Experimental and computational results of direct energy converters (DECs) for advanced fueled fusion such as D-3He are presented. Kinetic energy of thermal component of end loss plasma is converted to electricity by using the Cusp DEC. The proof-of-principle experiments of a single slanted cusp have been carried out and verified the faculty of the configuration. To improve a separation of electrons from ions, numerical simulation shows a Helmholtz magnetic configuration with a uniform magnetic field is more effective than the Cusp DEC. The fusion-produced high-energy ions like 15 MeV protons in D-3He fueled fusion can pass through the Cusp DEC without disturbing their orbits and enter a traveling-wave direct energy converter (TWDEC). Small scale experiments have shown the effectiveness of the TWDEC and the numerical simulation on optimization of interval of electrodes in a decelerator gives high conversion efficiency up to 60 %.