Cogging Torque Minimization of PMBLDC Motor for Application in Battery Electric Vehicle

Since the beginning, researchers have focused globally on the automotive industry, which recently yielded a notable increase in the development of electric vehicles. The cogging torque of the motor is the leading cause of acoustic noise and vibration. Therefore, this paper aims to reduce the cogging torque of Brushless DC motors in electric vehicles. The power rating of the two-wheeler battery electric vehicle is determined with kinematic dynamic equations. The choice of material and the combination of pole slots impact the vehicle’s overall performance, particularly in raising the average torque of the motor. Finite element based Ansys Maxwell electromagnetic field simulation software has been used to design and analyze the electric and magnetic field parameters of BLDC motor using several rotor poles embrace factor values. The findings of this study are expected to reduce vibration and noise in electric vehicles with increased average torque

ADVANCED SYNCHRONOUS MACHINE MODELING

The synchronous machine is one of the critical components of electric power systems. Modeling of synchronous machines is essential for power systems analyses. Electric machines are often interfaced with power electronic components. This work presents an advanced synchronous machine modeling, which emphasis on the modeling and simulation of systems that contain a mixture of synchronous machines and power electronic components. Such systems can be found in electric drive systems, dc power systems, renewable energy, and conventional synchronous machine excitation. Numerous models and formulations have been used to study synchronous machines in different applications. Herein, a unified derivation of the various model formulations, which support direct interface to external circuitry in a variety of scenarios, is presented. Selection of the formulation with the most suitable interface for the simulation scenario has better accuracy, fewer time steps, and less run time. Brushless excitation systems are widely used for synchronous machines. As a critical part of the system, rotating rectifiers have a significant impact on the system behavior. This work presents a numerical average-value model (AVM) for rotating rectifiers in brushless excitation systems, where the essential numerical functions are extracted from the detailed simulations and vary depending on the loading conditions. The proposed AVM can provide accurate simulations in both transient and steady states with fewer time steps and less run time compared with detailed models of such systems and that the proposed AVM can be combined with AVM models of other rectifiers in the system to reduce the overall computational cost. Furthermore, this work proposes an alternative formulation of numerical AVMs of machine-rectifier systems, which makes direct use of the natural dynamic impedance of the rectifier without introducing low-frequency approximations or algebraic loops. By using this formulation, a direct interface of the AVM is achieved with inductive circuitry on both the ac and dc sides allowing traditional voltage-in, current-out formulations of the circuitry on these sides to be used with the proposed formulation directly. This numerical AVM formulation is validated against an experimentally validated detailed model and compared with previous AVM formulations. It is demonstrated that the proposed AVM formulation accurately predicts the system\u27s low-frequency behavior during both steady and transient states, including in cases where previous AVM formulations cannot predict accurate results. Both run times and numbers of time steps needed by the proposed AVM formulation are comparable to those of existing AVM formulations and significantly decreased compared with the detailed model

Small and high-temperature electrical machine for vehicle applications

PhD ThesisInterior permanent magnet (IPM) motors are a very promising design alternative in comparison with other types of electrical motors. Even though the price of rare-earth magnets has become a severe concern, IPM motors are gaining increasing attention due to their high torque density and excellent field weakening performance. Therefore, researchers have attempted to reduce the use of magnet materials but, at the same time, maintain the output performance of IPM motors. One solution is to reduce the size of the machine, which will also reduce the amounts of all materials used. Generally, a small scale is a profound advantage. Still, it may constitute a deficiency from the thermal point of view by contributing to higher loss density and problems operating at a higher temperature. An IPM motor may fail due to winding failure or the demagnetization of permanent magnets. It is crucial to make sure that these motors can run safely. The purpose of this study is to develop a new electrical machine for automotive applications that is smaller in size with minimised use of magnets and which meets all requirements. The focus is on design alterations to reduce the size of the motor. Furthermore, high-temperature materials are used to ensure that the motor can work safely, even in hotter conditions. A comparison is conducted on the performance of different sizes of the motor using finite element analysis in attempting to reduce the usage of the magnet material. Then, the temperature and heat transfer exposure of IPM motors are predicted by applying thermal modelling. Research is also conducted to find the most suitable material for smaller IPM motors to run at higher temperatures. Besides using neodymium-iron-boron as magnet material for an existing IPM motor, this study also analyses an IPM motor with samarium-cobalt, which has advantages in terms of higher temperature operation. The characteristics of IPM motors equipped with distributed and concentrated winding for automotive applications are also considered, and a proper motor winding is proposed. Two prototype IPM motors with different sizes and magnet materials are built and tested to validate the finite element analysis results. The first machine is developed using the same materials as in the existing Nissan Leaf machine, while the second is designed using high-temperature materials. The most suitable size of a smaller IPM motor is ultimately determined, which can reduce the usage of permanent magnet and other material, but which maintains the output performance of existing IPM motors. The design allows significant weight and size reductions in comparison with existing PM motors due to the use of high-temperature materials, which makes this electrical motor the right candidate for traction drive applications. The motor also satisfies all safety requirements