CAS 2004 – 4Q Power Converters Technologies
Switched Mode Converters
(4 Quadrants)
Yves THUREL
CERN
CAS2004 / Warrington / 12-18 May 2004
Y. Thurel
1 / xx
CAS 2004 – 4Q Power Converters Technologies
4 Quadrant basic background
4Q. Conventions
4Q. Working area / loads
4Q. Basic schematics
4 Quadrant topologies Review
Principle schematics (main ones presented)
Advantages / Drawbacks
Some realizations
4 Quadrant practical realization & example
LHC Specifications
LHC Topology choice explained
LHC Converter principles
Technical points highlighted (loops, circulating current,…)
Realizations
CAS2004 / Warrington / 12-18 May 2004
Y. Thurel
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CAS 2004 – 4Q Power Converters Technologies
4 Quadrant basic background
4Q. Conventions
4Q. Working area / loads
4Q. Basic schematics
4 Quadrant topologies Review
Principle schematics (main ones presented)
Advantages / Drawbacks
Some realizations
4 Quadrant practical realization & example
LHC Specifications
LHC Topology choice explained
LHC Converter principles
Technical points highlighted (loops, circulating current,…)
Realizations
CAS2004 / Warrington / 12-18 May 2004
Y. Thurel
3 / xx
4Q. Conventions
CAS 2004 – 4Q Power Converters Technologies
4 Quadrant Operation: Definition (applied to R-L circuit)
1 Quadrant mode
+
I [A]
V [V]
0
20
40
60
80
2 Quadrant mode
+
-
+
100
I [A]
V [V]
0
20
40
60
80
100
V
4
1
3
2
Control of the decreasing
current is still possible within
drastic conditions and limits.
(RCIRCUIT acts as discharger.)
Current is controlled (being
always in the same sense),
when increasing or
decreasing.
4 Quadrant mode
+
-
+
CAS2004 / Warrington / 12-18 May 2004
I [A]
V [V]
0
20
40
Y. Thurel
60
80
100
II
No theoretical operation
limitation.
4 / xx
4Q. Work. Area
CAS 2004 – 4Q Power Converters Technologies
4 Quadrant Operation: Loads Typical Cycle (R-L)
PGENE-PEAK
VCIRCUIT=R.I+L.dI/dt
dI/dtLOW
800
[A]
CIRCUIT
LCIRCUIT
(CABLE)
LCIRCUIT
(MAGNET)
I [A]
600
400
200
dI/dt MAX
0
-200
0
200
400
600
800
[t]1000
L
= 1H
R
= 7mOhms
dI/dtMAX= 5A.s-1
IMAX = 600A
-400
-600
-800
10
8
4QAREA
PRECEP-PEAK
[V]
V [V]
6
L.dI/dt
4
2
0
-2 0
200
400
600
800
[t] 1000
KEY FEATURES
L.dI/dt = 5V
R.IMAX = 4.2V
VMAX = 9.2V
-4
-6
-8
-10
CAS2004 / Warrington / 12-18 May 2004
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4Q. Work. Area
CAS 2004 – 4Q Power Converters Technologies
4 Quadrant Operation: Load Influence on topology
“Pulsed” Machine
[V]
[A]
Cycle Period
High Power
to be absorbed / Often
Î High Energy
“Slow” Machine: LHC Type / Magnet or orbit Correctors
12h or more run
Power to be
absorbed / sometimes
Î Low Energy
CAS2004 / Warrington / 12-18 May 2004
Y. Thurel
[V]
[A]
Operation close
to 0V / 0A
6 / xx
4 Quadrant Operation: Load Impact on cost & design parameters
Circuit Characteristics
Circuit Key Features
• L = 1H
LHC Machine
• dI/dt = 10A.s-1
LHC Machine
• I = [-600A;+600A]
LHC Machine
• PCable < 15kW
LHC Tunnel
•L•di/dt = 10V
•10mOhms <
Rcable
< 21mOhms
6V
< Rcable•IMAX < 12V
20 mOhms
10 mOhms
