Implementation of the Master-Slave Windings Scheme for the Low Pulse Ratio Operation in Motor Drivers

A master-slave windings scheme is proposed to enhance the motor torque performance under the low pulse ratio inverter operation. The inverter connected with the master windings operates under the low pulse ratio and aims for the major power transmission. To compensate the torque ripple from the master windings, an open-winding inverter with high pulse ratio is connected to the slave windings. According to the theoretical loss comparison under the same torque ripple, the reduction in the switching and conduction loss of the proposed scheme are around 80% and 40%. The detailed control strategy for the cooperation between the master and slave windings is also presented. It is proved that the high performance torque operation in both steady and dynamic states get ensured. The simulation and experimental results are demonstrated for verification.