Power Optimization Of Direct-drive Wave Power Generation System Based On Backstepping Sliding Mode Control

Wave energy is a clean and renewable new energy with high energy density and broad development prospects.It can play an important role in future new energy power generation and play a vital role in the transformation of the world's energy structure to low carbon.However,the wave motion is disordered,random and time-varying,and the wave power generation system controlled by the traditional control method is inefficient and unstable,and it is difficult to commercialize it.This thesis takes the direct-drive wave power generation system as the research object,and proposes a scheme for the purpose of optimizing the power control of the system and realizing the MPPT control.According to Newton's second law and the principle of equivalent circuit,the force of the float is analyzed,and the optimal wave energy capture conditions and the system optimal load formula are obtained.Combined with the mathematical model of the permanent magnet linear motor,the control expectation corresponding to the maximum wave energy capture is obtained.The traditional BP neural network and particle swarm optimization algorithm are applied to the power optimization of the direct-drive wave power generation system,and it is easy to fall into the local optimum.A scheme of crisscross optimization algorithm is proposed.Through the automatic optimization function of the vertical and horizontal cross operators,the shaft current and the electromagnetic force of the motor under the resonance condition of the system are tracked and their optimal values are obtained to realize the optimal control of the system power.Analyze the hydrodynamic equation of the wave energy conversion device,determine the optimal electromagnetic force output under the maximum wave energy power,and take this as the control target of the wave power system;use the space vector modulation current control based on Clark-Park coordinate transformation to achieve Whole system control.Using the backstepping sliding mode variable structure control strategy,combined with the speed outer loop control,the current inner loop control and the Lyapunov function,in view of the irregular,random and multi-disturbance actual sea conditions,the backstepping method reduces the dependence on system parameters and reduces the sliding mode variable structure The chattering phenomenon in the system improves the stability and anti-interference of the system,optimizes the expected current tracking of the system,and realizes the optimal power state tracking control.Based on the environment simulation of Matlab-Simulink,the results show that the control method based on the crisscross optimization algorithm can effectively improve the system wave energy capture efficiency and power output under the irregular ocean wave input environment.The backstepping sliding mode control scheme can realize the maximum wave energy capture control of the wave power generation system under the condition of irregular wave input.Compared with the traditional PI control,it has better control performance.