Design Of Linear Motor Driving Control System Based On DSP

Compared with the traditional feed mode of rotary motor, the technology of direct drive of permanent magnet linear synchronous motor omitting the intermediate conversion mechanism has been widely used in servo feed systems with its excellent properties of high speed, high precision, fast response etc. Since the requirement of the permanent magnet linear synchronous motor in electrical control is higher than rotary motor, more efficient control methods must be adopted and detection element of higher accuracy must be selected. This paper proposes the method for motor control that combines the voltage space vector pulse width modulation and closed-loop control strategy. The three closed-loop control of current, speed and position is realized with the digital signal processor TMS320F2812 as its control centre.Firstly, the mathematical model of the motor under the control method is built in the Matlab/Simulink environment. Due to the adoption of id=0 control, the mathematical model of the motor is established in the dq axis coordinate system, including the equations of voltage, flux and motion. The strategy of closed-loop control and vector control are described in detail, while the SVPWM algorithm is derived and the SVPWM module is built in accordance with the derived formula. Then the model of current, speed and position closed-loops are built.The simulation results verifies the feasibility of the control method.Secondly, the platform of the experiment is set up, including hardware and software parts. Hardware circuit includes rectifier module, sampling module and driving module. With the TMS320F2812 as the core of controller, the main part and the interrupt part of the program are written in the CCS3.3 development environment, including motor initial position module, current sampling module, SVPWM algorithm module, electrical angle calculation module, speed calculation module, the detection of both ends of motor and position detection etc. Some control flow diagrams are given in the paper.Finally, the function of the system is proved realized by measuring the current, speed and position waveforms and the analysis of the performance. The position closed-loop can achieve the initial function as the outer loop. A plan of linear motor drive system is provided to be the foundation to achieve high-precision control in the near future.