ABB 60 - 65 A perfect fit

A perfect fit ABB’s powerful propulsion converters are energy efficient, reliable and very compact, making them suitable for all rail vehicle designs

HARALD HEPP – In modern rail vehicles driven by electric motors, all movement is controlled and powered by traction converters built on insulated gate bipolar transis tor (IGBT) semiconductors. ABB is a leading supplier both of power semiconductors and of a very broad portfolio of power electronic systems and applications, in particular of motor drives for all industry segments and power ranges. In the past ten years, ABB, leveraging a unique combination of power electronics expertise, brought new, highly successful traction converters to the railway market that excel in energy efficiency, reliability, compact ness and service-friendliness. In the global market, ABB is one of the very few independent suppliers of traction converters or even complete traction chain packages. ABB is not building rail vehicles but supplying key power sub-systems.

f one compares the electric traction motors in trams, motor coaches or locomotives to muscles in the hu man body, the traction converters would be both the heart and the cerebel lum. As the heart, the converter ensures the proper energizing bloodstream, and as the cerebellum it takes care of smooth and precise movement and coordination through sophisticated control algorithms. Speaking more in the language of railway electrics, a traction converter provides the exact voltage wave patterns for the traction motors to control their speed and torque as well as the energy flow to the wheels – or from the wheels back when the vehicle brakes in regenerative mode. A state-of-the-art energy-efficient 1.5 MW converter from ABB (BORD LINETM CC1500_AC) for double-deck EMU trains of Stadler Rail is shown on page 60. The traction converter is the “intelligent link” between, on the one side, the energy supply through catenary, transformer or Diesel-generator, and the traction motors on the other side.

Motor-side challenges On the motor side, the traction converter receives input signals from the motors, for example phase currents, speed, and motor temperature. This information is combined with the driver’s or vehicle control’s commands which tell the con verter how the train shall start, acceler ate or brake. Control algorithms process these signals in milliseconds, taking into account the motor characteristics in dif ferent regimes of the motor frequency/ load diagram. In reality, however, a drive control system for rail vehicles is much more complex. The system has to cope with wheel slippage, which depends on weather conditions, slope, and the wear of the rail track and wheels. Another challenging aspect can be the coordi nation of different motor axles of the vehicle. As an ex ample, ABB con verters showed benchmarking trac tion effort in field trials with a new multi-system CoCo locomotive of the Spanish system in tegrator Construc ciones y Auxiliar de Ferrocarriles (CAF) S.A. ➔ 1. The most essential functions of the drive control are the protection algorithms that make sure that the control reacts properly, reli ably and safely in all imaginable irregular states of the complete propulsion sys tem.

One of the key advantages of ABB trac tion converters is that they are built on the AC 800PEC control platform [1], probably the most powerful modular controller for high-speed performance on the market ➔ 2. This control platform is also used in ABB wind converters, high-power industrial drives, plant auto mation, high-power rectifiers and many other applications. The AC 800PEC soft ware is implemented on three perfor 

If the electric traction motors in trams, motor coaches or locomotives were compared to muscles in the human body, the traction converters would be both the heart and the cerebellum.

mance levels, and this provides an excel lent range of control and communication functionality in cycle times that extend from the sub-microsecond to the milli second level. The controller is comple mented by a variety of input/output mod ules as well as engineering and service tools ➔

Several teams of ABB hardware and software engineers dedicated entirely to working on traction converters, develop traction-specific hardware configurations and software modules, and tailor them to the customer’s vehicles and projects. Compared to most other commercially available traction control systems, the application software in the AC 800PEC is built in a way that speeds up train com missioning significantly. The commis sioning engineer can adjust parameters

ABB traction converters are built on the AC 800PEC control platform, probably the most powerful modular controller for high speed performance on the market.

and algorithms in real time to ensure smooth and powerful motion over all speed and load ranges. Often the sys tem integrators and rail operators are surprised at how quickly new vehicle de signs using ABB converters and drive control come to life when they are pow ered and started for the first time.