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YayınlayanAltincicek Akkoz Değiştirilmiş 2 yıl önce

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Güç Elektroni ğ i Ocak 2012, Yalova Yalova Üniversitesi | Enerji Sistemleri Mühendisliği| Yrd. Doç. Dr. Kayhan INCE

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Study Groups I recommend You need to install MATLAB/SIMULINK in your Laptops Project: Design of DC-DC Converter using MATLAB/SIMULINK Textbook: Digital Power Electronics and applications Fang Lin Luo Hong Ye Muhammed Rashid

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Projects Ders dönemi boyunca öğrenciler aşağıdaki konuyu Matlab ortamında simule edeceklerdir. Final tarihine kadar projelerini bitirmeleri gerekmektedir. DC-DC Konvertör tasarımı (MATLAB / SIMULINK) (Buck, boost, buck-boost)

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Projects

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EMI and Layout Fundamentals EMI (Electromagnetic Interference) is the unwanted coupling of signals from one circuit or system to another Conducted EMI: unwanted coupling of signals via conduction through parasitic impedances, power and ground connections Radiated EMI: unwanted coupling of signals via radio transmission These effects usually arise from poor circuit layout and unmodeled parasitic impedances Analog circuits rarely work correctly unless engineering effort is expended to solve EMI and layout problems Sooner or later, the engineer needs to learn to deal with EMI The ideal engineering approach: – figure out what are the significant EMI sources – figure out where the EMI is going – engineer the circuit layout to reduce EMI problems Build a layout that can be understood and analyzed

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EMI and Layout Fundamentals Wires are perfect (equipotential) conductors This assumption ignores wire resistance wire inductance mutual inductance with other conductors

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EMI and Layout Fundamentals The space surrounding a wire is a perfect insulator (dielectric constant = 0) This assumption ignores capacitance between conductors

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EMI and Layout Fundamentals The ground (reference) node is at zero potential

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About inductance of wires Single wire in space Larger wire has lower inductance, because B-field must take longer path length around wire

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EMI and Layout Fundamentals A more realistic scenario: current flows around a closed loop

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Example: Buck converter switched input current i1(t) contains large high frequency harmonics hence inductance of input loop is critical inductance causes ringing, voltage spikes, switching loss, generation of B- and E fields, radiated EMI the second loop contains a filter inductor, and hence its current i2(t) is nearly dc hence additional inductance is not a significant problem in the second loop

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EMI and Layout Fundamentals Parasitic inductances of input loop explicitly shown: Addition of bypass capacitor border the pulsating current to a smaller loop: high frequency currents are shunted through capacitor instead of input source

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EMI and Layout Fundamentals Even better: minimize area of the high frequency loop, thereby minimizing its inductance

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Electronics information ElectronicsPower electronics measurement data Technology control Engineering rectifiers AC-DC inverters DC-AC converter AC-AC / DC-DC digital technologyanalog technology Çevirici Tipleri 1. AC - DC (denetimsiz) 2. AC - DC (denetimli) 3. DC - DC (izole edilmemiş) 4. DC - DC (izole edilmiş) 5. DC - AC 6. Sert ve yumuşak anahtarlamalı 8. AC – AC

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1.Diode (1940) polariteye bağlı iletkenlik, en çok kullanılan yarı- iletken, Üretici: Tüm yarı-iletken üreticileri 2.Transistor (bipolar) (1948) lassen sich im Vergleich zur Diode mit Hilfe eines Steueranschlusses ein– und ausschalten, Hersteller siehe Dioden 3.Transistor (Feldeffekt) (1969) typ.: Kesim gerilimi 200 V, Akım 100 A, açılabilir ve kapanabilir, Üretici : Siemens, Semikron, 1980’den beri MOSFET in olarak bilinmektedir 4.Thyristor (1958)Kesim gerilimi 5500 V, Akım 3000 A, sadece açılabilir Üretici: ABB (IGCT), Siemens, GTO (1975) Kesim gerilimi 4500 V, Akım 3000 A, açılabilir ve kapanabilir, Üretici: Toshiba, ABB,... 6.IGBT (1987) Kesim gerilimi 3300 V, Akım 1200 A, açılabilir ve kapanabilir, Üretici : eupec, Semikron, ABB, Fuji,... 7.TRIAC Kesim gerilimi V, Akım A, paralel bağlı 2 adet tristör, Üretici: ABB, Siemens,.... Switches

