Study On The Control System For Multiphase Permanent Magnet BLDC Motor

Permanent Magnet Brushless DC Motor(PMBLDCM) is a kind of mechanical and electronic system which is consist of power electronic converter and permanent magnet motor. It is widely used as a high-performance driving machine because of its advantages such as simple structure, reliable operation and convenient maintenance which the AC motors have and the inherent advantages as a DC motor of high efficiency, low magnet excitation loss and excellent speed controllability. So since the end of the last century the research upsurge of the motor is formed. The theoretical analysis and the application of such kind of the motor is the emphasis of this thesis.First, this paper introduces the development history, present research status and trend of the PMBLDCM. And some existing problems are raised. Then the structure and the operation principle of the motor are described. And the mathematic model of the motor is given.Secondly, to solve the problem of the torque ripple of the PMBLDCM, the affections that different PWM modes act to the torque ripple are studied. And the best PWM mode is adopted to reduce commutation torque ripple of PMBLDCM motors. Then an electrical regenerative braking is raised to improve system performance and save energy.Then, as for the high-power permanent magnet motors, the exciting magnetic poles are normally constructed with blocks of magnet block. On considering the decentralization property and the errors during manufacture, an optimized configuration method of the magnetic steel is proposed in the view of the engineering application. This method can guarantee the equality of the flux density and the balance of the flux of each pole and ameliorate the performance of the system from the point of the motor design. Finally, on the base of the theoretical analysis, a multiphase PMBLDCM system is developed on the platform of the single chip processor and IPM. And detailed compare of different schemes are given. The experimental and simulation result give a further support of the correctness and the practicability of the theoretical analysis. At the same time, some analysis and improvement of the system are given to solving some practice problems.