A method is provided for operating a resonant power conversion apparatus The method may include charging a capacitor connected to a power source in parallel, and determining a discharge time point and a discharge period of a discharge circuit, where the discharge circuit includes a resistor and a switch connected in series and is connected to the capacitor in parallel. The method may also include outputting, by a switch control circuit, a switch control signal by determining the switch control signal based on the discharge time point and the discharge period, and discharging the charged capacitor through the resistor based on the switch control signal applied to the switch. A resonant power conversion apparatus for performing the above-described method is provided.