(V: Output Voltage Power converter)
(P: Output power Power converter)
30
30
13.2 kW
[V]
22 VMAX
20
[V]
9.6 kW
20
16 VMAX
10
10
I[A]
I[A]
0
0
-800
-600
-400
-200
0
200
400
600
800
-800
-600
-400
-200
-20
-1.25kW
0
200
V [V]
P [kW]
-30
-20
600
800
-2.5kW
V [V]
P [kW]
-30
PMAX
13.2kW
100%
PMAX
9.6kW
73%
PABSORBED
1.25kW
100%
PABSORBED
2.5kW
200%
Cable Losses 14.4kW
100%
Cable Losses 7.2kW
50%
CAS2004 / Warrington / 12-18 May 2004
400
-10
-10
Y. Thurel
Î
Price
4Q. Work. Area
CAS 2004 – 4Q Power Converters Technologies
Ï
Ò
7 / xx
4Q. Conventions
CAS 2004 – 4Q Power Converters Technologies
4 Quadrant Operation: Receptor mode
Goals:
• Absorbing magnet energy
No Resistance
[V]
[A]
I [A]
V [V]
600
Energy Receptor
Concepts
8
6
400
4
200
2
0
0
• Still regulating magnet reverse voltage, i.e dI/dt
•Solutions:
Ideal Magnet
800
-200
0
50
100
150
-2
-400
-4
-600
-6
-800
-8
• Variable resistor (active)
• Voltage source added for 0 A transition:
No voltage can be obtained when 0 Amp
in the magnet.
V
I>0
• Converter magnet-mains, giving back
energy to mains.
• Converter magnet-capacitor, storing the
magnet energy.
V>0
• This capacitor is charged by the magnet
and the needed generator converter
•Alternative (not very used) solutions could
be: rotative machine, or (supraconductor)
inductor…not treated here.
CAS2004 / Warrington / 12-18 May 2004
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4Q. Basics Sch.
CAS 2004 – 4Q Power Converters Technologies
4 Q Stage: Main topologies
2x Thyristor bridge in anti//
Very well known
Power returned to mains
Bip. / Mos.
Transistor
Linear dissipative Stage
Basic background known, (push-pull stage)
4Q operation to be explained later
Dissipation in the transistors, acting as
programmable resistor
LL RL
Switching Stage
Conventional H bridge (L-C Filter)
Power returned to capacitor or dissipated in
brake chopper.
CAS2004 / Warrington / 12-18 May 2004
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4Q. Basics Sch.
CAS 2004 – 4Q Power Converters Technologies
(* The 2 voltages are always the same)
4Q Stage: Linear basic principle
…Combined with double* DC fixed voltage output
0A..100A
100A
12V
2V
10V
12V
LL RL
0A
12V
10V
2V
0..
100A
22V
100..0A
12V
LL RL
0A
Efficiency!!!
10V
100A
12V
20V
-8V
100A
14V
0A
12V
LL RL
20V
12V
-8V
100A
..0A
0A
20Vx100A in Q1!!!
4V
0..
-100A
LL RL
12V
4V
0A..100A
100A
0A
0A
2V
GENERATOR
CAS2004 / Warrington / 12-18 May 2004
Y. Thurel
-100A
-8V
-8V
RECEPTOR
GENERATOR
10 / xx
4Q. Basics Sch.
CAS 2004 – 4Q Power Converters Technologies
(* The 2 voltages are always the same)
4Q Stage: Linear basic principle
…combined with double* DC variable voltage output
for better efficiency an losses reduced in receptor mode
0A..100A
100A
12V
2V
10V
12V
LL RL
0A
4V
2V
2V
0..
100A
22V
100..0A
4V
6V
0A
Efficiency better
10V
100A
0V
8V
-8V
100A
LL RL
0A
0V
LL RL
0A
8Vx100A in Q1
10V
14V
-8V
100A
..0A
-8V
0..
-100A
LL RL
10V
2V
0A..100A
100A
0A
0A
2V
GENERATOR
CAS2004 / Warrington / 12-18 May 2004
Y. Thurel
-100A
-8V
-8V
RECEPTOR
GENERATOR
11 / xx
4Q. Basics Sch.
