Syntegra
Syntegra is a rail transport technology system developed by Siemens AG , in which the chassis, drive and brake technology has been merged into a mechatronic system.
introduction
The drive units , running gear and braking equipment in rail vehicles with conventional technology are coordinated, yet fundamentally independent components. Together they form a motor bogie or generally a motor undercarriage.
With Syntegra, on the other hand, there is a complete integration of traction , the wheelset and the braking system. The conventional mechanically very complex traction drive and the conventional brake unit are replaced and the chassis concept is completely changed.
Direct drive
The Syntegra system uses a three-phase synchronous motor with permanent magnets instead of a mechanically complex conventional traction drive with a gear stage . This new engine has already been tested on the example of a drive for mainline railways .
State of the art
A characteristic of numerous metro and subway vehicles with underfloor traction equipment is a drive system that consists of a voltage-impressing traction converter . This feeds two or four asynchronous traction motors electrically connected in parallel. In contrast to the permanently excited synchronous motor, such a drive alone cannot generate a sufficiently high torque . Therefore, a transmission is required for the translation of the drive motor torque. This in turn causes investment costs, energy loss, noise and maintenance costs.
Two versions of the gear-based drive system are common. On the one hand there is the half-sprung transverse drive with an axially mounted gear and a fully sprung travel motor suspended in the chassis . In conventional systems, the torque must be transmitted via a short oil-lubricated cardanic tooth coupling to compensate for the movements .
Syntegra propulsion system
The gearless drive is completely encapsulated. However, the motor of the Syntegra drive system is designed with a high number of poles, as the bore volume of an electrical machine is decisive for the usable torque. With asynchronous machines, a high number of poles leads to low power factors and low levels of efficiency . For this reason, a direct drive seems to be sensible only on the basis of permanently excited machines (PM). For the tubular installation space around a gear set , a PM synchronous machine with a more classic structure with a radial flux arrangement and three-phase winding is ideal. A fundamental innovation in the framework is the combination of wheelset and traction motor bearings into a common main bearing.
Synchronous drives are always designed as single-axis drives . This single-axis drive has advantages over the group drive at the system level. The wheel diameter can be freely selected during reprofiling and there are higher drive redundancies and a simpler failure concept.
landing gear
State of the art
Traction drives and mechanical friction brakes are found in power units with rigid frame constructions, as found in numerous trains today.
For example, in conventional running gears, the braking and driving forces as well as the wheelset managers are absorbed by the running gear frame and forwarded to the car body . Given such given technical and economic boundary conditions, modern power units are considered to be optimized.
Syntegra landing gear
In contrast to today's chassis , the direct drive is an integral part of the Syntegra chassis. The chassis is linked directly to the car body via the drive motor housing. This means that the chassis frame is free from traction forces. The resulting symmetrical loading of the traction motors enables optimal utilization of the installed traction power. In addition, in spite of the short wheel set, Syntegra only has slight wheel set relief, which would increase sharply with conventional running gear. The Syntegra chassis frame of the prototype exhibited at InnoTrans 2006 and RWTH Aachen University in 2007 consists of a cross member and two articulated longitudinal members. All horizontal executives, connections of dampers and stabilizers are taken over by the cross member. Finally, the vehicle mass is only distributed over the two side members, comparable to a beam scale , to the primary springs. Therefore, the stiffness of the primary spring has almost no influence on the safety against derailment. In addition, due to the integration of the traction motor and wheelset bearings , the new wheelsets are internally stored in a common main bearing. These can easily be relubricated during maintenance . One advantage of the new system is that it reduces the load on the wheelset shaft . In contrast to external bearings, the horizontal transverse forces on the wheel counteract the vertical bearing forces with internal bearings.
The total length of the prototype on display is around 2400 mm, the top edge of the air spring is between 700 and 800 mm high and the wheel set base is 1600 mm. The wheel diameter of the prototype chassis is 690/630 mm with a wheelset load of 14 t.
Braking technology
State of the art
The state of the art in metro vehicles is the use of two largely independent braking systems. “Extensive independence” because the braking torques generated by both systems come together on the wheelset shaft . Therefore, both the wheelset shafts and the wheels are common components of the braking systems.
The electrodynamic (ED) brake is used for operational braking and the full-fledged electropneumatic (EP) friction brake is used for failure and emergency braking . ED braking is carried out as a generator with feedback into the supply network or braking unit clocks on a braking resistor . The common technique for stopping braking is blending , the replacement of the ED brake with the mechanical brake in the lowest speed range.
Today, the mechanical brake is mainly designed as a compressed air-based disc brake . The system is very complex due to the large number of its components. Functionalities such as anti-skid protection must be provided on both the electrical (ED) and the mechanical side (EP). Because it is used as an emergency and safety brake, the highest demands are placed on the availability and reliability of the system.
Syntegra braking concept
In contrast, with Syntegra there is the option of using only a mechanical brake with significantly reduced actuator force as a holding brake on the platform, as a parking brake in the depot and to support a safety brake.
The permanently excited synchronous machine generates an inherent braking torque (inherent electrodynamic brake, IED) with suitable wiring. This physical property enables safe braking to a standstill. The IED consists of additional braking protection and an additional braking resistor. The shortening of the response time from triggering to availability of the maximum torque is advantageous. In principle, the IED braking system is slide protected. This effect results from the physical properties of the permanently excited synchronous machine .
advantages
A comparison with a conventional chassis with the same drive power and driving force reveals a mass advantage of the Syntegra prototype. With a projected axle load of 14 t, this should undercut the state of the art by 1000 kg. But since further measures to reduce mass are planned, the weight advantage will supposedly increase to almost 30%.
Due to the reduction in the absolute mass, the rotating mass and the higher drive efficiency, the energy consumption of the trolleys should be reduced by up to 20%.
The Life Cycle Costs (LCC) should decrease through lower energy consumption and lower maintenance costs. Low noise emissions from the drive system are achieved by eliminating the drive motor fan and the gearbox, the lower motor speed and the higher inductance of the drive motor.
In addition, the completely encapsulated drive has no clutch, no gearbox and no fully-fledged mechanical brake. At the same time, greater safety and better driving characteristics should be achieved through an articulated chassis frame.
Prototype vehicle
Syntegra is integrated as a prototype in a metro vehicle. In the first step, the system was tested in the Wegberg-Wildenrath test center.
The Wegberg-Wildenrath test center is a test track for railway vehicles. Almost all operational conditions that a rail vehicle experiences in regular use can be simulated here. In the second step, the vehicle was approved for passenger traffic .
The Syntegra technology was used in the regular passenger service of the Munich subway . The prototype vehicle of the B series (train no. 498, Syntegra technology only in car 7498) drove for the first time in regular Munich subway traffic on August 12, 2008 and was recognizable by the Siemens advertising and audible other driving noises. The double multiple unit has been part of the Bahnwärter Thiel cultural center since October 2018 .
References
- ↑ MVG press release: Premiere of Siemens Syntegra chassis in the Munich subway ( page no longer available , search in web archives ) Info: The link was automatically marked as defective. Please check the link according to the instructions and then remove this notice.
