Research On Application Of BBO Algorithm In Harmonic And Torque Ripple Suppression Of Motorized Spindle

NC(abbr.numerical control)machine tools is a strategic industry of national equipment manufacturing industry,and motorized spindle is the key functional component of NC machine tools.The performance of motorized spindle control system affects the processing quality of NC machine tools,so it has practical significance to improve its control performance.The output torque ripple strength of motorized spindle and the output current harmonic of inverter have important effects on its control performance.When the identification result of stator resistance was deviated,the stator flux trajectory was distorted and the output torque of motorized spindle was fluctuated.The motor spindle is powered by an inverter.When there were current harmonics in the power supply,harmonic effect was formed and electromagnetic harmonic loss was generated.On the basis of deeply studying the BBO(abbr.biogeography-based optimization)algorithm and torque ripple suppression and current harmonic suppression in this dissertation,the performance of control system of motorized spindle is improved.The main research work and innovative achievements summarize as follows:Based on the static and dynamic mathematical model of motorized spindle,the mathematical model of inverter and the essence of DTC(abbr.direct torque control),a DTC simulation model of motorized spindle has established,and the torque ripple mechanism of motorized spindle in DTC revealed.Simulation results showed the influence of stator resistance on torque ripple.SHEPWM(abbr.specific hannonic elimination pulse width modulation)used to analyze the existence of current harmonics in spindle control system,it revealed the mechanism of current harmonics generation,and demonstrated the influence of switch angle on inverter current harmonics through simulation.Based on the simulation analysis of hannonic loss and torque ripple of spindle under DTC,it revealed the mechanism of inverter output current harmonic and spindle output torque ripple in DTC system.The application strategy of BBO algorithm in DTC is proposed.The initial values of stator resistance,switch angle and voltage vector action time affected the exploration ability and convergence speed of BBO algorithm,and BP(abbr.back propagation)neural network model was used to optimize it.The BPBBO algorithm obtains better convergence speed by optimizing the probability value in algorithm.A strategy based on BPBBO algorithm to suppress inverter current harmonics is proposed.It studied the influence factors of switching angle in CHMPWM(abbr.current harmonic minimum pulse width modulation).Based on CHMPWM model,BPBBO algorithm was used to optimize the switching angle,and the suppression effect of CHMPWM modulation method on the current harmonics of inverter was verified by simulation and experiment.Through simulation and experiment,it verified that the switching angle optimization of BPBBO algorithm in CHMPWM can reduce the THD(abbr.total harmonic distortion)of current,it realized the purpose of suppressing the current harmonic of inverter,and thus reduced the electromagnetic loss of motorized spindle caused by current harmonic.A strategy based on BPBBO algorithm to suppress torque ripple of motorized spindle is proposed.Research on TRMPWM(abbr.torque ripple minimum PWM)in DTC system can suppress torque ripple of motorized spindle.BPBBO algorithm was used to optimize the action time of voltage vector based on TRMPWM model.Based on the analysis of stator resistance influence factors,the BPBBO algorithm was used to identify the stator resistance online.Through simulation and experiment,it verified that BPBBO algorithm can improve stator resistance identification accuracy and optimize the action time of voltage vector,it achieved the purpose of suppressing torque ripple of motorized spindle,and thus improved the performance of motorized spindle control system.Based on BPBBO algorithm,stator resistance identification,switching angle optimization and voltage vector action time subdivision studied in this dissertation,an effective methods of inverter current harmonic suppression and motorized spindle torque ripple suppression are proposed,which lays foundation for application of BBO algorithm in motorized spindle control system.