Transcutaneous energy transmission systems (TETSs) use electromagnetic induction to transfer power to an artificial heart. The aim of this study is to develop a TETS where the primary coil is located away from the body. In this case, a fluctuation in the relative position between the primary and secondary coils causes a large change in the output voltage. To stably drive an artificial heart, it is necessary to control the output voltage using feedback control. However, feedback control requires the use of an additional information transmission system in TET circuits. Therefore, we developed a novel method for reducing the fluctuation in the output voltage without using feedback control; this method involved uniformalizing the coupling magnetic coefficient k. As a result, the fluctuation in the output voltage was maintained to within 8.6V. These results suggest that fluctuation in the output voltage can be maintained at a sufficiently low value so as to stably drive an artificial heart without using feedback control.