Analysis of Magnetic Properties of AlNiCo and Methods of Mitigating Dynamic Voltage Limits in the Combined-Magnetic-Pole Memory Motor

Memory motors have recently been proposed to reduce loss over an electrical vehicle drive circle by manipulating magnetization state (MS) dynamically. The combined-magnetic-pole memory motor is investigated in this paper. Firstly, the magnetic properties of AlNiCo permanent magnets are analyzed and a magnetization model of AlNiCo in the state of magnetization and demagnetization is established. In order to improve efficiency regions of the motor, MS should be manipulated over a wide speed range. However, the existing direct id pulse method has a significant dynamic voltage limitation when increasing MS for reaching the voltage capacity of the inverter, several methods have been proposed to mitigate the dynamic voltage limitation, such as reverse rotating current vector trajectory (RRCVT) method. The accuracy of the magnetization model is evaluated experimentally by a magnetization characteristic tester.