pulse pattern modulated strategy for harmonic current ...€¦ · pulse pattern modulated strategy...

Pulse Pattern Modulated Strategy for Harmonic Current Components Reduction in

Three-Phase AC-DC Converters

P R E S E N T E R : P O OYA DAVA R I

2 4 S E P 2 0 1 5

WWW.NHTD.ET.AAU.DK

Pooya Davari 1, Firuz Zare 2 and Frede Blaabjerg 1

1Department of Energy Technology, Aalborg University, Denmark

2Danfoss Power Electronics A/S, Grasten, Denmark

2

Introduction

Electronic Inductor Concept

Proposed Method

Experimental Results

Future Development & Conclusion

Outline

ECCE 2015

3 Introduction

Typical Three-Phase Motor Drive System

LdcDiode Rectifier

CdcGrid

InverterLac

Lac

Lac

IM

Non-sinusoidal current

Zg

Zg

Zg

AC or DC side passive filtering (inductor): simple and effective to some extent. But they are bulky, costly, causes resonance, worsen system dynamic, and etc.

Active harmonic mitigation solutions have been introduced to improve the input current quality. But most of them are complex, costly and reduce system efficiency.

ECCE 2015

Simple

Cost effective

Efficient

AC or DC side passive filtering After passive filtering (THDi ≈ 40%)

Before passive filtering (THDi > 120%)

ia,n/ia,1

Harmonic order (n)

AC/DC

4 Introduction

Three-Phase Diode Rectifier with DC Side Passive Filtering

Vph,rms = 3 X 220 V

fg = 50 Hz

Po = 3 kW

Cdc = 470 µF

20 mH 4 mH

λ

LdcDiode Rectifier

Cdc


iabc

ZgGrid

vabc

Vo

RL

Vr

20

10

0

-10

-20

400

-400

-200

0

200

0 5 15 2010

t (ms)

Cu

rre

nt (A

)

Vo

lta

ge

(V

)

van

ia,(4mH) ia,(20mH)

THDi = 63% THDi = 31%

ECCE 2015

5 Introduction

Three-Phase Diode Rectifier with DC Side Passive Filtering

Vph,rms = 3 X 220 V

fg = 50 Hz

Po = 0.75 kW – 3 kW

Ldc = 8mH

Cdc = 470 µF

3 kW

1.5 kW

LdcDiode Rectifier

Cdc


iabc

ZgGrid

vabc

Vo

RL

Vr

The effective impedance reduces proportionally with the reduction in the load current.

λ

20

10

0

-10

-20

400

-400

-200

0

200

0 5 15 2010

t (ms)

Cu

rre

nt (A

)

Vo

lta

ge

(V

)

van

ia,(1.5 kW) ia,(3 kW)

THDi = 60% THDi = 39%

6 Electronic Inductor

Basic Concept

Diode Rectifier

Grid

Lg

Lg

Lg

Vo

Cdc

Rg

Rg

Rg

ia

Idc

RL

VrVa

Emulating the behavior of an ideal infinite inductor

λ ≈ 0.95

THDi ≈ 30%

THDi and Power Factor (λ) independent of the load profile.

