An algebraic approach to determine the current supply in a faulty 5-phase PM BLDC drive. Part I - model setup and its application to the case of one open phase fault

This paper (Part I), together with a companion one (Part II), deals with the fault-tolerant operation of a 5-phase permanent magnet (PM) brushless DC (BLDC) drive. In particular, this paper proposes an algebraic approach to set up a model of the motor current supply in healthy conditions. Afterwards, a faulty drive is considered with one or more open phases and, by constraining the proposed model with fault-specific conditions, scheduling and magnitude of the currents in the surviving phases are determined automatically as well as the maximum magnitude of the currents and the maximum torque developed by the motor. At last, the paper applies the model to the case of a drive with one open phase fault. In the companion paper the model is applied to the cases of more-than-one open phase faults.