Application Status and Issues of Electric
Double Layer Capacitors for Electric Railway
Beijing Jiaotong University
Zhongping YANG
2012. 3. 1
1
Energy storage technology and
Electric Railway
• In recent years, energy storage technology is rapidly developing.
• Energy storage devices
– Secondary battery, fuel cell ,flywheel, electric double layer
capacitor , SMES etc.
• The appearance of energy storage devices makes the electric railway
become more energy-saving, environmentally-friendly mode of
transportation.
Lithium ion battery
Flywheel
EDLC
2
Applications of energy storage
in electric railways
–
–
–
–
–
–
1988, Flywheel, Keihin Electric Express Railway, Japan
2000, Flywheel, hybrid DMU ‘LIREX’, Germany
2002, Pure flywheel tram ‘PPM’, Seven Valley Railway, UK.
2003, Lithium-ion battery, hybrid LRV ‘Hi-tram’, Japan
2005, Ni-MH dual LRV, France
2006, Lithium-ion battery + fuel cell, hybrid EMU, East
Japan Railway
– 2007, EDLC, Seibu Railway, Japan
– 2007, EDLC, Line 5, Beijing Subway, China
– ……
3
The expected effects (1)
Vehicle
• Regenerated energy absorbed and reused
– Preventing regeneration failure
– Energy saving
• Improvement of acceleration characteristics
• Ability to drive to the next station in the case of
electric power failure
• Hybrid railway vehicle can be developed
4
The expected effects (1)
Vehicle
Not be absorbed
I
Regeneratived current
0 Pantograph voltage 1700V
Engine
V
1830V
CKD6E5000 (China)
5
Lithium-ion battery
The expected effects (2)
Power feeding system
• Suppressing catenary voltage fluctuation
• Reduction of peak power
ΔV=line resistance（Ω/km）*distance（km）*regenerated current(A)
DC1830V
DC1700V
Regenerated energy
DC1500V
＋
Substation
Powering
Braking
－
6
The expected effects (3)
Environment and operation
• The LRV may run in partially non-electrified
line to maintain the beauty of landscapes
• The catenary is fully or partially removed
• Direct operation between electrified and nonelectrified line
7
Which storage device is suitable (1)
Energy density and power density
 Battery: high energy density, low power density
 EDLC: high power density, low energy density
Source : Maxwell Technologies SA
8
Which storage device is suitable (2)
Efficiency and lifetime
Battery: Lifetime depends on charge / discharge cycles
EDLC: High numbers of cycles, long lifetime,
rapid charge / discharge
Source : www.electricitystorage.org
9
Which storage device is suitable (3)
• All energy storage devices have been
applied
• There are no conclusions about which one
is the best.
• In this lecture, the application of EDLCs
will be discussed.
10
Some cases of the application
EDLC parameters
Installation
year
Line/Vehicle
2003
LRV of Mannheim,
Germany
On-board
1800
2007
Line 5 of Beijing
Subway , China
Wayside
2007
Seibu Railway,
Japan
2008
Voltage
[V]
Energy
[kWh]
Weight(kg)/Size
(mm)
45
200~400
0.85
477/1900×950×455
2600
69.64
~515.2
2.57
Wayside
——
20.25
512~1280
——
——
313 series, JR
Central, Japan
On-board
800
1.4
700~1425
0.28
430/900×900×730
2008
Portugal MTS
company 750V LRV
On-board
——
——
——
——
——
2009
Line T3 of Paris,
France
On-board
——
——
——
1.6
——
2013
Shenyang.LRV,
China
On-board
——
——
——
——
Installation
Cell
Total
capacity [F] capacity [F]
/860×2800×2600
—— 11
Some cases of the application
Germany
Hybrid LRV with ‘ MITRAC
Energy Saver’ in Mannheim.
Cell capacity （F）
1800
Cell voltage （V）
Number of component
in series/parallel
Total capacity（F）
2.5
Range of voltage（V）
200-400
Energy capacity（Wh）
850
Maximum power（kW）
300
Weight（kg）
477
Dimension（mm）
L1900 W 950 H 455
Energy saving
Up to 30%
160s 4p
45
12
Some cases of the application
France
Hybrid LRV with EDLC
‘Citadis’ on Line T3 in Paris
network.
