Andrew Ewen Ritchie

BEGA - a biaxial excitation generator for automobiles: comprehensive characterization and test results

This paper presents the design and test results for a biaxial excitation generator/motor for automobiles (BEGA), which has a three-phase stator and a salient-pole excited heteropolar rotor with multiple flux barriers filled with low-cost permanent magnets (PMs). For this new generator, the low-voltage regulation is obtained by the flux-barrier PM combination with field (excitation) low-power control and a full-power diode rectifier in the stator. Good power/volume and superior efficiency (up to 80%) are obtained at costs comparable to those of an existing Lundell generator. The generator configuration, principle, equations, finite-element field analysis, design optimization, performance characteristics, and test results, together with the generating system simulations, constitute the core of the paper.

Determination of High-Frequency

This paper presents a reliable method for the experimental determination of high-frequency d- and q -axis inductances for surface-mounted permanent-magnet synchronous machines (SMPMSMs). Knowledge of the high-frequency d- and q-axis inductances plays an important role in the efficient design of sensorless controllers using high-frequency signal injection techniques. The proposed method employs a static locked-rotor test using an ac +dc power supply. By injecting a high-frequency rotating voltage vector into the machine, the d- and q-axis inductances may simultaneously be determined with no need to change the rotor position. Measurements are carried out at steady state. The recording of instantaneous waveforms using a dedicated data acquisition system is avoided. In this paper, experimental results are presented, on a commercial SMPMSM, using the proposed method.

d

A test system for small cylindrical samples of magnetic material is designed, The magnetic flux density is measured using a small secondary winding and the magnetic field strength by a set of potential coils. The initial design with cylindrical pole shoes caused errors in the measurement of the field strength. Calculations of the field distribution in the system have shown where the problem arises. It is shown that changing the shape of the pole shoe from cylindrical to a truncated shape improves the measuring accuracy of the potential coils. This is verified by measurements performed on the test system.