Study Case of the Current Shape Influence on Inductor Motor Start-Up Process in Step Drive with Current Inverter

Abstract

The work of the inductor stepper motor in the drive with a current inverter, which provides the formation of the shape of pulses of a given shape is considered. Based on the analysis of circuit-technical solutions of the current inverter, it is concluded that it is advisable to generate current pulses of a given shape at the output, which should be determined based on pre-accepted conditions. Ensuring the uniformity of the rotor rotation and achieving the maximum pick-up frequency are assigned as such conditions. It is proposed to distribute the current in phases proportionally to the positive derivatives of the phase flux coupling with the field of excitation to ensure the uniformity of the rotor rotation distribution in the prescribed mode. The resulting shape of the current pulses is a symmetrical curvilinear triangle. Several variants of current pulses of a simple geometric shape similar to a curved triangle at the highest frequency of pickup are compared on the mathematical model of a stepper drive with an inductor motor. According to the results of computational experiments performed on the model with a load of «dry friction» and with a predominance of the potential load from the weight of the regulatory body, the advantage of a drive with current pulses with a piecewise linear approximated curvilinear triangle is established. The conclusion on shaping current pulses with most high amplitude and loading inverter keys by maximum short-time current appropriateness close to preservation input electric power on motor was drawn.