Electro-Mechanical Characteristics of Dual-Winding Motor According to Winding Arrangement for Brake Systems in Highly Automated Driving Vehicles

Manufactures of automotive parts are struggling to secure redundancy in various ways. An alternative is to configure the system via a dual-winding motor and two electronic control units (ECUs). The dual-winding motor contains different winding arrangements according to poles/slots, and when only one of the two circuits is used owing to a failure, the electrical and mechanical characteristics differ depending on the winding arrangement. In this study, the electrical and mechanical characteristics were analyzed and compared according to the winding arrangement when the failure occurs. In particular, the winding arrangement of the motor is divided into line symmetry, point symmetry, and alternating symmetry. For each winding arrangement, the back-electromotive force, torque, and torque ripple were compared and analyzed through simulation and test. Also, vibration caused by electromagnetic force was analyzed. Here, to consider the tooth modulation effect, concentrated force was investigated and tangential force as well as radial force were considered. Additionally, the thermal characteristics were analyzed during fault operation using a lumped parameter thermal network with piecewise stator-housing modules. Lastly, the mechanical design characteristics of the motor hardware size that need to be changed according to the winding arrangement of the brake motor are explained. This study provides guidelines for the winding arrangement selection of a dual-winding motor with a similar magnetic field distribution suitable for the design purpose, by analyzing the electromechanical characteristics and size according to the winding arrangement during fault operation. The characteristics of other motor types or pole and slot number combinations can also be inferred from the results of this study, since the magnetic flux density distribution will be determined with line, point and alternating symmetry.