021 - Evaluation of an Advanced Harmonic Filter for Adjustable Speed Drivesusinga Toolbox Approach

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www.danfoss.com021-Evaluation of an Advanced Harmonic Filter for Adjustable Speed Drives using a Toolbox Approach

NORPIE, 2004, Trondheim, Norway

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Evaluation of an Advanced Harmonic Filter for

Adjustable Speed Drives using a Toolbox Approach

Nordic Workshop onPower and Industrial Electronics

NORPIE / 2004June 14-16, 2004, Trondheim, Norway

Aalborg UniversityInstitute of Energy TechnologyDk-9220, Aalborg, Denmark

Lucian Asiminoaei, Steffan Hansen, Frede Blaabjerg

Danfoss Drives A/S

Dk-6300, Graasten, Denmark

Presented by Lucian Asiminoaei


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Outline

1. Introduction

2. Harmonic Calculation Toolbox

3. Filter Description and Analysis

4. Validation of the Harmonic Toolbox

5. Design Case

6. Conclusion


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1. Introduction

Harmonic facts (in general)

- Continued increase of the electrical applications

- Increase of the harmonic distortion on the grid

- Harmonic limitation standards

- Demands for the harmonic calculation reports in design

- Assessment of the harmonic emission level

- Decision to install apropermitigation solution

Common industrial applications

- Adjustable Speed Drives (ASDs)

- Typical front-end topology: 3-phase rectifier

- Harmonic emission issues

- Solutions to reduce harmonics

Passive solutions

Active solutions

Other type of solutions

Ldc

Cdc

Ls

Io

Idc

UI

saUsa

Usb

Usc

Isb

Isc

Ls

dc

Motor

Inverter


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1. Introduction

How to compare different mitigation solutions?

- Line-reactors, dc-link reactors

- Types of passive filters

- Multi-pulse drives

Comparison criteria

- Harmonic indices (ex. ih, THDi, THDv, TDD, PWHD)- Cost of the equipment and installation

- Maintenance and engineering

- Life time and failure rate

TransformerGrid

Ldc

6-pulse

rectifier

Generic

LoadCdc

?




5


The user-interface of the harmonic toolbox

Initially developed for the 6-pulse ASD with only:

Line reactor (Lac)

Dc-link reactor (Ldc)

Graphical interface from the harmonic toolbox Danfoss MCT 31.

Input parameters requiredfor the harmonic calculation




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Harmonic calculation

- Different methods of modeling:

The characteristics of the existing toolbox

- Simplicity in implementation

- Practical-used input parameters

- Not used for advanced design

- Provides an acceptable accuracy

-The actual goals

- Integration of the Advance Harmonic Filter

Numerical(Simulated)

Analytical(Mathematical)

Table Based(Empirical)

Ideal(Theoretical)

Level IVLevel I Level IIILevel I I

LowAccuracy

Few

High

Parameters Many




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Harmonic currents

Empir ical /

Table Based

Simulations

Analytical

Database

Input

parameters

Harmonic currents

Interpolation

Experiments

Toolbox

Usage

Toolbox

Development

Table Based Approach

Other related

harmonic data

vh, THDi, THDv, PF, Losses

ih

Database

ih




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3. Filter description and analysis

Advanced Harmonic Filter

- A passive harmonic filtering solution

- Dedicated for 6-pulse ASDs (Danfoss)

- Reduce the THDi:

AHF010: THDi=10%, nominal load ASD

AHF005: THDi= 5%, nominal load ASD

Analysis

- Initial assumptions:

sinusoidal voltages

balanced system

parameter linearity

- Establishing the number of input parameters:

ac-reactance

Load

- The results:

Harmonic currents 6k+1, up to the 50th order

),()( loadacASDAHFh RLfi 0

LacVc

D3Advanced

Harmonic Filter

Vb

D1

Cload

D4

D5

Va

Lac

D6

Ldc

D2

Lac

Rload6-pulse

ASD

ih(AHF+ASD)

Principle one-line diagram of

the Advance Harmonic Filter




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3. Filter description and analysis

Simulations

ac-reactance, Lac:

0% - 25% / ( 1% increment)

Load:

10% - 160% / (20% increment)

Collecting the results

- database for each harmonic current

DataBase(Lac, Load)

Minimizing the database

- Dominant harmonics: 5th, 7th

- Higher Harmonics > 11th(in total: 14 harmonic currents)

0 50 100 150 2000

1

2

3

4

Load [%]

i11/i1

[%]

Lac=0%4%8%12%16%24%20%

Simulated and estimated 11th harmonic currentfrom the AHF in respect to the load variation.

05

1015

2025 0

50100

150

0

0.5

1

1.5

2

2.5

3

3.5

4

Load [%]

i11/i1

Lac [%]

Simulated harmonic currents versus load and ac-reactance Lac

for the 6-pulse ASD with the AHF.a) 5th harmonic current, b) 11th harmonic current

i5/i1

a) b)

( ) ( , )h AHF ASD aci DataBase L Load Reduction 0%

( )( , ) (0, ) ac

f L

h ac hi L Load DataBase Load e

k

cxbxaxxfLf ac

)]()[()()(

2

a=-0.026415, b=0.58113

c=0.30377, k=15.5

Reduction 90%




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4. Validation of the toolbox

Laboratory experiments

2 cases for validation:

ASD alone

ASD with AHF

Circuit diagram with the AHF010 connected to the ASD.

Snom=3 kW

Three phase ASDLs= 8 mH

Cdc=200F

Measuredcurrent

400 V / 50 Hz

Lac(Grid)

Power

Supply

Load

3 kW

AHF

010

Advanced Harmonic

Filter, THDi 10%

(a)

(b)

Comparison of laboratory measurements and harmonic toolbox results.

Input parameters


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021-Evaluation of an Advanced Harmonic Filter for Adjustable Speed Drives using a Toolbox Approach


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5. Case study

Circuit diagram of the water pump station.

MotorSnom=50 kVA

Three phaseASD

Measurements

PCCex=5%, er=1%Sxfr=200 kVA

MV=10.4 kV LV=400 V

Cable

Case study

- Water pumping station application with ASD

- Only limited data are available

Input parameters

Comparison of measurements and harmonic toolbox results.





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5. Case study

Possible solutions

- Intention to minimize the harmonic currents

- Investigation of:

additional Lac

AHF010 (10%)

AHF005 (5%)

TransformerGrid

Ldc

6-pulse

rectifier

Generic

LoadCdc

?

Lac

AHF010

AHF005

Toolbox harmonic results with the proposed solutions for

the water pumping station. a) Harmonic currents. b) Harmonic voltages.

Comparisons of the harmonic indices (THDi and THDv)

for the proposed solutions and the actual measurement at full load.





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5. Conclusion

Investigation of the harmonic currents from a dedicated harmonic filter for ASD

The currents are expressed as a function of 2 dependencies

The amount of data is minimized by analytical expressions

Some initial ideal assumptions are considered

The achieved data are integrated into an existing harmonic calculation toolbox for 6-pulse ASD

Comparisons between different harmonic mitigation solutions can be tested

Such toolbox proves to be of practical use due to the minimum required input parameters

( )( , )

h AHF ASD aci f L Load

( )( , ) (0, ) ac

f L

h ac hi L Load DataBase Load e


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Thank You for Attendance!

If there are questions?

Toolbox downloadDanfoss VLT MCT 31 Harmonic Calculation Software

http://drives.danfoss.com/SW/DDsoftwaredownload/en

021 - Evaluation of an Advanced Harmonic Filter for Adjustable Speed Drivesusinga Toolbox Approach

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