Since 1981 SMA has been successfully developing and manufacturing customized products in the field of power electronics. Experienced development engineers select the optimum power electronic topology within the preliminary planning of the project considering all customer requirements. It is thus possible to develop a custom-tailored solution within a very short time. Of course we will mass-produce these devices on demand.

For more than 30 years now, power and micro-electronics is an essential component in rolling stock. It has drastically changed in the course of time. In the field of power converters not only the enclosure dimen-
sions but mainly the electronic components used have been changed. Specifically changing from GTO to IGBT technology resulted in great advantages. However, such a process of change in technology causes that the power converter's electric components are only avail able in limited quantities after years. Repair and maintenance costs of old devices are thus drastically increased and a complete or partial exchange of these devices is therefore more efficient in most cases.

This was the case for the traction power converter in the diesel-electric dual engine cars VTA of the local traffic operator AKN in Kaltenkirchen, Germany. The original equipment manufacturer used traction power converters on the basis of bipolar transistors for the 19 vehicles. Since these transistors are hardly available as spare parts AKN decided to replace the installed traction power converters with SMA IGBT power units. All other components, such as enclosures, cooling systems, filters, software and control units remain unaffected.

Conclusion
When designing custom power electronics, SMA relies on the know-how of its highly qualified and dedicated employees developing a solution specific for any application. Our experienced development team only needed six months from planning to installing the first prototype.