Elektronika Daya Materi 1dsfs

PENGENALANELEKTRONIKA DAYAM. Khairul Amri Rosa

Definisi

Proses konversi dan kontrol aliran daya listrik denganmemberikan tegangan dan arus yang paling sesuai terhadapbeban

Power Processor

Controller

Load

measurementreference

POWERINPUT

POWEROUTPUT

vi , ii vo , io

Source

Blok diagram dasar

Mengkonversi energi listrik dari satu bentuk ke bentuk lain darisumber menuju beban, dengan:

Efisiensi tinggiKeandalan tinggiBiaya rendahUkuran kecilBobot ringan

Aplikasi statis : mencakup komponen-komponen mekanis yang tidak bergerakContoh: Power supply DC, UPS, Pembangkitan dan Transmisi(HVDC), electroplating, welding, heating, cooling, electronic ballastAplikasi drive: mencakup komponen-komponen bergerak atauberputar seperti motor.Contoh: kereta listrik, mobil listrik, AC, pompa, kompresor, conveyer.

Aplikasi statis : power supply dc

FILTER BEBANKonverterDC-DC

DIODERECTIFIER

Tegangan AC

1Φ atau 3ΦVcontrol

dari rangkaian umpan balik

Aplikasi Drive: Air-Conditioning System

time

Vs (Volt)

+Vs

_

Vo

time

Vdc

Suplay dari PLN: 220 VL-N, 50 Hz

Pelanggan membutuhkan tegangan DC

Dapat digunakan penyearah setengahgelombang sederhana sehinggadidapatkan tegangan DC yang tetap.Ini merupakan sembuah sistem PE sederhana

+Vo

_

Bagaimana jika pelanggan menginginkantegangan DC yang variabel?

+vo_

+vs_

igia

vo

ωt

vs

ωtα

Dibutuhkan rangkaian yang lebih kompleksmenggunakan SCR

Tegangan output rata-rata

Dengan mengontrol sudut penyalaan α tegangan output dc dapat divariasikan

Dibutuhkan sistem elektronik yang lebih rumit untuk mengatur pulsa penyalaankepada SCR

Konverter PE

AC – DC : Rectifier DC – DC : Chopper

AC input DC output DC input DC output

AC – AC : AC Controller DC – AC : Inverter

AC input AC output DC input AC output

Permasalahan dalam ketenagalistrikanpada saat ini

Ketersediaan sumber energiMengurangi pemakaian sumber energi fosil akibatcadangan yang menipis BBM, gas, batu baraPengembangan sumber energi terbarukan solar, angin, fuel-cell, gelombang laut, dsb.Penghematan energi dengan mengaplikasikan PE :

AC dengan sistem kompresor kecepatan variabelmenghemat 30% energiLampu dengan balast elektronik meningkatkan efisiensilampu floresen sebesar 20%

Permasalahan lingkunganPenggunaan energi nuklir : Plant nuklir menghasilkanradioaktif yang dapat bertahan ribuan tahunAkibat pembakaran energi fosil:

Emisi gas buang seperti CO2, CO, SO2, NOX, dsb.Pemanasan global (efek rumah kaca), hujan asam, polusiakibat asap.

Solusi dengan penerapan PESumber energi terbarukanPemusatan power station di daerah yang jauh daripemukimanKendaraan listrik

Perkembangan PE

PE berkembang pesat disebabkan:Perkembangan dalam sakelar semikonduktorKemajuan dalam mikroelektronika DSP, VLSI, mikroprosesor, mikrokontroler.Ide-ide baru dalam algoritma kontrolKebutuhan masyarakat terhadap aplikasi-aplikasi baru

PE merupakan bidang yang interdisiplin- Elektronika digital/analog - Komputer, simulasi, software- Listrik dan energi - Fisika dan divais solid state- Mikroelektronika - Packaging- Sistem kontrol - Perpindahan panas

Devais semikonduktor daya

Sakelar daya: inti dari sistem PEMode operasi:

Fully ON : rangkaian tertutup, terkonduksiFully OFF : rangkaian terbuka, blocking.

Digolongkan berdasarkan pengontrolannya:Uncontrolled : DiodaSemi-controlled : Thyristor (SCR)Fully controlled : IGBT, BJT, GTO, MOSFET,

Dioda daya

Anoda

Katoda

+Vd

_Id

SimbolKarakteristik dioda

Dioda daya

Ketika dibias maju, dioda terkonduksi mengalirkanarus dengan tegangan maju Vf yang kecil (0,2-3V)Ketika dibias mundur (blocking), terdapat arusyang sangat kecil dalam orde μA sampai mA(dapat diabaikan) sampai tejadi breakdown.Dioda tidak boleh dioperasikan pada teganganmundur yang lebih besar dari VBR.

Jenis-jenis dioda daya

Line frequency (general purpose): On state voltage: very low (below 1V)Large trr (about 25μs) (very slow response)Very high current ratings (up to 5kA)Very high voltage ratings(5kV)Used in line-frequency (50/60Hz) applications such as rectifiers

Fast recoveryVery low trr (<1μs). Power levels at several hundred volts and several hundred ampsNormally used in high frequency circuits

SchottkyVery low forward voltage drop (typical 0.3V)Limited blocking voltage (50-100V)Used in low voltage, high current application such as switched mode power supplies.

Thyristor (SCR)

Anoda

Katoda

+Vak

_

Ia

Simbol

Gate

Ig

Ia

Vak

VBR

Ig=0Ig>0IhIbo

Vbo

Thyristor (SCR)

Jika tegangan maju breakover dicapai, thyristor terkonduksi secara self-triggered.Adanya arus gate menurunkan Vbo.Thyristor ON dalam kondisi normal:

Devais dalam keadaan blocking maju (Vak positif)Sebuah arus positif (Ig) diberikan kepada gate.

