Auxiliary Power Supply for Metro Application

SMA provides auxiliary power supplies for a total of 42 three-car metro trains forMetro Kaohsiung. The trains will be used in revenue service in Taiwan as of the beginning of 2007.

Compact and ultra-lightweight auxiliary power supply

Modular system for for 750 V DC or 1,500 V DC

Based on proven platform MEE-NTSD

High overload ability of converters

Compact and lightweight input filters due to highly dynamic input current control

Ultra-lightweight, non-welded stainless steel underfloor container

Can be project-specificallyadapted due to numerousoptions

For short- and long-distance traffic

Figure 1: Vehicles for Metro Kaohsiung in the depot

The auxiliary power supply for thenew metro trains for Metro Kaohsiungbelongs to SMA's product familyMEE-NTSD (SD = Short Distance) forregional trains and is based on theplatform MEE-NT. SMA has thus aninnovative and sophisticated moduleplatform proven in daily use for aux-iliary power supplies in different ap-plications.

Integration into vehicle

Each metro train for Kaohsiungconsisting of three cars is equippedwith 2 identical MEE-NTSD establish-ing a partly redundant system. Theauxiliary power supply is providedwith an input voltage of 750 V DCfrom 3rd rail. If one power supplyfails the other MEE-NTSD suppliesimportant consumers. The outputand coupling contactors requiredare integrated into the auxiliarypower supply. The two MEE-NTSD

are connected in parallel to one

single DC board supply and chargea battery.

Design

The auxiliary power supply systemconsists of the function units indicat-ed below:

· high-voltage input converter with integrated battery charger

· 3-phase output inverter

Innovative, redundant auxiliary power supply for sophisticated metro trains

Figure 2: Block circuit diagram of an MEE-NTSD for Metro Kaohsiung

A number of additional functionalcomponents can be integrated into theMEE-NTSD. It is thus possible to simplyadjust the system to the diverse re-quirements of sophisticated metrotrains. The MEE-NTSD Kaohsiung istherefore equipped with a high volt-age input contactor, output and cou-pling contactors. An upgrade for anemergency starting unit is available.

For 750 and 1,500 V DC

The high-voltage input converterconsists of 2 compact and light-weight electronic modules withassociated inductive components.This converter is equipped with twoseparate outputs. One output isdirectly used as battery chargerwhile the other generates a DC linkin order to supply the output invert-ers connected.

Due to the input converter's modulardesign it is possible to realize auxil-

for Metro Application

Figure 4: Detail of the MEE-NTSD output inverter module

iary power supplies for input volt-ages of 750 V DC and 1,500 V DC,both typical for metro trains. In caseof MEE-NTSD Kaohsiung (750 V DC)the two modules of the input convert-er are connected in parallel, whilethe modules are connected in seriesfor applications with an input volt-age of 1,500 V DC.

Because the battery charger wasintegrated into the input converter itwas possible to reduce dimensions,weight, complexity and costs whilemaintaining performance.

supply. It is therefore possible toachieve an output voltage qualitycomparable to the public grid.Other project-specific output volt-ages and frequencies are possibleas well.

The 3-phase output inverters with anominal power of 135 kVA eachprovide a 3 x 220 / 380 V, 60 Hz,AC board supply. The invertersgenerate a neutral wire that isgrounded in the auxiliary power

Single-phase loads are supplied viaan additional transformer. This solu-tion allows the supply of single-phase loads of another voltagelevel. In case of the MetroKaohsiung project the single-phaseAC voltage output has a nominalvoltage of 1x 110 V AC, 60 Hz.

The air conditioning systems are themain consumers of electric power.Air conditioning requirements arevery high in Taiwan. As the airconditioning systems are directlyconnected to the inverter withoutunloading or soft start the invertershave been designed with an ex-tremely high overload ability.

Inverter with high overload

Figure 3: MEE-NTSD input converter module

for Metro Application

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Non-welded underfloor containers made of stainless steel

Figure 5: Entire system in open non-welded underfloor container

ConclusionSMA's MEE-NTSD is a sophisticat-ed platform of auxiliary powersupplies for short-distance traffic.Based on this innovative and trend-setting platform it was possible todevelop a very compact and ultra-lightweight auxiliary power supplyfor metro applications. Specificallythe low system weights of wellbelow 900 kg are an outstandingsystem feature.

Input voltage 750 V DCAC output 1 3 x 220 / 380 V, 60 Hz, 135 kVAAC output 2 1 x 110 V, 60 Hz, 2 kVADC output 110 V DC, up to 137.5 V, 125 ADimensions of underfloor container 1,500 x 1,700 x 560 (mm)Weight approx. 850 kg

Technical DataTechnical data MEE-NTSD (Example)

Each MEE-NTSD auxiliary powersupply is integrated into one sepa-rate underfloor container. A partlyredundant double system, as for theMetro Kaohsiung, therefore consistsof two separate underfloor contain-ers that can be positioned side by

side or underneath different vehi-cles as well.

The underfloor containers are non-welded enclosures made of stain-less steel. This technology makes itpossible to design ultra-lightweight

enclosures. A modular system isused for the containers as well allow-ing to simply adjust them to the vehi-cle requirements.

As for dimensions and weights, newstandards are set. An MEE-NTSD

auxiliary power supply has aweight of 825 kg to 900 kg accord-ing to input voltage and equipment(options, such as contactors oremergency starting units).

In addition to the requirementsreferring to modularity and noiseemission, different ambient condi-tions were considered in the devel-opment of the enclosure technolo-gy. Thus, the system can be usedworldwide without complex adjust-ments.

SMA Railway Technology GmbH

Miramstrasse 8734123 KasselGermanyTel. +49 561 50634-6000Fax +49 561 50634-6001E-Mail: Info@SMA-Railway.com www.SMA-Railway.com