Research On The Sensorless Control Of Five-phase Induction Motor With Non-sinusoidal Power Supply

Compared to the traditional three-phase drive systems,multiphase drive system has shown promise prospect to solve the task and has instructive significance for further research of technological innovation in many high-power field,since it has can realize the same total power at comparatively low voltage level high power,high power density,high reliability,more control freedoms to realize more complex control strategy for different optimization goals,etc.Under such circumstances,this paper is based on the research of the five-phase induction motor drive system,relatively in-depth focusing on the key drive techniques for better application.The organization of the article is shown as below:Firstly,according to the winding function method,spatial and temporal distribution of the multiphase motor's MMF is calculated.The essence of the multiphase machine drive characteristic is also revealed.Meanwhile,by means of vector space decomposition,the mathematics model is analyzed in the synchronous coordinate frame that the model parameters can be controlled on comparatively independent space harmonic plane.Then,the multiple control freedom theory and its application is stated,laying the mathematic foundation for future research.Secondly,the dual-plane vector control system of five-phase induction motor is constructed to provide high steady and transient response.The parameters of PI controllers in the system are also analyzed and designed.Then,the rotor field oriented dual-plane vector control theory is detail introduced,based on it,transfer function model of the whole system is built.Furthermore,the precise controller design takes consideration of sampling time,expected bandwidth,and model parameters.The excellent performance of the dual-plane vector control system is verified by the experiment.Thirdly,in order to improve the iron utilization and enhance torque density,the non-sinusoidal power supply technique is researched.The reasons of why the performance evaluations noted before can improve are also declared.For the reason that neglecting the impact of rotor leakage flux,the magnetic deviation problem would cause by the traditional non-sinusoidal power supply technique under heavy load.In order to solve the problem,an improved non-sinusoidal power supply technique is proposed.This method is based on the rotor flux oriented vector control on the fundermental harmonic plane and air-gap flux oriented current injection on third harmonic plane.Experimental results show that this algorithm can realize the real-time adjustment of the flux direction on third harmonic plane,which means the phase angle of the air-gap caused by leakage flux can be eliminated effectively.Moreover,the method ensures flux density waves be flat-topped under various load.Finally,in order to remove the hidden dangers of the mechanical encoder under poor working conditions and strengthen the fragile speed agency,a detailed study on the mixed IRP-MRAS sensorless control method utilizing the reactive power for five-phase induction motor drives with non-sinusoidal power supply is proposed.This method combines the advantanges of Q-MRAS and X-MRAS.Compared to the traditional MRAS based sensorless control,the proposed algorithm has excellent low-speed performance,satisfactory estimation of speed over a wide range maintaining the drive's stability and can operate stably for four quadrant operation.Moreover,it is insensitive to the stator resistance variation.The adaptive mechanism is designed by the Popov's stability and a small signal stability study is carried out to investigate the drive's stability in the low speed region.Experimental results also confirm the effectiveness of proposed method.