The Study Of Fault Detection And Diagnosis On The Electric Drive System Of Vehicle

Electric drive system has the advantage in energy saving, environmentalprotection, power and acceleration, and mute to engine powertrain, thus it has gotmore and more attention in the modern all-electric aircraft, all-electric ships andelectric vehicles. For electric drive systems, security and reliability are veryimportant, how to detect and diagnose the failure of the electric drive system hasbecome the hot topics of the moment, this thesis study the electric drive system faultdiagnosis technology under the background of electric vehicles.This thesis studies the operation characteristics and analyses the faultsmechanism of electric drive system. The faults are classified by the need of self-testtest and online diagnosis. The fault tree of self-test and online diagnosis is finished.According to the structure characters of electric drive system, the built-inself-test system and integrated online diagnosis system are designed under thepremise of ensuring that the system work independently and safely and diagnosisinfo is stored safely. Achieve the self-test and online faults diagnosis of electricdrive system. The hardware and software are all finished, the design adopt the basicdesign principle and use the original hardware of electric drive at most.。Base on the study of self-test methods of DC bus capacity fault and windinginter-turn short-circuit fault, this thesis proposes a novel capacity self-test method inthe pre-charge step. This method make use of the charge resistance, use theresistance voltage replace the DC bus current, calculate the ESR and ESC with theincreasing DC bus voltage and current and diagnoses the capacity status by the ESRand ESC. The diagnosis of winding inter-turn short-circuit fault use a method baseon high frequency signal injection, the experiment results proofs this sample methodis right.The online diagnosis methods of IGBT open-circuit fault, winding inter-turnshort-circuit fault and rotor position deflection error fault are studied. This thesispropose a novel diagnosis method base on the derivative of three-phase currents,though the contrast of the forecasted voltage and the derivative of detected currents,this diagnosis time of method is only0.13pulse period. A novel diagnosis method torotorcraft position deflection error fault base on power forecasting and table. Thismethod have advantages in engineering appliances and diagnosis time. The onlinediagnose of winding inter-turn short-circuit fault adopt a method base on negativesequence, this method adapt to the electric drive system.