Cheapening stepper motors extends them scope of application which requires developing new control algorithms using of microprocessor technology. One of the most promising modes of stepper motors is microstepping mode that allows fix shaft in intermediate positions between steps, and thus provide for positioning a uniform movement without disruption of step. Purpose of work is determine the dependenceof rotation angle of the rotor on the ratio of currents in motor windings and development of control algorithm currents in the windings of the stepper motor. Developed laboratory stand and on its basis the mathematical model allows to explore new automatic control system of electric drive based on stepper motor and the processes occurring in its mechanical parts. During researches found that the motion of the rotor is significantly affected by the moment created by the permanent magnet motor. The practical application of microstepping mode complicates the process in the power switch when using pulse width modulation to form the desired shape of currents.