| By virtue of its small size, simple structure, high air gap magnetic flux density and reliable performance, Permanent Magnet Synchronous Motors (PMSMs) have been widely used in these years, which in turn has promoted the development of the control system of PMSMs. The thesis studied the sensorless contreol system of PMSMs which is now extensively used in home applicance industry.The main work can be summaried as follows:First of all, the author made a brief analysis on PMSM, the controlled object. And then, based on the idea of coordinate transformation, the writer presented its mathematic descriptions respectively under Three-Phase Static Stator Frame, Static Stator Frame and Two-Phase Arbitrary Frame, at the same time the writer also proposed an improved mathematic simulation model of PMSM which can serve as object of future design of its control system and simulation experiment.Secondly, the thesis analyzed the control strategy on the basis of PMSM model by adopting vector control-based Double Closed Loop Control. Discussion of Space Vector Pulse Width Modulation (SVPWM) and its implementation method can also be found in the thesis.Thirdly, taking into consideration of both the amount of calculation and its accuracy, the thesis proposed a new EKF-based algorithm and demonstrated its use in observing rotor speed and position angle of PMSM. Deducing process of the new algorithm and discussion of its parameter selection were also included in this thesis. With a minute increase of calculation, the new algorithm can reduce truncation errors and improve observation accuracy. An overall simulation experiment was carried out in Simulink to test the speed adjusting control system of PMSM, the result of which was discussed whereafter.With the result of the simulation experiment serving as a guidance, the writer has build up the speed control platform of PMSM on the basis of TMS320LF 2407A and completed the design of related hardware and software, which is under debugging process at present. |
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