Research On Magnetostrictive Actuator For Vibration Suppression Of Hydropower Station Pumps

The safe operation of the pump of the hydropower station is closely linked to the overall operational efficiency of the hydropower station.However,the pump of the hydropower station often has vibration hazard during the operation,and the pump will cause damage when the vibration is too large.Current conventional methods of damping are passive damping or improved pump assembly accuracy,but these methods are not able to actively suppress pump vibration in real time.On this basis,combined with the theory of active vibration suppression,the energetic vibration pumping system of the power station is examined.The key to look into the dynamic vibration suppression system lies in the study of actuators.Since the magnetostrictive material has the advantages of larger driving force,fast response time,stable performance output,etc.during driving,it is chosen as the driving element of the actuator.However,magnetostrictive materials have problems such as eddy current loss,uneven magnetic field distribution,high excitation magnetic field and low output displacement.These problems all affect the overall performance of the magnetostrictive actuator.In this paper,the research on these problems is carried out.Firstly,three kinds of magnetostrictive composite rods with different structures are developed by classical eddy current loss model and the finite element analysis method.Then the fiber composite structure rod was processed and prepared.Finally,the Tb-Dy-Ho-Fe of discrete structures and the Terfenol-D material commonly used in the actuator were checked by the test system.Experimental and calculated data show that Tb-Dy-Ho-Fe composite fiber material can effectively reduce the eddy current loss and improve output performance under low magnetic field.After the driving material is determined,the magnetostrictive actuator structure is designed.The key to the design is the driving magnetic field,the magnetic circuit structure and the overall fit design.The magnetostrictive rod is determined by the mathematical model calculation and finite element analysis of the actuator.The size,the number of turns of the drive coil,the structure of the magnetic circuit,and the size of each part.Through calculation and simulation results,the magnetic field distribution is uniform and the output performance is stable.After the design is completed,the magnetostrictive actuator is processed and the investigations test platform is set up to test the static and dynamic performance of the actuator.The static performance drive current is tested for the 0A~4A static displacement variation,and the forceful displacement variation of dynamic performance at different drive currents(2A,2.8A)and different frequencies is tested.The results show that the unvarying maximum output displacement is 13?m.The dynamics of the same drive current at different frequencies,the higher the frequency,the smaller the peak-to-peak value.At the same frequency and different currents,the larger the current,the larger the peak value,the largest measure the frequencies are 600 Hz and 800 Hz,respectively.The test results have not been much different from the simulation results and calculation results,which can effectively improve the output frequency and overall output performance of the actuator.Finally,the vibration active suppression experiment platform was built,and the vibration experiment of the hydropower station pump was suppressed by Matlab/Simulink simulation.The simulation results show that the actuator can achieve the operational vibration suppression effect,which provides some reference for the development and application of the magnetostrictive actuator in suppressing the pump vibration of the power station,which has certain research significance.