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Power ElectronicsPower Electronics
Chapter 10
Application of Power Electronics
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Application of Power ElectronicsApplication of Power Electronics
10.110.1 DC motor drivers ( thyristor-DC motor DC motor drivers ( thyristor-DC motor system )system )
10.2 Frequency converters and AC drivers10.2 Frequency converters and AC drivers
10.310.3 Uninterruptible Power Supply ( UPS )Uninterruptible Power Supply ( UPS )
10.410.4 Switching Power SupplySwitching Power Supply
10.510.5 Power factor correction (PFC)Power factor correction (PFC)
10.610.6 Application in utility power systemApplication in utility power system
10.710.7 Other applications Other applications
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10.1 DC motor drivers10.1 DC motor drivers ( Thyristor-DC motor system ) ( Thyristor-DC motor system )
10.1.1 Rectifier mode of operation10.1.1 Rectifier mode of operation
10.1.2 Inverter mode of operation10.1.2 Inverter mode of operation
10.1.3 Reversible DC motor drive system10.1.3 Reversible DC motor drive system
(four-quadrant operation(four-quadrant operation))
L
ud
a
b
c
VT2
VT1
VT3M
o
LB
LB
LB id
+
-EM
iTv1
iTv2
iTv3
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10.1.1 Rectifier mode of operation10.1.1 Rectifier mode of operation
Waveforms of 3-phase half-wave Waveforms of 3-phase half-wave rectifier with DC motor loadrectifier with DC motor load
(10-1)(10-1)
2
3 BMB
XRRR
UIREU dMd
Waveforms and equationsWaveforms and equations
(for 3-phase half-(for 3-phase half-wave)wave)
wherewhere
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Speed-torque (mechanic) characteristic Speed-torque (mechanic) characteristic when load current is continuouswhen load current is continuous
For 3-phase half-waveFor 3-phase half-wave
nCE eM (10-2)(10-2)
cos17.1 2UUd
UIRUE dM cos17.1 2
e
d
e C
UIR
C
Un
cos17.1 2
For 3-phase bridgeFor 3-phase bridge
22.34 cosd
e e
U Rn I
C C
(10-3)(10-3)
(10-4)(10-4)
(10-5)(10-5)
O
n
a 1< a 2< a 3
a 3
a 2
a 1
Id
(R B +RM + )IdC e
3X B2
For 3-phase half-waveFor 3-phase half-wave
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Speed-torque (mechanic) characteristic Speed-torque (mechanic) characteristic when load current is discontinuouswhen load current is discontinuous
EMF at no load (taking 3-phase EMF at no load (taking 3-phase half-wave as example)half-wave as example)
For For 6060ºº
For For 6060ºº
d isc o n tin u o u tsm o d e c o n tin u o u s m o d e
E
E 0
E 0'
O
Id m in
Id
(0 .5 8 5U 2 )
( U 2 )2
)60cos(2 20 UE
20 2UE
For 3-phase half-waveFor 3-phase half-wave
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Speed-torque (mechanic) characteristic Speed-torque (mechanic) characteristic when load current is discontinuouswhen load current is discontinuous
For different For different
The point of EMF at no The point of EMF at no load is raised up.load is raised up.
