Performance comparison between Surface Mounted and Interior PM motor drives for Electric Vehicle application

Electric Vehicles make use of permanent magnet synchronous traction motors for their high torque density and efficiency. A comparison between interior permanent magnet (IPM) and surface mounted permanent magnet (SPM) motors is carried out, in terms of performance at given inverter ratings. The results of the analysis, based on a simplified analytical model and confirmed by FE analysis, show that the two motors have similar rated power but that the SPM motor has barely no overload capability, independently of the available inverter current. Moreover the loss behavior of the two motors is rather different in the various operating ranges with the SPM one better at low speed due to short end connections but penalized at high speed by the need of a significant de-excitation current. The analysis is validated through finite-element simulation of two actual motor design

A study of energy efficiency opportunities in Putrajaya Maritime Centre towards green building

Nowadays, people are more concerned about energy efficiency, energy consumption and conservations in buildings. With this in view, a project to investigate the potential of energy saving in selected building in Putrajaya Maritime Centre was carried out. The scope of the study includes identifying energy consumption in a selected building, to study energy saving opportunities, and to analyse cost investment in term of economic. As a public building and a recreation centre, these building should take the initiative to protect the environment towards green building. According to the research and analysis, several solutions are proposed to help reduce energy consumption and energy cost in the Maritime Centre. First, by improving physical properties of building components. Second, by changing the air condition temperature control setting. This paper also discuss about the improvement of lighting system efficient. From the data analysis, it has been found that huge amount of energy can be saved for a better green environment

Three-phase modular permanent magnet brushless machine for torque boosting on a downsized ICE vehicle

The paper describes a relatively new topology of 3-phase permanent magnet (PM) brushless machine, which offers a number of significant advantages over conventional PM brushless machines for automotive applications, such as electrical torque boosting at low engine speeds for vehicles equipped with downsized internal combustion engine (ICEs). The relative merits of feasible slot/pole number combinations for the proposed 3-phase modular PM brushless ac machine are discussed, and an analytical method for establishing the open-circuit and armature reaction magnetic field distributions when such a machine is equipped with a surface-mounted magnet rotor is presented. The results allow the prediction of the torque, the phase emf, and the self- and mutual winding inductances in closed forms, and provide a basis for comparative studies, design optimization and machine dynamic modeling. However, a more robust machine, in terms of improved containment of the magnets, results when the magnets are buried inside the rotor, which, since it introduces a reluctance torque, also serves to reduce the back-emf, the iron loss and the inverter voltage rating. The performance of a modular PM brushless machine equipped with an interior magnet rotor is demonstrated by measurements on a 22-pole/24-slot prototype torque boosting machine

Comparison of Induction and PM Synchronous motor drives for EV application including design examples

Three different motor drives for electric traction are compared, in terms of output power and efficiency at the same stack dimensions and inverter size. Induction motor (IM), surface-mounted permanent-magnet (PM) (SPM), and interior PM (IPM) synchronous motor drives are investigated, with reference to a common vehicle specification. The IM is penalized by the cage loss, but it is less expensive and inherently safe in case of inverter unwilled turnoff due to natural de-excitation. The SPM motor has a simple construction and shorter end connections, but it is penalized by eddy-current loss at high speed, has a very limited transient overload power, and has a high uncontrolled generator voltage. The IPM motor shows the better performance compromise, but it might be more complicated to be manufactured. Analytical relationships are first introduced and then validated on three example designs and finite element calculated, accounting for core saturation, harmonic losses, the effects of skewing, and operating temperature. The merits and limitations of the three solutions are quantified comprehensively and summarized by the calculation of the energy consumption over the standard New European Driving Cycl

Direct Flux Field Oriented Control of IPM Drives with Variable DC-Link in the Field-Weakening Region

This paper presents the direct flux control of an interior permanent-magnet (IPM) motor drive in the field-weakening region. The output torque is regulated by the coordinated control of the stator flux amplitude and the current component in quadrature with the flux, and it is implemented in the stator flux reference frame. The control system guarantees maximum torque production taking into account voltage and current limits, in particular in case of large dc-link variations. The field-oriented control does not necessarily require an accurate magnetic model of the IPM motor, and it is able to exploit the full inverter voltage at different dc-link levels with no additional voltage control loop. The feasibility of the proposed control method is investigated in discrete-time simulation, then tested on a laboratory rig, and finally implemented on board of an electric scooter prototype. The motor under test is an IPM permanent-magnet-assisted synchronous reluctance machine, with high-saliency and limited permanent-magnet flu

Optimal design and implementation of a drivetrain for an ultra-light electric vehicle

This paper presents an integrated design of a drivetrain for a single-person ultra-light electric vehicle (ULEV). To calculate losses and efficiency of the inverter, the permanent magnet synchronous machines (PMSMs) and the gearbox, parameterised analytical models are used. For the gearbox - which has a single gear ratio - the studied parameters are the gear ratio, the number of stages, the number of teeth and the module of each spur gear combination. The novelty of the paper is that it learns how the total average efficiency and the total mass of the drivetrain depend on the gear ratio, on the number of stages in the gearbox, on the motor parameters and on the chosen several driving cycles including the new European driving cycle (NEDC). On the basis of the presented results, it is possible to choose the right configuration of power electronics, PMSM and gearbox in order to have a good trade-off between high efficiency and low mass

