A-Seminar-A Review of Active Power Filter

8/3/2019 A-Seminar-A Review of Active Power Filter

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1

A Review

of

ACTIVE POWER FILTERS

Prepared by

PARK K I-WON

R&D Center , POSCON

2001 . 02. 09


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2. Source o f Harm onic s

Non-linear magnetization of a transformer

Very small compared to rated current

Power electronics based equipment

UPS, PC, Welder, Printer

Rectifier, Variable Speed Drive

Due to discontinuous current flows

[ ]Wb

[ ]Ai [sec]t

( )t ( )ti


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4

( )tiline

C

LoadLoadLoadLoadACACACAC

SupplySupplySupplySupply

Voltage Source Type Harmonic Diode rectifiers with capacitive filtering


5/47

5

Current Source Type Harmonic Thyristor converters with inductive filtering

( )tiline

L

LoadLoadLoadLoadACACACAC



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6

3. St andards/Guides on Harm onic L im i t s

IEC 1000-3-2( International Electrotechnical Commission )

Harmonic current emission limits for individual equipments

Small equipments < 16A

European standard (CELENEC)

IEC 1000-3-4

Harmonic current limits of overall installation

Medium to large installations >16A Related to line stiffness (SCC)

IEEE 519-1992

Limits at PCC (Interfacing)

Harmonic voltage limits for utility company

Harmonic current limit for customers(


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4. How Harm onic Reduc t ion/El im inat ion?

Line-Friendly Load

Multi-pulsed system : Series and/or parallel

Active current shaping( PFC converter )

Passive Filters

Simple, low cost, robust

Sensitive to environments: line impedance, load change, ageing of component

Subject to parallel/series resonance Easily overloadable : switch off or be damaged, plant modification

Over Compensation at which have already a good power factor

Active Filters


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8

Series vs. Shunt

Shunt Tuned Filter

High voltage: 50 < Q < 150

Low voltage: 10 < Q < 50

LC

1 C

L

R

C

L

RQ

1=

C

1 L

R

FZ

)(FZ

5. Passi ve Fi l t ers


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9

LC

1 C

L

R

FZ

C

1 L

R

)(FZ

bRbR

CRb

1

Damped High-Pass Filter (2nd order)


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Non-linearload

Powersystem I5 I7 I11 Ih

IS I1

IL

5th

tunedfilter

7th

tunedfilter

11th

tunedfilter

High-passfilter

Typical Passive Filter System


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11

6. Paral l e l Resona nc e Due to load current harmonic Voltage distortion will be very high

Overvoltage

ACACACACSupplySupplySupplySupply

L

C

parallelZ

hihi

)1(11

1

2

2=

=

+= LCwhen

LC

Lj

CjLj

CjLj

Zparallel


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Para l le l Resonance w i t h Pass ive Fi l t e r

FZ

SZ

LhI

ShI LhI

FhI

FSSF ZZZ ||=

LC

1

R

C

1

L

)||( LLS

SL

1 (0dB)

CLS

1

CLLS )||(

1

Lh

Sh

I

I

SFZ

LL

L

S +

CLS2

1

Parallel resonance Tuned frequency

CLLS )(

1

+

CLLSp

)(

1

+

C

LL

RRQS

Sp

+

+

1


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13

Possible Cause of Parallel Resonance

Detuning Filter : shift of resonance frequency

Capacitance change due to fuse blow

C and L may be damaged

Temperature

Line structure change

Typical Design Practice

Tuned to slightly lower harmonic frequency (3~10%)

Effect of Ls (SCC)

High Ls : good for avoiding parallel resonance

Higher Ls : Higher Q for parallel resonance


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7. Ser ies Resonan c e

hv

DistortedDistortedDistortedDistorted


L

C

seriesZ

hi

hv

)1

(011

CLwhen

CLj

CjLjZseries

=

=+=

Due to line voltage harmonics Excessive harmonic current flow

Overload, Breakdown


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Series Resonance Due to Neighborhood Harmonic Source

1TRZPCCPCCPCCPCC

h

i

............

