Power Density Of Motor Research Articles

Development of High Power-Density Motors for Electric Axles using Nd-Based Bonded Magnets

Development of High Power-Density Motors for Electric Axles using Nd-Based Bonded Magnets

Design and Analysis of an Interior Permanent Magnet Synchronous Motor for a Traction Drive Using Multiobjective Optimization

With the development of new energy industries, the demand for the driving range and power quality of electric vehicle (EV) drive systems is growing rapidly. The drive motor is faced with the challenge of continuously improving power density and performance. This paper proposes a multiobjective optimization method for an interior permanent magnet synchronous motor for a traction drive (IPMSMTD). Based on the flat wire winding technology, the multiobjective optimization design of the IPMSMTD is carried out to improve the motor power density and high-efficiency range, reduce the torque ripple, and suppress the electromagnetic vibration and noise. The structure and size equation of the IPMSMTD are described. The mathematical model considering iron losses is established, and the optimization objectives are determined. Based on the genetic algorithm, a multiobjective optimization mechanism of the magnetic pole structure is established. The operation performance of the motor is analyzed by the finite element simulation and efficiency map. In order to ensure the comprehensive operation index of the IPMSMTD, the vibration noise and modal analysis are carried out, which verifies the rationality of the designed motor and the optimization method.

State-of-the-Art Lightweight Implementation Methods in Electrical Machines

The demand for high-power density motors has been increasing due to their remarkable output capability and compact construction. To achieve a significant improvement in motor power density, lightweight design methods have been recognized as an effective enabler. Therefore, extensive investigations have been conducted to reduce motor mass and achieve lightweight configurations through the exploration of lightweight materials, structures and manufacturing techniques. This article provides a comprehensive review and summary of state-of-the-art lightweight implementation methods for electrical machines, including the utilization of lightweight materials, structural lightweight design, and incorporation of advanced manufacturing technologies, such as additive manufacturing techniques. The advantages and limitations of each approach are also discussed in this paper. Furthermore, some comments and forecasts on potential future methodologies for motor lightweighting are also provided.

Study of the Dielectric and Corona Resistance Properties of PI Films Modified with Fluorene Moiety/Aluminum Sec-Butoxide.

With the policy tilt and increased investment in research and development in the world, new energy vehicle technology continues to progress and the drive motor power density continues to improve, which puts forward higher requirements for the comprehensive performance of the core insulating material enameled wire enamel for drive motors. Polyimide (PI) has excellent electrical insulation properties, and heat resistance is often used to drive the motor winding insulation. To further improve the corona resistance and insulating properties of PI wire enamel varnish, in this paper, firstly, fluorene groups with a rigid conjugated structure were introduced into the molecular chain of the PI film by molecular structure modulation, and then uniformly dispersed alumina nanoclusters (AOCs) were introduced into the PI matrix by using an in situ growth process to inhibit the migration of high-energy electrons. The quantum size effect of the alumina nanoclusters was exploited to synergistically enhance the suppression and scattering of energetic moving electrons by PI-based composite films. The results show that the breakdown field strength of the PI-based composite film (MPI/1.0 vol% AOC) reaches 672.2 kV/mm, and the corona resistance life reaches 7.9 min, which are, respectively, 1.55 and 2.19 times higher than those of the initial PI film. A PI-based composite film with excellent insulating and corona resistance properties was obtained.

Design and optimisation of oil injection pipe cooling structure for permanent magnet synchronous motors in hybrid electric vehicles

AbstractIn recent years, with the continuous improvement of motor power density, oil cooling technology has been widely used in permanent magnet synchronous motors (PMSMs) for electric vehicles (EVs) as an efficient cooling method. A PMSM with a rated capacity of 53kW for hybrid electric vehicles (HEVs) is designed, and the motor is cooled by the oil injection pipe. In order to improve the heat dissipation efficiency of the end winding, the number of injection pipes and the structure of the nozzle are optimised, and a novel nozzle structure is proposed. By using the moving particle solution (MPS) method to simulate the fluid flow, the optimal cooling structure of the motor is determined. In addition, different from the equivalent winding model in the traditional temperature field simulation, a hairpin winding model that can more realistically reflect the geometry of the end winding is established. On this basis, the temperature field of the motor is simulated. It is verified that the cooling structure designed can effectively improve the thermal performance of the end winding.

