Method and apparatus for hysteresis control

A hysteresis control apparatus comprising:

• a reference value setting section that sets an arbitrary reference value which serves as a reference for deciding an existing position of a control width in a control section of a plurality of control sections which are input value operating variation widths having hysteresis control sections at both ends;
• a difference detection section that calculates a difference between an input value this time and the arbitrary reference value in the control section to which a preceding input value belongs;
• a position information generation section that generates position information indicating a positional relationship between the input value this time and the arbitrary reference value in the control section to which the preceding input value belongs from the difference result calculated by said difference detection section;
• a control width selection section that selects the control width in the control section to which the preceding input value belongs;
• an input value variation width calculation section that calculates an input value variation width extending over control sections from the difference result calculated by said difference detection section and the control width selected and output by said control width selection section;
• and
• a control value output section that calculates a control value for the input value this time from the input value variation width and a direction of increase/decrease from a control value in the control section to which the preceding input value belongs obtained from the position information.