| Permanent magnet synchronous motor (PMSM) has some advantages, such as high efficiency, simple structure. Currently the AC servo system,as an object to PMSM, has been widely used in aerospace, military defense, industrial production and other areas of national life. Because PMSM is a strong coupling, multi-variable nonlinear system, the traditional PID control is difficult to achieve the increasing performance demands when the PMSM is used in the occasion of high-precision and strong immunity. Requiring some researches combining with advanced modern control theory and motor body, seeking some new methods to improve the drive performance of PMSM servo system. The main contents in this paper are as follows:This paper describes and analyzes PMSM structure and derives its mathematical model in the common coordinate systems. Comparing several common vector control methods and selecting the most appropriate id= 0 vector control. At the same time several traditional methods of PMSM were introduced.Proposing a hybrid current control strategy consisted of time optimal control (TOC) and PI control used in small inductor PMSM for the improvement of PMSM vector control dq-axis stator current dynamic performance. Based on time TOC theory, the optimal switching curve of dq axis current control has been derived. Getting the dq-axis voltage based on the current error and this curve, then the dq-axis current reaches a given value in the shortest time. Since the actual model of the system is not continuous and the motor inductance value is small, the experiment can not achieve the effect achieved in simulation, the TOC controller has been improved,which combined with the PI control to get respective merits and made a switch using the fuzzy controller. Ultimately dq axis current has good dynamic and static performance.Proposed a position control new strategy combining with the linear quadratic (LQ) optimal control and sliding mode control (SMC). Under ideal conditions, the mathematical model of PMSM has been described as a linear model by the coordinate transformation. Design a position controller by LQ optimal control theory, the predetermined performance indicators can be obtained. But the actual PMSM system can produce a variety of uncertainties. When an external disturbance, like parameter changes and other issues appeear, LQ control can not meet the set performance indicators. However it is capable of handling uncertain nonlinear systems characteristics combining SMC and can effectively improved the poor robustness problem of the LQ control.To validate the proposed control strategy, a set of high-performance, good stability PMSM servo hardware and software system combined with the characteristics of vector control and made TMS320F2808 DSP as the core has been designed. The key parts of the implementation methods have been described. The experiment results show that the hardware system can meet the needs of the proposed control scheme and has advantages of high reliability and real-time. |
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