Rotor Eddy-Current loss in permanent-magnet brushless AC machines

This paper analyzes rotor eddy-current loss in permanent-magnet brushless ac machines. It is shown that analytical or finite-element techniques published in literature for predicting rotor eddy-current loss using space harmonic based approaches may not yield correct results in each magnet segment when one magnet-pole is circumferentially segmented into more than two pieces. It is also shown that the eddy-current loss in each equally segmented piece may differ by a large margin, which implies that the temperature distribution in the magnets will be uneven and the risk of demagnetization has to be carefully assessed. The theoretical derivation is validated by time-stepped transient finite-element analysis

The works of Naṣā’iḥ al-‘Ibād by Nawawi al-Bantani and Sirāj al-Ṭālibīn by Ihsan Muhammad Dahlan al-Jampasi al-Kediri: a comparative research on the methods of writing the hadith

Kitab Naṣā’iḥ al-‘Ibād oleh Nawawi al-Bantani dan Sirāj al-Ṭālibīn oleh Ihsan al-Jampasi merupakan antara beberapa kitab utama yang dirujuk di Nusantara dalam ilmu Islam berkaitan nasihat-nasihat agama dan tasawuf. Dalam kedua-dua kitab tersebut memuatkan banyak hadithhadith. Walau bagaimana pun, tidak dinyatakan tentang kedudukan hadith tersebut. Oleh kerana itu, kajian ini bertujuan melihat metodologi penulisan hadith oleh Nawawi al-Bantani dan Ihsan al-Jampasi dalam kitab Naṣā’iḥ al-‘Ibād dan Sirāj al-Ṭālibīn. Selain itu, kajian ini juga menganalisis perbandingan metode kedua-dua kitab tersebut bagi mengetahui titik persamaan dan perbezaan di antara metode-metode tersebut. Metodologi kajian ini adalah kualitatif melalui kaedah kepustakaan dan reka bentuk analisis kandungan kitab Naṣā’iḥ al-‘Ibād dan Sirāj al-Ṭālibīn. Kajian ini mendapati bahawa wujudnya persamaan metode penulisan hadith dalam kitab Naṣā’iḥ al-‘Ibād dan Sirāj al- Ṭālibīn iaitu penulisan hadith tanpa sanad dan hanya menyatakan mukhrīj hadith sahaja. Selain itu, keduanya menggunakan lafaz (sighat) qāla pada awal permulaan hadith. Manakala perbezaanya pula ialah Nawawi al- Bantani menulis hadith tanpa sanad dengan menambah rāwī a‘lā di peringkat tabi’in dan sahabat. Beliau turut menggunakan metode riwayat bi al-lafẓi. Pendekatan Ihsan al-Jampasi pula menggunakan pelbagai sighat (format) untuk menyampaikan hadith, menyatakan sumber hadith dan kadang-kadang menggunakan metode riwayat bi al-ma‘nā

Comparison of stator-permanent-magnet brushless machines

This paper quantitatively compares two emerging stator-permanent-magnet (PM) machines, namely, the doubly salient PM and the PM hybrid brushless types. Both of them are attractive for electric vehicles and wind power generation. For comparison, both machines adopt the outer-rotor 36/24-pole topology and are designed based on the same peripheral dimensions. By using the circuit-field-torque time-stepping finite element analysis (CFT-TS-FEM), both steady-state and transient performances of the two machines are critically compared. © 2008 IEEE.published_or_final_versio

Design and implementation of hybrid vehicle using control of DC electric motor

The electric motors and its control technology are key components of hybrid electric vehicles (HEVs). Control of the electric motor is a fundamental issue for traction application in electric vehicles and HEVs. This paper presents the design, development and implementation of a hybrid vehicle using both an electric motor and petrol engine to increase efficiency and decrease carbon footprint. Initially, a prototype of a HEV is designed and the performance values are calculated, before a control system is developed and implemented to control the DC motor speed using a microcontroller as the vehicle’s electronic control unit along with simple proportional integral derivative (PID) control using speed as a feedback mechanism. The prototype made incorporated voltage, current, speed and torque sensors for feedback resulting in a closed loop control system which successfully matched the speed input of a user-controlled pedal sensor. A user interface was developed to show the driver of the vehicle key variables such as the revolutions per minute (RPM) of the motor, the speed of the vehicle along with the current being drawn, and the voltage applied to the motor with overall power. To output a variable voltage from the Arduino, a digital output was used with pulse width modulation (PWM) capabilities in order to provide a variable DC voltage to the speed controller

Design and analysis of a flux-controllable linear variable reluctance machine

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A new magnetless flux-reversal HTS machine for direct-drive application

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Stator-flux-oriented fault-tolerant control of flux-switching permanent-magnet motors

Flux-switching permanent-magnet (FSPM) motors are a newly developed brushless AC (BLAC) machine having magnets in the stator. This paper proposes and implements a stator-flux-oriented (SFO) control strategy for fault-tolerant operation of FSPM motors. The key is to set the q-axis component of armature current invariant before and after the fault. In the rotor reference frame, by building a SFO-dq equation of the FSPM motor, the fault-tolerant control strategy is deduced. The finite-element method and the field-circuit cosimulation method are employed to analyze the performance of the FSPM motor drive. Finally, a dSPACE-based FSPM motor drive platform is built for experimental verification. Both the steady-state and dynamic performances at normal and fault-tolerant operations are tested, confirming that the proposed fault-tolerant operation can keep the output torque invariant while offering good dynamic performance during fault. © 2011 IEEE.published_or_final_versionThe IEEE International Magnetic Conference (INTERMAG2011), Taipei, Taiwan, 25-29 April 2011. In IEEE Transactions on Magnetics, 2011, v. 47 n. 10, p. 4191-419

Development of smart solar tracking system

The project is to design an active solar tracking system which able to track the sunlight with the aid of light dependent resistor (LDR) as input sensor to read the intensity of sunlight. The solar tracking system uses platform as a base and it is moved by a servo motor as the platform needs to be moved towards the sunlight to get the optimum light. The solar tracking system is programmed by using microcontroller Arduino Uno as a main controller. After the setup of the hardware and program, the tracking motion of the tracking system has been implemented to track the sun based on sunlight direction. In this work, it is designed that the motion of the tracking system is depends on the value read by LDR. As a conclusion, the solar tracking system can increase the solar panels efficiency by keeping the solar panels perpendicular with sun’s position

Mechanical offset for torque ripple reduction for magnetless double-stator doubly-salient machine

Paper no. EQ-07This journal issue contains selected papers from the 2014 IEEE International Magnetics (INTERMAG) ConferenceThis paper implements the new design structure, so-called the mechanical offset (MO) into the double-stator multitoothed swiTChed reluctance (DS-MSR) machine to form the new MO-DS-MSR machine. The major distinction of the MO structure is to purposely mismaTCh the outer and inner rotor teeth with a conjugated angle. With the MO structure, the outer and the inner torque components can be compensated with each other, hence minimizing the resultant torque ripple. By employing the finite element analysis, the characteristics and performances of the proposed machines are analyzed and compared.published_or_final_versio

A Survey of Synchronous Reluctance Machine used in Electric Vehicle

International audienceDue to more environmental problems and more attentions paid on renewable energy, electric vehicle (EV) has been a hot research topic. As a key equipment in EV, various drives have been studied. Synchronous reluctance machine (SynRM) is also studied widely as a drive in EV for its advantages. This paper presents an extensive survey on the application of SynRM in EV and reviews its working principle, various structures and control strategies