The influence of the inverter switching frequency on rotor losses in high-speed permanent magnet machines : an experimental study

Harmonic content of the output voltage of pulse width modulated voltage source inverters (PWM VSI) is determined by the switching frequency. On the other hand, rotor losses in high-speed permanent magnet (PM) machines are caused, among other factors, by harmonics in stator currents. These harmonics are determined by the harmonics in the inverter output voltage, and therefore dependent on the switching frequency. In high-speed PM machines, due to the high fundamental frequency, harmonics in the stator currents caused by PWM are located at very high frequencies. Measurement of rotor losses caused by these harmonics in a structure with a conductive retaining sleeve on the rotor which is prone to eddy currents might be very challenging. This paper investigates issues related to this measurement and presents a measurement method which results are compared with results from a 2D analytical model that takes into account eddy currents in the rotor.</p

Analysis and design of a slotless tubular permanent magnet actuator for high acceleration applications

This paper presents the design of a linear actuator for high acceleration applications. In the analysis, a slotless tubular permanent magnet actuator is modeled by means of semianalytical field solutions. Several slotless topologies are modeled and compared to achieve the highest acceleration. A design has been proposed and built, and measurements are conducted to verify the model

Candidates of motor drives for 48V automotive applications

Abstract-In automotive systems, reliability and cost are paramount for the success of electrical drive systems. Considering the interior permanent magnet motor, the cost of the rareearth permanent magnet is becoming a big concern. In this paper, the switched reluctance motor, variable flux reluctance motor and synchronous reluctance motor are analyzed and compared as candidates for the 48V automotive applications. A recommendation is given for the selection of the motor drives

Three-Dimensional Magnetic Field Modeling of a Cylindrical Halbach Array

A semi-analytical description of the 3-D magnetic field distribution of a cylindrical quasi-Halbach permanent magnet array is derived. This model avoids the necessity of time-consuming finite element analyses and allows for fast parameterization to investigate the influence of the number of segments on the magnetic flux density distribution. The segmented magnet is used to approximate an ideal radial magnetized ring in a cylindrical quasi-Halbach array. The model is obtained by solving the Maxwell equations using the magnetic scalar potential and describes the magnetic fields by a Fourier series