Book reviewPower sources for electric vehicles: studies inelectrical and electronic engineeringB.D. McNicol and D.A.J. Rand (Eds.)Elsevier Scientific Publishing Company, 1984, 1066 pp.,$211.50ISBN 0-444-42315X

The book is a large and comprehensive work with contri-butions from 21 authors who are clearly experts in thesubject matter covered.

The whole technology of electrochemical power sourcessuitable for electric road vehicles is covered in this onevolume. Balance and perspective is added to what is aspecialist subject by chapters covering the arguments forelectric vehicles, their history and potential future. Thisvolume is an essential 'read' for the scientist/engineerseeking a detailed knowledge of one or more of the multi-tude of alternative electrochemical systems that have beenresearched.

Interest in battery-powered electric vehicles has been re-awakened by factors such as the desire to reduce air pol-lution in industrialised countries and the increasing needto conserve valuable liquid fuels.

The book starts with a consideration of all the elementsthat have been raised in the electric vehicle debate, anddevelopment initiatives that have been taken place aroundthe world in recent years are described.

The world resource of primary energy and alternativeliquid fuels for transport is considered. It is concluded thatfuels which can be used in conventional motor vehicles willbe with us at a reasonable price, for many years to come.However, the methanol fuel cell, if successfully developed,may prove an attractive proposition for widescale use,though there are practical snags. It is recognised that theexisting internal combustion based infrastructure is enor-mous and this alone will make the acceptance of alterna-tives slow. Change may likely be faster in commercialtransport where the economic advantages of electric vehi-cles are thought to be clear.

Electric vehicles have been with us for longer than onemight think. Robert Davidson built a primary cell driven,reciprocating electric motor vehicle in 1837. Surprisinglylarge quantities of electric vehicles were built before 1900.Even more surprisingly, the first hybrid or mixed electricand internal combustion engined vehicle (ICEV) was con-structed in 1905.

The increased range offered by ICEVs, the introductionof electric starters and the high cost of providing batterycharging networks, it is claimed, hastened the demise ofthe battery electric vehicle in favour of ICEVs for generalpublic use. Only in recent times have the major advancesmade in electrochemical systems, combined with politicalthreats to oil supplies, changed the economic scene and,once again, made electric vehicles an attractive proposi-tion.

Since 1970, many countries have undertaken majorresearch programmes leading to the significant develop-ment of new electric drives and improved electrochemicalsources. 15 Chapters of this book, representing about 80%of the contents, are given to a detailed consideration of alltypes of battery and fuel cell which may be candidates astraction power sources. A whole chapter is given to theintroduction, history and general characteristics of electro-chemical cells as a precusor for the more detailed chaptersthat follow. The rechargable storage battery and the fuelcell are the basic electrochemical energy sources. They

differ fundamentally in that the storage battery requires asupply of electricity, whereas the fuel cell requires a fuelsupply.

It is possible that batteries were in use as early as 2000BC in the electroplating of metals. However, the firstrecorded observation of battery activity comes from Pro-fessor Luigi Galvani who stumbled across the electro-chemical battery when experimenting with frogs' legs. Heincorrectly interpreted what he observed and it was left toProfessor Allessandro Volta to correctly reason that elec-tricity flowed between two dissimilar metals when placedin a suitable conducting liquid. Thus, the primary cell wasdiscovered.

Michael Faraday placed the then new phenomenon ofelectrochemistry firmly on a quantitative basis and intro-duced the terms electrolyte, electrode, anode and cathode.Batteries quickly increased in sophistication until, in 1860,Plante demonstrated the first useful rechargable cell basedon lead electrodes and sulphuric acid electrolyte. Theoryfollowed practice in 1880.

Developments in the lead/acid battery system have con-tinued since that time and given us the efficient lead/acidbatteries that are in use today. Alkaline electrolyte systemsfollowed, leading to the commercial introduction of nickel/iron and nickel/cadmium cells from 1900 and 1909, respec-tively. Thomas Edison was much in evidence in the earlydevelopment of nickel/iron batteries.

For traction applications, energy density and specificrate of discharge are the important parameters. Thus,materials which favour these parameters are of majorinterest for traction battery systems. These include nickel/zinc, aluminium/air, iron/air, zinc/air, zinc/bromine, zinc/chlorine, lithium/sulphur and sodium/sulphur. Over 30different systems have been proposed for electric roadvehicles. However, only a few use materials that are plenti-ful and low in cost.

Fuel cell operation was known as early as 1839 andevolved from experiments by William Grove. Oxidation offuel at one electrode (anode) releases electrons which canperform work via an external conductor circuit connectedto a second electrode (cathode) at the surface of which anoxidant is reduced. The electrodes operate in an ion-conducting electrolyte.

The electrodes serve simply as conductor-electrolyteinterfaces and do not take part in electrochemical reac-tions in the manner of battery electrodes. Power is gener-ated, not stored, as long as fuel is supplied.

F.T. Bacon is considered to be the pioneer of modernfuel-cell research and he demonstrated 5 kW fuel-cellsystems for traction in 1979. Major growth in researchcame as a result of the US Gemini and Apollo prog-rammes.

Four types of fuel cell are currently under developmentfor energy conversion applications. Acid-electrolyte cellsappear good candidates for road vehicle applications.They operate in temperature range 6O-200°C.

The detailed treatment of specific secondary batterytypes starts with aqueous electrolyte batteries by D.Pavlov. A very detailed coverage of lead/acid battery tech-nology and traction cell design is covered in about 400pages of text with 342 references.

