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Preface

Power electronics deals with applications of solid-state electronics for controlling and converting electrical current. Mazen Abdel-Salam, King Fahd University of Petroleum and Minerals, Saudi Arabia Muhammad Sarwar Ahmad, Azad Jammu and Kashmir University, Pakistan Eyup Akpnar, Dokuz Eylül Üniversitesi Mühendislik Fakültesi, BUCA-IZMIR, Turkey.

TAblE P.2 Suggested Topics for One-Semester Course on Power Electronics and Motor Drives
TAblE P.2 Suggested Topics for One-Semester Course on Power Electronics and Motor Drives

He received the 2002 IEEE Educational Activity Award (EAB), Meritorious Achievement Award in Continuing Education with the citation "for contributions to the design and delivery of continuing education in power electronics and computer-aided simulation." He is the recipient of the 2008 IEEE Undergraduate Teaching Award with the citation "For his distinguished leadership and dedication to quality undergraduate electrical engineering education, motivating students, and publishing excellent textbooks." He is series editor of Power Electronics and Applications and Nanotechnology and Applications with CRC Press.

Introduction

Power electronics can be defined as the application of solid-state electronics to the control and conversion of electrical current. Modern power electronics equipment uses (1) power semiconductors that can be considered the muscle, and (2) microelectronics that have the power and intelligence of a brain.

TAble 1.1 Some Applications of Power Electronics Advertising
TAble 1.1 Some Applications of Power Electronics Advertising

Research and development of energy-efficient cars will also lead to greater use and development of power electronics. This is the beginning of the third power electronics revolution in renewable energy processing and energy saving worldwide.

FIgure 1.2 History of power electronics. (Courtesy of Tennessee Center for Research and Development, a University of Tennessee Affiliated Center.)
FIgure 1.2 History of power electronics. (Courtesy of Tennessee Center for Research and Development, a University of Tennessee Affiliated Center.)

When transistor Q1 is turned on by applying a gate voltage VGE, the dc supply is connected to the load and the instantaneous output voltage is vo = +Vs. When MOSFETs M1 and M2 are turned on by applying gate voltages, the dc supply voltage Vs appears across the load and the instantaneous output voltage is vo = +Vs.

FIgure 1.4 Dc–dc converter.
FIgure 1.4 Dc–dc converter.

DesIgn of power eleCtronICs equIpment

The DC-AC converter supplies emergency power to the load via an isolation transformer. The input voltage to a rectifier circuit can be a single-phase or a three-phase supply.

DetermInIng the root-mean-square Values of waVeforms

If a waveform can be broken down into harmonics whose RMS values ​​can be calculated separately, the RMS values ​​of the actual waveform can be satisfactorily approximated by combining the RMS values ​​of the harmonics. Irms(1) and Irms(n) are the rms values ​​of the fundamental and nth harmonic components, respectively.

  • Ideal Characteristics

In the on state when the switch is turned on, it must (a) have the ability to carry a high forward current IF, tending to infinity; (b) a low forward voltage drop VON in the on state, tending to zero; and (c) a low resistance RON in the on state, tending to zero. Turning on and off requires (a) a low gate drive power PG, tending to zero; (b) a low gate drive voltage VG, tending to zero; and (c) a low gate drive current IG, tending to zero.

Figure 1.12 shows the block diagram of a typical power converter including isola- isola-tions, feedback, and reference signals [9]
Figure 1.12 shows the block diagram of a typical power converter including isola- isola-tions, feedback, and reference signals [9]

It should only require a pulse signal to turn on and off, that is a small pulse with a very small width tw that tends to zero. The ability to maintain any fault current for a long time is required; that is, it must have a high value of i2t that tends to infinity.

Negative temperature coefficient on the conducted current is required to result in an equal current sharing when the devices are operated in parallel

Thus, it must have (a) a low delay time td, tending to zero; (b) a low rise time tr, tending to zero; c) a low storage time ts, tending to zero; and (d) a low fall time tf, tending to zero. It requires a very low thermal impedance from the internal junction to the ambient RIA, tending to zero, so that it can easily transfer heat to the environment.

Low price is a very important consideration for reduced cost of the power elec- tronics equipment

  • Characteristics of practical Devices
  • switch specifications
  • power semIConDuCtor DeVICes
  • Control CharaCterIstICs of power DeVICes
  • DeVICe ChoICes
  • power moDules
  • IntellIgent moDules
  • power eleCtronICs Journals anD ConferenCes

Check that the TRIAC can match the voltage, current and frequency of the intended applications. Power Devices www.hitachi.co.jp/pse Honda R&D Co Ltd http://world.honda.com Infineon Technologies www.infineon.com/.

