Research And Realization On The Control Algorithm Of Stepping Motor

Stepping motor has been widely used in industry and consumer electronic because of its low cost and simple control. But the motor cann’t run normally directly using the AC or DC power supply, and it must use the special device, the stepping motor driver. The working performance of the motor is determined not only by the motor itself but also by the control mode and control algorithm. So, the control algorithm research of the motor is in progress along with the research of the motor itself.Firstly the paper introduces the feature of the 3-phase hybrid stepping motor and the control system and the current situation of domestic and overseas stepping motor driven system. The paper deduces the static torque characteristic and dynamic running mathematical equation of the motor and the relation between the rotor position controls with the target current by means of the vector control principle in d-q axis, and designs the sine multistep drive algorithm. According the algorithm, the stepping motor driver prototype is successfully developed which is low cost and reliable using microcontroller. This prototype includes four modules and they are control module, power drive module, protecting circuit and switch power supply, and it realizes the input signal sampling and signal shaping from the upper system, the reference current wave generation, the hardware PWM driver control of current close loop feedback, the fault protection and the current phase recording in power failure. The advanced multiway output switch mode power supply is used in the system which guarantees the normal working of the system. All these can make the driver system reach the target of multistep function and high speed control.In this paper, a driver testing platform is developed and many tests of the prototype are taken on the testing platform in order to examine the working performance, and improve the problems in design, such as the coding optimaizing of the MCU, high speed controlling, the sampling speed and accuracy of the feedback current, high-power drive circuit design, the parameter matching and the software and hardware reliability of the system. The driver can respond to the controlling signal in high frequency reaching up to 300 kHz, and the motor can rotate steadily and reliably. From the tests it proves that the control algorithm and the solution of the prototype is feasible and reasonable and the driver can meet most of the requirements of CNC machine and gives the practical industrialization direction of stepping motor control system in the future.