Setelah terkonduksi, arus anoda terkunci. Vak turunmenjadi tegangan drop maju (1,5 – 3 V).Pada mode bias mundur, thyristor berlaku sepertidioda.

Konduksi thyristor

Thyristor di-ON-kan dengan memberikan arus positif pada gate

Thyristor TIDAK dapat di-OFF-kan dengan memberikan arus gate negatif. Thyristor akan OFF jika Ia negatif.

Secara natural terjadi pada siklus negatif gelombang AC (natural commutation).

Metode lain untuk mematikan thyristor adalah dengan Forced Commutation

Arus anoda dialihkan kepada rangkaian lain

+vs_

igia

Jenis-jenis thyristor

Phase controlled rectifying line frequency voltage and current for ac and dc motor driveslarge voltage (up to 7kV) and current (up to 4kA) capabilitylow on-state voltage drop (1.5 to 3V)

Inverter gradeused in inverter and chopperQuite fast. Can be turned-off using “force-commutation” method.

Light activated Similar to phase controlled, but triggered by pulse of light.Normally very high power ratings

TRIACDual polarity thyristors

Sakelar terkontrol (Transistor daya)

Can be turned “ON”and “OFF” by relatively very small control signals. Operated in SATURATION and CUT-OFF modes only. No “linear region” operation is allowed due to excessive power loss. In general, power transistors do not operate in latched mode.Traditional devices: Bipolar junction transistors (BJT), Metal oxide silicon field effect transistor ( MOSFET), Insulated gate bipolar transistors (IGBT), Gate turn-off thyristors (GTO)Emerging (new) devices: Gate controlled thyristors (GCT).

Bipolar Junction Transistor

VCE

IB

v-i characteristicsVCE (sat)

+VCE_

IC

IB

C (collector)

B (base)

E (emitter)

Ratings: Voltage: VCE<1000, Current: IC<400A. Switching frequency up to 5kHz. Low on-state voltage: VCE(sat) : 2-3V

Low current gain (β<10). Need high base current to obtain reasonable IC .Expensive and complex base drive circuit. Hence not popular in new products.

Metal Oxide Silicon Field Effect Transistor (MOSFET)

+VDS_

IDD (drain)

G (gate)

S (source)

+VGS

_

ID

VDS

+VGS_

Ratings: Voltage VDS<500V, current IDS<300A. Frequency f>100KHz. For some low power devices (few hundred watts) may go up to MHz range.

Turning on and off is very simple. To turn on: VGS =+15V To turn off: VGS =0 V and 0V to turn off.

Gate drive circuit is simple

MOSFET Characteristics

Basically low voltage device. High voltage device are available up to 600V but with limited current. Can be paralleled quite easily for higher current capability.

Internal (dynamic) resistance between drain and source during on state, RDS(ON), , limits the power handling capability of MOSFET. High losses especially for high voltage device due to RDS(ON) .

Dominant in high frequency application (>100kHz). Biggest application is in switched-mode power supplies.

Insulated-Gate Bipolar Transistor (IGBT)

IC

VCE

VGE

v-i characteristicsVCE (sat)

+VCE_

ICC (collector)

G (gate)

E (emitter)

+VGE _

Combination of BJT and MOSFET characteristics.

Gate behaviour similar to MOSFET - easy to turn on and off.Low losses like BJT due to low on-state Collector-Emitter voltage (2-3V).

Ratings: Voltage: VCE<3.3kV, Current,: IC<1.2kA currently available. Latest: HVIGBT 4.5kV/1.2kA.Switching frequency up to 100KHz. Typical applications: 20-50KHz.

Gate Turn-Off Thyristor (GTO)Anoda

Katoda

+Vak_

Ia

Ig

Ia

Vak

VBR

Ig=0Ig>0IhIbo

Vbo

Behave like normal thyristor, but can be turned off using gate signalHowever turning off is difficult. Need very large reverse gate current (normally 1/5 of anode current).Gate drive design is very difficult due to very large reverse gate current at turn off. Ratings: Highest power ratings switch: Voltage: Vak<5kV; Current: Ia<5kA. Frequency<5KHz.

Insulated Gate-Commutated Thyristor (IGCT)

Anoda

Katoda

+Vak_

Ia

Ig

IGCT

Among the latest Power Switches.Conducts like normal thyristor (latching), but can be turned off using gate signal, similar to IGBT turn off; 20V is sufficent.Power switch is integrated with the gate-drive unit.Ratings:

Voltage: Vak<6.5kV; Current: Ia<4kA. Frequency<1KHz. Currently 10kV device is being developed.Very low on state voltage: 2.7V for 4kA device

Rating daya sakelar semikonduktor

10Hz 1kHz 1MHz100kHz 10MHz

1kW

100kW

10kW

10MW

1MW

10MW

1GW

100W

MOSFET

IGBT

GTO/IGCT

Thyristor

Perbandingan sakelar semikonduktor (2003)

Thy BJT FET GTO IGBT IGCT

Availabilty Early 60s Late 70s Early 80s Mid 80s Late 80s Mid 90’s

State ofTech.

Mature MatureMature/improve

MatureRapid

improveRapid

improvementVoltage ratings

5kV 1kV 500V 5kV 3.3kV 6.5kV

Currentratings

4kA 400A 200A 5kA 1.2kA 4kA

SwitchFreq.

na 5kHz 1MHz 2kHz 100kHz 1kHz

On-state Voltage

2V 1-2V I* Rds (on) 2-3V 2-3V 3V

DriveCircuit

Simple Difficult Very simple Very difficult Very simple Simple

CommentsCannot turn

off using gate signals

Phasing out in new product

Good performance in high freq.

King in very high power

Best overall performance.

Replacing GTO