L. Ojefors presents nickel/zinc technology and J.McBreen, nickel/zinc. 'Metal/air systems' by F.G. Willreviews the major alternatives and presents details of zinc/air, iron/air and aluminium/air batteries. Zinc/halogen

346 IEE PROCEEDINGS, Vol. 132, Pt. B, No. 6, NOVEMBER 1985

systems, covered by R.J. Bellows and P.G. Grimes,includes zinc/bromine and zinc/chlorine batteries.

R.W. Glazebrook reviews non-aqueous, high tem-perature electrolyte technology including lithium alloy/metal sulphide and sodium/sulphur types. B.C.H. Steelepresents organoelectrolyte and solid state systems.

In the concluding chapter on secondary cell technology,D.A.J. Rand considers all the candidate systems. He con-cludes that it is not easy to pick a winner that would bethe optimum system for widespread use at this timebecause significant developments are still to be expected.

Fuel-cell systems are introduced with a chapter by P.Stonehart on acid systems. The direct methanol/air fuel-cell is reviewed by B.D. McNicol. E. Jennings Taylor andSupramaniam Spinivasin cover alkaline fuel-cell systems.

An overview of candidate fuel-cell systems by A.J.Appleby and P.N. Ross concludes that the most likelyfuture cells will be methanol and hydrogen based, but thatmajor breakthroughs are needed before fuel-cells can beconsidered for general transport use.

Hybrid fuel-cell/battery vehicles are considered by K.V.Kordesch and C.H. Fabjan.

The last three chapters of this major reference workcover laboratory testing of electric vehicle batteries (A.F.Burke), vehicle testing (A.F. Burke) and consideration ofwhat the future might hold (R.M. Dell).

G.B. SMITH

4183B

Power semiconductor drivesSB. Dewar, G.R. Sleman and A. StraughenWiley Interscience, 1985, 354 pp., £57.75ISBN 0-471-89831-7

A power semiconductor drive is a complex combination ofpower conditioning equipment, electromechanical energyconversion and external loading. The art of successfullyimplementing a drive appropriate to a particular situationis the interfacing of the three areas. This interfacing is aparticular strength of the present volume. The style isreadily assimilated and resembles the integrated presen-tation of the well-established volume, 'Electric machines'by Professors Sleman and Straughen. Prof. Dewar's exper-tise in power electronics lifts this book into the uniquecategory for comprehensiveness.

The book lays a firm foundation of basic dynamicsrelated to electrical drives. It is good to see the four-quadrant speed-torque diagram presented as a mechanicalsystem related to the dynamics of rotating systems. Loaddynamics are classified into typical systems, e.g. compres-sors, pumps, fans and traction (transportation) loads,winches and hoists. The required drive characteristics areused to define required speed changes and the systemspeed-time characteristic. Overall, this early Section is ofimmense value on its own. It presents simply and conciselyone of the 'grey' areas in the minds of many electrical engi-neers.

This fundamental system basis enables the power con-version function to be defined and an appropriate selection

of drive elements to be made. The reader can see broadlythat he needs a controlled rectifier, chopper, inverter orcycloconvertor before he investigates the detail of thepower electronic system.

DC power electronic equipment is developed very com-prehensively. The reader is led point by point throughseparately excited drives, series excited drives, full and half-wave conversion in controlled rectifiers to the nature of themotor, its time constants and ratings. Controlled rectifierswith motor loads are discussed in single- and 3-phaseinput terms. Regeneration and dynamic braking, electricalpower considerations, the generation of harmonics and theassociated heating of the motor are analysed.

Basic control system theory is briefly revised and blockdiagrams of motor and power electronics developedleading to the system transfer functions. Rectifier transferfunctions allowing for 'dead time' allow mathematicalmodels of the whole system to be derived.

The controlled rectifier DC drives lead into choppercontrolled DC drives. Class A and Class B choppers arepresented leading into four quadrant DC chopper drives.DC links and source-filter requirements broaden thepicture.

The latter part of the book on AC drives lacks the com-prehensiveness of the DC drive sections. A rather idealisedlumped parameter induction motor model is presented andan impression can be gained that harmonics are more of aproblem in DC drives than AC drives. However, powersemiconductor control in induction motor pump and fandrives with the comparison and contrast of voltage- andcurrent-source inverters is clear. An added bonus of com-prehensiveness is the discussion of slip-energy recoverysystems, synchronous and reluctance drives. The brushlessDC motor is an omission, but it might be derived from thesynchronous system.

The analysis of voltage and current waveforms ofpower-electronic convertors operating with rotatingmachines is well developed and comprehensive. It may notallow individual devices to be selected but it allows thesystem to be studied in depth.

Overall, this is not a book on power-electronic systemsas such. The reader will not be able to design a convertoror an inverter from the material presented. Pulse andtiming circuitry and protection is not discussed. It is pos-sible, however, to select an appropriate convertor relatedto the load requirement and to select the motor. This bookis unique, in my experience, in its comprehensiveness, andI commend it to professional engineers working in rotatingdrives. As a reference book for drive selection, it is invalu-able. I commend it to all libraries, public and personal andto all final year electrical engineering students working inthis area, if they can afford it.

Finally, the worked examples are based on real engin-eering situations, clearly presented and backed by manyother examples to which numerical answers are given.

Dr. P.G. HOLMES

4184B

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