| With the development of world energy,hydraulic wind turbines have become a popular research direction in recent years.Due to the many advantages of hydraulic wind turbines,scholars at home and abroad have carried out various aspects of hydraulic wind turbines that use "quantitative pump-variable motor" power generation in variable speed and constant frequency,low voltage ride through,hydraulic energy storage system,digital pump wind turbine applications,and hydraulic wind turbine generator grid connection.Since hydraulic wind turbines show a trend toward largescale development,there is currently no mature single quantitative hydraulic pump that can be applied to megawatt-level hydraulic wind power generation systems.At the same time,when a single large-displacement fixed-quantity hydraulic pump is used in a hydraulic wind power generator set,there is usually a non-rated working condition of the pump at low and medium wind speeds,resulting in the phenomenon of low efficiency of the entire unit.Therefore,for megawatt-level hydraulic wind turbines,research on the use of multiple quantitative hydraulic pumps and variable hydraulic motor transmission schemes has important theoretical value and practical guiding significance.The research object selected in this paper is the multi-pump transmission system of a hydraulic wind turbine with a capacity of 5MW.The impact of the multipump switching on the characteristics of the wind wheel and the working characteristics of the entire hydraulic system in the multi-pump transmission system is studied.The methods include theoretical analysis,simulation research,and experimental exploration.The specific research contents are as follows:Firstly,by analyzing the working principle of the hydraulic drive wind turbine,a multi-pump multi-motor drive system scheme for a megawatt hydraulic wind turbine is proposed.Based on the data of 5MW rated power wind turbine published by NREL,the characteristic curve of the wind wheel was drawn using MATLAB.Calculate and select the main parameters of the hydraulic pump and hydraulic control valve of the multi-pump transmission system of the 5MW wind turbine,formulate the closed-loop control scheme of the rotor speed according to the characteristic curve of the wind wheel,and formulate the multi-pump switching rules at different wind speeds of the multi-pump transmission system.Secondly,the principle of the multi-pump transmission system of the 5MW hydraulic wind turbine is elaborated.In order to better analyze how the multi-pump operation affects the characteristics of the wind wheel and the hydraulic system,the hydraulic pipeline,the wind wheel-quantitative hydraulic pump,and the proportional relief valve is mathematically modeled and the output pressure equation for the simulated load is established.And using the AMESim software to verify the correctness of the multi-pump transmission system scheme established in the article.The PID parameters of the closed-loop control of the wind wheel speed were adjusted to the best,and the operation of the single and double pump switching at constant wind speed,the operation of the double pump when the wind speed was changed,and the characteristics of the operation of the wind wheel and the hydraulic system were analyzed.The effect of the control valve switching time on the characteristics of the wind wheel and the operating characteristics of the hydraulic system is further analyzed.Finally,in order to verify the correctness of the theoretical analysis and simulation research,a multi pump transmission system platform of the hydraulic wind turbine is designed,and the main component parameters of the platform are calculated and selected.The measurement and control system is designed in LabVIEW to prepare for the subsequent experimental monitoring of the relevant performance.In this paper,the scheme of multi pump transmission system is studied,which provides important guidance value for the development of new hydraulic wind power technology. |
PDF Full Text Request