Review of High-Power-Density and Fault-Tolerant Design of Propulsion Motors for Electric Aircraft

As the electrification process of aircrafts continues to advance, the propulsion motor system, as its core component, has received more attention and research. This paper summarizes and analyzes the development status, research focus and typical cases in this field in recent years. Firstly, it analyzes the basic structure and principle of five common motors, summarizes the current status of their respective applications in electric aircrafts, and compares them to determine the most suitable type of motor for use as a propulsion motor, focusing on various performance indexes. Then, the optimized design of propulsion motors is generally divided into two categories, namely high power density and fault tolerance. Starting from the basic relationship equation of motor design, the basic method to improve the power density of motors is pointed out; at the same time, according to the basic principles and objectives of the fault tolerance of motors, the fault tolerance design is divided into two aspects, namely the redundant design and the design to improve the fault tolerance capability. Finally, this paper summarizes the current development status of the propulsion motor system and the existing problems and points out the main development direction of this field in the future, so as to provide reference for the further development of the electric propulsion system of aircraft.

Loss calculation and thermal analysis of ultra-high speed permanent magnet motor

The ultra-high speed permanent magnet motor (UHSPM) for hydrogen fuel cell air compressor is characterized by high speed, high motor power density, small size, and high reliability. Compared to the conventional motor, the loss per unit volume is increased and therefore the calculation of the temperature field is more important than that of conventional motors. In this paper, a UHSPM with a rated speed of 90000 r/min is designed. Firstly, a finite element (FE) model of the UHSPM is established and the losses of each part of the high-speed motor are calculated, and the calculated losses are introduced into the fluid field in the form of a heat source for motor temperature analysis. The calculated losses were introduced into the fluid field in the form of a heat source and used in the motor temperature analysis. The temperature rise was then calculated for the unidirectional and bidirectional magneto-thermal coupling (MTC) respectively. The results show that the bidirectional magneto- thermal coupling (BMTC) simulation results are about 2-3°C smaller than the experimental measured values, which can more accurately predict the motor temperature. The measurement results verify the accuracy of BMTC, and provide basic theoretical support for the subsequent cooling optimization scheme of high-speed motor.

Improving the induction motor power density by its operation at liquid nitrogen bath

This work presents a study of an induction motor at two different operating temperature conditions: room temperature and 77 K. The goal is to analyze its performance and obtain its most relevant features. Experimental tests were carried out in the laboratory under room temperature and liquid nitrogen (LN2) bath. The authors designed a prototype bench with a controlled load to measure magnitudes like torque, speed, current, power, power factor, efficiency, and others. The results show a considerable increase in the torque and efficiency, but in contrast, the starting torque is drastically reduced at cryogenic temperature. Besides, at 77 K, the slip is much lower than at room temperature. The experiments show a substantial rise in the motor’s power density, indicating that cooled induction motors can be applied in applications where volume and weight are restricted.

Design and Research on High Power Density Motor of Integrated Motor Drive System for Electric Vehicles

Although many PMSMs are used as the driving source for electric vehicle motor drive systems, there is still a gap compared with the power density index in the DOE roadmap. Considering that the motor occupies a large space in the motor drive system, it is of great significance for the system to increase the motor power density and thus reach the system power density index. This article starts with electrical machine basic design theory and finds the motor power density influence factors. Guided by the theory and considering motor driver influence, this article proposes a high power density motor for electric vehicle integrated motor drive system. The motor for the system is a five-phase interior permanent magnet synchronous motor (IPMSM) with a double-layer rotor structure and fractional slot distributed winding. Compared with Ver1.0 motor, Ver2.0 motor power density improves significantly. In order to prevent damage from excessive temperature, a temperature field solution model is established in this article to compare the cooling effect and pressure loss of the spiral, dial, and axial water jackets. The temperature is checked at motor main operating conditions using an optimal cooling structure. Finally, the power density of the designed Ver2.0 motor reaches 3.12 kW/kg in mass and 15.19 kW/L in volume.

Optimization of Power Density of Axial Flux Permanent Magnet Brushless DC Motor for Electric Two-Wheeler

The main objective of this work is to optimize the power density of axial flux permanent magnet brushless dc (PMBLDC) motor based on genetic algorithm (GA) technique for performance improvement of electric 2-wheeler. Power density is one of the important performance parameter of motor as it significantly influences overall performance of electric 2-wheeler. Firstly, the rating of electric motor is determined according to the application requirements and vehicular dynamics. Axial flux PMBLDC motor of 250 W, 150 rpm is designed to fit in to the rim of electric 2-wheeler based on assumption of various design variables. The salient contribution of this work is to suggest the best combination of design variables with the application of GA optimization technique for power density optimization. Comparative performance analysis is carried out between initially designed motor and optimized motor. Finally, 3 dimensional (3-D) finite element analysis (FEA) is performed to verify the results obtained from design optimization. Results obtained from FEA fairly validates the initial design and optimized design. It is analyzed that the power density of motor is enhanced by 42.85 % with the proposed optimization technique. The proposed technique is implementable and complexity free. It may further be applied to the performance improvement of a non-linear design comprising different design variables.
 HIGHLIGHTS
 
