12 m long trolleybus with traction battery driven
(for Szeged Transport Company, Hungary, Szeged)
The 12 m long trolleybus was rebuilt from existing SKODA manufactured diesel bus by the Transport Company of Szeged in Hungary in 2012 with traditional asynchronous traction system.
In frame of rebuilding our company, Sedulitas-Pro Ltd. provided a brand new, CAN-Open based vehicle control system and a traction battery group equipped with management system. Besides these our company made the 3D battery group location plan and detailed design of battery containers for mechanical manufacturer partners.
The new vehicle control system supervises the classical operation like lighting, door control, heating, ventilation, communication with traction system and provides high quality diagnostic features further contains a colour interactive display for driver. The system and software design was done by our company. Additionally the new control system superintends the traction battery operation by means of connection to BMS via CAN-Open.
The trolleybus is equipped with high energy density LiFeYPO 4 battery cells which are connected in serial and by means of high current contactors are switched on high voltage traction network as well. In the rear part of vehicle 120 cells are located that results 384 V dc nominal voltage for traction and the capacity is 90 Ah. The estimated running range is near 4 km with full load, the weight of battery pack is 450 kg with container and ventilation. Thanks to the good parameters of battery there’s no needed any air-conditioning for batteries because the maximum operational temperature is 85 degrees.
The battery management system (BMS) is the Sedulitas-Pro’s equipment, measures the cell voltages, temperatures then provides the protection tasks, battery state calculations and cell balancing. The system is built from measuring nodes, mounted directly on cells, and communication centres named as gateways which units are suitable for operation in railway circumstances. BMS is integrated into the vehicle control system via CAN and provides information for driver through the cab’s monitor.
The battery pack is charged by our roof mounted charger unit controlled by vehicle control system and BMS via CAN-Open line. The cells can be charged by constant current or constant voltage depending on BMS’ command where the charging current can be set between values 2-25 A.
Main technical points of trolleybus:
- Well proven CEGELEC asynchronous traction system,
- New CAN-Open based vehicle control system, also for suitable for SAE and Ethernet communication,
- CAN based BMS built from own developed components,
- Battery balancing function controlled by SEDPRO BMS,
- Lithium Yttrium Power batteries (LiFeYPO4) with high cycle number,
- Roof mounted traction battery charger (SEDPRO - VAT-1-25),
- High starting and electro-dynamic brake effort,
- Smooth, continuous effort control,
- IGBT based auxiliary inverter
- Silent and high efficiency rotary compressor specialized for railway application driven by asynchronous motor
- Renewed traditional pressured air type brake systems
Technical parameters
| Operator | Szeged Transport Company, Hungary |
| Type | Skoda 21 Tr |
| Maximum speed | 60 km/h designed; 50 km/h limited, 35 km/h battery operation |
| Power of traction motor | 160 kW |
| Length of vehicle | 12000 mm |
| Vehicle width | 2500 mm |
| Mass | 18,5 t |
| Wheel diameter | 930 mm |
| Line voltage | 600 V dc (400-720 V dc) |
| Traction battery | |
| Type of cells | LiFeYPO4 |
| Number of cells | 120, serial connection |
| Capacity | 90 Ah |
| Weight of group | Approx 450 kg |
| Dimension of battery group | |
| Maximum discharge current | 200 A |
| Voltage of group | 384 V nominally (min. 336 V, max 480 V) |
| Driven axle | ZF AV 132 |