ANALYSIS OF ELECTROMAGNETIC FORCE OF THE LINEAR GENERATOR IN POINT ABSORBER WAVE ENERGY CONVERTERS

In recent decades energy shortage and environmental pollution have increasingly become challenges faced by the world. New innovation technology to harness renewable energy such as wave energy is considered to be the key to solve this problem. Point absorber wave energy converter (WEC) is one of the most effective means to utilize wave energy. Several different types of power take off (PTO) devices have been used in the design of point absorber WEC amongst which linear generator has the advantages of direct drive, structural simplicity, high-efficiency and so on. This paper studies the electromagnetic force of the linear generator, and the responses of point absorber WEC with line generators. An analytical model is built to simulate the electromagnetic force of a linear generator. Finite element method (FEM) and empirical equation are used to calculate the electromagnetic force, magnetic flux and vector field of magnetic induction. Comparison between the results from FEM and the analytical method shows great agreement. By using analytical model of electromagnetic force of linear generator, the motion equations of the WEC are developed and the dynamic responses of the whole WEC system are obtained. This work is helpful for designing WEC and understanding of the motion mechanism.