An inverter apparatus is provided. The inverter apparatus includes a direct current to direct current (DC/DC) converter, a direct current to alternating current (DC/AC) converter and a control circuit. The DC/DC converter is arranged for converting an input power to a DC power according to a control signal. The DC/AC converter is coupled to the DC/DC converter, and is arranged for receiving the DC power, and generating an AC power according to the DC power. The control circuit is coupled to the DC/DC converter, and is arranged for generating the control signal according to a reference power and the input power so as to control an operation of the DC/DC converter, detecting the control signal to generate a detection result, and controlling the reference power according to the detection result so as to adjust a duty cycle of the control signal.