Teaching Utility Applications of

gilamonsterbirdsElectronics - Devices

Nov 24, 2013 (3 years and 8 months ago)

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Ned Mohan, Amit Jain, Philip Jose

University of Minnesota


and


Raja Ayyanar

Arizona State University


Teaching Utility Applications of
Power Electronics in a First
Course on Power Systems

2

Outline


Importance of teaching power electronics in a power
systems course


Description of proposed approach consisting of four
segments


Functional aspects of power electronics


Power device capabilities and Power Electronic Structures


Role of power electronics in utility applications


Details of the power electronics structures



3

Control Center
Micro-Turbine

Hospital

Commercial
Building
Fuel Cell

Smart House

Performance
Building
Combined Heat and Power
Plant (CHP)

Factory

Commercial Building

House

Apartment Building
Wind Power Plants

Village

Commercial
Building
Central Power
Station
Solar Power Plants

CHP House
Importance


Increasing applications of Power Electronic
Equipment in Power Systems


Availability of high power

semiconductor devices


Decentralized renewable

energy generation sources


Increased power transfer

with existing transmission

system


Effective control of power

flow needed in a

deregulated environment


Norms for Power quality

Future Power System

4

Approach


Top

Down

approach

consisting

of

four

segments


Function

of

power

electronics

as

an

interface,

and

the

listing

of

utility

applications

requiring

power

electronics

interface


(
1

lecture)


Power

device

capabilities

and

the

resulting

structures

of

power

electronic

interfaces

to

exploit

them

(
1

lecture)


Importance

and

the

role

of

power

electronic

interfaces

in

various

applications

(
2

lectures)


Discussion

of

power

electronics

interface

in

appropriate

detail

(
3

lectures)

5

Segment 1: Function of Power
Electronics in Utility Applications








Enabling technology providing interface between two
(ac/dc) electrical systems


E.g.


Interconnection of two asynchronous ac systems


dc to ac conversion is required to connect fuel cells or
photovoltaics to the utility grid

Converter
Controller
Source
Load
6

Segment 1: Listing of Power Electronic
Applications


Distributed

generation

(DG)


Renewable

resources

(wind

and

photovoltaic)


Fuel

cells

and

micro
-
turbines


Storage
:

batteries,

super
-
conducting

magnetic

energy

storage,

flywheels


Power electronics loads: Adjustable speed drives


Power quality solutions


Dual feeders


Uninterruptible power supplies


Dynamic voltage restorers


Transmission and distribution (T&D)


High voltage dc (HVDC) and medium voltage dc


Flexible

AC

Transmission

Systems

(FACTS)
:

Shunt

and

Series

compensation,

and

the

unified

power

flow

controller

7

Segment 2: Power Device Capabilities &
Resulting Power Electronic Structures


Power Semiconductor Devices and their Capabilities


Polarity of voltage blocked and direction of current conduction


Switching speeds and power ratings

IGBT
MOSFET
Thyristor
IGCT
10
1
10
2
10
3
10
4
10
2
10
4
10
6
10
8
Thyristor
IGBT
MOSFET
Power (VA)
Switching Frequency (Hz)
IGCT
8

Segment 2: Structure of Power
Electronic Systems


Voltage
-
Link Systems


Transistors and diodes that

can block voltage of only

one polarity




Current
-
Link Systems


higher power bipolar voltage
-

blocking capabilities of thyristors



Solid State Switches


bidirectional voltage blocking

and current conduction


AC1
AC2
AC1
AC2
9

Segment 3: Role of Power Electronics in
Important Utility Applications


Distributed Generation (DG) Applications

Power electronic interface depends on the source
characteristics

(c)

AC
DC
DC
AC
Wound rotor
Induction Generator
Generator-side
Converter
Grid-side
Converter
Wind
Turbine
Isolated
DC-DC
Converter
PWM
Converter
Max. Power-
point Tracker
Utility
1
f
Wind Power Generation with
Doubly Fed Induction Motors

Photo
-
voltaics Interface

10

Segment 3: Role of Power Electronics in
Important Utility Applications


Power Electronic Loads: Adjustable Speed Drives


(c)

Controller
Motor
Utility
Rectifier
Switch-mode
Converter
11

Segment 3: Role of Power Electronics in
Important Utility Applications


Power Quality Solutions for


voltage distortion


unbalances


voltage sags and swells


power outages









(c)

