Federal Federal UniversityUniversity ofof Santa Santa CatarinaCatarina -- UFSCUFSCPostPost--graduation in Electrical Engineering graduation in Electrical Engineering -- PPGEELPPGEEL
Study and Design of a Voltage Line Conditioner Study and Design of a Voltage Line Conditioner with Serial Compensation and Fed by Load Sidewith Serial Compensation and Fed by Load Side
Master Thesis PresentationMaster Thesis Presentation::
July, 2007
Power Electronics Institute Power Electronics Institute -- INEPINEP
Eng. MSc Thiago Batista Soeiro
Presentation ContentsPresentation Contents
•• IntroductionIntroduction
•• Voltage Line Conditioner: Power StageVoltage Line Conditioner: Power Stage
•• Voltage Line Conditioner: Control StageVoltage Line Conditioner: Control Stage
•• Experimental ResultsExperimental Results
•• ConclusionsConclusions
MotivationsMotivations
22-- The existence of standards limiting the harmonic pollution in The existence of standards limiting the harmonic pollution in electric power systemelectric power system;;
33-- To aid the national industries in the development of highTo aid the national industries in the development of high--quality quality voltage sources.voltage sources.
11-- The increase of voltageThe increase of voltage--sensitive equipments results in greater sensitive equipments results in greater demand for highdemand for high--quality voltage sources;quality voltage sources;
33-- To evaluate the performance of the topology proposed under To evaluate the performance of the topology proposed under unbalanced and distorted system voltagesunbalanced and distorted system voltages;;
Main ObjectivesMain Objectives
44-- To study and formulate control techniques to provide the To study and formulate control techniques to provide the conditioning of the load voltage conditioning of the load voltage
22-- To establish general voltage compensation methods to be applied To establish general voltage compensation methods to be applied in voltage line conditionersin voltage line conditioners;;
55-- To develop and test a voltage line conditioner prototype to To develop and test a voltage line conditioner prototype to validate the analysis.validate the analysis.
11-- To study concepts and topologies of voltage line conditionersTo study concepts and topologies of voltage line conditioners;;
1S
2S
3S
4S
5S
6S
7S
8S
oL
oC
a b
+−
riv+ −
dsv
Inverter
Rectifier
•• TheThe Principle of Serial Voltage Principle of Serial Voltage CompensationCompensation, applied in Stabilizers in , applied in Stabilizers in 1950 by 1950 by PatchettPatchett
The Studied Topology was based on two The Studied Topology was based on two concepts:concepts:
• Indirect acIndirect ac--ac Converter with ac Converter with Direct link presented by BongDirect link presented by Bong--
Hwan Kwon in 2002Hwan Kwon in 2002
riv
rv
dpv
Important ConceptsImportant Concepts
iv
oi
+− riv
+
−
( ), ,o i ov v i d
+
−
LZ d
The Voltage Line Conditioner Operation Principle:The Voltage Line Conditioner Operation Principle:
Important ConceptsImportant Concepts
= +i F Hv v v
= +o F Hi i i
+− riv
ov
′iv dsv
+− = +ds dsF dsHv v v
ov
′iv
+ =
SZ
Voltage Line ConditionerVoltage Line ConditionerGeneralization of Serial Voltage Conditioners:Generalization of Serial Voltage Conditioners:
•• The Serial Voltage CompensationThe Serial Voltage Compensation::
Car
ga
ov+
−iv+
−
vΔ +−
ConversorCA-CA
Inversor
Conversorca ca−
Direct CompensationDirect Compensation
vΔ +−
Car
ga
ov+
−iv+
− Conversorca ca−
TransfTransf. + Filter. + Filter
vΔ +−
Car
gaov+
−iv+
− ConversorCA-CA
Inversor
Conversorca ca−
vΔ +−
Car
ga
ov+
−iv+
− ConversorCA-CA
Inversor
Conversorca ca−
TransfTransf. + . + FilterFilter
Filter by the load sideFilter by the load side