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ANAHTARLAMA ELEMANLARININ ANMA DEĞERLERİ ElemanTipiAnma Gerilimi (V) Anma Akımı (A) Üst Frekans (Hz) Anahtarlama zamanı ( s) İ letim Direnci ( ) Do ğ rultucu Genel Amaçlı k1000,16 m Yüksek Hızlı k2-51 m Schottky k0,2310 m Kesime götürülen Tristörler Ters Tıkama k2000,25 m Yüksek Hızlı k200,47 m Ters Tıkama k402,16 m Ters İ letim k402,1 m GATT k82,24 m Işık tetiklemeli ,53 m Triyaklar ,57 m Kendili ğ inden kesilen tristörler GTO k152,5 m SITH k6,55,75 m Güç transistörleri Tek k94 m k631 m k1,715 m Darlington k3010 m SIT k0,551,2 Güç MOSFETleriTek5008,6100 k0,70, ,7100 k0, k0,60,4 m IGBTTek k2,360 m MCTTek k2,218 m

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Metals and Semiconductors Solids in which the outermost atomic electrons are free to move around are metals Metals typically have ~ 1 “free electron” per atom ~5 ×10 22 free electrons per cubic cm Electrons in semiconductors are not tightly bound, nor are they free, but can be easily “promoted” to a free state Quartz, SiO 2 insulators metalssemiconductors Si, GaAsAl, Cu poor conductors excellent conductors

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Semiconductors General The electrical conductivity of a substance is primarily dependent on the number of free charge carriers. The electricity is transported by free electrons. Those electrons that are removed from the core farthest are called valence electrons. The energy of an electron increases with the distance from the core. Energy band model conduction band Prohibited band Energy Valence band

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The major semiconductor silicon and germanium are 4-valent. The crystal is built tetrahedral shape. The element acts at a temperature of 0 K, as the ideal insulator. Semiconductors

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PN junction without load voltage No voltage is applied from the outside, only the previously discussed diffusion currents and field currents flow at the boundary layer. At the terminals of the semiconductor can therefore no voltage be measured. PN-junction, unloaded Semiconductors P-doped zone N-doped zone P-neutral territory N-neutral territory P-neutral territory Space charge zone

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PN junction forward load If a voltage is applied to the positive terminal (+) of the P-region and the negative (-) to the N-region, then flows forward current. The mobile charge carriers must be transportiert against the electric field of the space charge zone in order to flow amount of current. Therefore, a certain minimum voltage is necessary so that a current flow is produced. PN-junction, forward load There are holes in the N-doped and electrons diffuse into the P-doped region. P-doped zone N-doped zone P-neutral territoryN-neutral territory Space charge zone

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PN junction blocking load If a voltage is applied to the positive terminal (+) of the N-region and the negative (-) of the P-region, then there is blocking load. The externally applied voltage amplifies the field in the space charge zone. PN-junction, blocking load The mobile charge carriers are sucked out of the border region and the space charge region expands to the potential difference is essentially equal to the applied voltage. P-doped zoneN-doped zone P-neutral territoryN-neutral territory Space charge zone

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Diodes circuit symbol, terminal designation The most commonly used semiconductor material is silicon (Si). In some cases, also germanium (Ge) is used. Previously, even diodes from selenium (Se) and copper oxide (CuO2) built. The semiconductor diode is the practical industrial application of a PN junction. Silicon brings advantages: Only in the region of very small voltages in the forward direction does the high forward voltage of silicon negative. The forward characteristic of silicon itself is then considerably steeper than for all other elements. This has caused the state losses for silicon diodes smallest. Cathode

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Half-wave rectifier without

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Necessary reverse bias voltage at the diode. ripple voltage average Diode current ripple Frequency of the ripple inrush current Periodic peak current Average output voltage

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Full-wave rectifier (B2 bridge circuit) Symbol of a B2 circuit B2 circuit There is finished assemblies in which four diodes are incorporated. without

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Common Terms:

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ripple voltage average Diode current ripple Frequency of the ripple inrush current Periodic peak current Average output voltage Open circuit output voltage Necessary reverse bias voltage at the diode.

