A microprocessor system for traction control

In the mid 1970´s, work on the development of an harmonic elimination pulse width modulation system (PWM) for a traction inverter was being hampered by the complexity of the digital electronics required for its implementation. The authors show how it was decided to investigate the use of one of the new eight bit microprocessors then becoming available in order to reduce this complexity. Somewhat arbitrarily, the Motorola 6800 was selected. Because of known problems with electrical noise on traction vehicles, dedicated hardware was designed, drawing on experience gained with relatively fast digital logic employed on the multiplexing system developed for the British Rail Edinburgh-Glasgow push-pull trains. The resultant PWM controller eventually formed part of the Brush contribution to the People Mover Group´s Birmingham Airport Maglev vehicle