| The servo system is a motor drag-system of high precision speed and location control,which has fast response characteristics.Permanent magnet synchronous motor(PMPM)has the merits of simple structure,high power density,high efficiency,high reliability,small volume and light weight.Combined with high-performance control strategy,AC servo system using PMSM as execution framework has become the major form in high precision and performance motion control occasions.At home and abroad,researchers all believe that the full digital high-precision control of position,speed and torque is the main stream in the development of AC motor servo control.However,as a strong coupling,nonlinear and multi-variable control object,PMSM has some disadvantages such as machine parameter coupling,velocity feedback perturbation,unknown initial position and external disturbances and so on for the implementation of high-precision three-closed-loop servo control.In order to improve the performance of PMSM three-closed-loop servo driving system,the motor key parameters need to be acquired accurately in real time to improve the servo control performance;Therefore,in this thesis,aiming at the improvement of three-closed-loop PMSM servo system's performance,a theory research and technical development in key areas ranging from position detection,speed control,initial position detection,and parameter identification of motors are carried out;the complete AC servo hardware/software system is developed.The main works are as follows:Firstly,by analyzing the principle of velocity measurement,the real time of velocity measurement and the accuracy of velocity measurement in different speed ranges of M method,T method and M/T method,a T measuring speed method with De-noising filtering function is proposed,it is more suitable for general AC servo system based on incremental photoelectric encoder.The formula of T velocity measurement method is derived.The effect of the burr signal of the feedback position pulse and velocity measurement interference error of the servo system on the velocity measurement accuracy of T method is studied.The traditional T velocity measurement method is improved by the combination of amplitude limiting filtering and segmental speed limiting filtering,and the error caused by the burr signal is eliminated.The digital low pass filtering algorithm is used to reduce the interference error of velocity measurement.At low speed,a timer predetermined scaling factor adaptive algorithm is used to extend the range of velocity measurement.Finally,the speed measurement circuit and software program are designed.The velocity detection effect is verified by the T full period of the velocity measuring experiments in different running interval through,effectively filtering the interference error,improving the system performance of speed,the server speed ring has better response characteristics.Secondly,for the estimation of sensorless initial rotor position of PMSM,a method is proposed by the combination of fluctuating high frequency voltage signal injection and identical width voltage pulse.Fluctuating high frequency voltage signal is injected into the estimated synchronous rotating coordinate system of motor.Initial rotor position is obtained by the comparison of difference of response current extreme value under different estimated angle.In order to solve the problem of dual solutions within 360 degree range for the identification results of fluctuating high frequency voltage signal injection method,an identical width voltage pulse method based on the principle of magnetization is presented.Six voltage pulses are applied to the motor armatures by using the iron saturation.The orientation zone of magnet pole of the rotor is acquired through the comparison of the absolute value of response current.Overall,the feasibility of the method in realizing the inspection of initial rotor position quickly for static state of PMSM and starting the motor is approved.Thirdly,a model reference adaptive control(MRAC)-based estimation algorithm is proposed for online multi-parameter identification of surface-mounted permanent magnet synchronous machines(SPMSM).By taking the dq-axis equations of a practical motor as the reference model and the dq-axis estimation equations as the adjustable model,a standard model-reference-adaptive-system-based estimator was established.Additionally,the Popov hyperstability principle is used in the design of the adaptive law to guarantee accurate convergence.In order to reduce the oscillation of identification result,this work introduces a digital low-pass digital filter to improve precision in the parameter estimation.The proposed scheme is then applied to the current loop of SPMSM control system.The experimental results reveal the effectiveness of the proposed method for the steady parameters and sudden severe change parameters.Finally,according to the demand of PMSM actual application,a main hardware/software system of general-purpose servo driver is designed,and three-closed-loop servo driving system has achieved successful operation based on SVPWM algorithm.At the same time,to improve speed loop response and anti-interference ability of the permanent magnet synchronous motor servo drive system,the anti-integral saturation PI speed regulator with a Bang-Bang control is added to the speed loop;The proposed algorithms are added into the PMSM servo system based on DSP(TMS320LF2812),and the position control,speed control,torque control of servo driver are studied experimentally,the experimental waveforms are given.The results of experiment prove that this servo system can operate reliably and stably,and meet practical engineering requirements,realize high accuracy position,speed and torque servo control. |
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