THE SCIENCE AND ENGINEERING REVIEW OF DOSHISHA UNIVERSITY, VOL. 52, NO. 3 October 20 Field Tests of a Power Storage System with a Li-ion Battery for a DC Railway Feeding System Shigeki UMEDA, Takayoshi NOBUHARA, Naoto NAGAOKA, Akihiro AMETANI (Received April 5, 20) A storage system of regenerated electric power for a railway system has been developed. It stores electric power by generative brake to an industrial large-sized lithium-ion battery, and releases the energy during powering trains. This system is installed on the ground. The feeding line voltage is stabilized, and thus the efficiency of the train system is improved. The battery current is determined according to the line voltage at the installed position of the storage system. When the state of charge (SOC) of the battery is at its maximum power point or less, the battery is charged by the maximum current of the battery (0C). The maximum discharge current is at around 5C because the average charging period is a half of the discharging period. The practical discharging current is controlled according to the SOC to keep the operational point of the battery. The optimum capacity is determined by a numerical simulation taking into account the control characteristic. The internal resistance of the battery affects on the maximum operational point. The thermal and time-varying characteristics of the resistance are measured. The characteristic of the voltage stabilization is confirmed from a measurement on a practical train system. Li-ion Battery, power compensation, voltage regulation, dc railway, EMTP 2 EMTP 2. 97 987 997 0 20 69 () 998 (2)(3) (4) West Japan Railway Co, Osaka 530-834, Japan Telephone:+8-6-6375-8733, Fax:+8-6-6376654, Email:shigeki-umeda@westjr.co.jp Department of Electrical Eng., Doshisha University, Kyoto 60-032, Japan Telephone:+8-774-65-6324, Fax:+8-774-65-680, Email:nnagaoka@mail.doshisha.ac.jp
64 (4) (5) 2 2 (6) 2 (7) (8) (9) 2 (0) 2 2 ()(2) 2. 500V 600V 00V 900V 800V Fig. 4 2 800A Fig.. Current and voltage of DC train 7 2000A 500AFig. 2 AB 600V (0.04/km) (5km) (000A) 200V(=0.045000) 800V 600V 0.04/km 000A (7Cars) 2000A 000A 0km 5km 0km Fig. 2. Image of feeding line voltage 2
65 3. 3. (Wh/kg) (kw/kg) (4) 2 (6) VVVF Fig. 3 (9) IGBT SL 2 IGBT 2 2 V B SL DC voltage source FL,8mH FC FC 9,600F IGBT IGBT 2 SL,6mH SFC 3,500F Fig. 3. Bidirectional converter circuit Lithium-ion battery 3.2 2 Table 7 7 3.4.V 20% I MAX 600A 60Ah C=60A A I MAX =0C Table. Specification of an industrialized Lithium-Ion battery Model LIM60H-7D-SR (block) LIM60H Cell Nominal voltage 25.2 V 3.6 V Maximum voltage 2.7 V 3. V Minimum voltage 28.7 V 4. V Maximum current 600 A (0 C) 600 A (0 C) Nominal capacity 60 Ah 60 Ah Mass 30 kg 4 kg Specific energy 50 Wh kg- 54 Wh kg- Energy density 69 / Wh L- 08 / Wh L- Dimension W80D76H60 mm W70D92H33 mm V B E 0 V r V r E V V d d 0 V () B 2 r V Fig. 3 d, d 2 =(-d ) r V r V 23 E 0 =600V V=200V V B 600900V Table 2682 V B =655.2V r V I t =2,000A 5.5kA(=I t r VC 2.02.75) 600A 0 3
66 3.3 SOC:state of charge Fig. 4 600A 300A V 0 R B V B V 0 R B V B V 0 R I (2) B Minimum voltage B Load test voltage Maximum voltage Open voltage Field test voltage Fig. 4. SOC vs. internal voltage(lim60h) 2 I MAX V BMAX Table 60Ah 2 Fig. 5 I MAX =600A(0C) 36% 36% 36% 27 600A(0C) 2 I MAX (600A) I MAX /2(=300A) ChargeCurrent(A) 600 500 400 300 200 00 0 Charge Discharge Discharge Charge 20 40 60 80 00 S.O.C(%)=StateofCharge Fig. 5. Charge and discharge cycle 3.4 2 2 Fig. 6.5 25 2 65 /2 2 4
