Permanent Magnet Synchronous Motor Sensorless Control Based On Improved Current Model

Permanent magnet synchronous motor(PMSM)has the advantages of high efficiency,good control performance etc,With the development of computer technology and the promotion of motor ontology manufacturing,PMSM has already been widely applied in various fields.Used the speed sensor in motor control applications has many disadvantages,such as increased costs,difficult to install,reduce reliability etc,which make the motor controller can’t reach the requirements of high performance,high reliability for the rapidly industrial development,These shortcomings prompt the researchers to study how to avoid the use of speed sensor in the application.The quick start performance,high speed stability and load capacity with low speed of motor are always the keys and difficulties in the application of speed sensorless control of permanent magnet synchronous motor.In this paper an improved current model of speed sensorless control of permanent magnet synchronous motor has been study,which has great performance.Based on the analysis of the PMSM model,the paper proposed a speed sensorless control method based on improved current model.Different from the commonly used algorithm which has the disadvantages of limited scope of application,poor robustness and the instability because combination of algorithm’s when switch state and so further affect motor’s startup performance,operation stability and low speed performance,the method proposed in this paper selected the observer parameters according to the appropriate principle and used the error signals between estimation current and actual detection current in each sampling period to correct the estimate speed value.so could quickly and exactly estimate the value of speed,and integrate the estimated speed could get the rotor position angle.By doing this,the motor can quickly start from stationary state with closed-loop vector control.Only using one control method in full speed range,there is no state switch,So avoid the state switch process which could lead to out of control while rapid acceleration,This method has good stability,strong load capacity and great robustness.Finally,the simulation model is built in MATLAB/Simlink to varify the control theory,set up the experimental platform,Write motor control program,and analyze the various kinds of working conditions,The experimental results verify the feasibility and reliability of the analysis,the motor can quickly start from stationary state and can accelerate to the rated speed(6 000 r/min)from zero within 1 s.In high speed range,the performance was very stable and the maximum velocity error was less than 0.2%.In low speed range,the capacity of load was great and it still can run stably with full load at the speed of 2%rated speed,this has greatly expand the applied range of the PMSM,has great engineering practical value and has been successfully applied in industrial products.