Browse Publications Technical Papers 2006-01-1355

Two-Phase Alternator with DC Stator Excitation 2006-01-1355

This generator is a new simplified design version of an alternator with DC stator excitation that was published by the authors in the SAE 2003 and SAE 2004 World Congresses. [7, 8]
In automotive applications, this type of electrical machine may be useful for regular cars, hybrid and fuel cell electrical vehicles with an electrical power source system of 12 VDC, 24, and higher.
Brushless car alternators with DC stator excitation have less rotor inertia because the excitation windings are located in the stator. Smaller rotor inertia eliminates drive belt slippage. This generator is more reliable in view of the absence of contact rings and graphite brushes in a rotor circuit, which exist in a standard claw-pole alternator [9]. The laminated salient pole rotor of the alternator is very simple in construction and has low cost of production.
The two-phase alternator is simpler than the three-phase, as it has only two output windings instead of three. The mutual inductance between its output windings is equal to zero. From a design point of view, the two-phase alternator with DC stator excitation represents two single-phase generators, which are located along the stator and shifted in space relative to one another. Due to the shift in space, the generator's output voltages carry a phase shift that equals one quarter of its period.
A three-phase generator can be designed using the same principle. The two-phase alternator can operate in a motor mode as well. In order to do so, it requires only two single-phase inverters instead of three that are needed for the three-phase generator.
This report will represent the results of the research based on the experimental setup of a two-phase alternator. The experimental setup is built using a frame of a standard car alternator. Two optical sensors were used in order to determine the position of the rotor and two H-bridge invertors were used to change the directional current in the stator windings.
The load properties in the designed model of the alternator were determined using the PSPICE modeling program.


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