Source: Jean-Paul Moskowitz Jean-Luc Cohuau ‘ALSTOM and RATP
experience of supercapacitors in tramway operation’
BB63000 Locomotive
13
Some cases of the application
Portugal
Hybrid LRV with EDLC
‘Combino’ in Portugal.
14
Some cases of the application
Japan
Hybrid commuter EMU ‘313
series’ with EDLC in JR
Central Japan.
Cell capacity （F）
800
Cell voltage （V）
Number of component
in series/parallel
Total capacity（F）
2.5
Range of voltage（V）
700-1425
Energy capacity（Wh）
280
Maximum power（kW）
200
Weight（kg）
430
Dimension（mm）
L 900 W900 H 730
570s
1.4
15
Some cases of the application
China
The SITRAS SES stationary energy
storage system has been used in
Line 5, Beijing Subway . There
were four sets of system installed in
four substations.
16
Some cases of the application
China
Item
Unit
Block
Module
Composition
7 cells
in series
6 units
in parallel
32 blocks
in series
Voltage [V]
17.5
17.5
560
Capacity [F]
371
2228
70
Energy capacity [kWh]
2.5
Maximum power [MW]
1
Total Dimensions [mm]
[depth x width x height]
D 860 W 2800 H 2660
Composition of EDLCs for Line 5, Beijing Subway
17
Applied Issues (1)
EDLCs own performance
• Further improvement in energy density
– The improvement of energy density is expected
to be as much as twice every 10 years
• Safety
– High temperature resistance
– Don’t release poisonous gases when electrolyte
solution is burned
• The voltage balance in series
• The reduction of cost
18
Applied Issues (1)
EDLCs own performance
+
Negative electrode
eHigh electric
conductivity
Nano-sized LTO
High ionic
accessibility
(ca. 5-20 nm)
‐
LTO/CNF composite
CNF
+
-
+
-
+
Li4Ti5O12 +
+ 3e⇔ Li7Ti5O12
-
+
-
+
-
+
-
+
+
3Li+
- Positive electrode
-
-
Activated carbon
-
Activated Carbon
Nanochitan lithium (nanoLTO) / carbon nanofibers
(CNF) composite
+
-
-
Pores
-
-
+
Source: NIPPON CHEMI-CON
・ Energy Density: 30Wh / L (about three times the
conventional activated carbon capacitor)
・ Power density: 6kW / L (equivalent to conventional)
19
Applied Issues (1)
EDLCs own performance
100
90
70
60
50
40
HEV regenerative
energy recovery
Lead-acid
battery
Energy density ／Wh・kg-1
80
Nano-hybrid capacitor
Railway applications
Copier and
printer
30
20
Conventional
activated carbon
capacitor
10
0
2
4
6
8
Power density ／kW・kg-1
10
12
20
Applied Issues (2)
The position of installation
• Wayside
• On-board
– The strong constraint on the weight and space.
– To achieve the objectives , choosing the smaller
capacity is important.
• Evaluation of life-cycle cost is strongly required by
users.
21
Applied Issues (3)
Capacity setting and control strategy
• It is important to determine the suitable
capacity on wayside or on-board
• Different purposes require different capacity
― Suppressing catenary voltage fluctuation,
preventing the regeneration failure etc.
