This study examines the application of topology optimization for improving the design of permanent magnet synchronous generators (PMSGs). These generators play a crucial role in power systems due to their efficiency and compact design, yet their performance is influenced by factors such as material use, magnetic field distribution, and mechanical stability. The research explores how structural modifications, guided by optimization techniques, can enhance generator efficiency while reducing weight. The methodology combines finite element analysis (FEA) and sensitivity-based optimization to refine rotor geometry and improve key performance indicators. A case study involving a 5 MW PMSG demonstrates that optimized designs lead to a 16.3% reduction in rotor mass and a 2% increase in efficiency, primarily due to improved magnetic flux distribution and reduced energy losses. These findings highlight the advantages of integrating topology optimization into electrical machine design, contributing to the development of more energy-efficient and cost-effective generators.