Improvement of torque ripple characteristics of double winding PMSM with using twin inverters

Double winding machine is known that these machines have fault tolerant feature, so it is got much attention especially for application which needs failure tolerance like aircraft, electric vehicle, electric rolling stock, and marine ship. Controlling each winding by independent inverters lets improvement drive characteristics like extending speed range, and reducing torque ripples. But controlling each winding by independent inverters expects letting improvement drive characteristics like extending speed range, and reducing torque ripples, so it is widely considered. In this paper, we use 2 inverter which controlled by 1 microcontroller for driving 10poles-12slots double winding PMSM, operate the motor in situation of current phase difference, and operate the motor in situation when 1 inverter is failure. Then we verify fault tolerance characteristics of the PMSM, and examine improving the PMSM torque characteristics by measuring the torque characteristics. Therefore, it is confirmed that double winding PMSM used in this paper with driving by 2 inverter can keep redundancy and get fault tolerant characteristics, and found that it is possible to reduce torque ripple by inverter phase differential operating. In this test motor, it is found that the torque ripple can reduce by exciting current having 30degree of phase difference to the motor.