| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a control method that can stably rotate a synchronous motor in synchronism with output frequency, even if a large phase error exists between an actual rotation axis and a control rotation axis. <P>SOLUTION: A phase error computing part 61 determines the phase difference between the motor current and the actual rotation axis as a first phase difference based on the size of the motor current, the size of the motor voltage, the phase difference between the motor current and the motor voltage, and electric constants of the motor. The phase difference between the motor current and a virtual rotation axis is found as a second phase difference. With the difference between the first phase difference and the second phase difference set as a phase error Δθ, the estimated position is corrected so that Δθ becomes zero. As a result, the phase error Δθ is found from values which do not depend on the position of the control rotation axis so that a proper position sensorless control system may be achieved, even if the phase error is large. <P>COPYRIGHT: (C)2004,JPO |
