"Entwicklung eines Antiblockiersystems mit Elektromotoren für starke Elektrofahrzeuge"
Entwicklung eines Antiblockiersystems mit Elektromotoren für starke Elektrofahrzeuge
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In this diploma thesis, for an electric vehicle with two independendly controllable permanent magnet synchronous motors (PMSM) which drive the rear wheels, several model based wheel slip controller for an anti-lock braking system (ABS) have been developed and were compared to a series ABS system. For the simulation in a MATLAB/Simulink environment a longitudinal vehicle model has been developed, which consists of a PMSM and a two-stage spur gear transmission for each rear wheel to drive and decelerate the vehicle. The physically-based modelling of the electric drives was based on existing parameters from a numerical field calculation. To consider motor losses measured values of a motor rig testing were used. The nonlinear motor model considers the effects of armature reaction, ferromagnetic saturation of the stator iron and varying magnetic reluctance in circumferential direction which causes an additional motor torque in the region of field weakening. For the field oriented torque control of the employed PMSM, a method is proposed which uses offine calculated current-maps to accomplish an effciency-optimal steady-state inversion of the torque relation. The inversion was formulated as an optimization problem which minimizes the emerging motor losses in stationary operation. The optimization problem was solved in MATLAB my means of a numerical method of sequential quadratic programming (SQP) for discrete operation points. These current-maps supply the reference values for the succeeding model-based current regulator with conditional feedback. Therefore, the well-known knowledge of the plant was used in the design to optimize the performance of the current regulator regarding disturbances and parameter variations. The second part of this work deals with wheel slip control with the PMSM as brake actuators, which allow to regenerate energy in generator mode during deceleration. In the simulation the exact vehicle velocity was known but has been arti cially disturbed wi