Integral sliding-mode flux observer for sensorless vector-controlled induction motors

The control performance of sensorless vector-controlled induction motors mainly relies on an accurate flux estimation. However, due to the variations of electrical parameters, the inaccuracy of estimated fluxes will cause the performance degradation of speed control. In this paper, an integral sliding-mode flux observer is provided to estimate the d-and q-axis fluxes in the stationary reference frame. To certify the closed-loop stability, the stability analysis based on the Lyapunov theory is also presented. In addition to simulations, a DSP/FPGA based experimental platform is setup to evaluate the feasibility of proposed control scheme. Simulations and experimental results illustrate that the responses of flux and speed can be performed as desire by utilizing the integral sliding-mode flux observer in a wide speed range.