Design Of Sensorless Control System For Permanent Magnet Synchronous Motor Based On High Frequency Signal Injection

Permanent Magnet Synchronous Motor(PMSM)are widely used in the fields of new energy vehicles,robotics,and servo control systems due to their simple structure,high power density,and high efficiency.Accurate detection of the rotor position of PMSM is crucial to achieving normal motor startup and speed control.The use of mechanical position sensors increases the volume and cost of the motor.To overcome these problems,sensorless control technology has been widely studied.The rotor position can be estimated by extracting the position information contained in the motor’s back EMF,but it can be only used for medium and high-speed detection.For Inner-mounted PMSM,the high-frequency injection method is commonly used to estimate the rotor position at zero and low speeds by utilizing the convexity of the motor.There is less literature on rotor position detection for Surface-mounted PMSM at zero and low speeds.In this context,this paper focuses on improving the accuracy of rotor position estimation at zero and low speeds for surface-mounted PMSM.The main work is as follows:Firstly,the development and application status of PMSM control technology and sensorless control technology are analyzed.Summarize the types of sensorless technology and analyze the advantages and disadvantages of several high-frequency signal injection methods in detail.Secondly,establish the mathematical model of PMSMs in different coordinate systems and give the coordinate transformation relationship.In-depth study of PMSM’s Space Vector Pulse Width Modulation(SVPWM)control technology,and build a vector control simulation model to verify the closed-loop control system designed in this project.Then,the principle of the PMSM high-frequency pulse voltage injection method is analyzed,and the mathematical model of PMSM under high-frequency excitation is derived.Based on the high-frequency pulse signal injection method,design a Linear Extended State Observer(LESO)to replace the Phase Lock Loop(PLL)for rotor position estimation.Establish a simulation model,and the simulation results show that compared with the PLL-based rotor position estimation method,LESO significantly improves the accuracy of rotor position estimation and enhances the stability of the control system.Finally,a hardware circuit is designed with TMS320F280023 C microcontroller as the core,and a sensorless control experimental platform is built.Based on vector control,the high-frequency pulse voltage signal injection method is used to verify the position estimation methods based on PLL and LESO.The experimental results show that both methods can achieve rotor position estimation for the PMSM.Compared with PLL,the LESO-based method has good stability and dynamic performance,effectively improving the accuracy of rotor position estimation.