Research On High-precision Feeding PMSM Servo Drive On NC Machine Tools

The subject comes from the project on “high-precision servo drive equipment applied innumeric control(NC) machine”. The main content is about high-precision feeding PMSMservo drive technology based on numeric control machine.After reading some relevant literature, reviwed the servo system based on NC systemand classified them, then three common control strategies are presented.As a complete description, deeply analyses the mathematical and physical models ofPMSM. The method based on rotor flux vector control is studied, so as to modeled anddecoupled motor and obtain performance like control DC motor. The strategy of space vectorPWM(SVPWM) is put into use for converter, which selects intelligent powermodule(IPM).DSP and FPGA are chosen being main control elements, the communicationbetween DSP and host through RS232serial port, and FPGA communicate with DSP via thedata bus, which deals with some auxiliary signals.The paper designs servo device on hardware and software system. The power supplysystem is presented. The power supply needs7DC outputs which is isolated with the DCpower supply. Including4routes outputs about15V for IPM,2routes outputs about5V for IClike DSP and FPGA, while the-15V and15V, respectively, for the fans and other ICs. Thecontrol chip selects TOP244Y and the total output power is40W.In addition, the structure ofservo drive is presented. The hardware circuit including control and driver panel, heatdissipation mode is forced air cooling. The control panel on parameter setting is designed,which can displays the running status and realize the jogging control.The servo drive use speed and torque(current) double-closeloop control structure. Thisarticle focuses on analysis of the deadzone in measuring speed of incremental encoder, aperiod optimization strategy is presented. Experiments show that using the current encoder,the control and process performance are improved in low speed.Finally, the servo drives are fixed in three feeding axes of CN machine. After debuggingand testing, the presented result of experiment show that the development of servo drivemeets the design requirement.