Washing machine and control method thereof

A control method of a washing machine, which includes a drum, balancer housings mounted on the drum, balancing modules movably disposed in the balancer housings, vibration sensors mounted on a tub, a first position identification unit mounted on the drum, a first position sensor to sense the first position identification unit and to generate a reference signal to detect a position of the unbalance and to detect positions of the balancing modules, second position identification units mounted on the balancing modules, and second position sensors to sense the second position identification units, comprising:

• rotating the drum;
• detecting a vibration value of the tub of the washing machine, when the RPM of the drum has reached a first RPM;
• detecting the position of unbalance applied to the drum and positions of the balancing modules within the balancer housings, when the detected vibration value of the tub is more than a predetermined reference value;
• determining positions of the balancing modules to compensate for the unbalance applied to the drum;
• and
• controlling movement of the balancing modules to the determined positions,
• wherein the detection of the unbalance applied to the drum includes detecting the relative position of the unbalance with respect to the first position identification unit through phase differences between the reference signal of the first position sensor and signals sensed by the vibration sensors.