| 摘要 |
It is an object of the invention to provide a method which can detect a magnetic pole position easily and surely by using high-frequency currents such as harmonics of an inverter output and carrier frequency components. In the invention, an arbitrary high frequency other than an output frequency of a voltage source PWM inverter is generated in input voltages or currents of a motor by means (6) for producing an arbitrary phase difference between respective two phases such as UV, VW, or WU in the inverter (7), the voltages or currents are converted to a two-phase stationary coordinate system in which U-phase of the motor is alpha-axis and an axis intersecting the axis at 90 deg. is beta-axis, a current of the arbitrary high-frequency component is detected in each of the alpha- and beta-axes, the voltages or currents are converted to a two-phase stationary coordinate system in which a phase is shifted by 45 deg. from the two-phase stationary coordinate system, or in which an axis that is shifted by 45 deg. from the alpha-axis is alpha'-axis and an axis intersecting the axis at 90 deg. is beta'-axis, a current of the arbitrary high-frequency component is detected in each of the alpha'- and beta'-axes, and a magnetic pole position of the motor is detected (12) by using the high-frequency current components that are detected respectively in the four axes.
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