A washing machine comprising: a housing including an inlet for laundry disposed on a front surface thereof; a water tub provided inside of the housing and configured to store water; a drum provided inside of the water tub and configured to rotate; a pulsator provided inside of the drum and configured to rotate independently of the drum; a motor comprising a single stator, a first rotor installed inside of the stator and connected to the drum, and a second rotor installed outside of the stator and connected to the pulsator; a phase detector configured to detect a phase difference between the first rotor and the second rotor; and at least one processor configured to: rotate the first rotor and the second rotor in directions opposite to each other, calculate the phase difference detected by the phase detector, apply a q-axis current to the stator to rotate the first rotor, and apply a d-axis current to the stator to rotate at least one of the first rotor or the second rotor based on the phase difference between the first rotor and the second rotor; and characterised in that: the at least one processor is further configured to apply a predetermined magnitude of d-axis current to the stator based on a forward and reverse rotation operation, and wherein the forward and reverse rotation operation is performed by: (i) performing a forward rotation operation rotating the first rotor and the second rotor in directions opposite to each other, and (ii) performing a reverse rotation operation in a direction opposite to the forward rotation operation, the reverse rotation operation rotating the first rotor and the second rotor in directions opposite to each other. a housing including an inlet for laundry disposed on a front surface thereof; a water tub provided inside of the housing and configured to store water; a drum provided inside of the water tub and configured to rotate; a pulsator provided inside of the drum and configured to rotate independently of the drum; a motor comprising a single stator, a first rotor installed inside of the stator and connected to the drum, and a second rotor installed outside of the stator and connected to the pulsator; a phase detector configured to detect a phase difference between the first rotor and the second rotor; and at least one processor configured to: rotate the first rotor and the second rotor in directions opposite to each other, calculate the phase difference detected by the phase detector, apply a q-axis current to the stator to rotate the first rotor, and apply a d-axis current to the stator to rotate at least one of the first rotor or the second rotor based on the phase difference between the first rotor and the second rotor; and characterised in that: the at least one processor is further configured to apply a predetermined magnitude of d-axis current to the stator based on a forward and reverse rotation operation, and wherein the forward and reverse rotation operation is performed by: (i) performing a forward rotation operation rotating the first rotor and the second rotor in directions opposite to each other, and (ii) performing a reverse rotation operation in a direction opposite to the forward rotation operation, the reverse rotation operation rotating the first rotor and the second rotor in directions opposite to each other. rotate the first rotor and the second rotor in directions opposite to each other, calculate the phase difference detected by the phase detector, apply a q-axis current to the stator to rotate the first rotor, and apply a d-axis current to the stator to rotate at least one of the first rotor or the second rotor based on the phase difference between the first rotor and the second rotor; and characterised in that: the at least one processor is further configured to apply a predetermined magnitude of d-axis current to the stator based on a forward and reverse rotation operation, and wherein the forward and reverse rotation operation is performed by: (i) performing a forward rotation operation rotating the first rotor and the second rotor in directions opposite to each other, and (ii) performing a reverse rotation operation in a direction opposite to the forward rotation operation, the reverse rotation operation rotating the first rotor and the second rotor in directions opposite to each other. the at least one processor is further configured to apply a predetermined magnitude of d-axis current to the stator based on a forward and reverse rotation operation, and wherein the forward and reverse rotation operation is performed by: (i) performing a forward rotation operation rotating the first rotor and the second rotor in directions opposite to each other, and (ii) performing a reverse rotation operation in a direction opposite to the forward rotation operation, the reverse rotation operation rotating the first rotor and the second rotor in directions opposite to each other. (i) performing a forward rotation operation rotating the first rotor and the second rotor in directions opposite to each other, and (ii) performing a reverse rotation operation in a direction opposite to the forward rotation operation, the reverse rotation operation rotating the first rotor and the second rotor in directions opposite to each other.