Design analysis and development of halbach array PMBDC motor for torquing the gimbal of control Moment Gyroscope

This paper gives the details of the design analysis and development of Halbach array PMBDC motor for torquing the gimbal of control moment gyroscope, initial design, selection of major parameters and airgap magnetic flux density are estimated using the analytical model of the machine. Three types of the machine configurations, Slotless PMBDC, Coreless enclosed rotor PMBDC with and without Halbach array magnet were analyzed using FE and compared. Coreless enclosed rotor Halbach array PMBDC machine delivers highest average torque among the three configurations. The proportion of Halbach array is optimized using FE to deliver near trapezoidal flux pattern in the airgap. The machine was realized and tested. This machine develops 1.3 Nm for IA excitation and 5.2 Nm for 4A. Power consumption for 2Nm at 50 RPM is 43% lesser than that of conventional slotless PMBDC machine. As the machine is coreless, cogging torque and magnetic stiction are eliminated and hence provide position stability.