Fractional slot PMSM motors enable high power density factors to be obtained provided that their electromagnetic circuit, appropriate mechanical structure and cooling system are properly designed, as well as when operating at a high frequency of power supply voltage (400–800 Hz) with high magnetic saturation and high current loads (approx. 12–15 A/mm2). Such operating conditions, especially in the case of fractional slot motors, may be the reason for excessive rotor losses, mainly in the rotor yoke and permanent magnets. One of the conditions for obtaining high values of continuous power of the motor is the reduction of these losses. This paper presents selected design methods for limiting the value of rotor losses with simultaneous consideration of their influence on other motor parameters. The analysiswas carried out for aPMSMmotor with an external rotorweighting approx. 10 kg and a maximum power of 50 kW at a rotational speed of 4 800 rpm.

The traditional industrial robots come with the prime mover, i.e. Electric Motors (EM) which ranges from a few hundred too few kilo watts of power ratings. However, for autonomous robotic navigation systems, we require motors which are light weighted with the aspect of high torque and power density. This aspect is very critical, when the EMs in robotic navigations are subjected to harsh high temperature survival conditions, where the sustainability of the performance metrics of the electromagnetic system of the EMs degrade with the prevailing high temperature conditions. Hence, this research work address and formulate the design methodology to develop a 630 W High Temperature PMSM (HTPMSM) in the aspect of high torque and power density, which can be used for the autonomous robotic navigation systems under high temperature survival conditions of 200°C. Two types of rotor configurations i.e. the Surface Permanent Magnet type (SPM) and the Interior Permanent Magnet type (IPM) of HTPMSM are examined for its optimal electromagnetic metrics under the temperature conditions of 200°C. The 630 W HTPMSM is designed to deliver the rated torque of 2 Nm within the volumetric & diametric constraints of D x L which comes at 80 x 70 mm at the rated speed of 3000 rpm with the survival temperature of 200°C with the target efficiency of greater than 90%. The FEM based results are validated through the hardware prototypes for both SPM and IPM types, and the results confirm the effectiveness of the proposed design methodology of HTPMSM for sustainable autonomous robotic navigation applications.