Patent ID: 8115445

Claim:
An operation control method for a variable speed generator-motor including a power fluctuation suppression circuit that causes a torque direction excitation current command value to be fixed to a value immediately before switching to follow a torque direction excitation current command target value calculated by a predetermined conversion circuit, filter circuit, and limiter circuit from an effective power during operation control using a synchronous operation method, the method comprising: exciting a secondary winding of a variable speed generator-motor whose primary winding is connected to a power system by a three-phase AC excitation current obtained by vector-synthesizing, based on a torque direction excitation current command value obtained by effective power adjustment computing to make zero deviations between a command value of an input/output effective power and detection value of an effective power of the variable speed generator-motor, a slip phase equivalent to a difference between a voltage phase of the power system and a rotation phase of the variable speed generator-motor, and a magnetic flux direction excitation current command value obtained by voltage adjustment computing to make zero deviations of a command value of an output voltage and detection value of an output voltage of the variable speed generator-motor; and operating to switch, by a synchronous operation Iq switching control circuit under arbitrary conditions, a variable speed operation method for controlling an excitation current by utilizing two components of a torque direction excitation current component and a magnetic flux direction excitation current component, and a synchronous operation method for changing over the torque direction excitation current command value to a value immediately before switching an operation method and at the same time for changing over a slip phase to a sine wave fixed to a slip frequency immediately before switching an operation method and for performing the control by an excitation current with a constant frequency.