Digital Hydraulic Transformer Structure Design And Experimental Research

As a secondary regulation element in the hydraulic system,the hydraulic transformer can not only drive the load in the forward direction but also realize the energy-saving control of the power matching.It can also drive the load and recover the energy at the load end.Although the concept has been proposed for more than fifty years,hydraulic transformers have not been widely used in the market.At present,the hydraulic transformers researched and applied both at home and abroad still have some problems such as narrow range of transformation,inconvenient processing,expensive price and difficult to control disadvantages.In view of this,the digital hydraulic transformer conceived in this paper combines the discrete,simple and easy-to-control features of digital components with the features of variable-voltage energy-saving of hydraulic transformers.A plurality of different displacement pump / motor units are combined to form a digital hydraulic transformer flow unit,and then through the state of the inlet and outlet valve groups to switch,to achieve the transformation ratio of digital control.According to the theoretical analysis results,the power bond graph model of digital hydraulic transformer was established,which further clarified the feasibility of the principle of transformer.The flow loss inside the flow cell is analyzed to provide the basis for optimizing the structure in the next step,so as to improve work efficiency and reduce losses.By using software to simulate and analyze the transformation process of digital hydraulic transformer,the author verified the characteristics of pressure,flow rate and transformation ratio in the process of operation,and explored the main factors that affect the transformation performance.Aiming at the discontinuity of transformation ratio,a(D+A)combination control method is proposed to eliminate the pressure fluctuations during digital transformation.By comparing the two control methods,(D+A)The effectiveness and feasibility of the combined control method.The experimental platform was set up to test the transformers' characteristics of digital hydraulic transformer under constant voltage network.By changing the pressure of constant pressure rail high-pressure lines,simulating the load size and transformer ratio,the working characteristics of digital hydraulic transformer under different operating conditions were studied.The feasibility of the principle of transformation.Proved the digital hydraulic transformer energy-saving features.