Sensorless Control System Research Of Stepper Motor Using Kalman Filter

As a kind of digital control motor, permanent magnet stepper motor has the disadvantage of out of step, large torque angle and low control precision. Therefore it is often used in the open loop system which has lower requirement of the accuracy and stability. Hybrid stepping motor can solve some of these above problems, however, complicated structure and high cost limiting its scope of application. Therefore, improving the performance of permanent magnet stepper motor can not only improve the stability of the stepper motor but also reduce the cost of hybrid stepper motor. It is crucial to prevent the motors from out of step in order to improve the performance of permanent magnet stepper motor. Mechanical sensors are traditionally used to detect the rotor position and speed, but the circuit design is complicated and easily interfered by environment. This paper researched and designed a sensor less synchronous motor drive system based on Calman filter. The work of this paper can be detailed as follows:Firstly, this paper established a mathematical model of two-phase permanent magnet stepper motor, linearization approach of nonlinear systems and set the extended Calman filter model of permanent magnet stepper motor in alpha beta coordinates. It completed the design of the sensor less synchronous motor drive system based on extended Calman filter to detect the rotor position and speed of permanent magnet stepper motor.Secondly, it uses PIC16F877 as the control core, adopted divided drive manner, with sensor less technique for permanent magnet stepper motor control system. This paper presents the implementation scheme of hardware and software to solve the problem of low frequency oscillation, low control precision, a nd large torque angle, improves the performance of motors’.Finally, in the MATLAB/Simulink environment, it established a simulation model of a two phase permanent magnet stepper motor with s sensor less synchronous motor drive system. After the simulation analysis of sensor less synchronous motor drive system, the results prove the excellent characteristics of sensor less synchronous motor drive system based on Calman filter.