there is provided an integrated control method for eliminating a low frequency ripple in a power conversion system for a fuel cell , more particularly , a control method of a power conversion system capable of eliminating a low frequency ripple , controlling a dc link voltage , and controlling an output power and a system using the same control method . a power conversion system that converts an output of a dc power supply received from an external power supply includes a converter that converts a voltage of the input power supply ; an inverter that converts an output voltage of the converter into an ac voltage ; and a converter control module that outputs a pwm signal for controlling a switch of the converter , and after receiving a power instruction value , the converter control module generates the pwm signal for controlling the converter based on the power instruction value .