The paper presents a method of computing electrical and mechanical variables of BLDC motors. It takes into account electrical, magnetic and mechanical phenomena in the power supply-converter-BLDC motor-load machine system. The solution to the problem is the so-called circuit-field method. The results determined with the use of time stepping finite element method were used as the parameters of equations of the developed mathematical model. Losses in the motor, losses in transistors and diodes of the converter as well as the actual back EMF waveforms, variable moment of inertia and variable load torque are accounted for. The designed laboratory stand and the test results are presented in the paper. The experimental verification shows the correctness of the developed method, algorithm and program. The developed computational method is universal with respect to different electromechanical systems with cylindrical BLDC motors. It can be applied to electromechanical systems with BLDC motors operating at constant but also variable load torque and moment of inertia.

The paper presents an algorithm and software for the optimal design of permanent magnet brushless DC motors. Such motors are powered by DC voltage sources via semiconductor switches connected to the motor phase belts. The software is adjusted to the design of motors with NdFeB high energy density magnets. An attention has been given to issues important in the design of the motors, i.e., permanent magnet selection, structure of magnetic circuit, and armature windings. Particularly, precision of calculation of the permanent magnet operating point, visualization of selection process of the winding belts, and magnetic circuit dimensioning have been investigated. The authors have been trying to make the equations more specific and accurate than those presented in the literature. The user software interface allows changes in the magnetic circuit dimensions, and in the winding parameters. It is possible to examine simultaneously the influence of these changes on the calculation results. The software operates both with standard and inverted (outer rotor) motor structure. To perform optimization, a non-deterministic method based on the evolution strategy (ž + λ) - ES has been used.