ECCE 2015

7 Proposed Method

Grid

Lg

Lg

Lg

Vo

Cdc

Rg

Rg

Rg

ia

RL

Ldc D

iL

DC-DC

va

vb

vc

vr

ia

Idc1 2π

ωt

ωt

ωt

S

iL

ib

icib

ic

2π

2π

2π

Idc1

ꜛ ꜛ

120o

ꜛ ꜛ

120o

ꜛ ꜛ

120o

ꜛ ꜛ

30o

ꜛ

ꜛ

Idc1

ꜛ ꜛ

Idc1

ꜛ

ꜛ

ωtDiode Rectifier

30oꜛ

ꜛ

π

Zg

van

Grid

Lg

Lg

Lg

Vo

Cdc

Rg

Rg

Rg

ia

RL

Ldc D

iL

DC-DC

va

vb

vc

vr

ia

Idc1 2π

ωt

ωt

ωt

S

iL=(|ia| + |ib|+ |ic|)/2

ib

ic

ib

ic

2π

2π

2π

Idc2

Idc1

Idc2

ꜛ

ꜛ

ꜛ

ꜛ

ꜛ ꜛ

θ

β

ꜛ ꜛ

2β ꜛ ꜛ

ꜛ ꜛ

120o

ꜛ ꜛ

120o

ꜛ ꜛ

120o

ꜛ ꜛ

30o

2β ꜛ ꜛ

ꜛ ꜛ

θ

Idc2

Idc2

ꜛ

ꜛ

ꜛ

ꜛ ꜛ

ꜛ

Idc1

ꜛ

ꜛ

Idc1

ꜛ

ꜛ

ωtDiode Rectifier

30oꜛ

ꜛ

π

Zg

van

ECCE 2015

8 Proposed Method

Harmonic Elimination

van

ia

Idc1

-Idc1

-Idc2

Idc2

Idc2

-Idc2

120o

30o

α1

α2

β β 2β

30o ωt

ωt

ωt

ωt

θ θ

2π

2π

2π

2π

π

π

π

π

π/2

Adding or subtracting phase-displaced current levels

+

+

=

9 Proposed Method

Harmonic Elimination

van

ia

Idc1

-Idc1

-Idc2

Idc2

Idc2

-Idc2

120o

30o

α1

α2

β β 2β

30o ωt

ωt

ωt

ωt

θ θ

2π

2π

2π

2π

π

π

π

π

π/2

Targeting up to two low order harmonics

ECCE 2015

10 Proposed Method

Increasing number of levels

Targeting higher number of low order harmonics

ECCE 2015

ia

π

2

iavan

ωtπ

2π

π

6α1α2 αm

Idc1

Idc2

Idc3

Idcm

α1α2 αm

π

3π

3π

3

+ + +

1 1 1

2

4 1 2cos cos( ) cos

6 3

m

n dc dck k dck k

k

i I n I n I nn

1 2 36 2

m

11 Proposed Method

ECCE 2015

Optimum Harmonic Solution

1 1(1)

(n)

(1)

a g

g

n n

g

Obj M i L

iObj L

i

2

obj n n nF w Obj L

0 1 2 0

3m

where n = 6k±1 with k being 1, 2, 3, ….

Instead of fully nullifying the distortions, the harmonics could be reduced to acceptable levels by adding suitable constraints (Ln).

Constraint

Objective Function Weighting Factor

Here, Fobj is formed based on a squared error with more flexibility by adding constant weight values (wn) to each squared error function

12 Proposed Method

System Structure

Employing conventional boost converter

Employing fast current control method

Boosting the output voltage

ECCE 2015

Ldc D

S

Boost Converter3ph Diode Bridge

iL

Vo

Cdc

Vr

Load

+-

+-

Vo

PIiL

Modulation

Signal

iava

Grid

SOGI-PLL

Lg Rg

iLω0t

iM

*

*

13 Proposed Method

ECCE 2015

ia

Idc1 2π ωt

ωt

ωt

iM

ib

ic

2π

2π

2π

Idc2

Idc1

Idc2

θ

β

2β

120o

120o

120o

30o

θ Idc2

Idc2

Idc1

Idc1

ωt

30o

2β

+ iM

ia

ib

ic

+

1/2

abs( )

abs( )

abs( )

|sin(3ω0t)|

β β

β

α1 α11

1 11

0

1 2

1

:

( sin(3 ) sin(3 ))

M dc dc

M dc

if t

i I I

else

i I

Synthesis of the modulation signal

1 11

0

1 2

1

:

( sin(3 ) sin(3 ))

M dc dc

M dc

if t

i I I

else

i I

14 Experimental Setup

Vph,rms = 3 X 220 V

Po = 3 kW

Vo = 700 Vdc

Ldc = 2 mH

Cdc = 470 µF

ECCE 2015

Ldc D

S

Boost Converter3ph Diode Bridge

iL

Vo

Cdc

Vr

Load

+-

+-

Vo

PIiL

Modulation

Signal

iava

Grid

SOGI-PLL

Lg Rg

iLω0t

iM

*

*

15 Experimental Results

Harmonic Elimination [7th and 13th]