CAS 2004 – 4Q Power Converters Technologies
4Q Stage: Linear basic principle (variation “linear” H bridge)
…combined with single DC variable voltage output
VE+
VE+
VL
LL RL
VL
VE
IL
LL RL
IL
Remark:
This solution is easier, from the inverter side,
but leads to polarity new transitions which can
be source of distortion, and finally lead to a
complex 4 quadrant stage
CAS2004 / Warrington / 12-18 May 2004
Y. Thurel
Polarity Switches
Single output
inverter
12 / xx
4Q. Basics Sch.
CAS 2004 – 4Q Power Converters Technologies
4Q Stage: Switching basic principle
H Bridge: 2 modes
T1
VE
It is possible to work in
Buck Mode so that both
IL
T3
VL
Vs
- ∆ I is reduced
(HF output voltage ripple)
- Losses are reduced
T2
T4
T1=T4=T2=T3
T
VE
α
1-α
Note:
transition between these 2
possible modes can be
source of distortions.
VMEAN
IMEAN
VMEAN=(2.α-1).VE
-VE
CAS2004 / Warrington / 12-18 May 2004
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CAS 2004 – 4Q Power Converters Technologies
4 Quadrant basic background
4Q. Conventions
4Q. Working area / loads
4Q. Basic schematics
4 Quadrant topologies Review
Principle schematics (main ones presented)
Advantages / Drawbacks
Some realizations
4 Quadrant practical realization & example
LHC Specifications
LHC Topology choice explained
LHC Converter principles
Technical points highlighted (loops, circulating current,…)
Realizations
CAS2004 / Warrington / 12-18 May 2004
Y. Thurel
14 / xx
CAS 2004 – 4Q Power Converters Technologies
Topologies: Key points, (how to classify them, how to select them?)
SIZE,
SIZE,WEIGHT,
WEIGHT,
COST
COST
POWER
POWERRANGE,
RANGE,
DISSIPATIVE
DISSIPATIVEOR
ORNOT,
NOT,
EFFICIENCY
EFFICIENCY
AC
ACMAINS
MAINSPERT.
PERT.REJ.,
REJ.,
EMC,
BF
&
HF
RIPPLE
EMC, BF & HF RIPPLE
TOPOLOGY CHOICE ????
NUMBER
NUMBEROF
OFCPTS,
CPTS,DESIGN
DESIGN
COMPLEXITY,
MTBF,
COMPLEXITY, MTBF,USE
USEOF
OF
COMMERCIAL
PART
COMMERCIAL PART
DISTORTION
DISTORTION
BANDWIDTH
BANDWIDTH
CAS2004 / Warrington / 12-18 May 2004
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CAS 2004 – 4Q Power Converters Technologies
Mains
Rectifier
bridge
4Q. AC-DC
Converter
Filter
Filter
DC-AC
Converter
4Q. DC-AC
Converter
LF Transfo.
(Volt. Adapt.)
HF Transfo.
(Volt. Adapt.)
4Q. Thyristor
bridge
Rectifier
bridge
Filter
Filter
4Q. Linear
Stage
Storage Energy
or B. Chopper
4Q. AC-DC
Converter
4Q. DC-DC
H Bridge
Filter
Filter
Load
CAS2004 / Warrington / 12-18 May 2004
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CAS 2004 – 4Q Power Converters Technologies
Topologies: Thyristor (Principle)
V
V
1
4
I
3
2
I
I
I
I
LF
Thyristor
bridge
Thyristor
bridge
I
ILOAD
VLOAD
50 Hz transfo.
Optimal voltage
output
(Galvanic Isolation)
LF
LF
LF
Low freq.
Output Filter
CAS2004 / Warrington / 12-18 May 2004
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CAS 2004 – 4Q Power Converters Technologies
Topologies: Thyristor (schematics Example)
Basic schematic
• [0,0] & [V] axis required circulating current between the 2 bridges
.
.
7.5m
B6C
7.5m
2.16m
Rmag
.
.
540u
4.7
.
.
alpha-refcircu
7.5m
.
.
.
.
.
.
2.16m
540u
Lmag
4.7
7.5m
B6C
• Active Filter increase
dynamic performance (low
amplitude bandwidth, low
frequency ripple,
perturbation…)
Adding a circulating current between the 2
thyristor bridges helps!!!
