Fault Detection and Isolation in Electric Vehicle Powertrain

The powertrain of an electric vehicle (EV) consists mainly of the battery, electric motor and power electronics. The safe and reliable operation of the electric vehicle depends on their fault-free operation. Fault detection and isolation methods work on the premise that small changes as a result of faults affecting a system causes variation in its operational response. This property can be used for the detection of such faults and their severity. This chapter discusses methods for detection and isolation of faults in electric vehicle powertrain components. Powertrain configuration and technologies are identified. Battery technology such as Lithium-ion batteries have gained a significant application as energy storage source in electric vehicles due to their high energy and power density, long lifespan, and low self-discharge performance under extreme temperatures. Model-based approaches are discussed for the determination of battery state of charge, state of health and effect of accelerated degradation. Fault detection in electric motor is considered. Brushless asynchronous induction motor, brushed externally excited synchronous motor and brushless permanent magnet synchronous motor are the options adopted for the electric vehicle powertrain. Signal processing-based approach such as the motor current signature analysis is explored for detection of broken rotor bar, shorten stator windings, air gap eccentricity, bearing failure and load variation effects. Lastly, fault detection in power electronics is explored. Electric vehicle electric components need complex electronics to control them. These come in the form of a power electronics module (PEM), and an inverter, which can be integral with the PEM or the electric motor itself. Inverters provide the interface between an alternating current electric component and the direct current battery. The current focus for electric vehicle power electronics is controllable solid-state switches such as insulated gate bipolar transistor. For these power drives, the major faults are: open switch fault and short switch fault. Signal processing-based approached are considered for detection of these fault.