FAULT MODEL OF AN INVERTER-FED PM MOTOR FOR X-BY-WIRE SYSTEMS

A dynamic model of an x-by-wire actuator applicable in e.g. Electronic Power Steering, Brake-by-Wire or Electronic Parking Brake is presented. The actuator includes Permanent Magnet Synchronous Machine (PMSM), inverter, controller and a simplified mechanical load model. The PMSM is approximated by a set of differential equations describing each coil or each phase, with the possibility to simulate winding short circuit faults. A three-leg inverter model is designed, where all transistors and diodes inside may have separate short circuit or open circuit condition to simulate inverter faults. A field-oriented torque and speed cascade controller is implemented. In “one fault at one time” failure condition, simulation results from model with independent coil equations and independent phase equations are investigated.