Model Predictive Torqur Control For Five-phase Permanent-magnet Synchronous Machines Drives

At present,the development of Chinese high-speed railway is at golden stage,the speed up of passenger trains are facing many challenges and need break through some key technologies.Lightweight is one of the significant factor for high-speed train to speed up.The multi-phase permanent magnet synchronous machine?PMSM?has the property of small size,low noise and high-power density,so it has been widely used in powerful and lower voltage occasion.Based on the goal of solving problems including studying the theory,subject frontier and application technology of the traction drive system for urban rail trains.This paper will focus on the research of direct torque control method and model predictive torque control method applied to five-phase PMSM,and the main contents of this paper are as follows:Firstly,this paper has derived the mathematical model of the five-phase PMSM motor on the basis of extended five-phase transformation matrix and motor's model in natural coordinates and establishes the mathematical model of five-phase PMSM in rotating coordinates.Then,based on the multidimensional subspace theory,the characteristics of spatial voltage vectors and the spatial distribution state of two level five-phase inverter are analyzed in detail,and the uniqueness of the five-phase system is summarized.Secondly,based on the analysis of traditional SST-DTC method,virtual voltage vectors are proposed firstly,which aims at reducing low harmonic components of stator currents.Then,the demagnetization of the stator flux is investigated when the motor runs at lower speed,and a modified switching table is provided to overcome this drawback.Finally,an asymmetric multi-level torque regulator has been proposed to reduce torque ripples.In addition,space vector pulse width modulation?SVPWM?technology applied to five-phase system has been analyzed,and a fixed switching frequency modified DTC algorithm of five-phase PMSM is proposed.Then,this paper studies three traditional finite-control-set model predictive torque control?FCS-MPTC?schemes,which can eliminate the low-order harmonic of current caused by d₃-q₃ subspace with the aid of designing a cost function contained the harmonic item.And then proposes a control strategy of FCS-MPTC with a deadbeat calculation for five-phase permanent-magnet synchronous motor?PMSM?drives,which can optimize the process of selection of the best switching vector during every control interval.The proposed algorithm not only brings the following benefits:fast control dynamic response and superior steady-state performance which are further compared with two conventional FCS-MPTC schemes,but also relieves the heavy calculation effort of the traditional FCS-MPTC method dramatically.Finally,the optimized DTC and MPTC program of the five-phase PMSM are designed on TMS320F28335 board respectively and compared with several traditional control methods.The correctness and validity of the proposed methods are verified.