Research On Drive And Control System Of Five-phase High-speed Permanent Magnet Synchronous Motor

With the development of motor control theories and modern power electronics technologies,the inverter-fed motor remove the limitation on the number of power supplies.Compared with three-phase motor,multi-phase motor has the advantage of small torque ripple,high power density,strong fault-tolerant control performance.It is widely used in ship propulsion,aerospace,electric vehicle and so on.In this thesis,five-phase permanent magnet synchronous motor(FP-PMSM)is the object of study,the mathematic model of FP-PMSM is established,and the key techniques of vector control and fault-tolerant control of FP-PMSM are studied,the platform of TMS320F28335-based FP-PMSM is constructed,and taking the correlative experiment on the platform.Firstly,mathematical model of FP-PMSM with symmetrical sinusoidal windings in the natural coordinate is established.The five-phase coordinate transformation matrix is used to decouple the motor model in the synchronous rotating coordinate.A FP-PMSM vector control strategy based on the fundamental current closed loop and the third harmonic current open loop is adopted.The topological structure and mathematical model of the five-phase inverter are studied.The near-two-vectors SVPWM algorithm of the three-phase inverter is directly extended to the five-phase inverter.Although higher DC bus voltage utilization can be obtained,it will introduce low-order harmonic components into the phase voltage,which is not conducive to the long-term operation of the system.Though the modulation factor of near-four-vectors SVPWM algorithm is reduced compared with near-two-vectors SVPWM,the generation of harmonic voltage can be minimized.Simulation verification of two SVPWM algorithms is performed using Matlab/Simulink.Secondly,the back-EMF waveform of the experimental motor is analyzed,and mathematical model of FP-PMSM with harmonic windings is adopted.It is pointed out that when the fundamental and the third harmonic current are simultaneously injected into the stator windings,FP-PMSM will generate corresponding output torque with the participation of the fundamental and the third harmonic windings,respectively.Therefore,the motor vector control system is designed as the fundamental and the third harmonic current dual closed loops.Because two SVPWM algorithms cannot effectively suppress the generation of low-order harmonic voltage in a FP-PMSM with third harmonic windings,a CPWM algorithm with zerosequence injection is adopted to simplify the software program and speed up the calculation,and the conclusion is verified by using Matlab/Simulink.Thirdly,fault-tolerant operation of FP-PMSM under three fault conditions(single-phase,adjacent double-phase,non-adjacent double-phase open)are analyzed.In order to reduce the pulsating torque component of the motor under fault conditions,calculating the motor's output average power and pulsating power under the condition that the ratio of third harmonics content to the fundamental content of the motor back-EMF is 0.1007.The phase angles and amplitudes of the currents under faults conditions(single-phase,adjacent double-phase,non-adjacent double-phase open)are given based on different constraints.According to the proposed faulttolerant control current can successfully operate FP-PMSM under different fault conditions with low pulsating torque and high output torque,and conclusion is verified by using Matlab/Simulink.At last,TMS320F28335-based FP-PMSM control system experimental platform is constructed.Experiments verify the rationality and correctness of the vector control strategy and fault-tolerant control for FP-PMSM.