CAS2004 / Warrington / 12-18 May 2004
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CAS 2004 – 4Q Power Converters Technologies
Topologies: Thyristor (Discussion)
Advantages
• Huge power possible
• Not Dissipative: power returned to mains
• High Efficiency
• Very well known topology
• Rather simple design
• No High frequency signal (low frequency operation): EMC easy to handle
Drawbacks
• Low Bandwidth (addition of active filter can help a bit in small signal)
• Poor AC mains perturbation rejection (speed loop limited by L-C filter)
• Distortion (crossing axes, and point [0,0]) requires some additional circuit
for high precision converter: Circulating current
• Size, weight of transformer and filtering elements
CAS2004 / Warrington / 12-18 May 2004
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CAS 2004 – 4Q Power Converters Technologies
Topologies: 50Hz + Linear (Principle)
DC Fixed
LF
LF
ILOAD
VLOAD
LF
L
I
N
E
A
R
DC Fixed
LF
50 Hz transfo.
Optimal voltage
output
(Galvanic Isolation)
CAS2004 / Warrington / 12-18 May 2004
LF
Rectifier +
Double Output
High Freq.
Filter
Y. Thurel
Linear Stage
(Dissipate Magnet
Energy)
20 / xx
CAS 2004 – 4Q Power Converters Technologies
Topologies: 50Hz + Linear (Principle variation)
LF
50 Hz transfo.
Optimal voltage
output
(Galvanic Isolation)
LF
Diode
bridge
C
H
A
.
LF
Low freq.
Output Filter
L
I
N
E
A
R
ILOAD
VLOAD
DC
Fixed
P
O
L
.
H Bridge
Linear Stage
(Polarity Changer
/
Dissipate Magnet
Energy)
CAS2004 / Warrington / 12-18 May 2004
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CAS 2004 – 4Q Power Converters Technologies
Topologies: 50Hz + Linear (Discussion)
Advantages
• Schematics and topologies are very well known
• Simple schematics
• Adding circulation current helps
• Bandwidth (10 kHz)
Drawbacks
• Dissipative
• Efficiency very low in generator mode
• Size, weight of transformer and filtering elements
• Often realized with several transistors in // (MTBF and avalanche failure)
CAS2004 / Warrington / 12-18 May 2004
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CAS 2004 – 4Q Power Converters Technologies
Topologies: 50Hz + Switching (Principle)
ILOAD
LF
LF
Diode
50 Hz transfo.
Optimal voltage bridge
output
(Galvanic Isolation)
VLOAD
DC
Fixed
LF
HF
Add.
Low freq.
PWM
Brake Chopper
Output Filter
Converter
(Optional)
(Magnet Energy
Hard
Î1/2.C.V²) (Dissipate Magnet Commutation
CAS2004 / Warrington / 12-18 May 2004
HF
High freq.
Output Filter
Energy)
Y. Thurel
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CAS 2004 – 4Q Power Converters Technologies
Topologies: 50Hz + Switching (Schematics Example)
Basic schematic
High Frequency Hard
commutation Bridge
50Hz Transfo + L
–C Filter
Commercial part
possible
Brake chopper:
absorb magnet
energy if Vcap.
too high
CAS2004 / Warrington / 12-18 May 2004
Y. Thurel
High Frequency
LC Filter (2 cells)
24 / xx
CAS 2004 – 4Q Power Converters Technologies
Topologies: 50Hz + Switching (Discussion)
±150A
±200V
Advantages
• Huge power possible
• Part of magnet energy re-used
• Very well known topology– possible to use commercial
standard elements
• High bandwidth (10 kHz)
• Good AC mains perturbation rejection
• No distortion of the signal (if H bridge not changing mode)
Drawbacks
• H bridge hard commutation @ high current
• 50Hz LC-Filter can be un-damped by H bridge negative equivalent resistor
• Size, weight of transformer and filtering elements
• Hard commutation EMC to cope with
• Low voltage high current not ideal (loss of the switching H bridge, fswitching limited)
• HF filtering Ripple difficult (if buck mode not used), at “only fswitching”
CAS2004 / Warrington / 12-18 May 2004
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CAS 2004 – 4Q Power Converters Technologies
Topologies: Switching + Linear (Principle)
LF
3Ph
Diode
Bridge
LF
Low
freq.