Voltage Line ConditionerVoltage Line Conditioner
•• Feeding the Feeding the acac--ac Converter:ac Converter:
Car
gaov+
−iv+
−
ConversorCA-CA
Inversor
Compensadorsérie
Car
ga
ov+
−iv+
−
ConversorCA-CA
Inversor
Compensadorsérie
ByBy thethe LineLine SideSide
ByBy thethe LoadLoad SideSide
Voltage Line ConditionerVoltage Line Conditioner
Car
ga
ov+
−iv+
−
ConversorCA-CA
Inversor
Compensadorsérie
auxv+ −
Auxiliary SourceAuxiliary Source
Voltage Line ConditionerVoltage Line Conditioner
•• acac--ac Converter Isolation:ac Converter Isolation:
By the By the Rectifier sideRectifier side
By the By the inverter sideinverter side
+
−
ov
+
−
+− dsv
iv
oLoC
1T +
−fv
Converterac ac−
Inverter
+
−
ov
+
−
+− dsv
iv
oLoC
1T+
−fv
ConversorCA-CA
Retificador Inversor
Converterac ac−
Inverter
Voltage Line ConditionerVoltage Line Conditioner
•• Conditioner Topologies:Conditioner Topologies:
Voltage Line ConditionerVoltage Line Conditioner
Fed by the line sideFed by the line side
+
−
ov
+
−
+− dsv
iv
oLoC
1T +
−fv
Converterac ac−
Inverter
ov
+
−
+− dsv
oL
oCfv
ConversorCA-CA
RetificadorInversor
Converterac ac−
Inverter
1T+
−
iv
+
−
ov
+
−
+− dsv
iv
oLoC
1T+
−fv
ConversorCA-CA
Retificador Inversor
Converterac ac−
Inverter
ov
+
−
+− dsv
oL
oCfv
ConversorCA-CA
RetificadorInverso r
Converterac ac−
Inverter
1T+
−
iv
•• Conditioner Topologies:Conditioner Topologies:
Fed by the load sideFed by the load side
Voltage Line ConditionerVoltage Line Conditioner
+
−
ov
+
−
+− dsv
iv
oLoC
ConversorCA-CA
1T
fvRetificadorInversor
Converterac ac−
Inverter
+
−
ov
+
−
+− dsv
iv
oL
fv
ConversorCA-CA
RetificadorInversor
Converterac ac−
Inverter
1T
oC
+
−
ov
+
−
+− dsv
iv
oLoC
1T
fv
ConversorCA-CA
RetificadorInversor
Converterac ac−
Inverter
+
−
ov
+
−
+− dsv
iv
oL
oCfv
ConversorCA-CA
RetificadorInversor
Converterac ac−
Inverter
1T
•• Conditioner Topologies:Conditioner Topologies:
Fed by an auxiliary sourceFed by an auxiliary source
Voltage Line ConditionerVoltage Line Conditioner
+
−
ov
+
−
+− dsv
iv
oLoC
ConversorCA-CA
1T +
−fv
Retificador Inversor
Converterac ac−
Inverter
ov
+
−
+− dsv
oL
oCfv
ConversorCA-CA
RetificadorInversor
Converterac ac−
Inverter
1T+
−
iv
+
−
ov
+
−
+− dsv
iv
oLoC
1T+
−fv
ConversorCA-CA
Retificador Inversor
Converterac ac−
Inverter
ov
+
−
+− dsv
oL
oC
ConversorCA-CA
RetificadorInverso r
Converterac ac−
Inverter
1T+
−
iv fv
Voltage Line Conditioner:Voltage Line Conditioner:Power StagePower Stage
1S
iv
+
−2S
3S
4S6S
7S
8SoC
1T
a b
+− dsv
oL
S dsL L+
5S
rv
Inverter Rectifier
Loiov
+
−
oi
Modulation StrategyModulation Strategy
0
2rT rT
t
0 ( )v t
( )rv t
1,4 ( )S t
2,3 ( )S t
Bidirectional Rectifier (S1 - S4)
PWM Inverter (S5 - S8)
Main WaveformsMain Waveforms
3 Level PWM Modulation
Rectifier
Inverter
iv
Adding voltage Subtracting voltage
0 π 2π 0 π 2π
1,4gv
2,3gv
rv
cv
abv
dsv
oviv
2sT
d ⋅2sT0
t t
ovRectifier input voltage Rectifier input voltage
Main Analytical ExpressionMain Analytical Expression
( )( )
Ng tN d t
=−
( ) ( )( )0 12Leq
s eq
V d t d tI
N f L⋅ ⋅ −
Δ =⋅ ⋅ ⋅
( )( ) ( ) ( )( )( )( ) ( )
2 116 4 1
Leq oCo
S o S o Leq
I N d t I d t d tV
N f C f C I N d t NΔ ⋅ − ⋅ ⋅ −
Δ = +⋅ ⋅ ⋅ ⋅ ⋅ ⋅Δ ⋅ − ⋅ −
Converter’s Static Gain
Voltage ripple
Transformation ratio
Current ripple
( )1N d t= ⋅Δ
Voltage Line Conditioner: Voltage Line Conditioner: Control StageControl Stage
0( )v t()iv t
1S 2S 3S 4S
_o refv5S 6S 7S 8S
+−SrrvSrrv vC (s)
Sensorde
Tensão
Red
e de E
nerg
ia
SR SL dPL
Car
ga
Compensador de TensãoModulador
Modulador
5S
6S
7S
8S
1S
2S
3S
4S0C
Comando
Mathematical ModelMathematical Model
•• Small signals model:Small signals model:• G(s), Transfer Function of output voltage vs. duty cycle;
( )
• F(s), Transfer Function of output voltage vs. input voltage .
