Research on position detection method of large-diameter PMSM based on magnetic encoder

In the operation of large-diameter PMSM system, position detection is the key and difficult point. The large-diameter permanent magnet synchronous motor studied in this paper has a load in the center and there is no bearing at the bottom of the center, which limits the position detection, so the off-axis position detection scheme is adopted. In view of the above factors, this paper proposes a position detection scheme for large-diameter PMSM based on magnetic encoder, designs a magnetic encoder processing circuit, uses an advanced AMR sensor as a magnetic sensing sensor to collect position information, and uses PLL to demodulate the sine and cosine pairs output by the sensor to obtain position information.