Design Of High Frequency Dual Three-phase Permanent Magnet Synchronous Generator And PWM Rectifier Control

Multiphase machines have many advantages,such as high power with low voltage,small torque ripple and good fault tolerance.In recent years,more and more researchers have been focusing on the related technologies.Meanwhile,for the space-vector pulse-width modulation(SVPWM),multiphase machines own much more voltage vectors than the traditional three-phase machines.Therefore,the multiphase machines can effectively improve the convertor equivalent switching frequency and the system performance for the high speed or high frequency machines.With the same switching frequency,the multiphase electrical machines exhibit lower torque ripple and less DC voltage pulsation after PWM rectifying.In this thesis,based on the analysis of a 10-pole and 30-slot ordinary three-phase permanent magnet synchronous generator,it is proposed to optimize the motor cogging torque through the auxiliary rotor are slots or permanent magnet auxiliary slots.Influence of different sizes and positions of the auxiliary slots on the motor cogging torque is analyzed with FEM simulation.Finally,a prototype with rotor core auxiliary slots is made and the back EMF of the motor is measured at rated speed.Secondly,a dual three-phase permanent magnet synchronous generator is designed and analyzed.Design principle of the high-frequency permanent magnet synchronous generator is proposed.Electromotive force distribution of a 44-pole 48-slot permanent magnet synchronous motor was obtained.The machine dimension is optimized,and the detailed simulation results such as back EMF,self-mutual inductance and flux linkage are obtained.Based on the optimization parameters,a prototype is manufactured and a test platform is built up.The experimental results match the simulation results and verify the design principle of the high-frequency permanent magnet synchronous generator.Thirdly,the mathematical model of the dual three-phase generator is built up.The dual three-phase machines decoupling transformation matrix is studied.Besides,the principle of vector control of permanent magnet synchronous motor is introduced.Finally,voltage space vectors of the dual three-phase motor are analyzed and the voltage space vector distribution of the dual three-phase motors in subspace and harmonic subspace is obtained.For the maximum two-vector algorithm,realization of the SVPWM is presented.Optimization of the overall performances such as PWM rectified voltage output,stator current harmonic content is studied.