Mechatronic model of oscillations in hybrid stepper motors

Abstract

Hybrid stepper motors combine the features of permanent magnet and variable reluctance motors, which makes them an attractive solution for a variety of low-cost applications. Oscillations in the phase current and in the motor position may however arise between two consecutive steps. This paper develops a model of the system, whose linearization yields closed form analytical expressions of the parameters (natural frequency and damping coefficient) characterizing such oscillations. A detailed simulation model of the system, including discontinuous effects of PWM amplification, is developed as well and validated with experimental data. The accuracy of the expression found for the oscillation parameters is also validated.

Modelling and Control of Stepper Motors for High Accuracy Positioning Systems Used in Radioactive Environments

“…This model differs from that typically found in the literature e.g. [71], where the variation is 90 • out of phase. This 180 • phase shift between phases can be explained by the fact that, for a two-phase HSM, when the rotor teeth are aligned with the stator teeth of one phase there exists the smallest air gap between the rotor and this phase, but the largest air gap between the rotor and the other phase.…”