In this paper, one of the main cogging torque minimization methods, magnet skew, is examined in detail for Axial Flux Permanent Magnet (AFPM) disc motor. Various magnet skewing methods, types, and effects on the machine performance are also investigated using 3D Finite Element Analysis. The results are compared with a reference AFPM motor, and the improvements on cogging torque component are de...

Based on Utkin’s research work regarding speed control of rotary motors, a position tracking algorithm for linear permanent magnet synchronous motors (LPMSM) is designed making use of multi-variable sliding-mode control and asymptotic observers. It is applicable to LPMSM’s with either interior or surfacemounted magnets, no matter whether the armature is stationary or movable. Furthermore, the c...

Permanent Magnet Synchronous Motor (PMSM) variable-speed drive is widely used in the industry because of its particularly high mechanical power density, simplicity and cost effectiveness. Eliminating the mechanical sensor mounted on the shaft of the motors gives further improvement. These drives are referred to as “sensorless” electrical drives. In this paper a novel sensorless algorithm is pro...

Variable speed main spindle drives of machine tools are usually fed by three-phase two-level inverters. Because of the switching operating mode of these inverters, the motor voltages and currents contain harmonics which do not contribute to torque formation but solely to an undesirable warming of motor spindle elements. This warming results in thermal elongation of the spindle shaft and therefo...