关键词: 开关磁阻电机, 无轴承, 平均悬浮力, 超前角, 控制系统

Abstract: A bearingless switched reluctance motor has complicated nonlinear characteristics, its control strategy is very important. Because of its high back electromotive force at high speeds, it is difficult to control the turnon current of levitated windings, which in turn results in difficulties to control the instantaneous levitated force. Therefore, it is necessary to study the motor control strategy based on the average levitated force and average torque. A control strategy of average levitated force and average torque is designed based on principles of radial force generation and mathematical models. In this strategy, all currents of the main winding and levitated windings are squarewave currents. The relationships between the winding currents and the average levitated force are derived. The theoretical equations of winding currents are obtained. Then the flowchart to calculate the advanced angle and winding currents are given. A control system based on digital signal processor (TMS320C2812) is designed for a bearingless switched reluctance motor of 12/8 structure. The waveforms of the winding currents and rotor displacements are acquired by experiments. These experimental results show steady levitation of the rotor and verify the feasibility of this control strategy.

Key words: switched reluctance motor, bearingless, average levitated force, advanced angle, control systems