67 A2 Fig. 6. Internal resistance vs. Temp. 4/May/2006 5:7 7/May/2006 06:06 22/May/2006 4:8 3.5 Fig. 7 T B 30 T P 60 Fig. 3.6 Fig. 7 /2 (I MAX =600A) I MAX T B /T P =300A Charge Current discharge 600A -300A 30S 30S 60S 80S 300S Fig. 7. Current model of Battery Time IGBT VVVF 700Hz 3.6 3.3 Fig. 4 Fig. 8 700V V 3 V 2 V 3 -V 4 I cc V 2 V -V 2 I cd V I cd 3.5 2 I cc I MAX (600 A) I cd I MAX /2(300 A) 3.3 5
68 Fig. 8 (a) (V 2 -V 3 ) I cr Fig. 4 Fig. 8 (b) I cd (36%) I cd I MAX (600A) I cd I cc I MAX IB Icc charge IB Icc charge Fig. 9 R P R Q 0.0280.020 R fk R rk 0.023/km 0.07/km I S I t Fig. 0 I B 27% I cd () I S EMTP Fig. V V 4 Fig. 4 Icr Icd V2 V discharge V3 V4 VL (a) Conventional control function (b) Improved control function Fig. 8. Control characteristic Icd V V2 discharge V3 V4 VL P B A Feeder line 4.3 km 0.3 km RP Rf Rf2 Compensator IS It EP Rr Rr2 Rail 4.0 km Rf3 Train Rr3 Q RQ EQ 3.7 2 Fig. 9 Fig. 0 (8) EMTP (Electromagnetic Transients Program) EMTP TACS (Transient Analysis of Control Systems) Line voltage Target SOC + K Fig. 9. A model circuit for EMTP simulation Icdmin charge Icc Icdmax V2 0 V Icd V3 V4 Icd SOC discharge s Initial SOC (t = 0) SOC VB IB Fig. 0. A control circuit for EMTP simulation VB Battery 6
69 Control characteristic number of unit 4 V MIN V 2 =530V V 4 =700V V MAX V 3 =670V V =500V 4 0 0 Fig.. Number of Battery units vs. voltage fluctuation 4. 4. Fig. 2 (3) A2 Fig. 2 Fig. 6 25 0.8m Internalresistanceat25m.6.4.2 0.8 0.6 0.4 0.2 0 2006//0 2007/05/0 2007//0 2008/05/0 2008//0 2009/05/0 2009//0 Fig. 2. Process of internal resistor at 25 4.2 Fig. 3 0 4 2 4 800V Fig. 70V 3.7 4 Fig. 3. Distribution of voltage 5. 2. 2 2. 2 7
70 3. 4 4. A C 60Ah C=60A0C=600A C A2 A- I V (3) V/I Voltage [V] 740 720 700 680 660 640 620 Battery voltage Battery current Open voltage V I 200 000 800 600 400 200 600-200 0 0 20 30 40 Time [s] Fig. A-. Voltage fluctuation at charging 0 Current [A] () 875 ISSN 099-995pp.4-5 (2002-6) (2) 875 ISSN 099-995pp.39-4 (2002-6) (3) K. Kawahara, S. Hase, H. Morimoto, S. Umeda, N. Takahashi Compensation of Voltage Drop using Substation Support Equipment for DC Feeding System IEE Japan, Vol. 23-D, No., pp.38-42 (2003-)(in Japanese) D23,, pp.38-42 (2003-) (4) 875 ISSN 099-995pp.32-35 (2002-6) (5),,,,,,, 5-055 (2008) (6) (2008-) (7) Umeda, S., Ishii, J., Nagaoka, N., Oue, H., Mori, N., and Ametani, A., Energy Storage of Regenerated Power on DC Railway System using Lithium-Ion Battery, Proc. International Power Electronics Conference, Niigata, Japan, pp. 455-460 (2005) (8) Nagaoka, N., Oue, H., Sadakiyo M., Mori, N., and Ametani, A., Umeda, S., Ishii, J., Power Compensator using Lithium-Ion Battery for DC Railway and its Simulation by EMTP, Proc. IEEE 63 rd Vehicular Technology Conference, Melbourne, Australia, 0-7803-9392-9/06 (2006) (9) pp.262-264 (2000) (0) pp.26-27 (200) () Nagaoka, N., Sadakiyo, M., Mori, N., Ametani, A., Umeda, S., and Ishii, J., Effective control method of power compensator with Lithium-Ion battery for dc. Railway system Proc. University Power Engineering Conference, Newcastle upon Tyne, Paper FAT-4c (2006-9) (2) Sadakiyo, M., Nagaoka, N., Ametani, A., Umeda, S., and Nakamura, Y., An Optimal Operating Point Control of Lithium-Ion Battery in a Power Compensator for DC Railway System, Proc. University Power Engineering Conference, Brighton, pp. 68-686 (2007-9). (3) Umeda, S., Nakamura, Y., Ishii, J., Sadakiyo, M., Nagaoka, N., Monitoring Equipment of Lithium-Ion Battery in Power Compensator for DC Railway IEEJ TER-06-69/LD-06-47(2006)(in Japanese) TER-06-69/LD-06-47(2006) 8