In this paper, a novel integrated multi-model optimization method is presented to improve the accuracy and practicality of the motor structure optimization for free-piston Stirling generator (FPSG). The imprecision of present studies is mainly due to the over-simplification of the coupling relationship between Stirling engine and motor. In proposed method, the thermodynamics, hydrodynamics, dynamic, and electromagnetic model of Stirling engine and motor are established and integrated. Based on it, the influence of the motor such as load force and mess on the stability, stroke, and frequency characteristic of the whole system can be considered adequately. Furthermore, the conformal transformation is applied to increase the computational efficiency. The optimization of the motor structure is carried out using the method. According to the results, the motor can reach a power density of 115.67w/kg. Finally, the proposed method is verified by the finite element analysis and the towing test bench.
