Fuel Cell

24.6.3 Fuel Cell

TABLE 24.2

A comparison between different types of batteries for Due to high efficiency and low emissions, fuel cell systems UPS systems

have been gaining popularity in recent years. A fuel cell uses hydrogen as fuel and produces electricity, heat, and water from

Battery type Energy density

Power density

Commercial

the reaction between hydrogen and oxygen. Each cell consists

(WH/kg)

(W/kg)

availability

of an electrolyte and two electrodes as anode and cathode.

Lead-acid

Very mature and

Figure 24.17 shows the configuration of a typical fuel cell sys-

readily available

tem. There are different kinds of fuel cell system depending on

Nickel–cadmium

Mature and

the types of electrolyte and hydrogen sources. Some fuel cell

available

systems have an on-board fuel reformer and generate hydrogen

Nickel hydride

Available

from natural gas, methanol, and other hydrocarbons. Recent

Zinc-air 350

Research stage

technology development in this field has made fuel cells a more

Aluminum-air 400

10 Research stage

reliable and cost-effective alternative for batteries. Fuel cells

Sodium chloride 110

Available

currently have a variety of applications in automotive, electric

Sodium sulfur 170

Available

utility, and portable power industries. Table 24.3 provides a comparison between the most popular types of fuel cells.

Zinc bromine

Available

640 A. Nasiri

TABLE 24.3

A comparison between different types of fuel cell system Fuel cell type

Disadvantages Proton exchange

Applications

Advantages

• Expensive catalysts membrane (PEM)

• Electric utility

• Solid electrolyte reduces corrosion and

• High sensitivity to fuel impurities • Automotive

• Portable power

management problems

• Low temperature • Quick start-up

Alkaline (AFC) • Military

• Expensive removal of CO 2 from fuel and • Space

• High performance

air streams required Phosphoric acid

• Expensive catalysts (PAFC)

• Electric utility

• Up to 85% efficiency in cogeneration of

• Automotive

electricity and heat

• Low power

• Large size/weight Molten carbonate

• Can use impure H 2 as fuel

• High temperature enhances corrosion and (MCFC)

• Electric utility

• High efficiency

• Fuel flexibility

breakdown of cell components

• Can use a variety of catalysts

Solid oxide fuel cell • Electric utility

• High temperature enhances the (SOFC)

• High efficiency

• Fuel flexibility

breakdown of cell components

• Can use a variety of catalysts • Solid electrolyte reduces corrosion and

management problems • Low temperature • Quick start-up

Direct alcohol fuel cell • Automotive

• Lower efficiency (DAFC)

• Compactness

• Portable power

• High energy density

• Alcohol passing between electrodes with- out reacting

ELECTRIC 4. F. Kamran and T. G. Habetler, “A novel on-line UPS with universal LOAD

I LOAD

filtering capabilities,” IEEE Transactions on Power Electronics, vol. 13,

V LOAD

no. 2, pp. 366–371, 1998.

5. J. H. Choi, J. M. Kwon, J. H. Jung, and B. H. Kwon, “High- performance online UPS using three-leg-type converter,” IEEE Trans-

actions on Industrial Electronics, vol. 52, no. 3, pp. 889–897, FUEL

OXIDANT

(O 2 OR AIR)

6. H. Pinheiro, P. K. Jain, and G. Joos, “A comparison of UPS for powering hybrid fiber/coaxial networks,” IEEE Transactions on Power

EXHAUST

Electronics, vol. 17, no. 3, pp. 389–397, 2002. 7. I. Youichi, I. Satoru, T. Isao, and H. Hitoshi, “New power conversion technique to obtain high performance and high efficiency for single-

ANODE

phase UPS,” in Proc. 36th IEEE Industry Applications Conference, vol. 4, ELECTROLYTE

CATHODE

pp. 2383–2388, 2001.

FIGURE 24.17 Configuration of a typical fuel cell system. 8. H. Gueldner, H. Wolf, and N. Blacha, “Single phase UPS inverter with variable output voltage and digital state feedback control,” in Proc. IEEE International Symposium on Industrial Electronics, vol. 2, pp. 1089–1094, 2001.

