Study On The SMC Control Performance Of PMSM With Sampling Rate

With the rapid development of new materials,computer control technology,and power electronics devices,coupled with the excellent control performance of permanent magnet synchronous motors,it has become one of the most popular motors in industrial control.Vector control based on magnetic field orientation has also become the research object of scholars and experts.In this paper,a sliding mode control strategy is adopted on the basis of vector control,and a new approach rate is proposed,and then the sliding mode control performance of permanent magnet synchronous motor is studied through the sampling rate.This article is carried out from the following aspects..First of all,the first part mainly introduces the development status related to the technology of this article.Many control strategies of sliding mode control are introduced.There are three main categories:one is by designing the sliding mode surface;the second is by approach rate;the third is the control strategy that combines sliding mode with other controls such as neural network and self-adaptation.The common point of these control strategies is to reduce the chattering problem caused by sliding mode control to the system and improve the control performance of the system.Sampling rate to the system research and development mainly introduces the sampling process of digital computer control system,and the influence of sampling rate on the control system is introduced in this project,and the development status of single sampling rate control system and multi-sampling rate control system are introduced respectively.Secondly,the mechanical structure,magnetic field distribution and other characteristics of the permanent magnet synchronous motor are introduced and the research object of this paper is determined based on the surface-mounted permanent magnet synchronous motor.The mathematical models of motors in different coordinate systems are given.In order to obtain a better control effect,the rotor field orientation control strategy with id=0 is determined.The advantages and disadvantages of the approach rate in some literatures are analyzed,and based on these advantages,the new energy fractional double-power fast approach rate is proposed,and the reachability and existence proof are given through the Lyapunov function.The related modules of the entire vector control system are introduced and the principle of SVPWM is explained with emphasis.Then the discretization principle of permanent magnet synchronous motor is introduced.Through the Fourier transform,both the time domain signal and the frequency domain signal can be discrete.Two filter analysis methods based on the infinite unit impulse response system are given.Transform from the time domain to the Z domain on the discrete sequence obtained by sampling the impulse response of the analog filter with a cycle T.Through Matlab simulation,the amplitude-frequency and phase-frequency characteristic curves of the digital filter are obtained and analyzed.The structure diagram of the speed control system is given,and the speed loop and current loop are analyzed through the root locus.The correction zero and gain of the minimum phase system of the current loop and the speed loop are compared and analyzed,and the correction zero and gain parameters with better control quality are obtained.The theoretical analysis of the sampling rate of the minimum phase system is carried out,and it is obtained that within a sampling period,the error estimate provides a theoretical proof for the stable convergence of the Lipschitz constant.And the sampling period can be obtained by multi-order linear matrix inequality.Then a sliding mode controller is designed for the proposed new approach rate,and the parameters of the controller are determined through debugging.And through the performance comparison with the traditional exponential approach rate sliding mode controller and PI controller,the comparison is made from three aspects: speed response,stator three-phase current,and motor electromagnetic torque.The sliding mode controller based on the new approach rate has more obvious outstanding effects on these three performance indicators.It is more in line with the original intention of the design approach rate to reduce chattering while improving control quality.In terms of the experimental platform,the software and hardware of the experimental platform are introduced.The main circuits of the control system include: power supply circuit,DSP main circuit,PWM drive isolation circuit,and given speed circuit.In terms of software,the main flow chart of the system,the PWM interrupt flow chart,and the detection method of the motor rotor position angle and speed are introduced.Finally,the design of the software to this experiment is introduced.Analyzing the effect of sampling rate on motors such as speed,overshoot,current and torque.The experiment proves that the optimal period for the stable convergence of the error estimation is proved.And the speed response when the sampling frequency is from 7K to12 K motor acceleration and deceleration and load acceleration and deceleration is given.And in a relatively small sampling interval,a conclusion is drawn that the performance of a certain item is relatively optimal.