Real-time Current Calculation for a Six-Pole Active Magnetic Bearing by Sequential Quadratic Programming

Abstract

　Six-pole active magnetic bearings (AMBs) have fewer poles than usual eight-pole AMBs, then, it is easier to miniaturize and suitable for small motors. However, because the magnetic circuit of the six-pole AMB is difference in the x- and y-directions, the calculation of coil currents becomes complex. In this paper, control currents of the six-pole AMB are calculated by nonlinear programming method. The power consumption is set for an objective function, and the magnetic bearing forces and current limits are set for constraint function. Sequential quadratic programming is implemented to the experimental setup, and a stable levitation is achieved by real time calculation.