Further Reading 9. J. Lee, Y. Chang, and F. Liu, “A new UPS topology employing a

PFC boost rectifier cascaded high-frequency tri-port converter,” IEEE Transactions on Industrial Electronics, vol. 46, no. 4, pp. 803–813,

1. S. Karve, “Three of a kind,” IEE Review, vol. 46, no. 2, pp. 27–31,

March 2000. 10. F. Kamran and T. G. Habetler, “A novel on-line UPS with universal 2. R. H. Carle, “UPS applications: mill perspective,” IEEE Industry

filtering capabilities,” IEEE Transactions on Power Electronics, vol. 13, Application Magazine, pp. 12–17, 1995.

no. 3, pp. 410–418, 1998.

3. R. Krishnan and S. Srinivasan, “Topologies for uninterruptible 11. B. Kwon, J. Choi, and T. Kim, “Improved single-phase line-interactive power supplies,” in Proc. IEEE International Symposium on Industrial

UPS,” IEEE Transactions on Industrial Electronics, vol. 48, no. 4, pp. Electronics, Hungary, pp. 122–127, June 1993.

24 Uninterruptible Power Supplies 641 12. A. Nasiri, S. Bekiarov, and A. Emadi, “Reduced parts three-phase

20. P. Mattavelli and W. Stefanutti, “Fully digital hysteresis modula- series-parallel UPS system with active filter capabilities,” in Proc. IEEE

tion with switching time prediction,” in Proc. 19th Applied Power 38th Industry Applications Conference, vol. 2, pp. 963–969, 2003.

Electronics Conference and Exposition, pp. 493–499, 2004. 13. S. da Silva, P. F. Donoso-Garcia, P. C. Cortizo, and P. F. Seixas, “A

21. P. Mattavelli, “An improved deadbeat control for UPS using distur- three-phase line-interactive UPS system implementation with series-

bance observers,” IEEE Transactions on Industrial Electronics, vol. 52, parallel active power-line conditioning capabilities,” IEEE Trans-

no. 1, pp. 206–212, 2005.

actions on Industry Applications, vol. 38, no. 6, pp. 1581–1590, 22. G. E. Valderrama, A. M. Stankovic, and P. Mattavelli, “Dissipativity- 2002.

based adaptive and robust control of UPS in unbalanced operation,” 14. A. Kuskoand and S. Fairfax, “Survey of rotary uninterruptible power

IEEE Transactions on Power Electronics, vol. 18, no. 4, pp. 1056–1062, supplies,” in Proc. 18th International Telecommunications Energy

Conference, pp. 416–419, 1996. 23. T. Tai and J. Chen, “UPS inverter design using discrete-time sliding- 15. A. Windhorn, “A hybrid static/rotary UPS system,” IEEE Transactions

mode control scheme,” IEEE Transactions on Industrial Electronics, on Industry Applications, vol. 28, no. 3, pp. 541–545, 1992.

vol. 49, no.1, pp. 67–75, 2002.

16. W. W. Hung and G. W. A. McDowell, “Hybrid UPS for standby 24. U. Burup, P. N. Enjeti, and F. Blaabjerg, “A new space-vector-based power systems,” Power Engineering Journal, vol. 4, no. 6, pp. 281–291,

control method for UPS systems powering nonlinear and unbalanced November 1990.

loads,” IEEE Transactions on Industry Applications, vol. 37, no. 6, 17. S. R. Bowes, “Advanced regular-sampled PWM control techniques for

pp. 1864–1870, 2001.

drives and static power converters,” IEEE Transactions on Industrial 25. N. M. Abdel-Rahim and J. E. Quaicoe, “Analysis and design of a mul- Electronics, vol. 42, no. 4, pp. 367–373, 1995.

tiple feedback loop control strategy for single-phase voltage-source 18. C. Rech, H. A. Grundling, and J. R. Pinheiro, “Comparison of dis-

UPS inverters,” IEEE Transactions on Power Electronics, vol. 11, no. 4, crete control techniques for UPS applications,” in Proc. IEEE Industry

pp. 532–541, 1996.

Applications Conference, pp. 2531–2537, 2000. 26. A. Nasiri and A. Emadi, “Digital control of a three-phase 19. J. Chen and C. Chu, “Combination voltage-controlled and current-

series-parallel uninterruptible power supply/active filter system,” in controlled PWM inverters for UPS parallel operation,” IEEE Transac-

Proc. IEEE 35th Annual Power Electronics Specialists Conference, tions on Power Electronics, vol. 10, no. 5, pp. 547–558, 1995.

pp. 4115–4120, 2004.

