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This paper proposes novel switched reluctance (SR) inverter for four-phase SR drive which generates high output torque without compromise in efficiency for medium and high speed operations. In prop...

Switched reluctance motors (SRMs) are simple in structure, easy to manufacture, magnet-less, brushless, and highly robust compared to other AC motors which makes them a good option for applications that operate in harsh environment. However, the motor has non-linear magnetic characteristics, and it comes with various pole-phase combinations and circuit topologies that causes many difficulties in deciding on which type to choose. In this paper, the viability of SRM as a low-cost, rugged machine for vehicle radiator cooling fan is considered. First, necessary design considerations are presented, then three commonly use types of SRM are analyzed: A 3-phase 6/4, 3-phase 12/8, and a 4-phase 8/6 to find their static and dynamic characteristics so the most suitable type can be selected. Simulation results show that the 8/6 SRM produces the highest efficiency with less phase current which reduces the converter burden. However, with asymmetric half bridge converter, eight power switches are required for 8/6 SRM and thus put a burden on the overall drive cost. As a solution, the Miller converter with only six switches for four phase SRM. To verify the proposed idea, the 8/6 SRM was manufactured and tested. The results show that Miller converter can be used for the proposed SRM with slightly reduced efficiency at 80.4%.

In a bid to respond to the challenges being faced in the installation of flywheel-based electric energy storage systems (EESSs) in customer-side facilities, namely high safety, high energy/power densities and low cost, research work towards the development of a novel, one-body, laminated-rotor flywheel, based on a switched reluctance machine (OBOLAR-Fly SR machine) is presented, where the laminated rotor provides both the energy storage and motor/generator functions. The one-body architecture improves compactness and robustness. Besides, the rotor&rsquo, s laminated body ensures inherently high safety. From the design perspective, the rotor&rsquo, s dual purpose causes the traditional electrical machines design aspects, such as power development, cooling, losses, torque ripple, etc., to clash with the typical requirements of a flywheel, namely in-vacuum operation and moment of inertia. This results in six main trade-offs to be addressed during the design process: rotor material, speed ratio, number of drive phases, split ratio, optimal vacuum level, and controller hysteresis band. A 60 kW, 2.2 kWh OBOLAR-Fly SR system is developed with a twofold objective: (1) provide an in-depth description of the six bespoke design trade-offs and give some useful guidelines to tackle them, (2) prove the OBOLAR-Fly concept and compare the prototype&rsquo, s performance with the current state of the art flywheels. Preliminary experimental results prove the viability of the OBOLAR idea and show its competitiveness in terms of efficiency and power density. On the other hand, a gap in energy density to be filled in future research works is highlighted.

Switched reluctance machines provide a feasible solution for automotive applications. However, a small and low cost power electronics driver is of interest for this purpose. This paper presents a control algorithm for a single-bus star-connected switched reluctance drive system. This algorithm enables the conventional Miller topology to control the phase currents in the multiphase excitation mode of operation. This control algorithm is introduced for motoring and generating modes of operation. The introduced algorithm is simulated under motoring and generating modes. Afterward, experimental measurements are illustrated to prove the practicality of the proposed concept.

Knowing the precise thermal behavior of switched reluctance machines (SRM) is important to increase the power density of such machines. Up to now, literature is lacking about how to model in detail...

This paper presents the design and an encoder-based starting strategy for a low-cost single-phase switched reluctance machine (SRM). The single-phase SRM cannot produce a continuous torque over one revolution. Therefore, applications that do not require a continuous torque, e.g., pumps and fans, are especially suitable. Another issue of single-phase machines is start up. The starting direction is affected by the initial rotor position. Due to the functional concept of SRM the machine produces no torque at aligned and unaligned position of the rotor and consequently, cannot be started from these positions. To start up from every rotor position a saturation-based starting method is used. The design of the rotor with the saturable area is shown and the principles of an encoder-based starting strategy for a fast start-up under 0.5 s are introduced. Finally, the build prototype and experimental results of the starting strategy are shown.

This article proposes two different methods for estimating the shaft position for a switched reluctance motor (SRM). Method 1 uses the self-inductance estimation technique to obtain the rotor position. First, by on-line measuring the slope of the stator current and compensating for the back electromotive force (EMF) effect, the self-inductance of the SRM can be detected. Then, the shaft position of the motor can be estimated according to the self-inductance. Method 2, on the other hand, uses the phase-locked loop technique to generate high-frequency signals. These signals can be used to estimate the shaft position of the SRM. The two proposed methods are compared and discussed in the article. Several experimental results are shown to validate the theoretical analysis. The adjustable speed range of the system is from 10 to 3000 rpm. Additionally, the proposed drive system can automatically start from a standstill to a setting speed.

