The design and adaptive control strategy of cascade hydraulic energy storage and generating system of WEC

Wave energy is the potential ocean energy resource. The hydraulic energy storage and generating system (HESGS) has been applied in wave energy converter (WEC) for its high reliability and smooth power fluctuation. WEC often works in greatly changed wave conditions to absorb wave energy as much as possible. The output power also varies in a wide range. To deal with the wide range and various wave conditions, a cascade hydraulic energy storage and generating system is proposed in this paper. The optimized adaptive control strategy is studied. Units are divided into different levels, which start and stop depending on the control pressure of valves. Gravitational Search Algorithm has been used for the calculation of the control pressure according to wave condition. The simulation has validated that the cascade HESGS with an adaptive control strategy has improved the stability and flexibility of the generating system of WECs.