Optimal current amplitude range for fault tolerant control of four-phase doubly salient electromagnetic motor

The influences of current amplitudes on four-phase 24/18-pole doubly salient electro-magnetic motor(DSEM) under fault-tolerant operation are studied in this paper. Taking average output torque, output torque ripple and stator copper losses into consideration, the optimal fault-tolerant current amplitude (FTCA) range is obtained. A four-phase full-bridge converter with two bilateral switches is applied to the fault-tolerant drive system. Once the fault of one phase open-circuit occurs, the bilateral switch connected to the faulty phase is switched on and the FTCA of the remaining three phases are adjusted to obtain the same excitation torque as that of normal operation. And the stator copper loss is analyzed as well. The relationship of average output torque, output torque ripple and FTCA are validated through co-simulations of Maxwell and Simplorer. At last, an optimal FTCA range, which ensures high output torque, low output torque ripple and low stator copper loss, is obtained.