On/off multi-poppet valve for switching manifold in discrete fluid power force system PTO in wave energy converters

Fluid power systems are the leading technology for power take off systems in ocean wave energy converters. However, fluid power systems often suffer from poor efficiency, especially in part loads. This degrades the PTO system efficiency and therefore lowers the energy production. To overcome the issues with poor system efficiency, a discrete fluid power system is proposed as a main part of the PTO system. For the discrete system to be feasible large fluid power switching valves are needed. The current paper presents a two stage 1,000 L/min@5 bar multi-poppet on-off valve with a switching time less than 10 ms. The pilot stage is directly actuated and utilises internal valve pressure as supply and an external tank connection as drain. The current paper presents the multi-disciplinary design process leading to the final valve design. This includes the geometric design of the main stage, the choice of pilot valve, structural mechanical issues and modelling and simulation of various valve configurations. Hence, a mechatronic design process is utilised to choose the best valve configuration.