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Automotive Applications of Power Electronics

David J. Perreault

25.1 Introduction .......................................................................................... 643

Massachusetts Institute of Technology, Laboratory for

25.2 The Present Automotive Electrical Power System .......................................... 644

25.3 System Environment................................................................................ 644

Electromagnetic and Electronic

Systems, 77 Massachusetts 25.3.1 Static Voltage Ranges • 25.3.2 Transients and Electromagnetic Immunity Avenue, 10-039, Cambridge

• 25.3.3 Electromagnetic Interference • 25.3.4 Environmental Considerations Massachusetts, USA

25.4 Functions Enabled by Power Electronics...................................................... 649

Khurram Afridi

25.4.1 High Intensity Discharge Lamps • 25.4.2 Pulse-width Modulated Incandescent Lighting Techlogix, 800 West Cummings

• 25.4.3 Piezoelectric Ultrasonic Actuators • 25.4.4 Electromechanical Engine Valves Park, 1925, Woburn,

• 25.4.5 Electric Air Conditioner • 25.4.6 Electric and Electrohydraulic Power Steering Systems Massachusetts, USA

• 25.4.7 Motor Speed Control

Iftikhar A. Khan

25.5 Multiplexed Load Control ........................................................................ 652

Delphi Automotive Systems, 2705

25.6 Electromechanical Power Conversion.......................................................... 654

South Goyer Road, MS D35 25.6.1 The Lundell Alternator • 25.6.2 Advanced Lundell Alternator Design Techniques Kokomo, Indiana, USA

• 25.6.3 Alternative Machines and Power Electronics

25.7 Dual/High Voltage Automotive Electrical Systems ......................................... 660

25.7.1 Trends Driving System Evolution • 25.7.2 Voltage Specifications • 25.7.3 Dual-voltage Architectures

25.8 Electric and Hybrid Electric Vehicles .......................................................... 663

25.9 Summary .............................................................................................. 665 References ............................................................................................. 665

25.1 Introduction

of the architecture of the present automotive electrical power system. The next section, Section 25.3, describes the envi-

The modern automobile has an extensive electrical system ronmental factors, such as voltage ranges, EMI/EMC require- consisting of a large number of electrical, electromechani- ments, and temperature, which strongly influence the design of cal, and electronic loads that are central to vehicle operation, automotive power electronics. Section 25.4 discusses a number passenger safety, and comfort. Power electronics is playing an of electrical functions that are enabled by power electron- increasingly important role in automotive electrical systems – ics, while Section 25.5 addresses load control via multiplexed conditioning the power generated by the alternator, processing remote switching architectures that can be implemented with it appropriately for the vehicle electrical loads, and controlling power electronic switching. Section 25.6 considers the appli- the operation of these loads. Furthermore, power electronics cation of power electronics in automotive electromechanical is an enabling technology for a wide range of future loads with energy conversion, including power generation. Section 25.7 new features and functions. Such loads include electromag- describes the potential evolution of automotive electrical sys- netic engine valves, active suspension, controlled lighting, and tems towards high- and dual-voltage systems, and provides an electric propulsion.

overview of the likely requirements of power electronics in This chapter discusses the application and design of power such systems. Finally, the application of power electronics in electronics in automobiles. Section 25.2 provides an overview electric and hybrid electric vehicles is addressed in Section 25.8.

644 D. J. Perreault et al.

Relay Alternator

Battery

Primary Fusebox Switches Loads

FIGURE 25.1 The 12-V point-to-point automotive electrical power system.

25.2 The Present Automotive Electrical

static and transient voltage ranges, electromagnetic interfer-

Power System

ence and compatibility requirements (EMI/EMC), mechanical vibration and shock, and temperature and other environmen-

Present-day automobiles can have over 200 individual electri- tal conditions. This section briefly describes some of the factors cal loads, with average power requirements in excess of 800 W. that most strongly affect the design of power electronics for These include such functions as the headlamps, tail lamps, automotive applications. For more detailed guidelines on the cabin lamps, starter, fuel pump, wiper, blower fan, fuel injector, design of electronics for automotive applications, the reader is transmission shift solenoids, horn, cigar lighter, seat heaters, referred to [1, 3–16] and the documents cited therein, from engine control unit, cruise control, radio, and spark ignition. which much of the information presented here is drawn. To power these loads, present day internal combustion engine (ICE) automobiles use an electrical power system similar to the

