Virtual ResistanceVirtual Resistance

Line conditioner Block Diagram:

0

1

sC

iv

d 0vCoi

0i

LeqiˆLeqvoV

N

1

eqs L

N D

N

D

N

o

L

V

Z N D

VirtualR

PWMG Vc s

0

Virtual

PWM

N R

V G

d

Converter ControlConverter Control

T

a

6D

5D

b7D

8D 4D

3D

1D

D

0( )v t()iv t

1S 2S 3S 4S

_o refv5S 6S 7S 8S

SrrvSrrv

2

vC (s)

Sensorde

Tensão

Red

e de

Ene

rgia

SR SLdPL

Car

ga

Compensador de TensãoModulador

Modulador

5S

6S

7S

8S

1S

2S

3S

4S0C

ComandoSensorde

Corrente

cI ( )s

0

RvC ( )s

Compensador de Rvirtual

Experimental ResultsExperimental Results

220 20% ViV

220 VoV

10 kVAoS

60 HzrF

20 kHzSF

4N

340 HeqL

20 FoC

PrototypePrototype

TTransformer

Voltage Sensor

Current Sensor

Command-control Board

Load Bar

Power Stage

Soft-Starter

Fan

Input voltage

Driver power Supply

Control SignalsControl Signals

ac-ac converter voltage signalsac-ac converter voltage signalsRectifier Inverter

Operation with Load TransientOperation with Load Transient

Without Virtual Resistance Control Loop With Virtual Resistance Control Loop

50% Load Transient

• • +20% transient in input voltage Vi(t):+20% transient in input voltage Vi(t):

Operation with input TransientOperation with input Transient

• • -20% transient in input voltage Vi(t):-20% transient in input voltage Vi(t):.

Operation with input TransientOperation with input Transient

• • THD correctionTHD correction::

Operation with input TransientOperation with input Transient

Nonlinear load OperationNonlinear load Operation

ov

100 H

10mF

10 The greatest requirements in terms of dynamic

response.

• Experimental Results:

• The control strategy was efficient with instantaneous correction of the output voltage when faced with input voltage and load variations;

ConclusionsConclusions

• Capability of supplying an output voltage with low harmonic distortion;

• When presented with the worst case scenario, a nonlinear load, the conditioner studied was able to correct the THD to fit the required standards of 5% (IEEE519/92);

ConclusionsConclusions

• A generalization of serial line conditioners was presented through 12 possible topologies;

• A control strategy was introduced to efficiently stabilize the output voltage of the studied structure;

.

• Contributions:

• This work focused on the study of a serial line conditioner with an ac-ac indirect converter with direct link, fed by load side. The capacitive filter was positioned on the load side to make use of the line impedance as a multi-functional filter;

ConclusionsConclusions

• Study of three-phase voltage line conditioners:

• Future works:

- Space vector Modulation;

- Digital Control and Nonlinear Control Techniques;

- Study of Rectifier control techniques;

- Study of combined series and shunt active power filters for simultaneous compensation of voltage and current;

- Hybrid and Matrix Converters;

The EndThe End