Output
Filter
HF
HF
High Freq.
Soft
Commutation
Inverter
CAS2004 / Warrington / 12-18 May 2004
HF
HF
HF
HF
High
Freq.
Transfo.
Rectifier +
Double Output
High Freq.
Filter
Y. Thurel
ILOAD
VLOAD
HF
L
I
N
E
A
R
Linear Stage
26 / xx
CAS 2004 – 4Q Power Converters Technologies
Topologies: Switching + Linear (Principle variation)
LF
LF
3Ph
Diode
Bridge
Low
freq.
Output
Filter
HF
HF
High Freq.
Soft
Commutation
Inverter
CAS2004 / Warrington / 12-18 May 2004
HF
High
Freq.
Transfo.
HF
HF
Rectifier +
Single Output
High Freq.
Filter
Y. Thurel
ILOAD
VLOAD
P
O L
L I
. N
E
C A
H R
A
.
H Bridge
Linear Stage
(Polarity Changer)
27 / xx
CAS 2004 – 4Q Power Converters Technologies
Topologies: Switching + Linear (Schematics Example)
Basic schematic
Input Module, Bd: 70Hz
Phase shifted Inverter
Rectifer + Filter
4 Quadrant
Linear Stage
VOUT
EMI
FILTER
HF Transfo.
300Hz L –C Filter
High Frequency Soft
commutation H Bridge
CAS2004 / Warrington / 12-18 May 2004
Y. Thurel
4Q Linear Stage
HF Filter
+ Rectifier
28 / xx
CAS 2004 – 4Q Power Converters Technologies
Topologies: Switching + Linear (Discussion)
Advantages
• Medium power possible
• Addition of 2 distinct well known topologies
• High bandwidth
• Good AC mains perturbation rejection
• No distortion of the signal (if circulating current used)
• HF filtering Ripple at 2x fswitching possible
• Efficiency OK, (no switching Loss at secondary side)
• EMC OK, since Soft commutation possible
Drawbacks
• Dealing with Inverter Loop & Circulation current Loop can lead to some complexity
• Double output voltage requires additional power components (L-C Filtering +
Rectifiers)
• Dissipative (No energy back to anywhere, except Output transistors!!!)
CAS2004 / Warrington / 12-18 May 2004
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CAS 2004 – 4Q Power Converters Technologies
Topologies: Switching + Switching Type 1 (Principle)
VLOAD
ILOAD
LF
LF
HF
50 Hz transformer
Optimal voltage output
Galvanic isolation
CAS2004 / Warrington / 12-18 May 2004
HF
Diode
bridge
HF
HF
Low freq.
Output Filter
Y. Thurel
HF
HF
HF
PWM Converter
Add.
Crowbar Hard Commutation
30 / xx
CAS 2004 – 4Q Power Converters Technologies
Topologies: Switching + Switching Type 1 (Discussion)
Advantages
• High power possible
• Part of magnet energy re-used
• Very well known topology
• High bandwidth
• Good AC mains perturbation rejection
• No distortion of the signal (if H bridge not changing mode)
Drawbacks
• Secondary H bridge hard commutation @ high current (Losses EMC to cope with )
• Low voltage high current not ideal (loss of the switching H bridge, fswitching limited)
• 2 HF filtering levels
• Complexity (2 inverters, Gate drives) & Cost
• Efficiency low
• HF filtering Ripple difficult (if buck mode not used), at “only fswitching”
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CAS 2004 – 4Q Power Converters Technologies
Topologies: Switching + Switching Type 2 (Principle)
LF
LF
LF
VLOAD
ILOAD
LF
LF
Diode Low freq.
Add.
bridge Output Filter Crowbar
CAS2004 / Warrington / 12-18 May 2004
HF
HF
High Freq.
Soft
Commutation
Inverter
Y. Thurel
HF
HF
HF
HF
4Q Converter
High
Freq. Soft Commutation
Transfo.
32 / xx
CAS 2004 – 4Q Power Converters Technologies
Topologies: Switching + Switching Type 2 (Schematic Example)
θr’
γ
Vdc +
TH1
on
Vin
TD1
TD3
off
off
•
TD2
TD4
off
off
Vdc -
IL
See Paper from
CERN & LEEI for
detailed
explanation.
