Power ElectronicsIntro+Switches).pdf · Why Power Electronics? • The efficiency of a linear...

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

! Electric Drives Control 4

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


12

EV Charging

Professor Mats Alaküla Industrial Electrical Engineering at Lund University

Senior Technology Advisor, AB Volvo

Scientific Leader, Swedish Electro Mobility Research Centre

13

Energy

Source

Energy

Transfer

Energy

Use

Conventional

Renewable

Inefficient

Dirty

14

The last Century

15

1912

The Charging Challenge is NOT new ...

https://www.google.se/url?sa=i&rct=j&q=&esrc=s&source=images&cd=&cad=rja&uact=8&ved=0ahUKEwiUmJqpt4zTAhVCOJoKHXy5DX0QjRwIBw&url=https://brunch.co.kr/keyword/%EB%AF%B8%EB%9E%98%EC%9E%90%EB%8F%99%EC%B0%A8&psig=AFQjCNF72AcE70V6lpidB2TlJj6lXmvLIQ&ust=1491451009553935

https://energizepseg.com/2015/07/24/are-ev-charging-stations-the-next-hot-amenity-at-work-and-home/

16

Possibilities

It’s not easy...

0 5 10 15 20 25 >30 [x10 km]

Days with certain range

Example: 1:342

Norway: 1:40

18

Static Charging

19

On board Off board

On board / Off board = AC / DC

• ”AC Charging”

• Automation missing

• High power plug missing?

• 10...100 MW/m2

• ” DC Charging”

• Automation missing

• 10...100 MW/m2

• ”Wireless Charging”

• 10...100 kW/m2

20

Current

Control

a b c 0 pe

Current

Control

NO PE !

AC

DC1

DC2 DC/DC

2bl Isol

Current

Control

21

a b c 0 pe

Current

Control AC

• 3 phase plug limited to 63 A

• Max charging power 44 kW

• Available from all OEMs for night time

charging

• E.g. 200 kWh in 5 hours night time.

• NOT Enough for Opportunity Charging at

+100 kW

• New Plug Needed for higher power levels!

22

Current

Control

a b c 0 pe

AC

DC1

DC2

• OppCharge an open ”standard”, capable of up to 600 kW

• Expensive stations, not compatible with most truck applications

• CCS/DC normally limited to 200 A.

• @ 750 V this gives 150 kW, e.g 4x0.25h = 150 kWh

• NOT automatic

• Pushed towards 500 A with water cooling = 375 kW

@ 750 V

23

a b c 0 pe

NO PE !

DC2 DC/DC

2bl Isol

Current

Control

• Siemens eHighway is currently leading

• Others follow very soon

• Significant battery size reduction (-60%...-80%)

• 150 kWh instead of 600 kWh

• No protective earth – requires special safety

solutions

24

Dynamic Charging

25

Is automatic

Works with both small and BIG vehicles

Can be used both when

standing still and when moving

Can be used both

in the city and on the highway

The Perfect Charging Connection ...

Conductive ERS concepts

Honda Elways Alstom Elonroad Siemens

27

Siemens/Scania

Elways

Alstom/Volvo

Elonroad

-80 % battery size !

Elonroad

Siemens

28

Vision of one technology supplier ...

A technology example...

Tesla Semi Analysis ...

• GVW = 80000 lbs = 36 287 kg

• Drag Coefficient = Cd = 0.36

• Drivetrain: 4 PM motors from Model 3

• Acceleration 0-60 mph = 0-97 km/h

– Tractor only: 5 seconds

– Full load (80000 lbs): 20 seconds

• Hill climbing: 5 % slope @ 65 mph = 105 km/h

• Range: 300/500 miles = 483/805 km

• Charging time: 400 miles = 644 km in 30

minutes

Technical facts Given Facts Calculated Facts

• Energy consumption = about 1 kWh/km

• Tractor weight = 9 tons

• Traction motors = 4 x 137/192 kW (cont/peak)

• Battery Energy = 850 – 950 kWh (depends on DoD)

• Battery Weight = 4.2 – 4.7 tons (@ 0.2 kWh/kg)

• Charging power

= almost 1.3 Megawatt for Fast Charging

= 100 kW for Night Time Charging

• MEGA Charging Connector: Seems to be 4xSUPER

Charging Connector

X 4 =

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 2019

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

4 Mats 2019-01-21 13-17 Intro + Semiconductors and bridges Mats 2019-01-23 13-16 Bridges, sw itch dynamics, snubbers Philip 2019-01-23 16-17 Lab Flyback converter preparation

5 Avo 2019-01-28 13-17 DC/DC conv +1 phase modulation Avo 2019-01-30 10-15 H-bridge + 2 phase modulation (+ thermal) Philip 2019-02-01 10-12 Lab H-bridge preparation Lab Flyback Philip / Akanksha

6 Mats 2019-02-04 13-17 Position and Speed control Mats 2019-02-06 10-15 DC Current Control Mats 2019-02-08 08-10 Lab H-bridge preparation + thermal

7 Avo 2019-02-11 13-17 Torque generation Avo 2019-02-13 10-15 DC Machine Theory and Control Samuel 2019-02-15 08-10 Lab DC-machine preparation

8 Avo 2019-02-18 13-17 AC-pow er + 3 phase modulation Avo 2019-02-20 10-15 AC Current Control 2019-02-22 08-10 Lab H-bridge Philip / Akanksha

9 Mats 2019-02-25 13-17 Static VAr compensation Mats 2019-02-27 10-15 Active Filters, design & control Max 2019-03-01 08-10 Lab Active Filter preparation Lab DC Samuel

10 Mats&Dan 2019-03-04 13-17 Guest lecture Active Pow er Filters Mats 2019-03-06 10-15 Passive components (Ind&Cap) Mats 2019-03-08 08-10 AF lab Q&A

11

12

13 Mats 2019-03-26 13-17 Synchronous Machine and PMSM Mats 2019-03-28 13-17 Control of PMSM, incl FW Lab AF Max

14 Samuel 2019-04-02 13-17 Lab PMSM preparation Mats 2019-04-04 13-17 Semiconductor I

15 Avo 2019-04-09 13-17 Semiconductor II Avo 2019-04-11 13-17 Thermal modelling (losses) Lab PMSM Samuel

16 Avo 2019-04-16 13-17 Thermal modelling (cooling)

17

18

19 Avo 2019-05-07 13-17 IM Modelling and Control Samuel 2019-05-09 13-17 Lab IM preparation

20 Mats&Bobbie 2019-05-14 13-17 Guest Lecture I (Automotive) Mats&Shao 2019-05-16 13-17 Resonant and Multilevel converters Lab IM Samuel

21 Avo 2019-05-21 13-17 EMC I TBD 2019-05-23 13-17 Old exam exercise

22 Mats 2019-05-28 13-17 Summary and recap before exam

23 Mats 2019-06-05 8-13 Tentamen

Acension Day

(Re)exam period

Easter Week

Self studies

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

– Avo Reinap, Associate Professor.

Course assistance, simulation exercises and Labs:

– Philip Abrahamsson and Akanksha Upadthey, PhD student

– 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


Lighttube


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


Some fundamental topologies

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


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

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.

LNLN

LN

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.

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

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.

That’s all folks...


Power ElectronicsIntro+Switches).pdf · Why Power Electronics? • The efficiency of a linear...

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