Wireless power transmitter and wireless power transfer method thereof

This specification provides a wireless power transmitter (100) capable of smoothly charging/discharging a resonant current in a manner of a pulse width modulation (PWM) control based on battery voltage information, and a method thereof. A wireless power transmitter disclosed herein includes a power supply unit that supplies an input voltage, a power conversion unit (111) that generates power in a wireless manner based on a driving signal, generated by the supplied input voltage and a first pulse width modulation (PWM) signal, and transfers the wireless power to a wireless power receiver (200), and a power transmission control unit (112) that applies the driving signal to the power conversion unit, wherein the power transmission control unit receives a voltage value of a battery charged with the wireless power through a wireless network (10b), and generates the first PWM signal based on the voltage value of the battery.