| 摘要 |
PURPOSE:To perform torque control surely without raising the capacity of a microcomputer inside a device. CONSTITUTION:A magnetic pole position detecting circuit 9 outputs magnetic pole position signals S1, S2, and S3, based on the induced voltages V1, V2, and V3 of a brushless motor 6A. A torque command output circuit 11 outputs a torque command to a base driver 5, based on these signals S1, S2, and S3 and the detection signal ID from a current detecting circuit 12. In this case, since there is such a corresponding relation that the number of cylinders of a compressor 8A is n, when the number of magnetic poles of the rotor of the brushless motor 6A is 2n (n=2, 3), the cycle of the magnetic pole position signal S1 accords with the cycle of the load ripple of the compressor 8A. Accordingly, even in the number of magnetic poles of the brushless motor 6A becomes four or six, a torque command output circuit 11 has only to output a torque command, on the basis of only the magnetic pole position signal S1, similar to the case of two poles. |