Computationally Efficient Optimization of a Five-Phase Flux-Switching PM Machine Under Different Operating Conditions

This paper investigates the comparative design optimizations of a five-phase outer-rotor flux-switching permanent magnet (FSPM) machine for in-wheel traction applications. To improve the comprehensive performance of the motor, two kinds of large-scale design optimizations under different operating conditions are performed and compared, including the traditional optimization performed at the rated operating point and the optimization targeting the whole driving cycles. Three driving cycles are taken into account, namely, the urban dynamometer driving schedule (UDDS), the highway fuel economy driving schedule (HWFET), and the combined UDDS/HWFET, representing the city, highway, and combined city/highway driving, respectively. Meanwhile, the computationally efficient finite-element analysis (CE-FEA) method, the cyclic representative operating points extraction technique, as well as the response surface methodology (in order to minimize the number of experiments when establishing the inverse machine model), are presented to reduce the computational effort and cost. From the results and discussion, it will be found that the optimization results against different operating conditions exhibit distinct characteristics in terms of geometry, efficiency, and energy loss distributions. For the traditional optimization performed at the rated operating point, the optimal design tends to reduce copper losses but suffer from high core losses; for UDDS, the optimal design tends to minimize both copper losses and PM eddy-current losses in the low-speed region; for HWFET, the optimal design tends to minimize core losses in the high-speed region; for the combined UDDS/HWFET, the optimal design tends to balance/compromise the loss components in both the low-speed and high-speed regions. Furthermore, the advantages of the adopted optimization methodologies versus the traditional procedure are highlighted

Performance Evaluation of Novel Rare Earth Free Magnets Based Motors for Electric Vehicle Applications

Electrical Vehicles (EVs) are regarded as an effective solution in a world where environmental protection along with energy crises is gaining higher attention. Permanent Magnet Synchronous Machines (PMSMs) are considered significant competitors for EVs amongst the other varied motor drives. Owing to their higher efficiency, higher output power to volume ratio, and higher torque to current ratio, they are regarded as a feasible option in several sorts of applications like wind turbines, along with EVs. For higher-performance applications, Permanent Magnet (PM) motors with Rare-Earth (RE) magnets are pondered as one of the best candidates. Conversely, replacing the Rare-Earth (Neodymium-iron-boron) in EVs with lesser or even no RE alternatives is the most critical concern in PM owing to their limited along with the unstable supply of RE elements. Therefore, to eliminate the usage of RE magnets as well as to identify the finest alternative materials, which assure lower cost along with mass production in manufacturing industries, various permanent magnetic materials are examined here with different PMSM designs for EVs applications. Manganese Aluminide (MnAl), Ferrite, Tetrataenite (L10FeNi), Iron Nitride (Fe16N2) and Nanocomposite magnetic materials are the varied magnetic materials utilized for evaluation. For varied magnetic materials, the simulation outcomes are obtained regarding the variations in cogging torque, average torque, efficiency, along with magnet mass. On analogizing RE with various magnetic materials, it was established that a higher performance was attained by replacing RE magnets with substitute magnetic material; in addition, it also proves to be highly effective. It is observed that although their electromagnetic performance of the various materials is similar, iron nitrade has an excellent demagnetization withstand capability. Finally, in contrast to the interior V type with rare earth magnets, iron nitrade and MnAl magnet machine can attain better torque development with high efficiency

Employability skills for hospitality students in Malaysia

Malaysia needs high skilled workforce to support growth of the industry. With dynamically changing job market and progressive technological change, employees are expected to keep abreast of global economics. In the process of achieving the status of developed nation by the year 2020, Malaysia needs to restructure its workforce to ensure that middle level workers are highly skilled. Current job environment demands multi-task and skills. Thus, university graduates must be prepared to meet the demand especially in the hospitality industry. The purpose of this study is to identify the level of employability skills in the hospitality field. This research applied quantitative methodology. The respondents consist of final year students in bakery and culinary programme. Stratified sampling was used to select students in hospitality programs from 22 vocational colleges in Malaysia. Questionnaires were distributed to 841 students in five regions which are Central, South, North, East and East Malaysia (Sarawak) in Malaysia. Descriptive analysis was used to analyse the quantitative data. The results showed that the level of hospitality employability skills among vocational students in Malaysia were at high level of competence (93.2%). The research has brought meaningful implications for hospitality vocational students, employers and policy makers

An Integral Battery Charger with Power Factor Correction for Electric Scooter

This paper presents an integral battery charger for an electric scooter with high voltage batteries and interior-permanent-magnet motor traction drive. The battery charger is derived from the power hardware of the scooter, with the ac motor drive that operates as three-phase boost rectifier with power factor correction capability. The control of the charger is also integrated into the scooter control firmware that is implemented on a fixed-point DSP controller. Current-controlled or voltage-controlled charge modes are actuated according to the requirements of the battery management system, that is embedded into the battery pack. With respect to previous integrated chargers, the ac current is absorbed at unitary power factor with no harmonic distortion. Moreover, no additional filtering is needed since the pulsewidth modulation ripple is minimized by means of phase interleaving. The feasibility of the integral charger with different ac motors (induction motor, surface-mounted phase modulation motor) is also discussed, by means of a general model purposely developed for three-phase ac machines. The effectiveness of the proposed battery charger is experimentally demonstrated on a prototype electric scooter, equipped with two Li-ion battery packs rated 260 V, 20 A