Research On Position Sensorless Control System Of Permanent Synchronous Motor

The rotor of Permanent magnet synchronous motor which use the permanent magnet instead of the excitation winding makes the PMSM has a simple structure,smaller volume,and what's more it can reduce the excitation loss by eliminate excitation winding is now widely used in different fields.The motor which used in high performance applications require closed-loop control so it needs the position of the rotor,the general way to detect the rotor's position is through the sensors,but there are many problems by this way,the main problem is the installation of the sensor increases the links between the controller and the sensor which decreased the anti-interference ability of the system and also leads to the higher cost of the whole control system and also the motor size becomes larger,so it becomes very important to do some researches on the sensorless control technology.Firstly,we will introduce the background and significance of the topic and we also introduce the common methods of vector control current mode in permanent magnet synchronous motor,on this basis,the research status of sensorless control technology at home and abroad is introduced.We will analysis the method commonly used in sensorless to find out a sliding mode observer which has a low request on the mathematics model,strong anti-interference ability and a control algorithm that is easy to implement after a comprehensive comparison.Secondly,we will analysis the mathematical model of PMSM and coordinate transformation and then have a deep study of the space vector PWM.We will set up a control simulation model of PMSM,and then introduce the principle of sliding mode variable structure and some of its features,on this basis,we designed a sliding mode observer to estimate the rotor's position and speed and analyze the reason of the existence of chattering,then put forward the optimization of the original sliding mode observer by using saturation function sat to replace symbol function sign and a fuzzy control to replace the original fixed gain constant gain.We use the Matlab/Simiulink to build the simulation model of sliding mode observer to estimate the information of rotor's position and speed,after comparing the results of the speed and rotor position estimation before and after optimization we found that the effect of optimization is more accurate than that of the rotor position and speed without optimizationFinally,we design the circuit diagram of the hardware platform of the whole control system,the software part is compiled according to the simulation analysis and the physical verification is done on the hardware platform.