Research For The Vector Control System Of PMSM Based On Sliding Mode Observer

With the rapid development of microelectronics, power electronics technology and moderncontrol theory, the position sensorless control technology of the permanent magnet synchronousmotor(PMSM) has made great progress. Sensorless motor control is by measuring the voltageand current quantities to estimate the rotor position and speed through the specific rotor positionestimation method, it has many advantages, such as simple structure, high reliability, easymaintenance, speed performance. Sliding mode control，as a nonlinear control strategy，has thecharacteristics of good robustness and fast response. This paper will introduce the Sliding ModeObserver (SMO) in control system of PMSM, research and implementation of sensorless vectorcontrol of permanent magnet synchronous motor.Firstly, this paper introduces the research background and the development of permanentmagnet synchronous motor, then analyzes several estimation methods of the sensorless control,selects a rotor position estimation method based on sliding mode observer which has simplecontrol algorithm, good robustness, and easy implementation of engineering application. Themathematical model of permanent magnet synchronous motor in different coordinate systemshas been established. After in-depth study of the vector control theory and the SVPWMalgorithm design, the vector control model of permanent magnet synchronous motor can beenestablished.Thirdly, theory of sliding mode variable structure is studied in depth, and the the causes ofthe chattering phenomenon are analyzed in detail. On this basis, according to the principle ofsliding mode observer to establish the state equation, the rotor position and speed of permanentmagnet synchronous motor can be estimated online. And Kalman filter is introduced, to solvethe problem of the chattering, saturation function is used to replace the switching function. Anew coordinate system is introduced, with SMO model established in this coordinate system.Using Matlab/Simiulink to built each simulation model of the control system, the simulationresults show that the control system is feasible and good robustness． Finally, the control system is designed based on DSP TMS320F2812which is the controlcore of the entire system. On the hardware side, the main circuit and the external control circuitare completed; On the software side, the main program and interrupt service routine are designed.On this basis, the commissioning of the system is completed.