The droop rate becomes The droop rate becomes steer. (softer than the steer. (softer than the continuous mode)continuous mode)
O
a 3
a 2
a 1
Id
b o u n d a ry
d isco n tin u o u sm o d e
cont i nuous mode
a 5
a 4
E 0
E
For 3-phase half-wave
(60º, 60º)
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10.1.2 Inverter mode of operation10.1.2 Inverter mode of operation
EquationsEquations– are just the same as in the are just the same as in the
rectifier mode of operation rectifier mode of operation except that except that UUdd, , EEMM and and nn be be
come negative. E.g., in come negative. E.g., in 3-phase half-wave3-phase half-wave
– Or in another formOr in another form
(10-3)(10-3)
e
d
e C
UIR
C
Un
cos17.1 2
(10-4)(10-4)
(10-11)(10-11)
(10-12)(10-12)eC
n 1 RIU dd cos0
0 cos( RIUE ddM
re c tif ie rm o d e
n
3
2
1
Id
4
2
3
4
1
== 2
in
crea
sing
in
crea
sing
in v e rte rm o d e
Speed-torque characteristic of a DC motor fed by a thyristor rectifier circuit
21.17 cosM dE U R I U
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10.1.3 Reversible DC motor drive system10.1.3 Reversible DC motor drive system(4-quadrant operation)(4-quadrant operation)
L
c o n v e rte r 1 c o n v e rte r 2
EMM
abc
Back-to-back connection of two 3-phase bridge circuits
+
-
+
-
+
-
+
-
+
-
+
-
+
-
+
-
A Cso u rce
c o n v e r te r2
c o n v e r te r2c o n v e r te r2
c o n v e r te r 1 c o n v e r te r2
+T- T
re v e rse m o to rin g
c o n v e rte r 2 in v e rtin g
fo rw a rd b rak in g (re g e n e ra tin g )
+ n
IdId
U d
M EM
Id
M EMMEM
Id
MEM
- n
U d
U d U d
O
A Cso u rce
A Cso u rce
A Cso u rce
E n erg y
E n erg y
E n erg y
E n erg y
c o n v e r te r 1
c o n v e r te r1
c o n v e r te r1
c o n v e rte r 1 re c tify in g
fo rw a rd m o to rin g
c o n v e rte r 2 re c tify in g c o n v e rte r 1 in v e rtin g
re v e rse b ra k in g (re g e n e ra tin g )
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4-quadrant speed-torque characteristic 4-quadrant speed-torque characteristic of Reversible DC motor drive systemof Reversible DC motor drive system
converter 1converter 2n
3
2
1
Id
4
2
3
4
1
== 2
'='= 2
'3
'2
'1
'4
'2
'3
'4
'11='1; '1=12='2; '2=2
in
crea
sing
'
incr
easi
ng'
in
crea
sing
in
crea
sing
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10.2 Frequency converters and 10.2 Frequency converters and AC drivers AC drivers
Composite convertersComposite converters
Indirect AC to AC convertersIndirect AC to AC converters(AC-DC-AC converters)(AC-DC-AC converters)
Indirect DC to DC convertersIndirect DC to DC converters(Isolated DC to DC converters)(Isolated DC to DC converters)
Composite converter:Composite converter:Combination of two or more converters in cascaded Combination of two or more converters in cascaded connectionconnection
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Indirect AC to AC convertersIndirect AC to AC converters(AC-DC-AC converters)(AC-DC-AC converters)
AC-DC-AC convertersAC-DC-AC convertersVoltage-source typeVoltage-source type
Current-source typeCurrent-source type
ClassificationsClassifications
According to type of the DC links:According to type of the DC links:
According to whether output voltage and frequency is According to whether output voltage and frequency is variable: variable:
In narrow sense, frequency converter only refers to In narrow sense, frequency converter only refers to VVVF AC-DC-AC converter.VVVF AC-DC-AC converter.
AC-DC-AC convertersAC-DC-AC converters
Variable voltage variable frequency Variable voltage variable frequency (VVVF)(VVVF)(AC-DC-AC frequency converters)(AC-DC-AC frequency converters)Constant voltage constant frequency Constant voltage constant frequency (CVCF)(CVCF)
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10.2.1 Configurations of AC-DC-AC converters10.2.1 Configurations of AC-DC-AC converters
Configurations with one-direction power flowConfigurations with one-direction power flow
A C
LoadA C
Sour ceA CLoad
A CSour ce
Voltage-source typeVoltage-source type Current-source typeCurrent-source type
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Configuration with regenerative energy Configuration with regenerative energy dissipating circuitdissipating circuit
Braking transistor and braking resistorBraking transistor and braking resistor
A C
LoadA C
Sour ceV 0
R 0
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Configurations with regenerative power feedback Configurations with regenerative power feedback through inversion-mode thyristor rectifier circuitthrough inversion-mode thyristor rectifier circuit
A CLoad
A CSour ce
A C
LoadA C
Sour ce
Id
U d U L
Voltage-source typeVoltage-source type Current-source typeCurrent-source type
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Configurations realizing bi-directional power Configurations realizing bi-directional power flow through double-sided PWM convertersflow through double-sided PWM converters
A CLoad
A C
Sour ce
UVW
abc
Source Load
16
Voltage-source typeVoltage-source type Current-source typeCurrent-source type
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10.2.2 Major Applications of AC-DC-AC 10.2.2 Major Applications of AC-DC-AC frequency converters (VVVF frequency converters (VVVF converters)converters)
Adjustable speed AC motor drivesAdjustable speed AC motor drives
Advantages of AC motors over DC motorsAdvantages of AC motors over DC motors
Energy saving on AC motorsEnergy saving on AC motors
