An observer-based traction control strategy for electric vehicles is proposed in this paper. The proposed strategy considers the combined effects of lateral and longitudinal traction forces, both for acceleration and regenerative braking, even in curved trajectories. Nonlinear reduced-order observers are designed for estimating tire-road friction condition on each traction wheel and vehicle lateral velocity from which side-slip angles are calculated. A detailed analysis of observers convergence is performed, and a method to know the quality of the estimated variables is also proposed. The proposed traction control strategy allows avoiding the traction wheels skidding during acceleration and braking both in straight trajectories and turning maneuvers. The performance of the proposal is verified through simulation on a complete vehicle model, under different situations and even considering a different vehicle tire model.

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ResumenEn este artículo se presenta una estrategia de diagnóstico de fallas por llave abierta en el convertidor del rotor de generadores de inducción con rotor bobinado. La estrategia utiliza observadores de estado basados en modelos dinámicos obtenidos a partir de un enfoque que utiliza geometría diferencial. Estos observadores permiten generar señales de residuo sensibles a cada falla considerada e insensibles a perturbaciones. A partir de estas señales se construye un vector de residuos con información que puede ser utilizada para la detección y el aislamiento de la falla. La estrategia de detección consiste en la evaluación de la envolvente de la norma del vector de residuos. El aislamiento requiere evaluar la región del plano recorrida por el vector de residuos y comparar dicha región con la asociada a cada escenario de falla. Finalmente se presentan resultados donde se demuestra que la propuesta permite detectar, aislar e identificar fallas de llave abierta, simples o múltiples, aún frente a errores paramétricos y otras perturbaciones.Palabras Clave: Generador de inducción con rotor bobinado, Convertidor del rotor, Falla por llave abierta, Observadores, Escenarios de falla, Diagnóstico de fallas Detection and Isolation of Faults on the Rotor Side Converter of Doubly Fed Induction Generators AbstractThis article presents a fault diagnosis strategy for open switch faults in the rotor side converter of doubly fed induction generators. The proposed strategy uses state observers based on dynamic models obtained from an approach based on differential geometry. These observers allow the generation of residue signals that are sensitive to each fault and insensitive to disturbances. From these signals a residual vector is constructed with information that can be used for the detection and isolation of the fault. The detection strategy consists of evaluating the envelope of the module of the residual vector. Isolation requires evaluating the region of the plane described by the residual vector and comparing that region with the one associated with each fault scenario. Finally, results are presented where it is demonstrated that the proposal allows to detect, isolate and identify open switch faults, both single and multiple, even against parametric errors and other disturbances.