25.3.1 Static Voltage Ranges

one shown in Fig. 25.1. Power is generated by an engine-driven In most present-day automobiles, a Lundell-type alternator three-phase wound-field synchronous machine – a Lundell provides dc electrical power with a lead-acid battery for (claw-pole) alternator [1, 2]. The ac voltage of this machine is energy storage and buffering. The nominal battery voltage rectified and the dc output regulated to about 14 V by an elec- is 12.6 V, which the alternator regulates to 14.2 V when the tronic regulator that controls the field current of the machine. engine is on in order to maintain a high state of charge on The alternator provides power to the loads and charges a 12 V the battery. In practice, the regulation voltage is adjusted for lead-acid battery. The battery provides the high power needed temperature to match the battery characteristics. For exam- by such loads as the starter, and supplies power when the

C regulation voltage of 14.5 V is specified engine is not running or when the demand for electrical power

ple, in [1], a 25 ◦

exceeds the output power of the alternator. The battery also with a −10 mV/

C adjustment. Under normal operating con- acts as a large capacitor and smoothes out the system voltage. ditions, the bus voltage will be maintained in the range of

Power is distributed to the loads via fuses and point-to-point 11–16 V [3]. Safety-critical equipment is typically expected to wiring. The fuses, located in one or more fuseboxes, protect

be operable even under battery discharge down to 9 V, and the wires against overheating and fire in the case of a short. equipment operating during starting may see a bus voltage as

Most of the loads are controlled directly by manually actuated low as 4.5–6 V under certain conditions. mechanical switches. These primary switches are located in

In addition to the normal operating voltage range, a wider areas in easy reach of either the driver or the passengers, such range of conditions is sometimes considered in the design of

as the dashboard, door panels, and the ceiling. Some of the automotive electronics [3]. One possible condition is reverse- heavy loads, such as the starter, are switched indirectly via polarity battery installation, resulting in a bus voltage of

electromechanical relays. −12 V. Another static overvoltage condition can

approximately

occur during jump starting from a 24-V system such as on a tow truck. Other static overvoltage conditions can occur due to failure of the alternator voltage regulator. This can result in a bus voltage as high as 18 V, followed by battery electrolyte boil-

25.3 System Environment

off and a subsequent unregulated bus voltage as high as 130 V. Typically, it is not practical to design the electronics for oper-

The challenging electrical and environmental conditions found ation under such an extreme fault condition, but it should in the modern automobile have a strong impact on the design

be noted that such conditions can occur. Table 25.1 summa- of automotive power electronic equipment. Important factors rizes the range of static voltages that can be expected in the affecting the design of electronics for this application include automotive electrical system.

25 Automotive Applications of Power Electronics 645 TABLE 25.1 Static voltage range for the automotive

SAE J1113/11 [4, 6] and DIN 40389 [1]. Table 25.3 illustrates electrical system [3]

the transient test pulses specified in SAE J1113/11. Each test

pulse corresponds to a different type of transient. The vehicle manufacturer determines which test pulses apply to a specific

Static voltage condition

Voltage

Nominal voltage with engine on

14.2 V

device.

Nominal voltage with engine off

12.6 V

Transients occur when inductive loads such as solenoids,

Maximum normal operating voltage

16 V

9V motors, and clutches are turned on and off. The transients

Minimum normal operating voltage

Minimum voltage during starting

4.5 V

can be especially severe when the bus is disconnected from the

Jump start voltage

24 V

battery, as is the case for the accessory loads when the ignition

Reverse battery voltage

−12 V

is switched off. Test pulse 1 in Table 25.3 simulates the transient

Maximum voltage with alternator regulator

130 V

generated when an inductive load is disconnected from the

failure followed by battery failure

battery and the device under test remains in parallel with it. When the inductive load is a dc motor, it may briefly act as

a generator after disconnection. This transient is simulated by

25.3.2 Transients and Electromagnetic

test pulse 2b. Test pulse 2a models the transient when current

Immunity

in an inductive element in series with the device under test is interrupted. Test pulses 3a and 3b model switching spikes

Power electronic circuits designed for automotive applications that appear on the bus during normal operation. Test pulse 4 must exhibit electromagnetic compatibility, i.e. the conducted models the voltage transient that occurs on starting. and radiated emissions generated by the circuit must not

