Permanent Magnet Synchronous Machine Parameters Identification for Load Characteristics Calculation

Self reactance X-d in direct axis 'd' and self reactance X-q in quadrature axis 'q' influence the load characteristics of the permanent magnet machine. Their calculation methods are known. All calculations should be verified by measurements. Measurement with AC variable voltage and frequency source applied on stator winding is correct when eddy currents do not exist. Other methods evaluate the DC current decay after initial direct current was applied on the stator winding. Accuracy of these methods is lowered because of the numerical evaluation of current decay curve. Another method performs the measurement on the machine loaded as a motor. The load angle beta is measured by a machine set of four machines. The accuracy is lowered by higher harmonics induced in no load in the helping synchronous machine. The load angle can be also obtained by geometrical construction of the vector diagram. In this paper the evaluation of the generator steady state regime of the machine is used. The generator works with different loads consisting of capacitance, inductance or arbitrary impedance or resistance. When the generator transfers from no load to load regime the rotor is shifting and the load angle changes. This angle is measured. The newly proposed measurement methods are simple in special cases of loads. Results of measurements and their experimental verification are published in the paper.