Although the structure of brushless dc motor is similar to the one of permanent magnet synchronous motor, its operating characteristics are the same as those of permanent magnet dc motor. These are the reasons that the commutators and brushes in the permanent magnet dc motor can be replaced by the power semiconductor devices and rotor positioning sensors for the brushless dc motor.
This thesis, using the resolver as the rotor positioning sensor, presents how simply a current controller can be designed to make a sinusoidal current waveform for constant torque generation and accurate positioning control.