Vph,rms = 3 X 220 V

Po = 3 kW

Vo = 700 Vdc

Ldc = 2 mH

Cdc = 470 µF

Harmonic Mitigation

Strategy

Harmonic Distribution and THDi (%)

ia (5)/ ia (1) ia(7)/ ia (1) ia(11)/ ia (1) ia (13)/ ia (1) THDi

7th and 13th harmonic

cancellation 32.7 0.5 9.4 0.8 35.3

Conventional method

(square wave) 20.8 13.1 8.8 7 29

Idc1 = 1, Idc2 = 0.618, α1= 42o

ECCE 2015

5ms/div

200Hz/div

5A/div

350mA/div

ia ib ic

5th

7th

11th

13th

32.7%

0.5%

9.4%

0.8%

FFT of the grid current (ia)

van:290V/div

16

Vph,rms = 3 X 220 V

Po = 3 kW

Vo = 700 Vdc

Ldc = 2 mH

Cdc = 470 µF


Harmonic Elimination [7th, 11th, 13th]

Harmonic Mitigation

Strategy

Harmonic Distribution and THDi (%)


7th, 11th, 13th harmonic

cancellation 38.4 8 4.5 3.4 41.1

Conventional method

(square wave) 20.8 13.1 8.8 7 29

Idc1 = 1, Idc2 = 0.733, α2= 38.3o Idc3 = 0.733, α2= 51.5o

ECCE 2015

5ms/div

200Hz/div

5A/div

350mA/div

ia ib ic

5th 7

th11

th13

th

38.4%

8%3.4%


van:290V/div

4.5%

17

Dynamic Behavior

Vph,rms = 3 X 220 V

Po = 3 kW

Vo = 700 Vdc

Ldc = 2 mH

Cdc = 470 µF


Startup

Shutdown ECCE 2015

ia:10A/div

vo:100V/div

van:100V/div 20ms/div

ia:10A/div

vo:100V/div

van:100V/div 20ms/div

18 Results

Harmonic Mitigation Strategy Harmonic Distribution and THDi (%)


7th and 13th harmonic cancellation 32.7 0.5 9.4 0.8 35.5

5th and 13th harmonic cancellation 2.1 38.5 25.4 1.5 48.6

Conventional method (square wave) 20.8 13.1 8.8 7 29

Harmonic Distribution of different cases


ECCE 2015

5ms/div

200Hz/div

3A/div

350mA/div

ia ib ic

5th

7th

11th

13th

2.1%

38.5%

25.4%

1.5%


Idc1 = 1, Idc2 = 0.653, α1= 70o Idc1 = 1, Idc2 = 0.618, α1= 42o

5ms/div

200Hz/div

3A/div

350mA/div

ia ib ic

5th

7th

11th

13th

32.7%

0.5%

9.4%

0.8%


Targeting 7th and 13th Targeting 5th and 13th

19 Future Development

Mixing nonlinear loads

ia

Harmonic order (n)

i a,n/i

a,1

THDi = 5.7%

0.5% 0.7%

Conventional 12-pulse rectifier achieves 10%<THDi<15% depending on the output power level. Applying the proposed method improves the THDi to 5.7%.

Targeting 11th and 13th harmonics

ECCE 2015

iabc

Grid

Zg

Ldc

vo

30o

Ldc

Cdc RL

iL1


Mixing nonlinear loads Adding more current levels

Conventional 18-pulse rectifier achieves 4%<THDi<7% depending on the output power level. Applying the proposed method improves the THDi to 3.8%.

Targeting 11th, 13th, 23th and 25th harmonics

ECCE 2015

ia

Harmonic order (n)

i a,n/i

a,1

THDi = 3.8%

2.5%

2.8%

iabc

Grid

Zg

Ldc

vo

30o

Ldc

Cdc RL

iL1


Mixing nonlinear loads

iabc

Grid

Zg

Ldc

vo

30o

Ldc

Cdc RL

M~

M~

M~

ASD1 ASD2 ASDn

PCC

Efficiency

ECCE 2015

22 Conclusion

Employing electronic inductor concept in three-phase front-end rectifiers

Further developments

Introducing pulse pattern at the DC-link (proposed method)

Obtaining THDi≈ 30%, λ ≈ 0.95

Achieving THDi and λ independent of the load profile

Eliminating specific harmonic orders

Achieving THDi and λ independent of the load profile

Validated through a hardware prototype

Studying different configurations such as multi-pulse rectifiers and multi-drive systems

System efficiency (i.e., having adjustable switching frequency)

ECCE 2015

23

Thank You

www.NHTD.et.aau.dk ECCE 2015

pulse pattern modulated strategy for harmonic current ...€¦ · pulse pattern modulated strategy...

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