Study On PMSM Main-Spindle Direct Drive System

In the field of industry, numerical control machine tool and manufacture center are the important equipments of mechanical manufacturing. In order to increase machining precise, performance improvements for main-spindle direct drive system are studied deeply. Among them, it is an important research that how to apply permanent magnetic synchronous motor (PMSM) system into direct main-spindle drives. The work of this thesis is approached based on the cooperative project"Study and Manufacture of main-spindle AC Drives System"of Harbin Institute of Technology and Qiqihar Machine Tool Electrical Apparatus Factory. The prospective object of the project is to develop wide range speed regulation, high performance and Full-digital PMSM AC servo system for direct main-spindle drive.In order to implement direct main-spindle drive, some key technique problems such as system model and control method, were studied deeply in the thesis. Firstly, many domestic and overseas correlative documents were consulted for knowing the development status of main-spindle drive system full-scale. The mathematic model of PMSM was deduced for theory analysis and simulation. Control method was studied in order to improve the performance of main-spindle direct drive system. System hardware circuit and software program were designed. At the end, the experiment and simulation were done.In the part of principle analysis and modeling, the mathematical model of PMSM was deduced according to the configuration of PMSM. The parameters of prototype were measured and were applied to simulation. And according to the mathematical model, vector control principle and minimal direct axis current control and its digital realized method were discussed.In the third part of the papers, four factors that affect the performance of PMSM running at low-speed were analyzed and the promoted schemes for the factors were designed. The dead-time effect on SVPWM inverters and the low-speed characteristic of the PMSM servo system were analyzed. In addition, a novel method of dead-time compensation based on SVPWM was proposed in the paper. The results verify this method has a good compensation effect.