Research On Sensorless Control Method Of Permanent Magnet Synchronous Motor Based On

In the field of motor control, it is essential to get access to the information of the motor speed and motor position especially in high performance motor control applications. The traditional way for getting motor speed and motor position information is to install a speed or position sensor on the motor shaft, which will bring some problems such as high costs and low reliability. Therefore, the motor speed sensor-less control, which makes the system has no more need of speed or position sensor and get the estimated speed and rotor position by algorithm, is gradually become a hotspot in the field of motor control. In this paper, the low-voltage permanent magnet synchronous motor (PMSM) used for driving the air conditioning compressor is selected as the object of the study. By relying on the internships and school laboratory equipment, the research on PMSM speed sensor-less control is carried out and verified by the simulation, the hardware platform is designed, on which the speed sensor-less control experiment is carried out.Firstly introduce the basic structure, principle of coordinate-transformation, on the basis of which the math model of the PMSM in different coordinate is derived. The main control method of PMSM and some commonly used algorithm for speed sensor-less control in nowadays is also introduced, among which the merits and demerits are analyzed and compared. As for the characteristic of the PMSM that nonlinear, strong-coupling and complex function process, the space vector pulse width modulation (SVPWM) is used for the control, and the simulation for the motor’s vector control with a speed sensor is carried out on MATLAB/Simulink software platform.Secondly, the basic principle of the variable structure control is introduced, the algorithm of which is deeply studied and programmed in MATLAB. On the basis of the vector control with a speed sensor and the sliding mode control algorithm, the simulation model of the speed sensor-less control system of PMSM based on the traditional sliding mode observer is set up. On the basis of the speed sensor-less control system, the algorithm is improved, the new speed sensor-less control system based on Sigmoid function is carried out. The simulation results verified the feasibility, correctness and the validity of the algorithm, which is a good theoretical basis for the hardware platform.Finally, the PWM waveform is produced by the control circuit based on TMS320F28027from TI, the circuit is also used for the system control. The power circuit of the motor driver based on PS21767is designed and debugged successfully. The speed sensor-less control hardware system, which is consists of the control circuit, power circuit and the PMSM, is set up. The CCS is used for DSP software design and programming. After doing the experiment again and again, the system can basically estimate the motor speed. The experiment results show that the experiment has achieved the desired effect.