High-performance AC motor drivesHigh-performance AC motor drives
Control of AC motors driven by AC-DC-AC frequency Control of AC motors driven by AC-DC-AC frequency converters (VVVF converters)converters (VVVF converters)
Constant voltage frequency ratio controlConstant voltage frequency ratio control
Slip frequency controlSlip frequency control
Vector controlVector control
Direct torque controlDirect torque control
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10.3 Uninterruptible power supplies (UPS)10.3 Uninterruptible power supplies (UPS)
Basic configuration of UPSBasic configuration of UPS
Source
Electricityutility
Rectifier Inverter
Load
Major Applications of CVCF convertersMajor Applications of CVCF converters
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UPS with back-up energy sourceUPS with back-up energy source
Source
Electricityutility Rectifier Inverter
Load
DieselEngine
S1
2
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UPS with back-up energy source UPS with back-up energy source and bypass linesand bypass lines
Source
Electricityutility Rectifier Inverter
Load
DieselEngine
1
2
34
Bypass lines
S1
S2
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10.410.4 Switching Power SupplySwitching Power Supply
Linear power supplyLinear power supply
• Switching power supplySwitching power supply
Regulated Regulated DC outputDC output
Line Line frequencyfrequencyAC inputAC input
InverterInverterFilterFilter TransformerTransformerDCDC
High High frequencyfrequency
ACAC
RectifierRectifier RectifierRectifier FilterFilter
ACAC
High High frequencyfrequency
IsolationIsolation
Indirect DC to DC converterIndirect DC to DC converter
Line Line frequencyfrequencyAC inputAC input
RectifierRectifier FilterFilter Series PassSeries PassRegulatorRegulatorTransformerTransformer
DCDCRegulated Regulated DC outputDC output
Line frequencyLine frequency
IsolationIsolation
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Point of load regulation (POL)Point of load regulation (POL)
Specifically means a particular switching Specifically means a particular switching power supply for a large size IC chip, such power supply for a large size IC chip, such as a CUP or a memory chip.as a CUP or a memory chip.
Synchronous BuckSynchronous Buck Synchronous BoostSynchronous Boost
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A typical application of switching power supplyA typical application of switching power supply
Power system for telecommunication equipmentPower system for telecommunication equipment
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Control of switching power supplyControl of switching power supply
Voltage mode controlVoltage mode control
Current mode controlCurrent mode control– Peak current mode controlPeak current mode control– Average current mode controlAverage current mode control
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Voltage mode controlVoltage mode control
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Current mode controlCurrent mode control
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Peak current mode controlPeak current mode control
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Average current mode controlAverage current mode control
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10.5 Power Factor Correction (PFC)10.5 Power Factor Correction (PFC)
Operation principle of typical PFC circuitOperation principle of typical PFC circuit– Single-phase boost PFCSingle-phase boost PFC– 3-phases single-switch boost PFC3-phases single-switch boost PFC
Single stage PFCSingle stage PFC
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Single-phase boost PFCSingle-phase boost PFC
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3-phases single-switch boost PFC3-phases single-switch boost PFC
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Single stage PFC ( )Single stage PFC ( )
A typical converterA typical converter
2S PFC
2S PFC
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10.610.6 Application in utility power systemApplication in utility power system
High voltage DC transmission (HVDC)High voltage DC transmission (HVDC)
Reactive power compensationReactive power compensation
Harmonics suppressionHarmonics suppression
Power quality control, FACTS and custom Power quality control, FACTS and custom powerpower
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High voltage DC transmission (HVDC)High voltage DC transmission (HVDC)
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Reactive power compensationReactive power compensation
Thyristor switched capacitor (TSC)Thyristor switched capacitor (TSC)
Thyristor controlled reactor (TCR)Thyristor controlled reactor (TCR)
Static var generator (SVG)Static var generator (SVG)
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Thyristor switched capacitor (TSC)Thyristor switched capacitor (TSC)
I
U
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TSC waveforms when the capacitor is TSC waveforms when the capacitor is switched in/outswitched in/out
The voltage across the thyristor must be nearly zero when The voltage across the thyristor must be nearly zero when switching in the capacitor, and the current of the thyristor must switching in the capacitor, and the current of the thyristor must be zero when switching out the capacitor.be zero when switching out the capacitor.
