Patent ID: 11860003
Assignee: NIDEC CORPORATION
Field: Electrical machinery, apparatus, energy (Electrical engineering)
Classification: CPC G  H | IPC G  H

Claim 7:
8. The method for signal processing, comprising:
a signal detection step in which N (where N is an integer of 3 or more) sensors each detect a magnetic field which is in accordance with a position of a mover and output a detection signal as an electrical signal, the detection signals being displaced in phase by an angle obtained by dividing 360 degrees by N;
a local maximum/local minimum detection step in which, for the detection signal of each phase, a correction section detects a local maximum and a local minimum for a respective pole pair and a maximum amplitude value and a minimum amplitude value per cycle of electrical angle, over the course of at least two cycles;
a mean calculation step in which, for the detection signal of each phase, the correction section calculates a mean of the maximum amplitude values and a mean of the minimum amplitude values;
an offset calculation step in which the correction section determines an offset correction value to be a maximum-minimum mean value which is calculated from the mean of the maximum amplitude values and the mean of the minimum amplitude values;
a first gain calculation step in which, for each detection signal, the correction section calculates a positive gain correction value for a respective magnetic pole pair that equates the local maximum with a predetermined maximum value;
a second gain calculation step in which, for the detection signal of each phase, the correction section calculates a negative gain correction value for a respective magnetic pole pair that equates the local minimum with a predetermined minimum value; and
a correction step in which, for the detection signal of each phase, the correction section adds the offset correction value, multiplies a positive signal value from a respective magnetic pole pair with the positive gain correction value, and multiplies a negative signal value from a respective magnetic pole pair with the negative gain correction value.