Design and control of a high speed flux switching generator for embedded power generation and variable speed application
This research focuses on the design and control of a new class of brushless machine known as the flux switching machine for high speed and high power application. This machine is a hybrid of the inductor alternator and the switched reluctance machine. The characteristic of this machine determined from an experimental generator shows that the power delivery capability of the machine is limited by the synchronous inductance of the machine especially at high speeds. Various power factor control techniques are proposed and evaluated as possible solutions to the attendant problems with the uncontrolled flux switching generator. This involves the use of series compensation and shunt compensation techniques. For the series compensator technique, a new class of series line compensation delivering controlled power factor using pulse width modulation is identified and tested on an experimental flux switching generator system. The shunt compensation technique for the flux switching generator system is a controlled rectifier, which uses phase angle pulse width modulation to deliver controlled power factor. The power factor control of the flux switching generator system shows that significant improvement in power delivery for the flux switching generator system can be achieved. Matlab/Simulink models are developed for each of the proposed technique and the results compared with experimental data shows reasonable agreement. These Matlab/Simulink models can now be effectively used for rapid design and prototyping of the flux switching generator system. Closed loop control of the output voltage of the flux switching generator system can be achieved. This is done using field current control and/or armature current control. The increased controllability of the FSG compared to other reluctance machines makes it a viable alternative for high speed, high power applications especially in mechanically harsh environment.