| 摘要 |
<p><P>PROBLEM TO BE SOLVED: To generate a magnetic field having a plurality of wavelengths. <P>SOLUTION: Excitation coils 16A-16F of a surface layer coil group 16 are arranged two-dimensionally, and excitation coils 18A-18F of a back layer coil group 18 are arranged two-dimensionally while being shifted byτ/6 in the arranging direction of coil for the excitation coils 16A-16F. An inverter 20 for surface layer supplies three-phase currents of a U phase, a V phase and a W phase, respectively, to the excitation coils 16A-16F, and an inverter 22 for back layer supplies three-phase currents of an R phase, a S phase and a T phase having phase differences for the three-phase currents generated from the inverter 20 for a surface layer, respectively, to the excitation coils 18A-18F. A magnetic field having different spatial harmonics is generated by altering the connection state of the excitation coils 16A-16F, 18A-18F and the inverters 20, 22 for surface and back layers, and altering the phase difference between the U, V, W phases and the R, S, T phases. <P>COPYRIGHT: (C)2007,JPO&INPIT</p> |