 Axial flux permanent magnet motors are the most compatible in electric vehicle applications
 Power density is one of the important performance parameters of axial flux permanent magnet motors
 Optimization of power density improves drive range and overall performance of electric vehicle
 Influential design variables are identified based on parametric analysis and its optimization is carried out with an GA based optimization technique with an objective of power density optimization
 Proposed optimization technique is validated with finite element analysis
 
 GRAPHICAL ABSTRACT

A Novel Method for Busbar Design of Electric Vehicle Motor Drive

At present, the DC busbar design is one of the bottlenecks restricting the improvement of the power density of motor drives. Therefore, this paper proposes a three-dimensional line probe algorithm, which can realize the automatic routing of laminated busbar in motor drives. The specific rules and implementation of this method are introduced in detail in this paper. Finally, an example of busbar design of a vehicle motor drive is given to verify the routing rate and execution speed of the algorithm.

A Review of Electric Aircraft Drivetrain Motor Technology

This article reviews the power density and torque density of permanent magnet (PM) motor technology that is currently commercially developed for use in electric aircraft. The review shows that in order to meet the ambitious electrical motor power density goals recently set forth, the power density of a motor needs to more than double. The requirements imposed by the maximum propeller rotor tip speed, as well as the diameter constraints set by the aerodynamic requirements, will further limit the practical electric motor design sizing options. This article advocates for considering using magnetic gearing (MG) and using an integrated contra-rotating motor propeller co-design approach as a way of both increasing propulsive thrust performance and thereby increasing the aircraft’s overall power density.

Superconducting motors for aircraft propulsion: the Advanced Superconducting Motor Experimental Demonstrator project

The European Union-funded Advanced Superconducting Motor Experimental Demonstrator (ASuMED) project started in May 2017 with the purpose of demonstrating the benefits of a new, fully superconducting motor for reaching the targets established by the Flightpath 2050 plan. The project aims at a motor power density of 20kW kg−1 using a high-temperature superconducting (HTS) stator. The rotor will use HTS stacks operating like permanent magnets. A highly efficient cryostat for the motor combined with an integrated cryogenic cooling system and associated power converter will be used. This article provides a general overview of the prototype that is currently being assembled and that will be tested soon.

Novel Permanent Magnet Synchronous Motor With Integrated Filter Inductor, Using Motor's Inherent Magnetics

A close functional and structural integration of passive elements is required to improve the power density of motor drives. Such power-dense motor drives are prerequisites in aerospace and automotive applications. This article presents a permanent magnet motor with an integrated filter inductor, which not only eliminates inductor losses but also removes its associated weight and volume. The motor with an integrated filter uses motor's inherent magnetics in order to use it as a filter inductance instead of adopting an external inductor option, which is traditionally placed outside the motor. A vector-controlled model, taking modulation and switching effect into account, has been developed by using MATLAB/Simulink tool. To experimentally validate the concept of the motor with an integrated filter inductor, the winding connections of an existing motor are modified. The comparative analysis, between the traditional and integrated motor drive systems, is carried out in terms of the magnitude of switching component, total system losses, weight, and volume. The total losses in the motor with integrated filter are reduced by 34.2% at 2100 r/min and 3-N·m load, when compared to the motor with traditional filter inductor, whereas, its weight and volume in the motor with integrated filter inductor are eliminated completely.

Stator Core Shape Design for Low Core Loss and High Power Density of a Small Surface-Mounted Permanent Motor.

In this paper, a stator core shape design method is proposed for an improvement in the power density of a small surface-mounted permanent magnet (SPM) motor. In order to improve the power density of a motor, it is necessary to increase its torque or reduce its weight. However, when a stator core shape is miniaturized to reduce the weight of the motor, the winding regions in a motor frequently decrease. Our stator core shape design method improves the power density of a motor by reducing its weight without decreasing the torque and keeping the winding regions constant. Moreover, the core loss of a motor also decreases when using our method. A Bezier curve is used for the determination of a stator core shape. The finite element method in consideration of the vector magnetic properties is used to evaluate the core loss of the motor shaped by our method. As a result, the power density of an SPM motor is improved, and the core loss of the motor decreases.

