Research On Dc Speed Regulating System Based On Predictive PI Algorithm

DC motor has good starting and breaking performance and its speed can be regulated smoothly within a wide range.It is widely applied in the dragging field which requires speed regulation or fast conversion of running direction.But DC speed regulation system with DC current cut-off negative feedback only solves the problem of over-current protection of the system,and does not improve the system's fastness and anti-jamming ability,so it is difficult to apply to the occasion requiring speed control system of higher standard.Therefore,the study of DC motor speed control system of industrial production has practical significance.For the above background,the main contents are as follows:1.Based on the analysis of the working principle of the DC motor and the mechanism modeling method,the mathematic model of the speed feedback DC motor speed regulation system is established.The static characteristic analysis of DC speed regulation system with current cut-off negative feedback is carried out.It is shown in the practical application that the current cut-off negative feedback can only play the role of current limit protection for the controlled system.2.A control strategy based on the combination of predictive PI algorithm and combinatorial integration is proposed in basis of the traditional DC speed control system,.The combinatorial integrating system has the function of mean value filtering.According to the controlled object,the PI controller is designed,and the simulation model of DC speed control system is set up in SIMULINK.Compared with the traditional control scheme,the simulation results indicate that the DC speed control system under the control of predictive PI algorithm not only has good dynamic performance but also has significantly improved anti-jamming capability;besides,the algorithm has the function of current limit.3.The new control algorithm was discretized and realized by programming languages which was similar to C.The communication between MATLAB and SIMULINK was combined by OPT22 software,the human-machine interface(HMI)of real-time monitoring was also developed.The specific value and change in the waveform of DC motor speed control system could be directly observed through the control interface by the user.4.The algorithm was applied to the hardware and software environment of DC motor speed control system provided by B&R.The connection between Automation Studio and simulink was realized seamlessly.The experimental results showed that the composite control strategy based on predictive PI and combined integral could achieve good control of the DC motor speed.The innovation of this paper was to introduce the combined integrating system into the DC speed control system and replace the traditional PID control algorithm with the predictive PI control algorithm.Composited control strategy of combined integral and predictive PI was realized.Take the best use of the two control methods' advantages,the combined integrating system was equivalent to the mean filter,which could make the input signal rise evenly and limit the maximum armature current.The PI control algorithm had good fastness and anti-interference ability.The simulation results and experiments showed that compared with the traditional PID control algorithm,the DC speed control system based on predictive PI algorithm and combined integral control had good dynamic performance and anti-disturbance ability.