• Especially, capacity setting on board needs to
be carefully considered for the restriction of
space and weight
22
Applied Issues (3)
Capacity setting and control strategy
• Effect factors of capacity setting
–
–
–
–
–
–
Line profile
Performance of vehicle
Substation
Time table
EDLC characteristics
Control strategy of EDLC
23
Applied Issues (3)
Capacity setting and control strategy
• Capacity configuration and charge/discharge control
– considering the charge /discharge control strategy is based
on the given capacity
– To set capacity with consideration of the charge /discharge
control strategy
• Varying the allowable value of SOC as line profile
• Optimal charge/discharge control is being studied
• For the practical application, it is important to
establish rational ‘ suboptimal ’ control strategy
24
Applied Issues (3)
Capacity setting and control strategy
Start
Step1: Multi-trains
running simulation
Step2: Analysis of train’s surplus
regenerative power/energy
Step3: Initial capacity
configuration
Step4: EDLC control
strategy selection
Modify
Modify
Step5: Analysis of
control effect&Evaluation
Surplus regenerative
energy fully absorbed
1 No
2 No
Yes
End
The block diagram of capacity configuration
25
The example of capacity setting
Simulation Parameters:
A
0km
B
:substation
5.85km
:Train(powering)
D
7.25 km
:Train(coasting)
270s/360s/450s
Headway
Catenary voltage
Substation internal
1500V
0.0416 Ω
resistance
Resistance of line
line inductance
E
9.39 km
F
su
tra
in
bs
ta
tio
n
0.04 Ω/km
0.001H/km
ta
tio
n
bs
su
sta
t
tra ion
in
bs
ta
tio
n
C
su
bs
su
2.17km
tra
in
upline
sta
ti
tra on
in
Type, configuration
Weight
Motor control
Traction motor
Top speed
Running resistance
ta
tio
n
Vehicle parameters
2M2T
170.34t
1C4M
Induction motor 220 kW × 4 per motor car
90km/h
R=20.286＋0.3822V+0.002058V2（N/ton）
downline
11.68km
:train(braking)
26
Applied Issues (3)
Capacity setting and control strategy
• Case study : Traction and regenerative brake curves
27
Applied Issues (3)
Capacity setting and control strategy
• Case study : The block diagram of simulation
TE=f(v)
Current limiter
V-t
Curve
Grades
Input:
Paranmeters
TPS
Speed limit
Max depth
of discharge
ESS
Pantograph current
p-t
Control
algorithm
Initial voltage
Pantograph voltage
a-t
s-t
Substation output power
DCRLS
Pc
Output:
Simulation
Resulsts
Surplus regenerated
power/energy
……
Substation location
Characteristics of substations
ESS: Engery Storage Simulatior
TPS: Train Performance Simulatior
DC-RLS: DC-railway loadflow Simulator
28
Applied Issues (3)
Capacity setting and control strategy
• Case study : DC-RLS（DC Railway Loadflow Simulator)
Upline
+ DC
……
+ DC
……
Downline
Sub
Sub
Topology will be changed with time
SubA
TrainA
Z1
TrainB
SubB
Z4
Z2
TrainC
Z5
Z3
I3
Rs
Rs
UA
+
-
UB
+
C
-
29
Applied Issues (3)
Capacity setting and control strategy
• Case study : DC-RLS（DC Railway Loadflow Simulator)
Substation B
Substation A
Idin+Iuin
Vuin
Vout
R
I
L
Idin+Iuin
Vout
Iuout
I
S
S
Rs
Rs
+
Cs
+
-
Vs Sub
_
Vs
30
Applied Issues (3)
Capacity setting and control strategy
• Case study: DC-RLS（DC Railwway Loadflow Simulator)
Iin
Vin
Vout
R
L
Train B
Iout
I
V1 V2 Vmax Vfc
0
Rf
Paux/Vfc
Iinv
Vfc
Lf
-Imax
Vfc
Cf
Current
limiter
P/Vfc
Iref
31
Iin
Train C
Vout
I
0
V1 V2 Vmax Vfc
Rf
Paux/Vfc
Iinv
Vfc
Lf
-Imax
Vfc
Cf
Current
limiter
P/Vfc
Iref
31
Applied Issues (3)
Capacity setting and control strategy
• Case study : Simulation result when headway 360s (Step 1)
2000
catenary current[A]
catenary voltage [V]
expected regenerative
current[A]
catenary voltage [V],current[A]
1500
1000
500
0
-500
Surplus regenerative
current
-1000
-1500
800
900
1000
1100
time[sec]
1200
1300
1400
32
Applied Issues (3)
Capacity setting and control strategy
• Case study : The analysis of surplus regenerative power/energy （Step 2)
upline
downline
Surplus regenerative energy
upline
downline
Surplus regenerative power
33
Applied Issues (3)
Capacity setting and control strategy
• Case study : Initial capacity setting（Step 3)
Cell
Module
