Design of Power Electronics Driven PMSM with Constant Torque by Special Magnetic Circuit and Permanent Magnet Configuration

Special and high efficiency variable speed drives use permanent magnet synchronous motors (PMSM) and power electronics. New dispositions for PMSM with regard to a special magnetic circuit design and new shapes of permanent magnet configurations are investigated. In order to obtain a better rotation performance and to reduce the torque ripple we propose the power electronics current control in support of a variable air gap. A variable air gap is a reasonable counter-measure for reducing the risk of demagnetization in case of short circuits that may occur will, drive arrangements. Today´s power semiconductor switches survive short circuits - PMSM generally do NOT. In this study the PMSM with radial flux distribution is used and magnet configurations are computed using two-dimensional finite element method magnetics (FEMM). PMSM design ideas are presented which exhibit constant torque and demagnetization risk reduction.