Square-wave drive is the simplest drive method. It rotates a rotor by switching the ON/OFF state of the power element according to the rotation angle of the rotor and then changing the current direction of the stator coil.
When the rotor is rotated once, the current direction is switched 6 times.
This method is the same as the driving principle of a brushed DC motor.
The motor drive uses an inverter circuit to control the voltage with PWM.
It is the most widely used drive method for sensorless motors.