The field-circuit analysis of the start-up operation of the brushless DC motor

Nowadays, we can observe growing concern about energy saving and the protection of natural environment. It is reflected in recent researches carried out by designers who try to find new, high, efficient machines. Therefore, development of constructions of the permanent magnet motors is being accelerated. The permanent magnet brushless DC (BLDC) motors state an important group of these types of machines. The BLDC motors have many advantages: high efficiency, high power density, wide speed range, good dynamic performance and long operational life [9, 17]. The BLDC motors are widely used in different industrial applications [1]. The further development of BLDC motors is possible owing to the development production technology and the improvement of permanent magnets parameters. Research and works connected with development of methods of simulation of transient and dynamic states in BLDC motors and advancement of optimization procedures will increase knowledge of these motors. The results of field-circuit analysis connected with optimization algorithm can show some new principle directions of the development of BLDC motor structures. In the paper an algorithm and computer code for the analysis of the outer rotor permanent magnet brushless DC motor dynamics is presented. The mathematical model of the devices includes: the equation of a electromagnetic field, the electric circuit equations and the equation of mechanical motion. The numerical implementation is based on the finite element method (FEM) and step-by-step algorithm. The nonlinear coupled field-circuit equations have been solved by using Newton-Raphson algorithm. The electric circuits of the converter during transient operation have been discussed. The computer code for dynamic simulation of the machine has been elaborated on the basis of Delphi environment. The start-up of the motor has been investigated. Selected results of the analysis are presented and discussed.