Position sensor-less vector control is applied to a compressor drive system using an IPMSM to realize higher efficiency. In this paper, a reduction control of cyclic speed change is proposed to achieve the high performance, such as low vibration and low acoustic noise. Designing a speed estimator using an adaptive observer with a wide frequency band, fundamental frequency component of the cyclic speed change is calculated by a band-pass filter. The proposed compensation method recognizing the fundamental component can reduce the cyclic speed change to acceptable level. Principle of the compensation method is presented as well as experimental results.