| 摘要 |
PURPOSE:To omit adjustment in operation by providing a magnetic flux control loop having a current loop as a minor loop with a magnetic flux simulation circuit, and at the time of executing an operation start test, finding out a value corresponding to an eddy current time constant through a magnetic flux detector and a simulation circuit, and feeding back a simulation value to allow the simulation value to follow a command value. CONSTITUTION:A magnetic flux practical value detected through a magnetic flux detector 12 is compared with a magnetic flux simulation value obtained through a simulation circuit consisting of a multiplier 7B and an integrator 8A, and their deviation is extracted by an adder/subtractor 9A. The deviation is multiplied by the simulation value by means of a multiplier 7A, and the multiplied value is integrated by an integrator 8B, and inputted to the multiplier 7B. The fed-back magnetic flux simulation value obtained from the simulation circuit and the magnetic flux conversion value of a current practical value obtained from a current voltage equivalent circuit 5 are led into an adder/subtractor 9B. At that time, the magnetic flux simulation value is equal to the practical value phi, and can be substituted for the practical value phi. On the other hand, the input of an integrator 8B is supervised by a comparator 11, when the value goes to '0', a switch is opened and the value (a) corresponding to the eddy current time constant is held, so that the detector 12 can be removed at the time of operation.
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