Theoretically, brushless motor should be a rectangular wave voltage and current waveform, the back emf waveform should be rectangular wave, such a brushless motor with a ordinary mechanical characteristics of motor, with a big start torque, speed fast, dynamic braking is simple, high efficiency, etc. Square wave motor is just get trigger point location information and position sensor is relatively simple, as long as with hall element to be able to do. Brushless motor counter electromotive force is sine wave and sine wave, sine wave brushless motor all-the-way tracking the position of the rotor, so as to obtain the synchronization with the rotor magnetic field sine position signal, position sensor is more complicated, such as using rotating transformer, such as grating encoder, now due to the emergence of advanced control technology, with hall element, without hall element or without complex sensor can achieve the purpose of sine wave control, but control technology for complex wave brushless motor
