Research On The Speed-adjustment System For Permanent Magnet Synchronous Motor

As the technology in power electronics, micro-electronics, new materials and the modern theories of motor control develop, the inevitable trend is that AC speed-adjustment replaces DC speed-adjustment. PMSM has the advantages of small size, light weight, high efficiency and rotor without fever problem; Speed-adjustment system made up of PMSM has the advantages of simple control method, good low-speed performance and good performance-price ratio. These advantages make PMSM widely used in servo field in which performance requirements of stable state and dynamic response are high. Speed-adjustment for PMSM is the research object in this paper.Firstly, from the unified theory of motor and vector control theory, the mathematical model of PMSM on the two-phase rotor synchronous rotating coordinate is introduced and the rotor flux-oriented control strategy is applied. Analysis of current feedback decoupling method and SVPWM is followed.Secondly, according to design experience of DC speed-adjustment system, the double closed-loop controllers are designed for PMSM speed-adjustment system. As the value of the speed controller parameter is linear with system inertia, the model reference adaptive system inertia identification algorithm is proposed. The algorithm is verified by simulation in MATLAB/SIMULINK environment and a simulation conclusion is obtained.Thirdly, the system hardware and software design is introduced, including hardware circuit, tasks of program module, flow charts and variable handling, etc.Finally, the wave-forms of the speed loop are presented. The experimental results verify the correctness of the controller design and show that the system has good dynamic performance and stable performance.