| Popis: |
In recent times, interior permanent magnet synchronous motors (IPMSMs) with high efficiency have been used in various applications. However, IPMSMs generate torque ripple and acoustic noise due to a radial electromagnetic force. In particular, the acoustic noise needs to be suppressed in applications where low noise levels are required. In this paper, the suppression of the 6th‐ and 12th-order radial electromagnetic forces, which contribute significantly to acoustic noise, is discussed. The relationship among the armature current, the permanent magnet of the rotor, and the radial electromagnetic force of the IPMSM is clarified. Moreover, the compensation current required to suppress the 6th‐ and 12th-order radial electromagnetic forces is derived. In addition, a method to suppress the 6th‐ and 12th-order radial electromagnetic forces is proposed through the feedforward addition of the compensation voltage calculated from the compensation current to the voltage command of the drive system based on a sinusoidal current tracking control. By setting the gain of the sinusoidal current tracking control as low as possible, the voltage command produced by the current control system is maintained low, and a margin is provided for adding a compensation voltage to suppress the radial electromagnetic forces. The effectiveness of the proposed feedforward voltage compensation method is verified by the results of frequency analysis of the sound produced by an IPMSM. In addition, the superiority of the proposed sinusoidal current tracking control is confirmed by comparison with the frequency analysis of the sound produced by a $d-q$ axis current controlled motor. |
