MACHINE CONSTANTS AND DESIGN CONSIDERATIONS OF A HIGH-POWER,HIGH-SPEED PERMANENT MAGNET DISC TYPE SYNCHRONOUS MACHINE

Abstract

Expressions for the element of the equivalent circuit of a disc type synchronous machine excited with permanent magnets are developed in terms of the principal machine dimensions. The calculations are based on a field analysis given by the authors in a previous paper using a linearised model

The internal leakage of the magnets and the finite permeability of the stator teeth are taken into consideration. The resulting expressions are useful in predicting the machine performance, in examining the influence of the main design parameters and are suitable for optimization purposes.     

IMPACT OF SLOT HARMONICS ON LOSSES OF HIGH-SPEED PERMANENT MAGNET MACHINES WITH A MAGNET RETAINING RING

ABSTRACT

This paper presents an analytical method for determining the harmonic content in the flux pattern of permanent magnet synchronous machines due to the slotting of the stator. The analysis based on a rotor construction with magnets radially magnetized and a retaining ring to support them against the centrifugal forces. Expressions for the eddy current losses in the magnets and their retaining ring are derived in terms of the machine dimensions and the physical properties of magnets and ring. The accuracy of the method is examined by comparison with numerical flux calculations using finite element method. The impact of some physical quantities like machine speed and magnet conductivity on the slot harmonics losses is examined aiming to exhibit the role of the magnet retaining ring in contributing to these losses