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Full wave rectifier circuit (M2 midpoint circuit) This circuit is used for transformers with center tap. For the same output voltage as a bridge circuit is twice the number of turns required in the transformer. The average current in the windings is to only half the size, because each half-cycle, a separate winding portion can be allocated. without

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ripple voltage average Diode current ripple Frequency of the ripple inrush current Periodic peak current Average output voltage Open circuit output voltage Necessary reverse bias voltage at the diode.

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Three-phase rectifier circuit (M3 midpoint circuit) If a greater power is required for the direct current side, one can use the three-phase network as a source of the rectifier circuit. In a three-pulse midpoint circuit only three diodes are needed. Based on the output voltage but they must have the double reverse voltage as in a bridge circuit. without

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ripple voltage average Diode current ripple Frequency of the ripple inrush current Periodic peak current Average output voltage Open circuit output voltage Necessary reverse bias voltage at the diode.

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Introduction to power electronics Power electronics is the design of electronic circuits to control the flow of energy. Electrical energy is consumed differently by different appliances, e.g. o 5V or 12V D.C.: e.g. domestic equipment (like P.C.s, TVs etc.) o Variable DC high-voltage: e.g. electric trains o Variable frequency AC: e.g. variable-speed A.C. machines These appliances need to be supplied correctly. Power electronics can perform the conversion from what’s available (e.g. 220VAC) to what’s needed (e.g. 12V D.C.) FİLTERS: Electrical power in one form as input, and output the power in another form.http://www.ipes.ethz.ch/ipes/e_index.html

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Common Terms: The dimmer switch (the potentiometer) Good power electronics maximizes the power to the load, and minimizes the power wasted. a bad power electronic circuit:

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Major applications of power electronics 1) Conversion to D.C. Most consumer electronics need a stable low voltage DC supply – very little variation in supply voltage Power requirements can be huge; e.g. PCs need more than 300W ! They need: o AC-to-DC converters o DC-to-DC converters (one D.C. level to another) 2) Conversion to A.C. AC motors are efficient, powerful and easy to maintain – especially big ones Controlling their speed required a variable-frequency AC power source Power electronics can create an A.C. signal at any desired frequency, to power A.C. machines at any desired speed. This D.C.-A.C. Process is called AC inversion.

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İdeal bir Anahtar… Anahtar: İdeal bir anahtar nasıl olur? 1. Kapalıyken enerji kaybı gerçekleşmez 2. Açıkken enerji kaybı gerçekleşmez 3. Açma kapama sırasında enerji kaybı gerçekleşmez 4. Kapamak için az güç gereksinimi duyar 5. Çift yönlü mü? 6. Uygun gerilim ve akım oranları 7. Kısa açma kapama zamanı Özellikleri: 1. yüksek kırılma gerilimi (BV) 2. Kapalıyken düşük direnç 3. Hızlı anahtarlama frekansı

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Harmonics in Power supplies Harmonic distortion Most poser supplies are polluted with higher-frequency components (called harmonics). They can degrade the performance of the devices powered in many ways, for example o Mains hum from an amplifier o High-frequency spikes in a supply to a microprocessor cause incorrect digital transitions o AC generators produce an imperfect sine wave So unwanted harmonics can be minimized, but never completely avoided Practically all periodic signals (voltages, currents, vibrations of any sort) can be represented as a sum of sine waves called harmonics. Each harmonic’s frequency is an integer multiple of the base frequency. The amplitude of each harmonic affects the shape of the signal.

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Example: a sinusoidal signal A pure sine wave has one harmonic. It shows a pure sinusoidal voltage, and its frequency spectrum. This is a graph of the power in the signal at different frequencies.

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Example: two sinusoidal signals A signal composed of two sine waves

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Common Terms: A rectified sinusoidal voltage What is the fundamental frequency of the rectified sinusoid? What is the frequency of the sine wave that created it?

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A Periodic Function

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