This article proposes a parameter design method based on natural frequency configuration, which enables the system to achieve approximately constant voltage output characteristics independent of load under the expected frequency operating conditions. Firstly, the natural frequency calculation method of the system was obtained by solving the eigenvalues of the second-order time-domain model of the system. Subsequently, a parameter configuration constraint equation was established for the parameter design method, and the approximate constant voltage output of the system at the expected operating frequency was obtained. And the constant voltage characteristic of the system at the designed frequency was verified by theoretically calculating the voltage gain expression of the system. Finally, the correctness of this method was verified through circuit simulation.