Measurement of parasitic losses in modular permanent-magnet generators

The modular permanent magnet synchronous machine exhibits several new forms of load and no-load loss which could lead to poor efficiency and unacceptable temperature rise if not taken into account in the design. Four such losses are identified. An analytical electromagnetic model of the modular machine and its structure has been developed to predict the losses. A test rig using modules which are representative of a full scale machine has provided data which validates the model. The approach adopted for measurement of parasitic losses employs a measurement of the magnetic flux passing along the section of the structure in which the loss takes place. An auxiliary rig is used to mimic the measured flux density in a similar section and to measure the corresponding loss by measurement of the power drawn by an excitation coil