Determination of permanent magnet synchronous motor parameters

Permanent magnet (P.M.) excited synchronous machines have shown increasing popularity in recent years for industrial drive applications. However, the limitation imposed by permanent magnet excitation causes some difficulties in evaluating the machine parameters. This thesis presents the experimental procedure of the determination of the P.M. synchronous motor parameters. The work is intended to evaluate the d- and q-axis reactances and the permanent magnet generated voltage under load condition. -- The air gap fields of the P.M. synchronous motor are evaluated for specific rotor and magnet configurations. An analog simulation of the interaction of these field quantities in the air gap is developed. A practical implementation of the digital measurement technique for determining motor torque angles is realized. A number of different test methods are developed and applied to a 3-phase, 60 Hz, 4-pole, 1 horsepower P.M. synchronous motor. Conventional test methods are modified for use on this type of the motor. A search coil test developed to locate variation of the generated voltage with increasing load. The influence of the armature reaction is also investigated. -- A flux linkage test is developed to measure the static inductance of the machine and the search coils inserted in the stator slots of the motor are used to measure air gap flux distribution. Calculation of the d- and q-axis reactances is based on the flux and the current measured. The measurement methods come from the transformation of the two-axis theory.