Plant #1Plant #1Plant #1Plant #1

2TRZ

Plant #2Plant #2Plant #2Plant #2

ACACACAC


FilterFilterFilterFilter


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Equivalent Circuits Transforms

hI

2TRZ

LIFZ1TRZ

ShV LIFZ

1TRZ 2TRZ

SZ

1TRhSh ZIV =

PCC

Series Resonancewill be occurred


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8. Troub les due to Harm onic Po l lu t ions

Heating of the electrical equipment

Trip of circuit breaker

Fuse blown Capacitor damage kWh fault Loss of motor winding and iron

Perturbing torques on the motor shaft

Damage of Sensitive electronic equipment Malfunction of PLL circuit Communication interference

Parallel and Series Resonance will occured Increase of RMS and Peak Value Excessive Neutral Currents


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9. Mot iva t ions fo r tak ing ac t ion aga ins t Harmon ics

Harmonics lead to premature ageing of the electrical Installation

Excessive amount of harmonics must eliminatefor economic reasons

The utility company impose penalties on users

Harmonic pollution may disturb equipment in other plants

THD limitation of voltage / current present at PCC

IEC 1000-3-6 : Assessment of emission limits for disturbing loadsin MV and HV power systems


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10. Func t ion of A PFs

Main function

Compensate current and voltage harmonic.

Additional functions

Current-related compensation

Reactive power, current unbalance, neutral current

Using shunt-APF for the most part

Voltage-related compensation

Voltage unbalance, flicker, spikes, regulation

Using series-APF for the most part


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Converter-based classification

VSI (Voltage Source Inverter) bridge structure

CSI (Current Source Inverter) bridge structureTopology-based classification

Shunt APF

Series APF

UPQC : Shunt APF + Series APF

Hybrid APF : Shunt or Series Active Filter + Passive Filter

Supply-system-based classification

Two-wire APF

Three-wire APF Four-wire APF

11. Class i f ica t ion o f Act ive Fi l t e rs


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12. Conver ter based c lass i f ica t ion

CSI

Switching frequency is restricted

Higher losses

Cannot be used in multilevel

VSI

Self-supporting dc voltage

Lighter, cheaper

Expandable to multilevel


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Shunt APF stand-alone

Eliminate current harmonics

Reactive power compensation

Balancing unbalanced current

Nonlinear

Load

Shunt Active Filter

iF

Nonlinear

Load

Seies Active Filter

vF

13. Topology based c lass i f ica t ion

Series APF stand-alone

Eliminate voltage harmonics

Regulate and balance the terminal voltage

Damp out harmonic propagation


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Nonlinear

Load

optional

Series Shunt

UPQC : Uni f ied Pow er Qual i t y Condi t ioner

Eliminate voltage and current harmonics

Damp out harmonic propagation

Load voltage regulation and current balancing

Another name is Universal APF Fundamental power flow control: Low power version of UPFC in FACTS

Large cost and control complexity


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Hybr id APF( Com binat ions of Pass ive-Ac t ive )

Parallel combination of shunt-APF and shunt passive filter

Current source vs. Harmonic sinkSeries combination of series-APF and series passive filter

Voltage source vs. Harmonic damping

Hybrid of series-APF and shunt passive filter

Harmonic isolation vs. Harmonic compensation

Reduced size and cost : Quite popularHybrid of shunt-APF and series passive filter

Harmonic isolation vs. Harmonic blocking

Series combination of shunt-APF and shunt passive filter

Resonance damping vs. Harmonic compensation

Parallel combination of series-APF and series passive filter

Enhancing passive filter vs. Harmonic blocking


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Nonlinear

Load

Shunt Active Filter

NonlinearLoad

Series Active Filter

Harmonic cancellation

Q control

Optimal sharing is needed

Commercialized

Harmonic damping

Existing passive filter

Low power

More circuit for Q control

Overcurrent protection

is difficult

Parallel combination ofshunt-APF and shunt passive filter

Hybrid ofseries-APF and shunt passive filter


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Nonlinear

Load

Series Active Filter

Harmonic cancellation and damping

Series-APF enhanced existing passive filter

Easy protection is possible

Current Transformer is minimized

No Q control

Under developed

Series combination ofseries-APF and shunt passive filter


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14. Supply-syst em based c lass i f ica t ion

Two-wire APF

Single-phase nonlinear loads, such as domestic appliances

Smaller rating

Three-wire APF

Three-phase nonlinear load without neutral, such as ASDs

Four-wire APF Single-phase nonlinear loads fed from four-wire supply system,

such as computers, commercial lighting

Eliminate excessive neutral current and unbalance


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Capacitor midpoint four-wire shunt APF

Used in smaller ratings,because entire neutral current flows through dc bus capacitor

