Patent ID: 8610389

Claim:
A speed control apparatus for a switched reluctance motor (SRM) comprising: a current control unit generating a command current corresponding to a deviation between a command speed and an estimation speed of a rotor in a sensorless control period and generating a command current corresponding to a magnetic flux error in an open-loop control period; a driving unit calculating a period in which a voltage is applied to each phase of the SRM using the command current output from the current control unit and a rotor estimation position and generating a pulse width modulation (PWM) signal to allow the voltage to be applied to the SRM; a magnetic flux error calculating unit receiving a command position according to the command speed and a detected voltage and current of the SRM to calculate the magnetic flux error in the open-loop control period and receiving the estimation position and the detected voltage and current of the SRM to calculate the magnetic flux error in the sensorless control period; a rotor position estimating unit receiving the magnetic flux error from the magnetic flux error calculating unit and calculating the estimation speed of the rotor using the received magnetic flux error to output the calculated estimation speed to the current control unit and calculating the estimation position using the received magnetic flux error to output the calculated estimation position to the magnetic flux error calculating unit; and a mode change-over unit allowing a command current corresponding to the magnetic flux error to be transferred from the current control unit to the driving unit and allowing the estimation position output from the rotor position estimating unit to be input to the magnetic flux error calculating unit in the open-loop control period according to a speed of the SRM and allowing a command current corresponding to the deviation between the command speed and the estimation speed of the rotor to be transferred from the current control unit to the driving unit and allowing a command position corresponding to the command speed to be input to the magnetic flux error calculating unit in the sensorless control period.