effect of the oil cooling the different solid components is predicted. The ability of the software in meshing complicated, intricate paths with relative ease combined with…
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Analysis of Vibroacoustic Behaviors and Torque Ripple of SRMs with Different Phases and Poles

Shenglong Hu, Xiaorui Hu
Tongji University-Shuguang Zuo
  • Technical Paper
  • 2020-01-0467
To be published on 2020-04-14 by SAE International in United States
In this paper, the vibroacoustic behaviors and torque ripple of switched reluctance motors (SRMs) with different phases and poles have been analyzed in detail. Also, the common four SRMs, i.e., three-phase 6/4 SRM, four-phase 8/6 SRM, five-phase 10/8 SRM, and six-phase 12/10 SRM, have been selected, which represent all the radial SRMs. First, the spatial-temporal distribution characteristics of radial force in SRMs were revealed by virtue of the analytical derivation, which was validated by the 2D Fourier decomposition based on the FEM results of radial force. Second, a multiphysics model, which was composed of an electromagnetic field, mechanical field, and acoustic field, was established to predict the noise behaviors of SRMs with different phases and poles. Third, the relationship between the torque ripple and the phases of SRMs, and the relationship between the noise and the radial force / phases / poles are all analyzed. Finally, the results show that the spatial orders of the radial forces, which are in all radial SRMs with any possible phase and pole, are kNs/(2Q) and the frequencies are…
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Electric motor for brakes – optimal design

Brembo Spa-Alessio Miotto
Politecnico di Milano-Antonino Di Gerlando, Massimiliano Gobbi, Giampiero Mastinu
  • Technical Paper
  • 2020-01-0919
To be published on 2020-04-14 by SAE International in United States
A multi-objective optimal design of a brushless DC electric motor for a brake system application is presented. Fifteen design variables are considered for the definition of stator and rotor geometry, pole pieces and permanent magnets included. Target performance indices (peak torque, efficiency, rotor mass and inertia) are defined together with design constraints that refer to components stress levels and temperature thresholds, not to be surpassed after heavy duty cycles. The mathematical models used for optimization refer to electromagnetic field and related currents computation, to thermo-fluid dynamic simulation, to local stress and vibration assessment. An Artificial Neural Network model, trained with an iterative procedure, is employed for global approximation purposes. This allows to reduce the number of simulation runs needed to find the optimal configurations. Some of the Pareto-optimal solutions resulting from the optimal design process are analysed. They show high improvements of the performance indices with respect to a reference solution.
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Integrated Electrical UAV Propulsion Design and Testing For High Efficiency

DARcorporation-Wanbo Liu, Drew Darrah, Joel Eppler
  • Technical Paper
  • 2020-01-0053
To be published on 2020-03-10 by SAE International in United States
This paper covers the design, modeling and analysis of an electric ducted fan system for sUAV (<55 lb) and the verification of predicted performance with test data. Analysis shows that the operating condition of the motor can significantly affect performance and should be considered when selecting or designing a rotor and vice versa. Motor manufacturers usually provide a list of compatible propellers for a motor design with thrust at RPM data coupled with gram per Watt efficiency. However, the gram per Watt value is not constant across the range of operation and a better modeling is needed depending on thrust requirements. Many of the electrical losses can be difficult to calculate directly, such as flux and iron losses in the motor and switching losses in the ESC. Incorporating an estimation/approximation of such losses during the rotor design phase enables a more accurate performance predication and a better overall system efficiency. Two rotors are designed to work inside of the duct and both have identical geometry except for a small blade pitch changes to increase maximum…
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Performance of Isolated UAV Rotors at Low Reynolds Number

Georgia Institute of Technology-Yashvardhan Tomar, Narayanan Komerath
Indian Institute of Technology-Dhwanil Shukla
  • Technical Paper
  • 2020-01-0046
To be published on 2020-03-10 by SAE International in United States
Vertical takeoff and landing vehicle platforms with many small rotors are gaining importance for small UAVs as well as distributed electric propulsion for larger vehicles. To predict vehicle performance, it must be possible to gauge interaction effects. These rotors operate in the less-known regime of low Reynolds number, with different blade geometry. As a first step, two identical commercial UAV rotors from a flight test program are studied in isolation, experimentally and computationally. Load measurements were performed in Georgia Tech’s 2.13 m × 2.74 m wind tunnel. Simulations were done using the RotCFD solver which uses a Navier-Stokes wake computation along with rotor-disc loads calculation using low-Reynolds number blade section data. It is found that in hover, small rotors available in the market vary noticeably in performance at low rotor speeds, the data converging at higher RPM and Reynolds number. This is indicative of the high sensitivity of low-Re rotor flows to minor geometrical differences/imperfections in the rotors. It requires proper handling in computations. CFD results show a higher deviation from the experimental thrust data…