METHOD FOR REDUCING ERROR IN ROTOR SPEED MEASUREMENTS

摘要

The method of reducing error in rotor speed measurement includes synchronously measuring a rotor having a target including at least one geometric imperfection. Time intervals for the passing of each tooth of a rotor are stored in a circular buffer memory array. Speed is always determined by extracting the time for a complete revolution, so that geometric imperfections and asymmetry of the rotating target do not influence the speed determination, which is always representing the average speed over the latest complete revolution.

主权项

1. A method measuring rotor speed, comprising:
positioning a sensor opposite a target, said target including a plurality of features; measuring a period corresponding to time between each of said plurality of features on said target passing said sensor; establishing an array of said periods, said array including up to a preselected number of said periods; removing old periods from said array when new periods are added and said preselected number of periods is reached; calculating an average period from a subset of said periods in said array, said average period corresponding to one of a complete revolution or a multiple of complete revolutions; and, calculating rotational speed of a rotor from said average period.