الفهرس | Only 14 pages are availabe for public view |
Abstract Recently, Brushless DC Generator (BLDCG) has received great attention to exploit its numerous advantages. These advantages are high efficiency and power density, light weight, compact design and low maintenance. The most popular applications, in which BLDCG has been employed, are wind energy and transportation systems. The main problem is related strongly to these applications, because they are featured by large speed fluctuations accomplished by wind turbines and internal combustion engines. This speed variation results in further changes in the BLDCG output voltage. Consequently, this voltage is not valid for supplying the loads. As a result, there is a need of employing a voltage controller to control the generator output voltage despite speed and load variation. In terms of vehicle application which is considered in this work, the dc series motor and the claw pole synchronous generator together are the most common machines employed in vehicles. The dc series motor acts as a starter for the internal combustion engine. While the synchronous generator is required for supplying the vehicle loads. However neither the dc series motor nor the synchronous generator can be operated as a starter / generator together. Hence, this work presents the BLDCG for vehicle application, because it can be operated as a starter and a generator together. A voltage control method based on a variable reactor (magnetic amplifier) is recommended to control the BLDCG output voltage against speed and load variation. Furthermore, the voltage control method based on a buck converter is studied for the sake of comparison. |