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The alleviation of environmental problems associated with personal, public and commercial transport in urban areas has become an important issue for both policy makers and the automotive industry. Future legislation in Europe and the USA is expected to introduce strict limits in vehicle emissions, and both electric and hybrid vehicles are considered to be strong contenders for meeting low / zero emissions targets. As a result, research into electrically driven powertrains, which have similar performance attributes as ICE (Internal Combustion Engine) vehicles, has led to the development of electrically actuated wheel technologies, with increasing attention being focused on research into novel antilock braking / traction control (ABS / TCS) strategies. This paper describes a comparison of traction control schemes using real - time observer based estimates of μ-slip characteristics.

The paper considers the implications of typical faults on the operation and control of a permanent magnet (PM) traction drive. The discussion is illustrated with analyses and test results taken from a vector controlled, imbedded magnet design of PM motor that has been prototyped for a future fuel cell powered mid size car. In particular the paper describes the outcome of an experimental investigation where a series of representative faults have been imposed on the prototype machine. The impact of the various faults and the subsequent fault control on the drive system are presented in terms of braking torque, and maximum current requirements.

The paper explores the design implications of accommodating the engine start function in a large variable frequency starter-generator. Using data from an existing 225kVA starter-generator the trade off between the stator current, which impacts the size and rating of the start inverter, and the field current, which affects the size, rating, and complexity of the excitation system is explored. The suitability of a 3-phase AC main exciter is assessed as a direct replacement for the conventional main exciter. An optimization of the 3-phase configuration is presented, aimed at achieving minimum input VA to the exciter for a given field excitation requirement during start. Results from this prototype start excitation system indicate high levels of field current are possible from a design which could be retrofitted within the mechanical envelope of the conventional exciter.

The design and control strategy for a prototype high-performance, electro-mechanical actuator operating in a sequential gearbox is presented. The actuator is modelled using a 3 dimensional finite element magneto-static model. A coupled field-circuit model is developed to analyse the dynamic performance of the actuator. A fuzzy control strategy is used to provide position control and soft-seating of the actuator. The controller is implemented using a Digital Signal Processor. Simulation and experimental results are presented to verify the performance of the closed-loop system.