Power Electronics - LTHIntro+Switches).pdf · Why Power Electronics? • The efficiency of a linear amplifier (converter) has a theoretical upper limit of 78.5 % • This is sufficient

Power Electronics

1

Lecture 1 – Introduction & Basic Switching

Electric Drives Control 2

We want torque !

We are mainly interested in the mechanical torque

on the electrical machine shaft

But, the torque is the result of a complex interaction

of electric voltages and currents, magnetic fluxes and

mechanical layout

Our source is (usually) a DC Voltage, that ...

– we convert to AC with PWM and feed to the

electrical machine to ...

– control the machine currents such that the

mechanical torque becomes the one we want.

Against us we have:

– A machine that require voltages that increase

with speed

– A battery with limited and almost constant

voltage

– A converter that needs to be controlled in a

microsecond time scale


How we do it?

We start knowing:

– The desired torque

– Lots of system states, like

speed, DC link voltage, phase

currents, battery SOC, ...

We calculate:

– The traction machine currents

needed

– The voltages needed to set

these currents

– The modulation pattern

needed to set these voltages

We modulate the swithes

accordingly !


Torque

control

Current

Control

Modu-

lation PEC

Torque Ref

Current refs Voltage refs Switch states Output Voltage

Current, Speed and Position feedback

DC Link Voltage

feedback

This course

Why Power Electronics?

• The efficiency of a linear amplifier (converter) has a

theoretical upper limit of 78.5 %

• This is sufficient in many low power applications, such as

home audio

• In trains the rated power may be as high as 4-8 MW

• For an efficiency of 78.5 % the losses would be 0.86-1.72

MW

• This means that huge amounts of power and money would

be lost

... but the main problem would be thermal management, i.e.

handling the heat power

• Typically, the efficiency of a power electronic switch mode

converter is >98 %

Simple low power amplifiers

A B och AB

Eff = 20 – 25% Eff = 60 %


Class D Audio Amplifiers

What is Power Electronics used for? • All kinds of electrical drives where electrical power is transfered to mechanical

and variable speed is required such as

• Traction applications such as trains, electrical vehicles and ship propulsion

• Pumps and fans

• All kinds of electrical drives where electrical power is transfered to mechanical

and position control (servo) is required such as

• Robots, cranes

• Power system applications such as

• HVDC (up to 3000 MW), Transistor based HVDC

• Feeding and priming power from renewable energy sources (solar, wind, ...)

• Active power filters, reactive power compensation, ...

• Power supplies

• Computers, tv-sets, ...

• Battery chargers for computers, mobile phones, hand-held tools, ...

- Back-up power, i.e. uninteruptable power supplies

• Many other applications

Electrical Motor Drives

http://www.irf.com

http://www.semikron.com

http://www.abb.com

Typical Motor Drive Applications - Except pumps, fans, cranes, …

Series Hybrid

http://www.hybridcenter.org/

http://www.toyota.com/

Prallel Hybrid


Series-Parallel Hybrid


Traction: for example trains and hybrid vehicles

http://www.abb.com

Robotics

Energy Conversion in Hybrid Vehicles


Volvo’s main system Electric motor

70 kW cont, 120 kW peak

400 Nm cont, 800 Nm peak

Energy storage

600 VDC

AMT gearbox

Diesel engine

Speed

To

rqu

e

Both

Potential Fuel Saving

Refuse Truck 20 % 5 %

30-40 % 20-50 %

Long Haul Truck

Wheel loader City Bus

Electric Traction Motors

– Are at least twice as energy

efficiency as combustion

engines

– Need almost no service, no

sparkplugs, no oil changes ..

– Are quiet

– Let out no exhaust

– Are much smaller than a

combustion engine for the

same rating

– Can recover energy when

slowing down or going downhill

Electric Drive is Good!

But Storing Energy is a double problem ... Time to charge 250 km Battery to store 250 km

5 minutes

7 days

9 hours

4 hours

150 kg diesel-tank

2500 kg battery

2500 kg battery

2500 kg battery

The Energy Path

Who needs an Automatic Charging Connection ... ? Commercial Vehicles

– May be Opportunity Charged up to

10 ... 20 times a day

– The power level is high!

– Automatic connection absolutely

necessary !!!

Autonomous private (?) vehicles

– Maybe a Spotify/Netflix/Uber kind of

vehicle

– Must be able to autonomously

arrange washing, charging,

workshop visit, ...