Comparison of Full-Area Simulation Method and Separated Simulation Method of Motor Temperature Field

Permanent magnet motor has become the main research direction of high power density motor, and the heat dissipation capability of the motor has become an important factor restricting the increase of motor power density. High-power density motor generates higher temperature when it works, and high temperature may cause motor insulation burnout, even irreversible demagnetization of permanent magnets. Therefore, thermal analysis and optimal design of cooling structure are very important for high power density motors. In this paper, a 3-D model of thermal simulation of permanent magnet motor is established, and the temperature field is calculated by two methods. 1. The fluid-solid coupling method is used to calculate the global temperature field of the motor and the cooling structure. 2. The fluid-solid coupling method is used to calculate the convective heat transfer coefficient of the cooling structure, then the heat transfer model is used to calculate the temperature field of the motor body. These two methods are introduced and compared in this paper, and the second method is considered to be well suited for optimal design of motor cooling structures.

Power Density Analysis and Optimization of SMPMSM Based on FEM, DE Algorithm and Response Surface Methodology

Surface-mounted permanent magnet synchronous motors (SMPMSM) with high power density and good speed regulation are widely used in industrial applications. In order to further improve its power density, this paper studied the relationship between the thickness of the stator yoke, the thickness of the rotor yoke, the relative magnet span of the motor and the motor power density using the finite element simulation method. On this basis, a response surface model between the three parameters and the power density of the motor was established. Based on this model and a differential evolution algorithm, the motor was optimized and the power density was improve; finally, the optimization results were verified using the finite element simulation method. In addition, the optimization results showed that, when other structure parameters remain unchanged, there is an optimal combination of parameters that can maximize the motor’s power density, including the thickness of the stator yoke, the thickness of the rotor yoke and relative magnet span of the motor.

Optimization of port size of high power density permanent magnet synchronous motor

The application of high power density motors is increasingly widespread, but the motor power density has been limited by the thermal load and the performance of the electromagnetic material. In order to reduce the thermal load of the motor, the relationship between the size of the motor Hs0 and Bs0 and the core loss of the motor is studied in this paper. It is found that the decrease of Hs0 and the increase of Hs0 can reduce the core loss of the motor. Meanwhile, with the increase of Bs0, the output torque of the motor increases first and then decreases. As the Hs0 increases, the output torque of the motor increases gradually. According to the above conclusions, the size of the notch of a high power density permanent magnet synchronous motor is optimized, and the core loss of the motor is reduced without affecting the output torque of the motor.

Mission Analysis and Component-Level Sensitivity Study of Hybrid-Electric General-Aviation Propulsion Systems

The system-level capabilities and component-level sensitivities of hybrid-electric propulsion systems were analyzed by modeling a twin-engine general-aviation aircraft. The flight-performance model was developed using performance variables for the Tecnam P2006T found in published papers authored by the aircraft manufacturer. Both parallel and series hybrid-electric drivetrains were integrated into the aircraft performance model, and performance data were produced for various missions, degrees of electrification, battery specific energy densities, and electric motor power densities. The results quantified the improvements in battery specific energy density and electric motor power density necessary to make specific mission ranges feasible for several variants of each hybrid architecture. It was found that current technology allows a parallel hybrid configuration to achieve a maximum theoretical range of approximately 175 n mile. The results also indicated that parallel hybrid architectures will offer an effective near-term configuration, by offering greater range performance than a series hybrid with incremental future advancements in battery specific energy density and electric motor power density. However, distant future advancements in these technologies will allow series-hybrid architectures to produce similar range capabilities with improved fuel economy over parallel-hybrid architectures.

Fault-Tolerant Control of a Five-Phase Permanent Magnet Synchronous Motor for Industry Applications

The next big change in various industry applications is associated with power dense motors, such as permanent magnet synchronous motors (PMSMs). Utilization of multiphase PMSM can offer an additional fault-tolerant capability to their applications. Combining both advantages, this paper proposes a simple yet robust current control strategy for a five-phase PMSM under normal operation and in a case of a loss of one phase. Traditional linear current controllers successfully applied to reference tracking of a healthy motor may become less efficient during postfault operation due to additional unmodeled dynamics. This paper proposes a modified angular transformation to a special rotating frame in which the postfault permanent magnet flux linkage remains unchanged and the motor model remains decoupled. Following this, a nonlinear current control scheme based on sliding mode control is proposed, which successfully treats model inaccuracies and provides good dynamic performance and tracking accuracy. Feasibility of the proposed control strategy is experimentally validated on a laboratory scale PMSM motor with a digital signal processor/field programmable gate array based drive.