A Preliminary Experimental Study on an Axial Flux Permanent Magnet Generator for Regenerative Braking

The axial flux permanent magnet generators (AFPMG) are often found in wind power plants. The AFPMG generator construction allows the installation of large quantities of permanent magnets to improve efficiency at low shaft rotation. The ratio between the power to volume or mass is relatively higher compared to similar generators with radial construction. Therefore, the axial flux permanent magnet generators can be used as a vehicle component, for example, the regenerative braking. A preliminary experimental study was carried out to manufacture and to characterize a prototype of axial flux permanent magnet generator. The generator consists of a stator and two permanent magnet rotors. The stator consists of 4 poles of the coil which are arranged in series and each rotor has 32 poles of the permanent magnet. An electric motor with a variable speed drive is used to rotate the generator shaft. A dummy load consisting of several resistive loads serves as an artificial electrical load. Generators are characterized to obtain values of voltage, current, power, and efficiency. The characterization results showed that the generator voltage at 700 rpm rotation was 13.07 Vdc (achieved at the highest rotation in the experiment and without dummy load). The highest output currents and electric powers are 0.7 A and 3.96 W, respectively (700 rpm rotor shaft rotation). The highest efficiency is 35.90% resulting in 700 rpm rotation with a dummy load of 2 W.