变频压缩机在低频运行时存在较为显著的转速波动。负载转矩的周期性波动导 致转速存在偏差。普通扰动观测器有限的灵敏度增益使得负载扰动抑制性能较差。针对 此问题，本研究采用周期扰动观测器估计负载扰动并进行电流补偿，以减弱低频范围的 转速偏差。周期扰动观测器通过扰动内模实现负载扰动补偿，包括基波和相应的谐波成 分。采用基于 Steiglitz-McBride 方法的自适应陷波器估计周期扰动基波频率。在变频压 缩机实验平台进行实验验证。结果表明: 与普通的扰动观测器相比，自适应周期扰动观 测器能够有效地抑制变频压缩机低频范围的转速波动。

Inverter compressor operating in low frequency range shows apparent speed fluctuation． It is the periodic load torque disturbance that brings about speed offset． The poor performance of periodic load disturbance is caused by the small gain of disturbance observation ( DOB) ． To solve this problem，a periodic disturbance observer ( PDOB) was proposed to estimate load disturbance and compensate current in this paper and attenuate speed deviation in low frequency range． Load disturbance is compensated by PDOB based on internal model theorem，including fundamental and related harmonic components． Adaptive notch filter based on Steiglitz-McBride method was constructed to estimate the fundamental frequency of periodic disturbance． Experiments were carried out on inverter compressor platform and results show that speed fluctuation of can be effectively suppressed by the proposed method comparing with general DOB．