The linear counterpart of the rotational switched reluctance drive is receiving increasing attention from academic and industrial societies. The special characteristics of this driving technology, that normally works in a highly magnetic saturation regimen, make the development of efficient design methodologies more difficult. This paper proposes a new numerical model of a Linear Switched Reluctance Actuator based on the flux tube method. For validation purposes, simulation results obtained from the application of presented model are compared with the ones obtained from the application of a commercial finite element tool. The modulation technique proposed here makes possible, with minimal computational effort, the evaluation of the impact in actuator behaviour caused by the changes on the magnetic circuit geometries.

There has been widespread research in the area of sensorless rotor-position measurement in switched reluctance (SR) motor drives. However, there is still a lack of detailed stability and accuracy analysis for the sensorless SR drive system. In this paper, a sensorless rotor-position-measurement method for an SR motor drive is presented. The method is based on estimating a particular rotor position on a phase-by-phase basis and measuring the flux linkage and current when the estimated position is reached. By comparing the measured flux linkage with the pre-stored flux linkage corresponding to the particular position for the measured current, the angular difference between the estimated and particular positions can be calculated. The method is applied to two practical systems, the first being a 0.3-kW 10000-r/min three-phase 6/4 SR motor with a variable load, and the second being a 1-kW 1500-r/min three-phase 12/8 SR motor with a fan load. This paper examines the theoretical stability of the measurement and shows that measurement errors are not compounded and act as a variable disturbance to the system. The theoretical accuracy of the measurement is examined and shown to be acceptable.

In this paper, several techniques of the efficiency improvement of SRM drives are described. One of these improvements is the optimization of applied voltage waveform. Drive efficiency is further increased by application of new low-iron-loss materials such as Super E-Core brand steel strip. Another step of the efficiency improvement consists in optimization of components incurring iron and copper losses by using computer program PC-SRD. As a result, the highest efficiency level achieved in the study was 94.3%. © 2007 Wiley Periodicals, Inc. Electr Eng Jpn, 162(2): 73–82, 2008; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/eej.20523

In this paper, several techniques of the efficiency improvement of SRM drives are described. One of these improvements is the optimization of applied voltage waveform. Drive efficiency is further increased by application of new low-iron-loss materials such as Super E-Core brand steel strip. Another step of the efficiency improvement consists in optimization of components incurring iron and copper losses by using computer program PC-SRD. As a result, the highest efficiency level achieved in the study was 94.3%. © 2007 Wiley Periodicals, Inc. Electr Eng Jpn, 162(2): 73–82, 2008; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/eej.20523

This paper presents the development of a four-quadrant switched reluctance machine (SRM) drive for high dynamic applications. Comprehensive fundamentals and analysis for operating switched reluctance machines in four quadrants are presented. The drive is designed based on a high dynamic control strategy called Direct Instantaneous Torque Control (DITC). The functionality of DITC is discussed in detail for both motoring and generating operation. A methodology to generate switching functions directly by the hysteresis torque controllers for SRMs is proposed. The proposed controller was prototyped and tested on a digital signal processor/field-programmable gate array development platform. High dynamic operation in both motoring and generating mode and the transition between these modes are validated by experimental results presented at the end of this paper.

Design parameters and measured drive performance of a commercially manufactured Switched Reluctance Drive and an inverter-fed Induction Machine are compared. Both drives are designed for the same rated torque and speed and for identical cooling conditions, namely totally enclosed, fan-cooled machines. Measurements and calculation show that the main outer dimensions of both motors are nearly equal for comparable thermal utilisation. The Switched Reluctance drive delivers a higher efficiency, but also a considerably higher noise level due to several sharp resonances.

A 1 kW switched reluctance drive is presented. The author introduces an efficient power converter requiring a small number of switches. An analytical model of the interactive behavior of the motor and the power converter is developed, which shows the drive to be essentially torque controlled. In order to improve the efficiency of the power converter, the author applies premagnetization. The necessity of time-leading activation of the power switches at higher speeds is demonstrated, and the optimal time lead is calculated. The controllability of torque, the premagnetization principle, and the time lead are studied experimentally, and the results agree quite well with the theoretical model. >

This paper introduces a PC based educational tool for a switched reluctance drive (SRD) with fuzzy logic which is prepared for undergraduate and graduate level students. The paper first describes how the switched reluctance drive system works. Then details are given of how to estimate the flux linkage by using fuzzy set theory. Finally an application of fuzzy logic control to an SRM drive is presented.

Electric vehicles are the only alternative for a clean, efficient and environmentally friendly urban transport system. With the increasing interest in electric drives for electric vehicle propulsion. This paper first tries to explain why the switched reluctance drive is a strong candidate for electric vehicle applications. It then gives switched reluctance drive design guidelines for battery or fuel cell operated electric vehicles. Finally, it presents the design and simulation of a switched reluctance motor power train.

This book is a long-expected second part of the original textbook. It covers the following topics: Modern Electrical Drives; Modulation Techniques for Power Electronic Converters; Current Control of Generalized Load; Drive Principles?; Modeling and Control of DC Machines; Synchronous Machine Modeling Concepts; Control of Synchronous Machine Drives; Induction Machine Modeling Concepts; Control of Induction Machine Drives; and Switched Reluctance Drive Systems.