Optimal Flux Selection of Induction Machine in the Field-Weakening Region

In this paper, an optimization for field current existing in field-weakening control is made. Taking the effect exerted by iron losses into consideration, a linearized compensation for it is proposed. The selection of field current is very important for indirect FOC, especially in the field-weakening region. Unreasonable selection will lead to reduction of current utilization factor and render decrease of the developed torque which in turn yields effect on loading capability, shortening the constant-power range and influencing on raising speed. This paper gives an optimization for field current, according to the principle of maximized utilization of current and voltage, and makes analysis of effect exerted by iron losses in high-speed interval, in which linearized compensation method is proposed. Finally, an experimental study is made by means of full-digital spindle drives based on digital signal processor (DSP). The experimental results show the proposed optimization solution for magnetic-field current and the compensation approach to iron losses are feasible, which can achieve noticeable enhancement of performance of the spindle drives system and is of great value in engineering application.