Search

Some electromagnetic and thermal aspects concerning special permanent magnet machines, employed in damping seismic oscillations in structural systems, are examined. The power generated by the machine during a seismic event is regulated by a suited converter and delivered to an external resistor. Some modeling features and selected simulations are examined, together with test results obtained by a prototype. Some special tests, aimed to identify the thermal parameters of the machines, are presented and discussed. Index Terms--Axial flux permanent magnet (PM) machines, concentrated winding electrical machines, electrical and thermal modeling, seismic vibration damping.

An equivalent circuit of universal motors is developed, based on the design data. After representing the magnetomotive force distribution in the air gap, an analytical expression of the flux linkage of the armature winding coils is derived; this allows for the determination of the expressions of the speed and transformer EMFs induced in the armature winding and their representation by means of circuit parameters, as a function of the magnetic core saturation. The motor performances are computed, using the circuit parameters determined both analytically (by the design data) and by measurements. Some quantities are also compared with the ones obtained by finite-element analyses. Finally, the model is validated by experimental tests. Index Terms--Equivalent circuit, parameter identification, universal motor.