| 摘要 |
PURPOSE:To perform efficient degaussing and demagnetization in a short time, by performing open loop control until magnetic flux generated in a structure reaches a prescribed amount less than a set magnetic flux and performing feedback control afterward. CONSTITUTION:To a computer 9, a magnetic flux set value theta0, a magnetic feedback FB value thetat, a switching constant alpha, and an expected current-magnetic flux conversion coefficient K are inputted, a proportional and integrating arithmetic at an open loop controlling region is executed and a current command Ip is outputted to a constant current controller ACR5. The ACR5 flows a current in which the polarity is alternately inverted in accordance with the command Ip to a coil 2 wound around the structure 1. The magnetic flux theta of the construction 1 is measured at a magnetism detector 6 and the current is increased in a fixed accelerating rate by the open loop control until the FB magnetic flux thetat reaches a switching schedule theta0(1-alpha). The relation between the constant alpha and the weight of the construction is listed as a table in advance, and when the magnetic flux thetat reaches the theta0(1-alpha), the control is automatically switched into the FB control, allowing to reduce the overshoot of the magnetic flux generated in the construction. |