( ) ( )
( )
2
222 2
eq oo
Lo
eqeq o
L
s L N VV N D
Z N DvG s
s L Nd s L C N N DZ
− ⋅ ⋅ ⋅+ ⋅ −
⋅ −= =
⋅ ⋅⋅ ⋅ ⋅ + + −
( ) ( )
( )2
22 2
o
eqieq o
L
N N DvF s
s L Nv s L C N N DZ
⋅ −= =
⋅ ⋅⋅ ⋅ ⋅ + + −
( ) ( ) ( ) ( ) ( )0 iv s F s v s G s d s= ⋅ + ⋅
Conditioner Analytical StudyConditioner Analytical Study
•• Load Influence over circuitLoad Influence over circuit’’s dynamic responses dynamic response::
There are some strategies to damp the voltage oscillation or compensate the absence of load:
•• To damp voltage oscillation with virtual resistance control straTo damp voltage oscillation with virtual resistance control strategy;tegy;
•• To insert a control loop to compensate abrupt voltage drop;To insert a control loop to compensate abrupt voltage drop;
• To insert input filter topologiesTo insert input filter topologies;;
Conditioner Analytical StudyConditioner Analytical Study
Virtual ResistanceVirtual Resistance
Line conditioner Block Diagram:
0
1sC
−
+
−
+ −
+
+
iv+
d 0vCoi
0i
LeqiˆLeqvoV
N1
eqs L⋅
N DN−
DN
( )o
L
VZ N D⋅ −
VirtualR
−
−
+ PWMG( )Vc s
0
Virtual
PWM
N RV G⋅⋅
d
Converter ControlConverter ControlT
a
6D
5D
b7D
8D 4D
3D1D
D
0( )v t()iv t
1S 2S 3S 4S
_o refv5S 6S 7S 8S
+−SrrvSrrv
2
vC (s)
Sensorde
Tensão
Red
e de E
nerg
ia
SR SL dPL
Car
ga
Compensador de TensãoModulador
Modulador
5S
6S
7S
8S
1S
2S
3S
4S0C
ComandoSensorde
Corrente
++
cI ( )s+−
+−
RvC ( )s
Compensador de Rvirtual
Experimental ResultsExperimental Results
[ ]220 20% ViV = ±
[ ]220 VoV =
[ ]10 kVAoS =
[ ]60 HzrF =
[ ]20 kHzSF =
4N =
[ ]340 HeqL μ≈
[ ]20 FoC μ=
PrototypePrototype
Control SignalsControl Signals
acac--ac converter voltage signalsac converter voltage signalsRectifier Inverter
Operation with Load TransientOperation with Load TransientWithout Virtual Resistance Control Loop With Virtual Resistance Control Loop
50% Load Transient
•• +20% transient in input voltage +20% transient in input voltage Vi(tVi(t):):
Operation with input TransientOperation with input Transient
•• --20% transient in input voltage 20% transient in input voltage Vi(tVi(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 Hμ
10mF
10ΩThe 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