Germany: In 2020, the freight operator, a subsidiary of national operator, Deutsche Bahn, placed an order with the Japanese manufacturer for 50 HDB 800 locomotives powered by diesel engines and two battery packs. The new locomotives are to replace the Class 290 vehicles produced by MaK from 1964 to 1974. Leasing company Railpool has also ordered 50 locomotives to hand them later over to DB Cargo, expecting that the new fleet will save at least 1 mln l of diesel fuel annually.
After a three-year delay, production of 10 pre-series locomotives began at Talbot Services in Aachen in mid-2023. The first two units were not ready until the end of 2024. Toshiba has told Czech media Railvolution that the locomotives are undergoing dynamic tests at Alstom’s site in Hennigsdorf, Germany. These tests are necessary for the approval of the rolling stock for operation in Germany. At the same time, six more locomotives are being assembled in Aachen.
In 2021, Hiroyasu Kinoshita and Kotaro Ogawa, experts from the Global Railway Systems Engineering Department of Toshiba Infrastructure Systems & Solutions described in detail the development of the HDB 800 and key innovative traction solutions in Toshiba Review. The ROLLINGSTOCK has adapted it for you.
Overview of the traction system
A contract was inked with DB Cargo for the design and manufacture of a hybrid locomotive, the HDB 800, as part of the Diesel-Electric Hybrid Locomotive (DEHLo) Project. The aim was to save more than 30% of fuel compared to DB Cargo’s current fleet of diesel locomotives. The traction battery system of the new locomotive has a traction power at the wheel rim of 750 kW and is equipped with the SCiB lithium-ion battery developed by Toshiba. The HDB 800’s permanent magnet synchronous motors (PMSMs) are highly efficient and easy to maintain.
The figure below shows the configuration of the main circuit system of the HDB 800. Dual modular redundancy is used in the vehicle, i.e. system components are duplicated to provide redundancy in case one of them fails. Each replication consists of a diesel engine, a generator, and four traction motors that are controlled by four inverters.
The configuration of the main circuit system of the Toshiba HDB 800 locomotive (enlarge). Source: Toshiba
There are two types of hybrid systems in use in the industry, parallel and serial, and we have opted for a serial system. An engine uses a generator to drive the locomotive, eliminating the need for a gearbox and transmission shafts. This reduces the number of parts and the failure rate of the system.
The HDB 800 is designed for two tasks: marshalling yard operations and short-distance mainline service. The hybrid system reduces the locomotive’s energy consumption when shunting. The batteries reduce diesel consumption when switching from idle to traction and back again, while regenerative braking charges the batteries.
SCiB traction battery system
The anode of the SCiB is made from lithium titanate oxide. Although this battery is classified as a lithium-ion, it features enhanced safety, long life, low-temperature operation, fast charging and high input/output power.
The traction battery system of the T-HDB 800 is designed to allow disconnection of faulty components. It consists of 56 series-connected SCiBs, with a total capacity of 120 kW⋅h. Water cooling of the traction battery system, as in the case of the power conversion cubicles, reduces the temperature rise of the battery to extend battery life.
PMSM, permanent magnet synchronous motors
The requirements for the strength of a bogie with traction motors installed are set out in EN 13749, on the basis of which we have analysed the strength using the motor model shown in the figure below.
Rendering of the PMSM. Source: Toshiba
To avoid undesirable effect of manufacturing variations, we have ensured sufficient safety of the traction motors by applying a safety factor in accordance with the Fracture Mechanics Proof of Strength for Engineering Components Guideline widely used in Germany.
Power conversion cubicle
Each cubicle includes a power unit consisting of one converter, two inverters, a power control unit, and an auxiliary power supply unit.
Power conversion cubicle. Source: Toshiba
Features of the power conversion cubicle include:
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- duplication of the power converter to ensure uninterrupted operation, as well as equipping each traction motor with a separate inverter to switch them off individually;
- forced water cooling system to reduce the size of the power supply;
- optimal distribution of control functions between the control and power units – so, although each traction motor is controlled by a separate inverter, now one control unit can control one converter and two inverters and further reduces the size of the power conversion cubicle;
- allocation, by means of a power supply unit, of additional space for a traction converter based on IGBT-transistors to realise traction from the catenary network, if necessary.
Tests and evaluations of test results
To confirm compliance with the EN standards required for electrical equipment to be supplied on the European market, we performed type tests on the power unit and traction motor to be mounted on the HDB 800 locomotive. These tests, which included vibration, temperature and efficiency checks, also were necessary to confirm compliance with the specifications.
All the tests were satisfactory. Following a rated load test, the efficiency of the traction motor and power unit was found to be 97.4%, exceeding the design target of 96%. This represents an efficiency improvement of around 5% compared with a conventional open-type induction motor.
Concept of new hybrid locomotive
The HDB 800 is designed to be able to be powered by an overhead wire.
Configuration of the main circuit system of the Toshiba HDB 800 with additional power supply from overhead wire (enlarge). Source: Toshiba
Developing such a locomotive presents many challenges. These include providing sufficient space for the necessary equipment and developing a technology that can switch between different power modes. This makes reducing the size of the equipment essential. One of our ideas was to use a single small diesel engine-generator solely to generate the energy needed for an emergency start-up.
Authors:
Kinoshita Hiroyasu, Global Railway Systems Engineering Department of Toshiba Infrastructure Systems & Solutions
Ogawa Kotaro, Global Railway Systems Engineering Department of Toshiba Infrastructure Systems & Solutions
Stolchnev Alexey, Russian Projects Editor, ROLLINGSTOCK Agency (adaptation and foreword)