TH3
Iout
•
LOAD
•
on
θr
TH3
on
TH4
on
TH2
TH1
•…….
Out -
TH2
•……
•……
TH4
Out +
THbis3
Iout1
iout2
THbis1
THbis2
THbis4
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CAS 2004 – 4Q Power Converters Technologies
Topologies: Switching + Switching Type 2 (Discussion)
Advantages
• Fully reversible with energy sent back to mains (thyristor bridge to be added)
• High frequency power converter (low volume and high dynamic performance)
• High bandwidth
• Good AC mains perturbation rejection
• No distortion of the signal (if H bridge not changing mode)
• Soft commutation possible on the 2 H-Bridges
• High efficiency
Drawbacks
±600A
±12V
• Complex control
CAS2004 / Warrington / 12-18 May 2004
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CAS 2004 – 4Q Power Converters Technologies
4 Quadrant basic background
4Q. Conventions
4Q. Working area / loads
4Q. Basic schematics
4 Quadrant topologies Review
Principle schematics (main ones presented)
Advantages / Drawbacks
Some realizations
4 Quadrant practical realization & example
LHC Specifications
LHC Topology choice explained
LHC Converter principles
Technical points highlighted (loops, circulating current,…)
Realizations
CAS2004 / Warrington / 12-18 May 2004
Y. Thurel
35 / xx
CAS 2004 – 4Q Power Converters Technologies
LHC: Specifications
•
Electrical Characteristics
–
–
–
–
–
–
•
Mechanical Characteristics
–
–
–
•
To be installed in LHC tunnel
Must be possible to change it as a plug-in module
Low volume and low weight
Electrical Environment
–
–
–
–
•
Low Output Voltage / High Output Current
High Efficiency (Losses in Tunnel must be as low as possible)
High bandwidth
No need for returning power to mains (slow machine)
Operation close to [0V-0A]
Low BF ripple (magnet current precision) & Low HF Ripple (EMC)
Good immunity to mains perturbation (phase loss of 100ms)
Very low level of distortion tolerated (high precision)
EMC behavior must be very good (IN & OUT)
To be integrated in a few ppm current loop regulation
Other key points
–
–
15 years of operation (MTBF)
Principle as simple as possible (operation)
CAS2004 / Warrington / 12-18 May 2004
Y. Thurel
LHC
Power Converters
Family
LHC ±600A ±40V
Transtechnik
Germany
LHC ±600A ±10V
Cirtem
France
LHC ±120A ±10V
CERN & EFACEC
Portugal
LHC ±60A ±08V
CERN & CEL
France
36 / xx
CAS 2004 – 4Q Power Converters Technologies
LHC ±120A ±10V: EMC Highlighted
Magnet loads are several magnets in series
(hundreds of meters “load”)
IEC478.3 C applied INPUT and OUTPUT side
400V ac
Iref
r
Vref
+-
Vout
L
RST
B
LHC Electronic : (control + DCCTS)
Power converter
Iout
Circuit
Digital & Analog signals exchanged between
Power converter
& High Precision Current Controller
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CAS 2004 – 4Q Power Converters Technologies
LHC ±120A ±10V Topology Choice
Minimum 50Hz Components for size & weight reduction
(tunnel installation)
EMC
Switching based topology
Linear base topology
High precision environment:
EMC must be as good as possible
No distortion / operation [0V-0A]
CAS2004 / Warrington / 12-18 May 2004
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CAS 2004 – 4Q Power Converters Technologies
LHC ±120A ±10V Topology Choice
Input Module, Bd: 70Hz
Phase shifted Inverter
Rectifer + Filter
4 Quadrant
Linear Stage
VOUT
EMI
FILTER
BREAKER &
INPUT FILTER &
SOFT COM. INVERTER,
ISOLATION &
CONTACTOR
SOFT-START
50kHz..100kHz
RECTIFIER + FILTER
CAS2004 / Warrington / 12-18 May 2004
Y. Thurel
4Q.L.S.
39 / xx
CAS 2004 – 4Q Power Converters Technologies
LHC ±120A ±10V Topology Choice
AC-DC
• 3 phases + Neutral (used for auxiliary power
supply)
• 1400V Rectifiers
• 70Hz Input filter (damped with C-4C) to give a flat
540V DC (around -20dB on 300Hz)
• Soft start based on “R + switch”.