– Usually connected 1...3 times per

day

– Automatic connection absolutely

necessary !!!

Future Charging Concepts

http://www.google.se/url?sa=i&rct=j&q=&esrc=s&source=images&cd=&cad=rja&uact=8&ved=0ahUKEwij286824rPAhUEIJoKHYCCD0YQjRwIBw&url=http://articles.sae.org/9881/&psig=AFQjCNGt3sXFTq6QLbGcUTEtoZyQ1ZiQbg&ust=1473800088324277

The reinvented trolley reduce the need for

batteries ...

... AND is automatic !


Siemens/Scania

Elways

Alstom/Volvo

Elonroad

-90 % battery size !


Vision


If ALL cars in Sweden were a

”Tesla”:

– 2 million m3 batteries

If ALL HDT were equipped fo

4h full electric mode

– 0.2 millioner m3 batteries

IF we stack these as a cone

...?

– With the same base as the Eiffel-tower ...

Societal value ...

325 meter

472 meter

47 meter

125 m

? m

4x

ER

S c

os

t Future Charging Concepts

http://www.google.se/url?sa=i&rct=j&q=&esrc=s&source=images&cd=&cad=rja&uact=8&ved=0ahUKEwiqgNr7kITMAhXE1ywKHckNCKcQjRwIBw&url=http://www.techspot.com/news/60240-tesla-residential-battery-system-leaked-here-everything-know.html&psig=AFQjCNGGpW0FReoG9jRV2DMPgVmQZHAlZQ&ust=1460379832544400

OFF Board High Power Charger

• High cost off board • (currently 7 k€/kW, excl installation)

• Low cost on board

• Robotic connector included

ON Board High Power Charger

• Low cost off board • (<< 1k€/kW, excluding installation)

• Moderate cost On Board • (Renault Cars @ 150 € for 43 kW by integration

!!!)

• Robotic Connector To Be Developed

Alternatives

Renault Traction System Renault logic:

– Energy Infrastructure MUST be

dense.

– DC connection for high power

charging NOT the right way to go

Standardize @ grid voltage,

NOT battery voltage.

– Low Cost High Power AC

infrastructure needed, with On

Board Charger

– The Power level will increase

Today 43 kW, tomorrow

>80 kW

– Robotized Connection necessary

Frequency Conversion

Japan East / West

50/60 Hz

600 MW

HVDC

Japan: Hokkaido to Honshu / 600 MW

HVDC and Transistor Based HVDC

http://swepollink.svk.se/ http://www.abb.com/

Camera with flash

Audio amplifiers


Renewable Energy Systems

http://www.toshiba.com

Converters Suitable for Solar

Cells

Without transformer

With transformer

Active Filters

-10

0

10

iLoad

[A]

-10

0

10

iLine

-10 0 10 20 30 40 50 60 70

-10

0

10

iAF

t [ms]

5 7 11 13 17 19 23 25 29 31 35 370

1

2

Ih

h

LoadLineAF

[Arms

]

iLoad

iLineiAF

Cdc

L2 L1

C

Vdc

Vbatt

3400 V50 Hz

Line sidefilter

Line sideconverter

DClink

Batterysidefilter

Batteryside

converter

Switch Mode Power Supplies - Forward Converter

http://www.irf.com

Thank You!

The Course 2017

Lectures 2 times a week

2…3 exercises a week

6 labs with home assignments / simulation exercises:

– The Flyback Converter

– The H-bridge

– Speed Control with a DC Machine

– Control of an Active Power Filter

– Control of PM Machines

– Control of Induction Machines

Teaching Plan

Week Who Date Time Lecture Content Who Date Time Lecture Content Who Date Time Lecture content Lab w ho

3 Mats 2017-01-16 13-17 Intro + Diode/Thyristor & Rectif ier Hans 2017-01-18 13-17 Buck converter, sw itch, snubbers Hans 2017-01-19 08-10 Lab Flyback converter preparation Philip

4 Mats 2017-01-23 13-17 DC/DC conv +1 phase modulation Mats 2017-01-25 13-17 H-bridge + 2 phase modulation Mats 2017-01-26 08-10 Lab H-bridge preparation Philip

5 Hans 2017-01-30 13-17 DC Current Control Hans 2017-02-01 13-17 Position and Speed Control Hans 2017-02-02 08-10 Torque Generation Lab Flyback

