Research On Servo Control Performance Optimization

Permanent Magnet Synchronous Motor (PMSM), with its simple structure, low losses, high power factor, and easy maintenance, is widely used in the servo drive system of small and medium-power, high-precision and wide speed range. Therefore, the optimization study of the servo system is significant and valuable. This paper is studied from several aspects, such as the control performance, speed algorithm, switching losses and hardware cost.Firstly, the fuzzy-PI rules table is designed. Consideration of acceleration, integral saturation, overshoot, low-speed oscillation and zero-speed oscillation, the control strategy is adjusted. The effectiveness of the proposed methods is verified by experiments. Compared with the traditional M/T method which just obtain encoder feedback pulse number in integer, the new kind of M/T method proposed in this paper can obtain the precise encoder feedback pulse number in fraction, so as to improve the accuracy of speed measurement. Secondly, in order to reduce switching losses of power device, several typical types of Bus-clamping pulse width modulation (BCPWM) are realized by reasonably selecting and placing the zero vectors on the basis of classical space vector pulse width modulation (CSVPWM). MATLAB/Simulink simulation model is built with four different kinds of SVPWM. The phase current harmonics, the phase voltage waveform, the switching losses and influence on the motor bearing due to the neural point voltage fluctuation are comparative analysis, which is helpful to judge the merits or defects of BCPWM strategy. And the feasibility of BCPWM is testified by experimental study. Finally, with the maximum use of hardware resources, a double-motor drive is designed, which is based on a piece of DSP28234and can independent control two servo motors in the same times.