Study On Parameter Identification Of Permanent Magnet Synchronous Motor

Permanent magnet synchronous motor(PMSM)first appeared in 1950s.Given permanent magnet excitation instead of current excitation,PMSM has high power,high efficiency,high reliability and some other advantages.However,the high price of permanent magnetic material and the lack of effective control method have retarded the development of PMSM.Since 1980s,with the popularity of permanent magnetic materials and the great advancement of AC servo control technology,the PMSM has been widely applied into various motor servo systems.In these systems,PMSM is always modeled as a complex plant,so more accurate model information is also required to guarantee a satisfying control performance.Plus,the design of servo systems,determination of controllers,supervision of work states are also dependent on accurate electromagnetic parameters.Thus,the parameter identification of PMSM is always an important research area.Aiming at improving the performance of parameter identification algorithm,obtaining the more accurate and reliable electromagnetic parameters,and providing accurate information for the PMSM applications,this dissertation mainly studies the parameter identification methods of PMSM.On-line identification is the development trend of motor parameter identification.On the aspect of optimization algorithm for on-line identification,this dissertation proposes a recursive algorithm method with variable discounted measurements based on Gauss modulation function.Compared with recursive forgetting factor method,the proposed method has superiorities both on accuracy and stability.Some other frequently-used identification algorithms are also analyzed in this dissertation.Contrast tests show that the proposed method has better identification performance.The error voltage caused by the dead time of inverter will not only bring the distortion to the motor current,but also make the on-line identification inaccurate.Based on the space vector pulse width modulation(SVPWM)process,the model of the error voltage vector is established and a correction method of current vector angle is proposed in this dissertation.The simulation results show that the proposed compensation method can effectively improve the accuracy of the identification parameters.The off-line identification is the most commonly used method for the identification of simple motor system.In this dissertation,several elementary off-line parameter identification methods are introduced,and a simple method is proposed to identify the direct and quadrature axis inductance without changing the circuit of the system.The experiment was carried out on the motor experiment platform based on DSP28335.The experimental results show that the proposed method can identify the coil resistance and the direct and quadrature axis inductance of the motor efficiently and quickly.