6 Mats 2017-02-06 13-17 DC-machine theory Mats 2017-02-08 13-17 DC Machine Control Mats 2017-02-09 08-10 Lab DC-machine preparation Lab H-bridge Samuel/Max

7 Mats 2017-02-13 13-17 AC-pow er + 3 phase modulation Hans 2017-02-15 13-17 AC Current Control Hans 2017-02-16 08-10 Lab Active filter preparation Samuel/Max

8 Hans 2017-02-20 13-17 Pow er Systems Applications Hans 2017-02-22 13-17 Synchronous Machine and PMSM Mats 2017-02-23 08-10 Lab DC

9 Mats 2017-02-27 13-17 Control of PMSM Hans 2017-03-01 13-17 Induction Machine Modelling Hans 2017-03-02 08-10 Lab AF Samuel/Max

10

11

12 Mats 2017-03-21 13-17 Control of Induction Machine Mats/Samuel? 2017-03-23 13-17 Lab PMSM preparation

13 Hans 2017-03-28 13-17 Semiconductor PN junction Hans 2017-03-30 13-17 Semiconductor Mos IGBT

14 Mats 2017-04-04 13-17 New materials, Silicon Carbide Mats / Gabriel? 2017-04-06 13-17 Lab Induction Machine preparation Lab PMSM

15

16

17 Hans 2017-04-25 13-17 Passive components (Ind&Cap) Mats 2017-04-27 13-17 Losses, Temp, cooling

18 Hans 2017-05-02 13-17 Resonance and Multilevel converter Hans 2017-05-04 13-17 Guest Lecture - ESS (Carlos?) Lab IM

19 Hans 2017-05-09 13-17 EMC Hans 2017-05-11 13-17 Guest Lecture - ERS (Dan Z, Lars L?)

20 Mats 2017-05-16 13-17 Guest Lecture - Hybrid Mats 2017-05-18 13-18 Guest Lecture - ERS

21

22 Mats 2017-05-30 8-13 Tentamen

Self studies

Self studies

Exam w eek

Easter w eek

Re-exam w eek?

Home Assignments

Content as similar as possible to the labs

Prepares you for the lab

Diagnostic tests can be used before the labs – You must pass!

Teachers

Lectures:

– Mats Alaküla, professor, Senior Scientific Advisor Volvo Powertrain

– Hans Bängtsson, professor, Adjunct Professor Lund University,

former Senior Specialist Power Electronics and EMC at Bombardier

Course assistance, simulation exercises and Labs:

– Max Collins, PhD student

– Samuel Estenlund, PhD Student

Components

Components 1 : The transistor

Works like a valve for electric current

Compare to a water tap

– Control a big flow with a small movement

– Flow x Pressure drop = Power

– Heats the water (a little)

A transistor

– Controls a big current with a small current

– The voltage drop across the transistor x the current = Power

– Heats the transistor (a lot)

Components 2: The Diode

Anod

Katod

+

-

i

u

Backriktning Framriktning

u

i

Spärrtillstånd

Ledtillstånd

Components 3: The IGBT – transistor

Symbol

Bottnad

Strypt Effektgräns

i

u

C

CE

i C

u CE +

+

- -

u GE

Gate

Kollektor

Emitter

u

u

u

GE2

GE3

GE1

Ökande u GE

Components 4: The Capacitor

Stores electric current with

increasing voltage like a hydrophore

stores a fluid or gas with increasing

pressure

iCdt

duc 1

+ uc - ic

Components 5: The Inductor

Stores currrent into magnetic energy

like a flywheel stores torque into

speed and mechanical energy

LL u

Ldt

di

1

iL

+ uL -

Never break an inductive current Never short a capacitive voltage

LL u

Ldt

di

1c

c iCdt

du

1

cu

Lu

Lici

Basic Switching

Fundamentals of Switching

Analogue Switched

Ut

Uload

Ia

U0

0 Ploss = Ut*Ia

Pload = Uload*Ia

Ut ≈ Uload

On

Ut ≈ 0 Ut = U0

Ploss = 0 Ploss = 0

Off

Ia = Iload Is = 0

Ploss ≈ Pload

Ia

t t


Never break an inductive current Never short a capacitive voltage


BASIC turn on current step, capacitive load. No problem

C

i

dt

du

I u

i

t

u,i


BASIC turn off current step, capacitive load. No problem

C

i

dt

du

I

u

i

u,i

t


BASIC turn on voltage step with capacitive load. Problem!

