Torque Area Method and Its Application in Analysis of HDD Spindle Motors With Sinusoidal Magnetization

Based on the Stieltjes integral, this paper investigates the characteristics of the torque area of surface permanent magnet motors with sinusoidal magnetization used in hard disk drives. Then, a simple torque calculation algorithm is proposed and verified through comparison with the finite element analysis. Meanwhile, an improved motor having the sintered NdFeB with sinusoidal magnetization and smaller airgap length is recommended.