Improved Efficiency for an In-Wheel Motor in Large Speed Operating

Summary form only given. A good efficiency should be a priority for every electrical machine operating within traction systems. The desired performances for each drive system are always accompanied by electro-mechanical necessities, translated in terms of high levels of power factor and efficiency. Our article proposes a synchronous motor variant with wide speed range and improved efficiency. An increased efficiency can be obtained, besides an adequate design, via a control strategy. That´s why we propose a combined strategy in order to increase the motor´s efficiency in wide speed operating. Up to a certain value of the excitation current we controlled the speed by controlling the d-axis current through the stator winding source and after that, we controlled the motor´s speed and we obtained the flux density decrease through the auxiliary field winding. The proposed and designed motor has the following data: 5500 W, 1500 rpm, 6 pole pairs, being supplied from a 48 Vcc battery. The design process involved 2D FEM modelling and Matlab/Simulink simulation of the machine-converter system