Load
Feeder 1
Feeder 2
Dual Feeders

Power Electronic
Interface
Load
Dynamic Voltage Restorers (DVR)

Uninterruptible Power Supplies

Rectifier
Inverter
Filter
Critical
Load
Energy
Storage
12

Segment 3: Role of Power Electronics in
Important Utility Applications


Transmission and Distribution: DC Transmission


most flexible solution for connection of two ac systems

AC1
AC2
HVDC

AC1
AC2
MVDC

13

Segment 3: Role of Power Electronics in
Important Utility Applications


Transmission and Distribution: Flexible AC
Transmission Systems (FACTS)

1 2
sin
E E
P
X


1
E
2
E
3
E
+
-
3
E
1
E
2
E
Shunt
converter
Series
converter
I
Shunt and Series Compensation

Series Compensation

Shunt Compensation

Utility
STATCOM
jX
14

Segment 4: Discussion of Power
Electronics Interface


Fundamental

concepts

for

understanding

the

operation

of

the

power

electronic

structures


voltage
-
link systems


current link systems


solid state switches

15

Voltage
-
Link Systems


Unifying approach: Power
-
Pole Building Block


building block of all

voltage
-
link systems

AC1
AC2
dA
i
A
v
A
i
d
V
control
v
1 or 0
A
q

A s
d T
+
-
+
-
PWM
Voltage

port

Current

port

16

Voltage
-
Link Systems


Power conversion using Pulse Width Modulation (PWM)


Power reversal with reversal of current direction









Averaged conversion

dA
i
A
v
A
i
d
V
control
v
1 or 0
A
q

A s
d T
+
-
+
-
PWM
Voltage

port

Current

port

A
v
t
d
V
A
v
A s
d T
s
T
on
A d A d
s
T
v V d V
T
 
17

Voltage
-
Link Systems


Averaged Representation of Power Pole


Average quantities are of main interest









dA
i
A
v
A
i
d
V
control
v
A s
d T
+
-
+
-
PWM
1:
A
d
dA
i
A
v
A
i
d
V
control
v
1 or 0
A
q

A s
d T
+
-
+
-
PWM
Voltag
e

port

Current

port

( ) ( )
A A d
v t d t V
 
( ) ( ) ( )
dA A A
i t d t i t
 
18

Voltage
-
Link Systems


Synthesis of AC voltages


voltage to be synthesized




duty ratio needed




dc side current














A
i
t

0

v

d
V
d
V
2
0
t

A
v
I
( ) sin
2
d
AN
V
v t V t

  
1
sin
2
A
d d t

  


1
( ) sin ( )
2
1
ˆ
sin sin( )
2
1
ˆ
cos sin( ) cos(2 )
2
dA
a
i t d t i t
d t I t
I d t d t

  
    
 
   
 
 
 
    
 
 
     
19

Voltage
-
Link Systems


Implementation of bi
-
positional switch

A
i
d
V
+
-
A
q

A
q
1
A A
q q

 
(d)

dA
i
A
v
A
i
d
V
1 or 0
A
q

A s
d T
+
-
+
-
20

Current
-
Link Systems


Exclusively thyristor based





One of (T
1
, T
2
, T
3
) and (T
2
, T
4
, T
6
)

conduct at a time


Average dc voltage controlled

by ‘firing angle’





Power flow reversed by reversing

voltage polarity

(d)

AC1
AC2
3 2 3
cos
d LL c d
V V L I
 
 
 
a
i
b
i
c
i
d
v
+
-
d
I
1
T
3
T
5
T
4
T
6
T
2
T
c
L
b
L
a
L
21

Solid State Switch









Can conduct current in both directions


Turn
-
on or off in an ac circuit in one
-
half of a line
-
frequency
cycle

(d)

22

Conclusion


Teaching

utility

applications

of

power

electronics

in

a

power

systems

course

is

very

important


A

top

down

approach,

starting

with

functional

aspects

and

going

to

implementation

details

is

suggested


Topics

outlined

in

the

four

segment

proposed

structure

will

introduce

students

to

future

practices

and

technologies

in

power

engineering


The

proposed

structure

may

be

adapted

based

on

individual

preferences