Analysis of A Linear-Rotary Magnetic Field Modulation Generator for Wave Energy Conversion

In order to solve the problems of low ‘power/volume’ or low ‘power/cost’ caused by the low speed of wave energy converter (WEC), a linear-rotary magnetic field modulation generator (LMFMG) is proposed. The three-dimensional structure and working principle of LMFMG are introduced. The air gap flux density of the magnetic gear screw is calculated to verify the magnetic field modulation principle and the speed-up mechanism. After comparative analysis, the optimized parameters and output parameters of the LMFMG are given. The back EMF, loss and efficiency of the rotary generator are calculated. Through magnetic field modulation, the proposed LMFMG can convert the linear motion of 0.5 m/s into a highspeed rotational motion of 10000 rpm. Compared with the existing WEC, the proposed LMFMG has higher ‘power/volume’ and ‘power/cost’, which makes it very potential in WEC. The prototype is manufactured and the experimental platform is built. The thrust, torque, current and back EMF are measured to verify the theoretical calculation results of LMFMG.