High Frequency Soft commutation Inverter
•
•
•
•
•
Fixed switching frequency (50..100kHz).
ZVS operation with Phase Shifted command.
ZCS for lagging leg
IGBT Bridge
“Voltage” or “current” mode possible
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CAS 2004 – 4Q Power Converters Technologies
LHC ±120A ±10V Topology Choice
Rectifer + Filter
Rectifier + DC Filter
• HF Ripple at 2x inverter Fswitching
• Schottky rectifiers.
• Double LC cell at 5..10 kHz.
4 Quadrant Linear Stage
• Linear Regulation based on Mosfets.
• Mosfet used as
- polarity switch in generator mode
- programmable resistor to dissipate Magnet
energy.
• Use of 4QLS as an active filter
• Use of 4QLS to pre-load inverter (continuous mode)
• Circulating current always present but value
depending from load current (no mode change
transition, both DCDC outputs always minimum
loaded
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4 Quadrant
Linear Stage
VOUT
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CAS 2004 – 4Q Power Converters Technologies
IHIGH
LHC ±120A ±10V Topology Choice
Highlights on 4QLS
VE
• A double power source programmable via inverter
(VE)
• 2 MOSFETS, Q1 & Q2, used as switch and
programmable resistor. (high level of power
possible)
• A command which works according to :
VGS HIGH
VOUT
IOUT
LL
RL
VE
VGS LOW
ILOW
VOUT = +(VE − R HIGH ⋅ I HIGH )
VOUT = −(VE − R LOW ⋅ I LOW )
RHIGH & RLOW are equivalent MOSFET resistance
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CAS 2004 – 4Q Power Converters Technologies
LHC: 4QLS without circulation current
• Remember a limitation of the linear stage…
• Main Loop (VOUT
linear regulation loop)
cannot provide needed
step for biasing
MOSFET
(-3V to + 3V)
• Playing with fixed
bias is a bad idea!!!
Discrepancies on
VGS ON ±1V !!!
LHC ±120A ±10V Measurements
IHIGH
VE
VGS HIGH
VDS HIGH
VOUT
IOUT
LL
Without Circulating Current
RL
VE
VDS LOW
VGS LOW
ILOW
1
VREF + -
VGS HIGH
PID
VOUT
Without Circulating Current
-1
VGS LOW
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CAS 2004 – 4Q Power Converters Technologies
LHC: 4QLS with circulation current
• Adding 2x circulation current loop
• To avoid 0A distortion
crossing , a circulating
can help, biasing
MOSFET gates.
• These additional loops
(one per MOSFET)
must not perturb main
loop. (must be slower)
LHC ±120A ±10V Measurements
IHIGH
VGS HIGH
VE
VDS HIGH
VOUT
IOUT
LL
With Circulating Current
RL
VE
VDS LOW
VGS LOW
• ICirculation can vary
ILOW
IHIGH
IREF
+
-
PID’
+
+1
VREF + -
+
VGS HIGH
PID
With Circulating Current
-1
VOUT
+
+
VGS LOW
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CAS 2004 – 4Q Power Converters Technologies
LHC: 4QLS with circulation current
different approaches:
•Circulating current always present, changing
its value depending on output current
• Its control is easy (reference is only
smoothly changing with IOUT)
• Inverter reference must always be set so
that this circulating current is possible leading
to higher losses in receptor mode.
• No changing mode (Gate of each side
MOSFET always biased)
Q1
Q1 & Q2
Q2
•Circulating current only present when close
to a potential transition
• This solution saves a lot of energy when
recovering, since inverter doesn’t inject
power in MOSFET when absorbing power.
• dI/dt Limitation exists, since if too fast,
circulating current doesn’t have time to
appear and MOSFET Gate are not well biased.
