| 摘要 |
PURPOSE:To eliminate the phase matching of a counter resetting point of a pulse coder to the zero position of a rotor phase by applying a current responsive to a rotor angle to phases of a motor, and storing the content of rotor angle counting means at that time as an offset value. CONSTITUTION:An absolute code ASC and an incremental code ICC arm provided on a rotary code plate 1a of a pulse coder 1. An incremental pulse is counted, and a counter 1d which is reset each time the absolute code becomes a predetermined value is provided. After the coder 1 is associated with a rotor 2, a current responsive to the zero of the rotor angle is applied to the phases of a motor, and the content of the counter 1d is stored as an offset value thetaOFS in a register 3a when the rotation of the rotor is stopped. A value obtained by subtracting the value thetaOFS from the counted value thetaR of the counter 1d is output as a rotor angle at the time of controlling an AC motor. |
