Control Strategy for Power Smoothing Converter with Energy Storage for Maximum Power Controlled Wave Energy Converter

Some active controls using resonance technique were proposed to maximize the power production for the point absorber type wave energy converter with a linear generator. However, the generated power is bidirectional because the motor drive and the power generation drive alternate in the wave cycle. So, power smoothing with energy storage is needed for grid connection. In the paper, a smoothing converter with energy storage and its control strategy for maximum power-controlled wave energy converter are proposed. The proposed converter consists of two types of storage and bidirectional choppers which controls each storage current. One of the energy storages is a lithium-ion battery for long-term power smoothing, and the other is an electric double layer capacitor for short-term power smoothing. The configuration of the proposed converter and the proposed control strategy for water tank experiment is modeled and simulated. It is confirmed that the proposed converter with the proposed control method works well.