Figure 1.15 shows the power range of commercially available power semiconduc- semiconduc-tors
Figure 1.15 shows the power range of commercially available power semiconduc- semiconduc-tors

Power Diodes and rectifiers

IntroDuCtIon

Power diodes play a significant role in power electronics circuits for converting electrical power. Inductors L and capacitors C, which are the energy storage elements, are commonly used in power electronic circuits.

SemIConDuCtor BaSICS

When the anode potential is positive relative to the cathode, the diode is said to be forward biased and the diode is conducting. When the cathode potential is positive relative to the anode, the diode is said to be reverse biased.

TaBle 2.1 A Portion of the Periodic Table Showing Elements Used in Semiconductor Materials Group
TaBle 2.1 A Portion of the Periodic Table Showing Elements Used in Semiconductor Materials Group

For practical purposes, one should be concerned with the total recovery time trr and the peak value of the reverse current IRR. Its value is determined from the area enclosed by the reverse recovery current curve. The reverse recovery time of a diode is trr = 3 μs and the rate of decline of the diode current is di/dt = 30 A/μs.

  • General-purpose Diodes
  • Fast-recovery Diodes
  • Schottky Diodes

The charge storage problem of a p-n junction can be eliminated (or minimized) in a Schottky diode. The charge recovered from a Schottky diode is much less than that from an equivalent p-n junction diode. A Schottky diode with a relatively low conduction voltage has a relatively high leakage current, and vice versa.

Figure 2.4 shows various configurations of general-purpose diodes, which basi- basi-cally fall into two types
Figure 2.4 shows various configurations of general-purpose diodes, which basi- basi-cally fall into two types

SIlICon CarBIDe DIoDeS

The corrective action depends only on the majority companies and as a result there are no excess minority companies to recombine. Because it is only due to the junction capacitance, it is largely independent of the inverse di/dt. Depending on the switching recovery time and the on-state drop, the current diodes are of three types: general purpose, fast recovery and Schottky.

SIlICon CarBIDe SChottky DIoDeS

SpICe DIoDe moDel

When the switch S1 is closed at t = 0, the current i through the inductor increases and is expressed as. We must note that at the moment when the switch is closed at t = 0, the current is zero and the voltage across the resistor R is zero. At t = 0 + (after a finite time at the start of the clock after zero) the switch has just closed and the current is still zero.

Figure 2.23 Plots for Example 2.7.
Figure 2.23 Plots for Example 2.7.
  • reCovery oF trappeD enerGy wIth a DIoDe

If the switch S1 is closed at t = 0, determine the expression for the voltage across the capacitor and the energy lost in the circuit. If switch S1 is closed at t = 0, determine (a) the steady-state diode current, (b) the energy stored in the inductor L, and (c) the initial di/dt. If switch S1 is closed at t = 0, determine (a) the steady-state diode current, (b) the energy stored in the inductor L, and (c) the initial di/dt.

Diode rectifiers

IntroDuCtIon

Depending on the type of input supply, the rectifiers are classified into two types: (1) single phase and (2) three phase. A single-phase half-wave rectifier is the simplest type, but it is not normally used in industrial applications. By "ideal" we mean that the reverse recovery time trr and the forward voltage drop VD are negligible.

It is the conversion efficiency that is a measure of the quality of the output waveform. The shape factor, which is a measure of the shape of the output voltage, is FF = Vrms. The ripple factor, which is a measure of the ripple content, is defined as RF = Vac.

The output voltage is discontinuous and contains harmonics at multiples of the supply frequency. Some of the advantages and disadvantages for the circuits in Figures 3.2 and 3.3 are listed in Table 3.1. Although an input-side transformer is not needed for rectifier operation, it is usually connected to isolate the electrical load from the supply.

Table 3.1 Advantages and Disadvantages of Center-Tapped and Bridge Rectifiers
Table 3.1 Advantages and Disadvantages of Center-Tapped and Bridge Rectifiers

The plot of the voltage ratio x against the load impedance angle θ is shown in Figure 3.5. The waveforms for the rectifier input current and input voltage are shown in Figure 3.9b. The power factor will depend on the load inductor and the amount of distortion of the input current.

Table 3.2 Variations of Angle β with the Voltage Ratio, x
Table 3.2 Variations of Angle β with the Voltage Ratio, x

The reverse peak voltage of each diode is equal to the maximum value of the line-to-line secondary voltage. The waveforms for the q-pulses are shown in Figure 3.10b and the output frequency is q times the fundamental component (qf). To find the Fourier series constants, we integrate from -π/q to π/q and the constants are.

FiguRe 3.10 Multiphase rectifiers.
FiguRe 3.10 Multiphase rectifiers.

If Vm is the peak value of the phase voltage, then the instantaneous phase voltages can be described by. A three-phase bridge rectifier has a purely resistive load of R. 3.36), the rms current of the transformer secondary,. Note: This rectifier has significantly improved performance over that of the six-pulse multiphase rectifier in Figure 3.10.