dt

duCi


uU

+

U

-

u

i

u,i

t

BASIC turn off voltage step, capacitive load. No problem

dt

duCi


uU

+

U

-

+

u

-

i

u,i

t

BASIC voltage ramp, capacitive load. No problem

dt

duCi

i

u,i

t

+

U

-


BASIC turn on current step, inductive load. Problem

dt

diLu

I

+

u

-

i

t

u,i


I > i

BASIC turn on current step, inductive load. Counter measure with capacitor

t

u,i


dt

diLu

I

+

u

-

i

I > i

BASIC turn off current step, inductive load. Problem

t

u,i


dt

diLu

I

+

u

-

i

BASIC turn off current step, inductive load. Counter measure with freewheeling diode

I

+

u

-

i

t

u,i


BASIC current ramp, inductive load. No problem

dt

diLu

I

+

u

-

i

u,i

t


BASIC turn on voltage step with inductive load. No problem

dt

diLu

U u

i

u,i

t

U


BASIC turn off voltage step, inductive load No problem

dt

duCi

+

U

-

+

u

-

i

u,i

t


Summary An inductance keeps a current ”constant”

L

u

dt

di

u

i


Summary A capacitance keeps a voltage ”constant”

C

i

dt

du

u

i


Single phase diode rectifier ideal

U0

-1

-0,5

0

0,5

1

0 50 100 150 200 250 300 350 400

Single phase diode rectifier ideal

-1

-0,5

0

0,5

1

0 50 100 150 200 250 300 350 400

Positive

Negaative

Single phase diode rectifier voltage

LNLNLN

TLNdc Eetdt

edtte

TV

22ˆ

2)()cos(

2

ˆ2)cos(ˆ

2

1 2

22

Line-to-neutral voltage and DC side voltage for a single-

phase diode rectifier

-1

-0,5

0

0,5

1

-4 -3 -2 -1 0 1 2 3 4

T/2

Quadrants

Power Electronic

Converter

+

u

-

i

u u u u

i i i i

1-quadrant 2-quadrant 2-quadrant 4-quadrant


Classification

DC Voltage

AC voltage

DC-voltage

conversion

AC voltage

conversion

Inversion

Rectification


Some fundamental topologies

The Buck Converter (Step-Down Converter)

Figure 1.16: Buck converter.

Figure 1.17: Ideal waveforms of the

Buck converter.

S ”on”

swloaddc

LL

Lloaddc DTL

VVi

dt

diLvVV

S ”off”

swload

LL

Lload TDL

Vi

dt

diLvV 1

The Boost Converter (Step-Up Converter)

Figure 1.18: Boost converter.


Boost converter. Replace

Vdc and Vload of the Buck

converter with Vout and Vin

S ”on”

S ”off”

swin

L DTL

Vi inSinL

L VvVvdt

diL

outinoutDinLL VVVvVv

dt

diL

swoutin

L TDL

VVi

1

The Buck-Boost Converter (Half-Bridge)

Figure 1.19: Buck-boost converter.


Buck-boost converter.

S ”on”

swloaddc

LL

Lloaddc DTL

VVi

dt

diLvVV

S ”off”

swload

LL

Lload TDL

Vi

dt

diLvV 1

General SMPS

Figure 1.20: Principal schematic of a switch-mode power supply.

The Flyback Converter

Figure 1.23: Principal schematic of a flyback converter. Only the devices needed to

understand the operation are included.

The Laboratory Flyback Converter

Flyback converter with input filter, inrush current limitation, diode rectifier, dc link capacitors, power

MOSFET, transformer, output filter and three snubber circuits. The controller circuits are not included in

the circuit.

Diode rectifier with capacitive DC link

Figure 1.1: A single-phase diode rectifier

with a capacitive DC link.

Figure 1.2: Line-to-neutral voltage and DC side voltage

for a single-phase diode rectifier with a capacitive DC link.

LNLNLN

TLNdc Eetdt

edtte

TV

22ˆ

2)()cos(

2

ˆ2)cos(ˆ

2

1 2

22

Figure 1.3: Line current (left) and its frequency spectrum (right),

for a single-phase diode rectifier with a capacitive DC link.

That’s all folks...


Documents

Power Electronics - LTHIntro+Switches).pdf · Why Power Electronics? • The efficiency of a linear amplifier (converter) has a theoretical upper limit of 78.5 % • This is sufficient