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Research On Direct Torque Control Methodof Six-phase Induction Motor Based On SVPWM

Posted on:2020-06-13Degree:MasterType:Thesis
Country:ChinaCandidate:X ZhangFull Text:PDF
GTID:2392330575470689Subject:Control Science and Engineering
Abstract/Summary:PDF Full Text Request
In recent years,as variable frequency speed control systems have been widely used in military,industrial,and life fields,their control accuracy and power level requirements have become higher and higher.In the case of high-power speed regulation,multi-phase motors have gained wide attention due to their advantages of high power and high reliability due to the use of low-voltage devices.In this paper,six-phase induction motor is taken as the main research object.The theoretical basis and control theory of six-phase induction motor are introduced in detail.Combined with direct torque control theory and inverter SVPWM strategy,the system simulation and experimental analysisare completed.Firstly,the structure of multi-phase induction motor is studied.The stator structure and phase number definition of multi-phase motor are introduced in detail,and the construction law of multi-phase winding is analyzed.Combined with the theoretical basis,the mathematical model of six-phase induction motor is established under the condition of natural coordinate system.Then combined with the multidimensional space decoupling transformation theory,the six-dimensional space is decoupled,and the six-dimensional space is divided into the fundamental space and the harmonic space,and the mathematical model under the harmonic basis is further obtained.Secondly,the principle of SVPWM modulation of inverter and the theory of direct torque control of induction motor are introduced in detail.Taking the six-phase induction motor as the control object and combining the six-phase induction motor stator winding structure characteristics,the six-phase motor is equivalent to two three-phase motors,and according to the three-phase SVPWM theory,the six-phase induction motor grouped SVPWM strategy is obtained.Then the six-phase motor large vector SVPWM theory is analyzed and simulated.Because the grouped control and the space-based large vector SVPWM strategy do not take into account the influence of harmonics on the control system,which may cause a series of problems such as high harmonic content and phase current fluctuation,this paper focuses on the analysis of the intermediate vector SVPWM theory.Based on the harmonic space,vector synthesis is performed,and SVPWM modulation is performed according to the synthesized vector,which greatly reduces the harmonic content and optimizes the control effect.Then,based on the intermediate vector SVPWM theory,this paper designs a SVPWM modulation strategy based on the two-vector synthesis intermediate vector of coaxial line.By establishing a simulation model and analyzing the simulation results,the improved SVPWM scheme not only simplifies the intermediate vector SVPWM theory,but also reduces the computational complexity and further optimizes the harmonic suppression effect.Thirdly,the hardware platform used in this research is introduced in detail.The hardware platform includes a control part,a driving part,and an experimental six-phase induction motor.The control part mainly uses TI's TMS320F2812 as the control system built by the main control chip;the drive part includes the rectifier module and the inverter module,in which three-phase uncontrollable rectification is used as the rectification part of the drive system,and Mitsubishi's 5th generation IPM is used as the drive module inverter device.Finally,combined with system simulation and hardware experiment platform,the control system software is designed.Use CCS3.3 as a software platform to complete the control system main program and interrupt program writing.The main program includes the initialization processing of the DSP function modules,variable assignment and other operations;the interrupt program applies the event manager's underflow interrupt in the DSP,completes the current,voltage sampling,speed sampling,Feedback adjustment and frequency converter modulation algorithm processing.This paper combines theoretical analysis,software simulation and hardware experiments to verify the feasibility of the SVPWM-based six-phase induction motor direct torque control algorithm,which has certain practical value for future research work.
Keywords/Search Tags:Six-phase induction motor, SVPWM, Intermediate voltage vector, Direct torque control, DSP
PDF Full Text Request
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