Voltage Model Rotor Flux Observer of Induction Motor Based on Second-order Variable Gain Sliding Mode
For the sensorless induction motor(IM)drive system,the second-order sliding-mode-based(SOSM)voltage model observer can effectively improve the robustness of speed estimation compared with the conventional open-loop voltage model observer.However,the existing SOSM-based voltage model observer still suffers from the problems of the following two aspects:1)the mismatch problem between the fixed-value of SOSM observer gains and the variable stability condition;2)the nonideal integrator problem due to the existence of dc offset.To cope with these two problems,this paper proposes the corresponding solutions:1)to achieve wide-speed stability and chattering suppression,the SOSM observer structure is modified,and a variable gain is designed according to the stability condition;2)to improve the accuracy of rotor flux estimation,an integrator with DC offset compensation is proposed based on the output of sliding-mode observer.Finally,the effectiveness of the proposed method is verified by the contrast experiments carried out on a 3.7 kW IM experimental setup.
induction motor(IM)sensorless controlvoltage model observersliding-mode observerDC offset compensation