Sae

Sbe

Sce

Sai

Sbi

Sci

Lai

Lbi

Lci

Cav

Cbv

Ccv

cL

n

CaiCbiCciCni

Sni

dcC

Non-Linear Four-wire

Unbalanced Loads

Lni

n

dcC


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Four-pole four-wire shunt APF Fourth pole is used to stabilized the neutral of APF

Sae

Sbe

Sce

Sai

Sbi

Sci

Lai

Lbi

Lci

Cav

Cbv

Ccv

cL

n

CaiCbiCciCni

Sni

dcC

Non-Linear Four-wireUnbalanced Loads

Lni

n


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Three-bridge four-wire shunt APF Quite common type Proper voltage matching for IGBT, Enhances the reliability of APF

Sae

Sbe

Sce

Sai

Sbi

Sci

Lai

Lbi

Lci

Cbv Ccv

n

Cai Cbi Cci

Sni

dcC

Non-Linear Four-wire

Unbalanced Loads

Lni

Cav


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First stage : Signal conditioning

Sensing system information by PT, CT, Isolation amplifiers

Monitor, measure, record

: THD, power factor, active/reactive power, crest factor

Second Stage : Derivation of compensating signal

Current level and/or voltage level

Frequency domain

: Based on Fourier transformation: Cumbersome computation, large response time

Time domain

: Based on instantaneous derivation

: pq theory, synchronous dq reference frame method, synchronous

detection method, flux-based controller, notch filter method

Third stage : Generation of gating signal

Hysteresis, PWM, SVPWM, sliding mode, fuzzy-logic

15. APF Cont ro l Stra t egies


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16. Com ponent c ons iderat ions o f APF

Series inductor : buffer between supply and PWM voltagePassive ripple filter : suppress switching harmonic and improve source THDDC bus capacitor : reduces dc ripples

Cai

Cbi

Cci

Cav

Cbv

Ccv

cL

dcCdcv

p

n

dci

dc bus capacitor

passive ripple filter

series inductor

IGBT


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17. Bas ic Conc ept o f Ac t ive Fi l t e r Cont ro l

Active Filter as a Harmonic Canceller

Harmonic current detection

AndCurrent control method

Harmonic voltage detection

AndVoltage control method

SL

Shunt-APF

fS ii = hfL iii +=

hC ii =

detectionih

Sv Li

SL

Series-APF

hC vv =

hf

S

vv

v

+=

detectionvh

Sv LifL vv =


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Active Filter as a Harmonic Damper

SL

Shunt-APF

h

hC

Z

vi =

detectionvh

Sv Li

SL

Series-APF

hhF iZv =

detectionih

Sv Li

Harmonic voltage detection

AndCurrent control method

Harmonic current detection

AndVoltage control method


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18. Cont ro l Based on Sync hronous d-q Transform at ion

Definition of Synchronous d-q transformation

3

2,

)sin()sin(sin

)cos()cos(cos

3

2

=

+

+=

where

f

f

f

f

f

c

b

a

q

d

=

=

s

q

s

d

ee

ee

e

q

e

d

e

q

e

d

ee

ee

s

q

s

d

f

f

f

f

f

f

f

f

cossin

sincos,

cossin

sincos

=

=

+=+=

+=+=

mk qkm

e

qh

e

q

e

q

mk

dkm

e

dh

e

d

e

d

iIiii

iIiii

311

3

11

sin

cos

Transformed current with harmonics

( ) ( )

( ) ( )[ ]

( ) ( )[ ]ke

k

mkemb

ke

k

mkemb

ke

k

mkema

kIIi

kIIi

kIIi

+++=

+=

+=

=

=

=

coscos

coscos

coscos

2

1

2

1

2

1


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Axes re lat ion be tw een abc and dq

Stationary frame Synchronously rotating frame

aa ff =

3

2j

bb eff =

3

2j

cc eff

=

s

df

s

qf

aa ff =

3

2j

bb eff =

3

2j

cc eff

=

s

df

s

qf

e+

e+

e

d

fe

q

f

e


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D-Q var iable in t im e dom ain

Sae Sbe Sce

mE

2

te

t

s

Sqes

Sde

mE

2te

e

Sde

e

Sqe

mE

2

te

Stationary

Synchronously


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Harmon ic loc us in Space Vect or