Perhaps the best-known electrical disturbance is the interfere with other equipment on board the vehicle, and the so-called load dump transient that occurs when the alterna- circuit must exhibit immunity to radiated and conducted dis- tor load current drops sharply and the battery is unable to turbances. The Society of Automotive Engineers (SAE) has properly buffer the change. This can occur when the battery laid out standards and recommended practices for the elec- becomes disconnected while drawing a large amount of cur- tromagnetic compatibility of automotive electronics in a set rent. To understand why a major transient can occur under this of technical reports [4]. These reports are listed in Table 25.2. situation, consider that the Lundell-alternator has a very large Here we will focus on two of the basic requirements of auto- leakage reactance. The high commutating reactance interacting motive power electronics: immunity to power lead transients with the diode rectifier results in a high degree of load regula- and limitation of conducted emissions.

tion, necessitating the use of a large back emf to source rated

A major consideration in the design of an automotive power current at high speed [7]. Back voltages as high as 120 V may electronic system is its immunity to the transients that can

be needed to generate rated current into a 14 V output at top appear on its power leads. A number of transient sources exist speed. Analytical modeling of such systems is addressed in [8]. in the vehicle [5] and procedures for validating immunity to Two effects occur when the load on the alternator suddenly these transients have been established in documents such as steps down. First, as the machine current drops, the energy

TABLE 25.2 SAE J1113 electromagnetic compatibility technical reports SAE specification

Type

Description

SAE J1113/1 Standard Electromagnetic compatability measurement procedures and limits, 60 Hz–18 GHz SAE J1113/2

Standard

Conducted immunity, 30 Hz–250 kHz

SAE J1113/3 Standard

Conducted immunity, direct injection of RF power, 250 kHz–500 MHz

SAE J1113/4 Standard

Conducted immunity, bulk current injection method

SAE J1113/11 Standard

Conducted immunity to power lead transients

SAE J1113/12 Recommended practice

Electrical interference by conduction and coupling – coupling clamp

SAE J1113/13 Recommended practice

Immunity to electrostatic discharge

SAE J1113/21 Information report Electrical disturbances by narrowband radiated electromagnetic energy – component test methods SAE J1113/22

Standard

Immunity to radiated magnetic fields from power lines

SAE J1113/23 Recommended practice Immunity to radiated electromagnetic fields, 10 kHz–200 MHz, strip line method SAE J1113/24

Immunity to radiated electromagnetic fields, 10 kHz–200 MHz, TEM cell method SAE J1113/25

Standard Immunity to radiated electromagnetic fields, 10 kHz–500 MHz, tri-plate line method SAE J1113/26

Recommended practice

Immunity to ac power line electric fields

SAE J1113/27 Recommended practice

Immunity to radiated electromagnetic fields, reverberation method

SAE J1113/41 Standard

Radiated and conducted emissions, 150 kHz–1000 MHz

SAE J1113/42 Standard

Conducted transient emissions

646 D. J. Perreault et al. TABLE 25.3 Transient pulse waveforms specified in SAE J1113/11

Pulse

Shape

Maximum excursion

Source impedance

Duration and repetition rate

−100 V

T pulse = 2 ms 0.5 s < T rep < 5s

2a v

100 V

T pulse = 50 µs 0.5 s < T rep < 5s

2b v

10 V

T pulse ≥ 200 ms

3a v

−150 V

T pulse = 100 ns

T pulse = 100 ns T rep = 100 µs

4 −7 V

T pulse ≤ 20 s

84 A

τ = 115 ms T pulse ∼ 4τ

in the alternator leakage reactances is immediately delivered to protection, a load dump can generate a transient with a peak the alternator output, causing a voltage spike. The peak voltage voltage in excess of 100 V lasting hundreds of milliseconds. reached depends on the electrical system impedance, and may Test pulse 5 in Table 25.3 (expressed as a current waveform in

be limited by suppression devices. Second, once the alternator parallel with an output resistance) is designed to simulate such current is reduced, the voltage drops across the leakage (com-

a load-dump transient; other load-dump tests are even more mutating) reactances are reduced, and a much larger fraction severe [1, 3]. of the machine back-emf is impressed across the dc output. The proper output voltage is only re-established as the voltage