The invention provides a power conversion apparatus and a power conversion method thereof. The power conversion apparatus includes: a rectifying unit and a power factor correcting unit. The rectifying unit can be used to rectify single-phase power externally inputted. The power factor correcting unit configured to correct a power factor of the power rectified by the rectifying unit. The power conversion apparatus includes: a control signal generating unit configured to detect a zero-crossing point based on the single-phase power inputted and generate a pulse single of which a width increases as time elapses based on the detected zero-crossing point. The rectifying unit includs a silicon-controlled rectifier thyristor (SCR) for rectifying single-phase power externally inputted. The control signal generating unit includes a signal detection device configured to detect the single-phase power, a single-phase PLL configured to detect the zero crossing point based on the single-phase power detected by the signal detection device, and to generate the carrier signal based on the detected ZCP, and a PWM generator configured to compare the reference signal and the generated carrier signal in order to generate the pulse signal.