Patent ID: 7626352
Filing Date: 2009-12-01
Classification: H02P

Abstract:
1. A control device for a stepping motor that determines, on the basis of a rotor position command (θ com ) for indicating a position of a rotor and a rotor position (θ fb ) as an actual position of the rotor, a phase (θi) of a winding current command, which commands an electric current fed to a winding, and forms current commands (I acom and I bcom ) for respective phases on the basis of the winding current command phase (θi), the control device comprising: positional-deviation calculating means for calculating a deviation (δ rotor-speed-command calculating means for calculating a rotor speed command (ω rotor-speed calculating means for calculating rotor speed (ω speed-deviation calculating means for calculating a deviation (δ fixed-value generating means for generating a positive fixed value (+K) and a negative fixed value (−K) when the positional deviation is positive and negative, respectively; first judging means for judging whether the positional deviation is within a predetermined range; second judging means for judging whether a sign of the positional deviation and a sign of the speed deviation coincide with each other; and phase setting means for setting the winding current command phase on the basis of the rotor position command, when the positional deviation is within the predetermined range, setting the winding current command phase on the basis of a value obtained by adding up the rotor position, the fixed value, and a lead angle correction value corresponding to the rotor speed when the positional deviation exceeds the predetermined range and a sign of the positional deviation and a sign of the speed deviation coincide with each other, and setting the winding current command phase on the basis of a value obtained by adding up the rotor position, the fixed value, a lead angle correction value corresponding to the rotor speed, and the speed deviation multiplied by a predetermined constant (K