Calibration of the initial position angle by back EMF zero crossing method based on DA chip

To obtain the accurate rotor position is the key to vector control of permanent magnet synchronous motor in relation to whether motor rotation and the rotation of the motor efficiency, The initial position angle can be observed directly by the zero crossing method of back EMF, the absolute position sensor gets accurately position angle of the rotor of the rotary transformer. and reuse Y-connected three resistance to obtain the back EMF signal of the motor, the oscilloscope to observe the position difference between the time when the rotor position for the decoding circuit is 0° and A phase back EMF over the zero, which can get permanent magnet synchronous motor rotor initial position. In the permanent magnet synchronous motor drive control system, the experimental verification and application of the method is verified, which proves that the method is, accurate and intuitive, simple programming, Reliable engineering application.