Vector Control Of Sensorless PMSM Based On Sliding Mode Observer

Permanent Magnet Synchronous Motor(PMSM) is one kind of the most widely used servo motors, its advantages are small,high efficiency, excellent performance and etc.Servo systems which use PMSM are more and more widely used in CNC machine tools, industrial robots and other industrial automatic equipments. Currently,we need to use position sensors(optical encoder, tachometer generators, etc.)to detect the rotor position when we control PMSM with vector control. However, the position sensors will increase the cost and make the size of motors bigger and other issues,sensorless control technology use the voltage and current of motors to estimate the position and speed of the rotor by means of specific control algorithms, sensorless control technology can make servo motors smaller,cheaper and improve the reliability of the servo systems. This paper attempts to solve these problems by sensorless vector technology which is based on sliding mode observer.This paper is based on the rotor flux oriented vector control technology and sliding mode control and set up the mathematical model which is based on sliding mode observer used in PMSM Vector Control. The paper analyzes the source that makes the control system chattering, and replaces the original switch function with saturated continuous function to suppress chattering. Then this paper build a simulation model of PMSM vector control in MATLAB / Simulink simulation software, respectively, with a position sensor and a position sensorless permanent magnet synchronous motor. The results show that the saturation continuous function can suppress chattering effectively,and sensorless vector control system based on sliding mode observer has good speed performance.Finally, this paper uses the DSP chip TMS320F28335 which is specifically developed for motor control by TI as the main controller, and designs the main circuit with IPM PS21765.The hardware contains a + 80 V / + 15 V switch power supply,the motor current&voltage detection circuit and the other peripheral circuits.The system software is designed modularly, and can verify the correctness of the entire program.