Development of a High-Speed Permanent-Magnet Brushless DC Motor for Driving Embroidery Machines

We describe the development of a permanent-magnet (PM) brushless DC motor for driving high-speed embroidery machines by employing advanced design and analysis techniques. In the design of the motor, magnetic field finite-element analyses accurately calculate the key motor parameters such as the air-gap flux, back electromotive force (EMF), and inductance. Using the numerical magnetic field solutions, a modified incremental energy method calculates the self and mutual inductances of the stator windings. A phasor diagram is derived to compute the motor's steady-state characteristics. To predict the dynamic performance and increase the prediction accuracy, a Simulink-based model simulates the motor performance with the real waveforms of applied phase voltage, back EMF, and current. The motor prototype tested with both a dynamometer and a high-speed embroidery machine validated the theoretical calculations.