Research on adaptive segmented control strategy used in direct-drive wave power generation systems

Abstract

The problem of unstable output power in direct-drive wave power generation systems (DDWPGS) caused by violent power variation in one cycle of wave is common. The wave power fluctuates violently in a short time, and the lower the frequency, the higher the amplitude. Energy storage devices are usually applied to smooth the power and stabilize the system. This paper proposed an adaptive segmented control strategy (ASCS). It adaptively divided the system voltage into five symmetrical segments and regulated the reference power based on the VMD decompose results according to the different segments. The impedance analysis method (IAM) is implemented to verify its stability. The simulation results confirmed that it can not only automatically adjust the output of the energy storage device to adapt to the frequency and amplitude of wave power signal, but also ensure the safe operation of the system under the impact of charging load and wave power.

Keywords

• Direct-drive wave power generation system
• Frequency decomposition
• Hybrid energy storage system
• Variational mode decomposition
• Impedance analysis method