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ICC REF
Fr. Icc loop
VGS Q2
Fr. Main loop
[t]
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CAS 2004 – 4Q Power Converters Technologies
LHC: 4QLS / Inverter Reference
LHC ±120A ±10V Measurements
• Inverter REF is built according to
– VBIAS MIN. not to saturate MOSFET (i.e saturate Loop)
– VBIAS OPT. For 4Q Linear stage acting as active filter (better
rejection of mains disturbances and 300 Hz)
– VMIN coupled to I circulation MIN to always minimum load inverter
(Conduction mode un-changed)
– Inverter Loop must be faster / transparent than 4Q stage loop
VBIAS
VBIAS
|VREF| +
VMIN
+
+
VMIN
PID’
-
INVERTER
VE
IHIGH
IREF
+
-
PID’
+
+1
VREF
+
-
PID
VOUT
+
VGS HIGH
-1
+
+
VGS LOW
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CAS 2004 – 4Q Power Converters Technologies
LHC: 4QLS MOS working Area (Example)
Practical case of
Circulation current
always ON, at the
same value: 5A.
VOUT
5A
11 V
-120 A
RDSON variations
11 V
limited by circulating
current.
10 V
1 V, 5 W
200 mΩ
11 V
21 V, 2.6 kW
168 mΩ
11 V
125 A
120 A
10 V
125 A
1 V, 125 W
8.00 mΩ
21 V, 105 W
4.20 Ω
5A
5A
Dissipate Power is:
1V
0A
•21V x 120A in
recovering MOSFET
instead of
10V x 120A required
by the load.
•Only valid if not
often the case.
1V
-120 A
11 V
-10 V
125 A
21 V, 105W
4.20 Ω
11 V
1 V, 125W
8.00 mΩ
11 V
125 A
CAS2004 / Warrington / 12-18 May 2004
IOUT
1 V, 5 W
200 mΩ
5A
5A
11 V
0V
1 V, 5 W
200 mΩ
Y. Thurel
120 A
-10 V
21 V, 2.6 kW
168 mΩ
1 V, 5 W
200 mΩ
5A
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CAS 2004 – 4Q Power Converters Technologies
LHC: 4QLS MOS Model (FB180SA10 I.R.)
10.0
Settings like:
- Circulating current value
- Difference voltage issued
from the inverter output
voltage
- Number of MOSFET in //
are the key to maintain a
stable efficient analog
loop.
Rdson at VDS= 5 V
9.0
Rdson [Ohms]
MOSFET is difficult to
control directly from the
main loop to the gate.
Indeed
gain
is
from
virtually 0 if saturated to
thousands when almost
OFF.
Rdson at VDS= 2 V
8.0
Rdson at VDS= 1 V
7.0
Rdson at VDS= 0.6 V
6.0
Rdson at VDS= 10 V
Rdson at VDS= 20 V
5.0
4.0
3.0
2.0
1.0
VGS [V]
0.0
3.7
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3.9
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4.1
4.3
4.5
4.7
4.9
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CAS 2004 – 4Q Power Converters Technologies
LHC ±120A ±10V Measurements
LHC: Practical Results
DISTORTION ?:
Crossing axis is OK. No
distortion, achieved
thanks to circulating
current.
CONTROL:
Bandwidth in generator & receptor quadrant
Crossing 0A is OK, being unchanged.
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CAS 2004 – 4Q Power Converters Technologies
LHC: Realizations
LHC ±120A ±10V
• 330 Converters
• Correctors
• CERN Internal Design
LHC ±60A ±8V
• 800 Converters
• Orbit Correctors
• Below Dipoles, in a radiation zone
• CERN Internal Design
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CAS 2004 – 4Q Power Converters Technologies
LHC ±600A ±10V
• 440 Converters
• 1x 6U Module
LHC ±600A ±40V
• 50 Converters
• 2x 6U module
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CAS 2004 – 4Q Power Converters Technologies
Thank you for your attention.
AND?…END.
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CAS 2004 – 4Q Power Converters Technologies
+
-
IHIGH
VE
VGS HIGH
VDS HIGH
VOUT
IOUT
LL
RL
VE
VDS LOW
VGS LOW
ILOW
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CAS 2004 – 4Q Power Converters Technologies
Reference
Care with test invisble so that
alignment is ok
LF
LF
LF
LF
LF
LF
LF
VLOAD
ILOAD
HF
P
O
L
.
C
H
A
.
HF
L
I
N
E
A
R
HF
HF
HF
HF
HF
HF
L
I
N
E
A
R
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