us
iC
uC
C
VT1
VT2
uVT1
t
t
t
tus
iC
uC
VT1
VT2t1 t2
uVT1
t
t
t
tus
iC
uC
VT1
VT2t1 t2
uVT1
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TSC with the electronic switch realized TSC with the electronic switch realized by a thyristor and an anti-parallel diodeby a thyristor and an anti-parallel diode
The capacitor voltage will be always charged up to the peak The capacitor voltage will be always charged up to the peak of source voltage.of source voltage.
The response to switching-out command could be a little The response to switching-out command could be a little slower (maximum delay is one line-cycle).slower (maximum delay is one line-cycle).
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Thyristor-controlled reactor (TCR)Thyristor-controlled reactor (TCR)
To control the effective current flowing through the To control the effective current flowing through the reactor by controlling delay angle, therefore control reactor by controlling delay angle, therefore control the reactive power absorbed by the reactor.the reactive power absorbed by the reactor.
ua ia
ub
uc
n b
a
c a) b) c)
4-12图
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Static var generator (SVG)Static var generator (SVG)
Also called static compensator (STATCOM)Also called static compensator (STATCOM)
CSC based SVGCSC based SVGVSC based SVGVSC based SVG
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Operation principle of SVGOperation principle of SVG
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Harmonic suppressionHarmonic suppression
Circuit configuration of an Active power factor (APF)Circuit configuration of an Active power factor (APF)
Two solutionsTwo solutionsPower factor correctionPower factor correction
Harmonic compensationHarmonic compensation
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Operation principle of APFOperation principle of APF
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Power quality controlPower quality control
Power quality problemsPower quality problems Power quality controllersPower quality controllers
Current harmonicsCurrent harmonics APFAPF
Reactive powerReactive power SVC or SVGSVC or SVG
Voltage sagVoltage sag Dynamic voltage restorer Dynamic voltage restorer (DVR)(DVR)
Voltage flickerVoltage flicker Universal power qualityUniversal power qualitycontroller (UPQC)controller (UPQC)
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Flexible AC Transmission System (FACTS)Flexible AC Transmission System (FACTS)
FACTS is actually a general term of application if FACTS is actually a general term of application if power electronic to the utility electric power power electronic to the utility electric power transmission system - for higher controllability and transmission system - for higher controllability and larger transmission capacity.larger transmission capacity.
Typical FACTA devicesTypical FACTA devices– SVCSVC– SVGSVG– Thyristor Switched Series Capacitor (TSSC)Thyristor Switched Series Capacitor (TSSC)– Thyristor Controlled Series Compensator Thyristor Controlled Series Compensator
(TCSC)(TCSC)– Static Synchronous Series Compensator (SSSC)Static Synchronous Series Compensator (SSSC)– Unified Power Flow Controller (UPFC) Unified Power Flow Controller (UPFC)
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Custom PowerCustom Power
Custom power is a general term of application of Custom power is a general term of application of power electronics to the utility electric power power electronics to the utility electric power distribution system for better quality and higher distribution system for better quality and higher reliability of the power supplying to different reliability of the power supplying to different customers.customers.
Typical Custom Power devicesTypical Custom Power devices– SVC or SVG (D-STATCOM)SVC or SVG (D-STATCOM)– DVRDVR– APFAPF– Solid State Transfer Switch (SSTS)Solid State Transfer Switch (SSTS)
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10.710.7 Other applicationsOther applications
LightingLighting– Power supply for different lampsPower supply for different lamps– Power supply for gas discharge lamps is Power supply for gas discharge lamps is
specifically called ballast.specifically called ballast.
WeldingWelding
Typical configuration of an electronic ballastTypical configuration of an electronic ballast
Typical configuration of a welding power supplyTypical configuration of a welding power supply