5th in stationary frame 7th in stationary frame

tj

m

tj

m

sss

dqee eFeFfff

5

515

1

5

1 +=+= tjmtj

m

sss

dqee eFeFfff

7

717

1

7

1+=+=

s

dqf

e

sf1

sf5

e5

s

df

s

qf

s

dqf

e

sf1

sf7

e7

s

df

s

qf


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5

th

and 7

th

in stationary frame 5

th

and 7

th

synchronous rotatingvariable in stationary frametj

m

tj

m

tj

m

ssss

dqeee eFeFeFffff

75

7517

1

5

1

7

1

5

1++=++=

tj

m

tj

mm

eeee

dqee eFeFFffff

66

7517

1

5

1

7

1

5

1++=++=

s

df

e

dqf

sqf

sdqf

e

sf1

s

df

s

qf


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Overa l l bloc k d iagram of shunt -APF c ont rol l er

Lai

Lbi

e

Ldi

e

Lqi

LPF

e

Ldi

===

)1(0

)0(

K

Kii

e

Lde

Sd

+

LPF

+

1-K

e

Lqie

Lq

e

Sq ii =

*e

Cdi

*e

Cqi+

IPcontroller

*dcv

dcv

+

synchronous

PI-controller

ee

*e

Cdv

*e

Cqv

seTjk

e

*'e

Cdv

*'e

Cqv

e

3 se

*s

Cdv

*s

Cqv

SVPWM

*aT

*bT

*

cT

e3

Cai

Cbi

e

Cdi

e

Cqi

HarmonicPhase DelayCorrection


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Harm onic Phase Delay Correct ion Met hod

)(*ki

e

C

LPF

)(*1 kie

C

)(*

5 kie

C

)(*

7 kie

C

5CI

7CI

seTj

e

6

LPF

5th Harmonic detection

7th Harmonic detection

+

seTje6

)(*

11 kie

C

)(*

13 kie

C

+

+

+

+

LPF1CI

Fundamental detection

+

+

+

)1(*1 +kie

C

)1(*

5 +kie

C

)1(*7 +kie

C

+

+

+

+

+

+

)1(*

11 +kie

C

)1(*

13 +kie

C

+

+)1(* +ki eC

eje6

ej

e

6 ej

e

6

eje6

Harmonic phase delay correction in synchronous rotating frame


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19. Cont rol Bas ed on p-q Theo ry

=

=

c

b

a

c

b

a

e

e

e

C

e

e

e

ee

2

3

2

30

2

1

2

1

132

=

=

c

b

a

c

b

a

i

i

i

C

i

i

i

ii

2

3

2

30

2

1

2

1

132

aa ie

,

bb ie

,

cc ie

,

32

32

32

a-Axis

b-Axis

c-Axis

0

ie

,

ie

,

-Axis

-Axis

0

- Transfomations


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ccbbaa ieieiep ++=

ieieiepieiep

+==+= ,

ieieieqieieq

+=== ,

Conventional instantaneous power

ie

ie

e

i

ie

REAL PLANE

IMAGINARY AXIS

-Axis

-Axis Instantaneous real power

Instantaneous imaginary power

=

=

q

p

ee

ee

i

i

i

i

ee

ee

q

p 1,

Instantaneous power vs. current


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p and q in Sinusoidal Case

tVva cos2=

)cos(2 += tVvb

)cos(2 = tVvc

)cos(2 = tIia

)cos(2 += tIib

)cos(2 = tIic

tVv cos3=

tVv sin3=

)cos(3 = tIi

)sin(3 = tIi

cos3VIivivp =+=

sin3VIivivq ==


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p and q in Non-Sinuso idal Case


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Overa l l bloc k d iagram of ser ies-APF c ont rol le r

Fav

Fbv

Fcv

HPF

HPF

Fv

Fv

Sai

Sbi

Sci

Si

Si

p

q

hp

hq

a

b

c

d

q

0=

a

b

c

d

q

0=

=

S

S

FF

FF

i

i

vv

vv

q

p

=

h

h

FF

FF

hS

hS

q

p

vv

vv

i

i1

hSi

hSi

a

b

c

d

q

0=

K

K

K

Sahi

Sbhi

Schi

*Cav

*Cbv

*Ccv


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20. Se lec t ion o f APF for spec i f ic c ons iderat ions

9. Voltage Sag & Dips

8. Voltage Flicker

7. Voltage Balancing

6. Voltage Regulation

5. Voltage Harmonics

4. Neutral Current

3. Load Balancing

2. Reactive Power

1. Current Harmonics

UPQCHybrid-APFSeries-APFShunt-APF

Active Power Filters TopologyCompensation forspecific application

Higher number of is more preferred

A-Seminar-A Review of Active Power Filter

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