This simulation shows the sensorless single-phase back-EMF estimation technique extended to a two-phase (alpha-beta) representation of a 3-phase motor. In addition, an angle demodulator is introduced which takes the estimated sine and cosine back-EMF angles to estimate the angle of the back-EMF vector, which lies on the q-axis. The flux vector will either be leading or lagging the back-EMF vector depending on the direction of rotation of the motor.
The actual back-EMF voltage sources are included in the stationary frame model for each phase, but information about these voltages is known only locally to each phase circuit. It is up to the observers to figure out the exact shape of these EMF signals.
TRANSIENTS: At t=0, the back-EMF observers and the angle demodulator are initiated, and start converging on their respective values.
PLOTS: Back-EMF Alpha, Estimated Back-EMF Alpha, Back-EMF Beta, Estimated Back-EMF Beta, Actual Frequency, Estimated Frequency, Angle Error.
REQUIREMENTS: Spice Executable, Support Pack
Unzip the files for this simulation into the same folder as the files extracted from the Support Pack. Then run "46 Alpha-Beta PMSM Digital Angle Observer.asc"
