Research On The Pressure Control Of Pump/Motor Energy Transfer Unit

Energy conservation is a permanent topic of common concern in the hydraulic industry. In recent years, as the industry downturn, enterprises lack of innovations. And homogeneity of the energy-saving technologies is very serious. The industry urgently expects the emergence of new energy-saving technology. In 2013, H.Murrenhoff research group in the RWTH Aachen, Germany broke the quiet, proposed a new matrix-based circuit thought "STEAM-system", and set off a new fashion of energy-saving technologies. However, one important issue the STEAM system faced in engineering practice is when there is energy feedback to the pressure network, only the energy stored in the current pressure level, cause the energy aggregation. If not timely output this aggregation energy, it will seriously affect the normal operation of the system, or even out of control. Therefore, in order to settle the issue of energy aggregation, this paper started from solving the energy aggregation problem, by proposing an energy transfer unit to balance the energy between different pressure levels.The main contents are as follows:First, the working principle of STEAM system was introduced; noting that inevitability of the energy aggregation, which lead to the research object of this paper: energy transfer unit. Then based on lots of investigations, the research and application of hydraulic energy transfer unit at home and abroad were introduced.Secondly, by the basic composition of the energy transfer system, it was divided into three parts to build math model: the constant pressure network, the variable mechanism and the body of transfer unit. About this new kind system, stability and controllability were analyzed first at whole. And simulation analysis was made about its starting characteristics and disturbance rejection characteristics.Then, for the traditional PID control, there was big overshoot and long adjusting time, in order to solve this issue, starting from the improvement of control method, proposed to add the feedforward compensation and fuzzy algorithm to the traditional PID controller, and simulation studied their performance on the improvement starting characteristics and disturbance rejection characteristics.Finally, experimental platform was built, and three control methods were studied on the platform contrastively. Verified the advantages of feedforward-feedback compound control and fuzzy PID feedforward-feedback compound control compared with the PID.