An improved model predictive control method for wave energy converter with sliding mode control. (15th November 2021)

• Record Type: Journal Article
• Authors: Wang, Zhenchun; Luan, Feng; Wang, Nianguo
• Is Part Of: Ocean engineering. Volume 240(2021)
• Publication Date: 2021-11-15
• Subjects: Viscous force -- Wave energy converters -- Model predictive control -- Sliding mode control; Ocean engineering -- Periodicals; Ocean engineering; Periodicals; 620.4162
• DOI: 10.1016/j.oceaneng.2021.109881
• Languages: English
• ISSNs: 0029-8018

Abstract

Abstract: The model accuracy and computational burden are key issues that remain in the realization of model predictive control (MPC) of wave energy converters (WECs). In this study, the viscous force is considered in a WEC model, and the accuracy of the model is improved. To solve the problems existing in the practical application of MPC in WECs, an improved model predictive control (IMPC) method with sliding mode control (SMC) is proposed that can reduce the quadratic programming (QP) performance requirements of the processor while maintaining a high energy conversion efficiency. The IMPC method includes two parts: 1) an advance prediction and calculation mechanism is used to provide the optimal control sequence and prediction trajectory, and 2) the SMC is used to compensate the model mismatch to improve the control accuracy. The effectiveness of the IMPC method with SMC was verified through numerical simulations. Highlights: The improved MPC (IMPC) method makes full use of the prediction trajectory and control sequence within the set time range, at the same time it calculates the next prediction trajectory and control sequence in advance. This algorithm can expand the time of calculating the objective function from one sampling time to multiple to reduce the performance requirements of the processor. Considering the influence of model mismatch on the control method, a sliding mode control (SMC) method combined with IMPC is applied to WEC. Simulation results show that the IMPC method with SMC can effectively reduce the impact of model mismatch and reduce the computational burden while maintaining efficient conversion efficiency. The proposed method has wide applicability: we can set the parameters of IMPC offline to adapt to different processors, and set the parameters of SMC offline to adapt to different sea conditions.