Capacity
3000F
Rated voltage
2.7V
125V
ESR
0.29mΩ
18mΩ
Power density
63F
5900W/kg
1800W/kg
Energy density
6Wh/kg
2.4Wh/kg
Weight
0.51kg
60.5kg
Energy storage
3.04Wh
143.4Wh
Volume
——
619×425×265（mm3）
34
Applied Issues (3)
Capacity setting and control strategy
• Case study : Initial capacity setting （Step3)
Regenerated energy from Vmax to stop
270s
Module
connection
12 in series × 4 in parallel×2 sets
Module
connection
7 in series × 4 in parallel×2 sets
Voltage range
750~1500V
Voltage range
500~875V
Weight
5566kg
Weight
847kg
Volume
6.444m3
Volume
0.98m3
Energy storage
9kWh
Energy storage
1.04kWh
360s
450s
Module
connection
8 in series × 2 in parallel×2 sets
Module
connection
12 in series × 2in parallel×2 sets
Voltage range
500~1000V
Voltage range
750~1500V
Weight
1936kg
Weight
2904kg
Volume
2.24m3
Volume
3.36m3
Energy storage
2.6kWh
Energy storage
4.3kWh
35
Applied Issues (3)
Capacity setting and control strategy
• Case study : the basic control principle （Step 4)
PL
(kW)
E1
ISC
P2
E2
t(s)
EDLC Current
P1
charge
1300 1450
discharge
1700 1800 Pantograph
voltage
Vehicle current
Id
I l _ lim
I l*
(1) SOC value：0.25~0.9
Current reference
Vt
(2) Current limiter：0.7Imax
36
Applied Issues (3)
Capacity setting and control strategy
• Case study : analysis of control effect (the current limiter-70%) (Step 5)
2000
catenary voltage [V],current[A]
1500
1000
500
0
-500
-1000
-1500
current-nosc[A]
current-nosc[V]
current-sc-control[A]
current-sc-control[V]
800
900
1000
1100
time[sec]
1200
1300
1400
37
Applied Issues (3)
Capacity setting and control strategy
• Case study : analysis of control effect (the current limiter-70%) (Step 5)
1000
Psc
Psc-Control
Pscmax-Control
500
Pscmax
0
-500
-1000
800
900
1000
1100
1200
1300
1400
time[sec]
EDLC energy[kWh]
EDLC power[kW]
1500
5
4
Esc
Esc-Control
Escmax
3
Escmax-Control
2
1
0
800
900
1000
1100
1200
1300
1400
time[sec]
38
Applied Issues (3)
Capacity setting and control strategy
• Case study :The result of capacity setting
Final capacity setting
Initial capacity setting
Module
connection
8 in series × 2 in parallel×2 sets
Module
connection
9in series × 2 in parallel×2 sets
Voltage range
500~1000V
Voltage range
550~1100V
Weight
1936kg
Weight
2178kg
Volume
2.24m3
Volume
2.52m3
Energy storage
2.6kWh
Energy storage
2.9kWh
37
Verification of control strategy
in Laboratory
• Experiments with car
• Experiments with the Mini model
Source: D. Iannuzzi,and P. Tricoli‘ Metro Trains Equipped Onboard
with Supercapacitors : a Control Technique for Energy Saving’
SPEEDAM 2010
38
Verification of control strategy
in Laboratory
Mini model of experimental platform in Beijing Jiaotong University
Line Current
L1
YD11
DC
C1 300V
AC210V
B1
Rectifier
Inverter Current
IL
I inv
R1
L2
Chopper
Current
I ch
T3
R2
M
C2
M
Traction inverter
L3
Vehicle
Substation
T1 I sc
Vch
C3
T2
Lsc
U sc
DC
r 150V-300V
EDLC
Bidirectional DC-DC Chopper
EDLC Energy Storage System
41
Verification of control strategy
in Laboratory
Experimental platform
EDLC Parameter
Rated voltage (V)
270
Rated current(A)
40
Capacitor (F)
6.6
Inner resistance (Ω)
0.2
Motor Parameter
The Platform of EDLC
Rated power（kW）
5.5
Rated voltage （V）
380
Rated current(A)
11
Rated speed (r/min)
Rated torque ( N·m)
1460
35
DC/DC Parameter
Rated power（kW）
15
Switching
1.5K
The Platform of train simulator
frequency(Hz)
Filter inductor(mH)
42
0.5
Verification of control strategy
in Laboratory
An example of experimental results
300V
275V
5A
310V
Catenary voltage
Train current
2.1A
EDLC current
2A
1.1A
Line current
Powering: voltage action value is 275V.
Braking: voltage action value is is 310V.
43
Summary
• Railway electrical energy storage technology
will be further applied and researched
• The energy density of EDLCs is necessary to be
more improved for expanding its application
• It is important to set control strategy and
capacity of EDLCs
• Evaluation of life-cycle cost is strongly required
by users
44
Thank you！
Late time question welcome to:
zhpyang@bjtu.edu.cn or yshouzhuo@yahoo.co.jp
45