摘要 |
A command rotation speed is set to an initial rotation speed (S2), and a forced commutation mode is started (S3). In the forced commutation mode (S3), a rotation speed is increased by a predetermined increase amount each time (S5) and forced commutation is executed until the rotation speed reaches a set rotation speed (S4). Then, a switchover to the sensorless control mode is made (7) when the rotation speed reaches the set rotation speed (S4) and a rotor position becomes detectable (S6). |