Developing marine resources (such as abundant wind energy and wave energy) is an inspiring way to ease the global fossil energy crisis. In this paper, a wind-wave combined energy conversion (WWCEC) system based on a linear-rotary generator is introduced. The corresponding novel double-stator linear-rotary permanent magnet generator (DSLRPMG) is presented, and its multi-objective optimization of key structural parameters is finished based on TOPSIS decision making to enhancing no-load back-electromotive force (BEMF), decreasing the cogging torque, detent force and total harmonic distortion (THD) of BEMF. The specific optimization process is given, including the sensitivity analysis of different structure variables and the weight coefficients determination of different optimization objects. The optimized and performances are exhibited through finite element calculation finally, which prove that the multi-objective optimization of the DSLRPMG is achieved, and the decision-making results are reasonable.

renewable energy generation， wind energy generation， wave energy generation， two-degree-of-freedom generator， optimization design