The plot of the voltage ratio x versus the load resistance angle θ is shown in figure 3.14. A single-phase bridge rectifier is supplied from a 120 V, 60 Hz source. a) Design a C filter so that the ripple factor of the output voltage is less than 5%. The rms value of the nth harmonic current appearing in the supply is obtained using the current-divider rule,

Table 3.3 Advantages and Disadvantages of Single Phase and Three-Phase Bridge Rectifiers
Table 3.3 Advantages and Disadvantages of Single Phase and Three-Phase Bridge Rectifiers

Because the average voltage of the rectifier is Vdc = 2 Vm/π, the average current is equal to For a continuous current through the inductor, the value of Le must be greater than the value of Lcr. With a high value of output filter capacitance Ce, the output voltage remains almost constant.

Table 3.6 shows the values of k(x) and k r (x) against the voltage ratio x.
Table 3.6 shows the values of k(x) and k r (x) against the voltage ratio x.
  • aC film Capacitors
  • Ceramic Capacitors
  • aluminum electrolytic Capacitors
  • solid tantalum Capacitors
  • supercapacitors

Determine the effect of the inverse recovery time on the average output voltage if the supply frequency is (a) fs = 2 kHz and (b) fs = 60 Hz. Calculate (a) the conduction angle δ of the diode, (b) the current-limiting resistance R, (c) the power rating PR for R, (d) the charging time ho in hours, (e) the rectifier efficiency η, and (f) the peak inverse voltage (PIV ) diodes. Calculate (a) the conduction angle δ of the diode, (b) the current-limiting resistor R, (c) the power rating PR of R, (d) the charge time ho in hours, (e) the efficiency of the rectifier j, and (f) the PIV of the diode.

FiguRe 3.27 Equivalent circuit.
FiguRe 3.27 Equivalent circuit.

Power transistors

IntroduCtIon

However, their voltage and current ratings are lower than those of thyristors, and transistors are usually used in low to medium power applications. With the development of power semiconductor technology, the ratings of power transistors are continuously improved. The gating circuit is an integral part of a power converter consisting of power semiconductor devices.

SIlICon CarbIde tranSIStorS

  • Steady-State Characteristics
  • Switching Characteristics
  • Silicon Carbide MoSFets

With a p-channel depletion-type MOSFET, the polarities of V , I , and V are reversed, as shown in Figure 4.1b. The load line of a MOSFET with a load resistance RD as shown in Figure 4.7a can be described by. Therefore, a MOSFET can be considered to have an internal diode, and the equivalent circuit is shown in Figure 4.8b.

Figure 4.6 shows the output characteristics of an n-channel enhancement MOSFET
Figure 4.6 shows the output characteristics of an n-channel enhancement MOSFET

CoolMoS

  • operation and Characteristics of JFets
  • Silicon Carbide JFet Structures

When the drain-to-source voltage is near zero, the depletion region formed between the p-type and n-type regions would have a nearly uniform width along the length of the channel, as shown in Figure 4.19a. Increasing the vDS above the breakdown voltage of the JFET causes an avalanche breakdown and the drain current rises rapidly. One of the modern designs of the SiC JFET is the so-called lateral channel JFET, as shown in Figure 4.21 [43].

FIgure 4.18 Biasing of JFETs.
FIgure 4.18 Biasing of JFETs.
  • Steady-State Characteristics
  • Switching Characteristics
  • Switching limits
  • Silicon Carbide bJts

Although there are three possible configurations—common collector, common base, and common emitter—the common emitter configuration, shown in Figure 4.28a for an NPN transistor, is generally used in switching applications. The base current is actually the input current and the collector current is the output current. The collector current has two components: one due to the base current and the other is the CBJ leakage current.

Figure 4.34a shows the extra storage charge in the base of a saturated transistor.
Figure 4.34a shows the extra storage charge in the base of a saturated transistor.

IGbtS

  • Silicon Carbide IGbts

The structure, dimensions, and concentrations of the n+ and p+ layers will determine the BJT's characteristics, such as rated voltage and current. In the NPT structure, the carrier lifetime is maintained longer than in the PT structure, resulting in conduction modulation of the drift region and reducing the on-state voltage drop. The structure, dimension and concentrations of the n+ and p+ layers will determine the characteristics of the IGBT such as voltage and current.

SItS

CoMparISonS oF tranSIStorS

Gambar

TAblE P.1 Suggested Topics for One-Semester Course on Power Electronics
TAblE P.2 Suggested Topics for One-Semester Course on Power Electronics and Motor Drives
TAble 1.1 Some Applications of Power Electronics Advertising
TAble 1.1 (Continued)
+7

Referensi

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DeVICe ChoICes SemIConDuCtor BaSICS SpICe DIoDe moDel Steady-State Characteristics Switching Characteristics IGbtS

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