Boldea Ion - Reluctance electric machines: design and control

Reluctance Electric Machines

Design and Control

Reluctance Electric Machines

Design and Control

Ion Boldea

Lucian Tutelea

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Library of Congress Cataloging-in-Publication Data

Names: Boldea, I., author. | Tutelea, Lucian, author.

Title: Reluctance electric machines : design and control / Ion Boldea and Lucian Tutelea.

Description: Boca Raton : Taylor & Francis, a CRC title, part of the Taylor & Francis imprint, a member of the Taylor & Francis Group, the academic division of T&F Informa, plc, 2018. | Includes bibliographical references.

Identifiers: LCCN 2018010557| ISBN 9781498782333 (hardback : acid-free paper) | ISBN 9781498782340 (ebook)

Subjects: LCSH: Reluctance motors--Design and construction. | Electric motors--Electronic control.

Classification: LCC TK2781 .B65 2018 | DDC 621.46--dc23

LC record available at https://lccn.loc.gov/2018010557

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Contents

Electric energy is arguably a key agent for our material prosperity. With the notable exception of photovoltaic generators, electric generators are exclusively used to produce electric energy from mechanical energy. Also, more than 60% of all electric energy is used in electric motors for useful mechanical work in various industries.

Renewable energy conversion is paramount in reducing the CO quantity per kWh of electric energy and in reducing the extra heat on Earth.

Electrical permanent magnet machines developed in the last two decades with torques up to the MNm range are showing higher efficiency for smaller weights. However, the temptation to use them in all industriesfrom wind and hydro generators; to ships, railroad, automotive, and aircraft propulsion (integral or assisting); to small electric drives in various industries with robotics, home appliances, and info-gadgets has led recently to a strong imbalance between highspecific energy magnet demand and supply, which has been solved so far mainly by stark increases in the price of high-quality permanent magnets (PMs).

In an effort to produce high-performance electric motors and generators, as well as drives for basically all industries, but mainly for renewable energy conversion, electric mobility, robotics and so on, the variable reluctance concept in producing torque in electric machines, eventually assisted by lower-total-cost PMs, has shown a spectacular surge in research and development (R&D) worldwide in the last two decades.

The extension of electric machines to lower-speed applicationswith less or no mechanical transmissionin an effort to keep performance high but reduce initial and maintenance costs has found a strong tool in the variable reluctance concept; it aims to produce electromagnetic torque (and power) by creating strong magnetic anisotropies in electric machines (rather than by PM- or direct current (DC)-excited or induced-current rotors).

Though the principle of the variable reluctance motor was patented in the late nineteenth century, it was not until power electronics developed into a mature industry in the 1970s that reluctance electric machines became a strong focus point in R&D and industry. Delayed by the spectacular advent of PM electric machines for a few decades, only in the last 10 years have reluctance electric machines enjoyed increased attention.

Very recently, such reluctance synchronous motor drives for variable speeds have reached mass production from 10 kW to 500 kW.

Given the R&D results so far and the current trends in the industry, reluctance electric machines and drives are expected to penetrate most industries.

Because of this, we believe an overview of recent progress with classifications, topologies, principles, modeling for design, and control is timely, and this is what the present monograph intends to do.

After an introductory chapter (), the book is divided into two parts:

Part 1. One- and three-phase reluctance synchronous motors in line-start (constant speed) and then in variable-speed applications, with PM assistance to increase efficiency at moderate extra initial cost and in variable-speed drives ().

Part 2. Reluctance motors and generators in pulse width modulation (PWM) converter-fed variable speed drives, where high efficiency at a moderate power factor and moderate initial system and ownership costs are paramount ().

Part 2 includes a myriad of topologies under the unique concept of flux modulation and includes:

Claw pole rotor synchronous motors,

Brushless DCmultiple phase reluctance machines (BLDC-MRMs),

Brushless doubly fed reluctance machines (BDFRMs),

Switched flux PM synchronous machines (SF-PMSMs),

Flux reversal PMSMs (FR-PMSMs),

Vernier PM machines,

Transverse-flux PMSMs (TF-PMSMs),

Magnetic-gear dual-rotor reluctance electric machines (MG-REMs),

DC+alternating current (AC) doubly salient electric machines,