Control design for axial flux permanent magnet synchronous motor which operates above the nominal speed

Abstract

The axial flux permanent magnet synchronous motor (AFPM motor) using magnet bearings instead of ball-bearings at both two shaft ends could allow rotational speed of shaft much greater than nominal speed. One of the solutions to increase motor speed higher than its nameplate speed is reducing rotor's pole magnetic flux of rotor (ψp). This paper proposes a method to boost the speed of AFPM motor above nominal speed by adding a reversed current isd of (ψp).