Iron loss reduction in an interior PM automotive alternator

Copyright © 2006 IEEEThis paper examines the iron loss characteristics of a high-flux interior permanent-magnet machine. The machine was designed as a concept demonstrator for a 6-kW automotive alternator and has a wide field-weakening range. Initial experimental results revealed a high iron loss during field-weakening operation. Finite-element analysis was used to investigate the cause of the high iron losses and to predict their magnitude as a function of speed. The effects of changes in the machine design were examined in order to reduce iron losses and hence improve the machine performance.Vlatka Životi´c-Kukolj, Wen L. Soong, and Nesimi Ertugru

Effect of open stator slots on the performance of an interior permanent magnet automotive alternator

This work describes a study of the effect of using open stator slots in an interior permanent magnet automotive alternator to increase its effective air gap and thus reduce its iron losses under field-weakening conditions. Analytical, finiteelement and experimental results are compared for the back-electromotive waveforms, inductance saturation/torque curves, iron loss and field-weakening performance characteristics for the alternator with both semi-closed and with open slots. It is shown for the highly saturated machine considered, that using open stator slots can reduce the field-weakening iron loss without significantly affecting the machine performance.Vlatka Životić-Kukolj, Wen Liang Soon

Modelling of saturation and cross-saturation effects in an interior PM automotive alternator

A rare-earth 6kW interior PM machine has been examined as a concept demonstrator for a high power automotive alternator. This machine has a high magnet flux density resulting in strong cross-saturation, and operates with high stator currents resulting in heavy saturation. It is desired to improve the machine design to reduce both saturation effects and hence increase the output power, particularly at low speeds. This paper examines the effect of saturation and cross-saturation on the output power, and uses finite-element analysis to model the machine flux-linkage curves. The finite-element results were verified against the experimental results.V Zivoti-Kukolj, WL Soong and N Ertugru

Modelling of saturation and cross-saturation effects in an interior PM automotive alternator

A rare-earth 6kW interior PM machine has been examined as a concept demonstrator for a high power automotive alternator. This machine has a high magnet flux density resulting in strong cross-saturation, and operates with high stator currents resulting in heavy saturation. It is desired to improve the machine design to reduce both saturation effects and hence increase the output power, particularly at low speeds. This paper examines the effect of saturation and cross-saturation on the output power, and uses finite-element analysis to model the machine flux-linkage curves. The finite-element results were verified against the experimental results.V. Zivotic-Kukolj, W.L. Soong and N. Ertugru

Investigation of iron losses in a high flux interior PM automotive alternator

This paper examines the iron loss characteristics of a high-flux interior PM machine. This was designed as a concept demonstrator for a 6kW automotive alternator and has a wide field-weakening range. Initial experimental tests showed a high iron loss during high-speed field-weakening conditions. This paper examines the causes of this high iron loss using finite-element simulations and experimental tests. It was found that the high iron loss was due to high harmonic airgap flux density components during field-weakening. Means to reduce these losses are discussed.V. Zivotic-Kukolj, W.L. Soong and N. Ertugru