Algorithm of Field-Oriented Control of a Dual Inverter-Fed Stepper Drive with Use of the Lookup Table

Abstract

Currently, a bridge circuit for power elements connecting is widely used for bipolar stepper motors control. The main disadvantages of this solution are the small rotational speed range at constant torque load of the stepper drive, the resulting high phase voltage ripple swing and consequently high switching losses in the inverter as well as a high torque ripple of the electric drive. These features aggravated by a significant value of the reactive power consumed by the stepper motor (SM) at high-speed region indicate the advisability of sequential inclusion of secondary (auxiliary) inverters (one for each phase of the motor) into the conventional inverter system. These secondary inverters compensate the reactive power consumed by the SM, which is confirmed by the previous studies. The purpose of this work is developing an algorithm of field-oriented control (FOC) of a stepper motor adapted to operate with this inverter. A feature of this algorithm is the use of a lookup table to select the switched on transistors configuration of the dual inverter. The performance evaluation of the dual inverter using the proposed algorithm in comparison with the conventional bridge circuit was carried out by the comparative simulation method in the Matlab / Simulink software environment. The results of simulation indicate a power losses reduction in the inverter, a decrease in the ripple amplitude of the torque produced by a SM and an increase of rotation speed range when the electric drive is operating using a dual inverter with a lower voltage of DC link. Prospective applications for this inverter are industrial facilities, autonomous robotic systems, aerospace systems, etc.