Observability Study and Observer-Based Interconnected Form for Sensorless Induction Motor

On Sensorless Induction Motor Drives: Sliding-Mode Observer and Output Feedback Controller

“…In [9], we have demonstrated that IM observability cannot be established in the particular case when the fluxes φ rα , φ rβ and the speed ω r are constant even if the higher derivatives of outputs are used. This operating case coincides with the following physically interpretations: 1) when the fluxes are constant (φ rα =φ rβ = 0), or equivalently the excitation voltage is zero (ω s = 0), it implies that: pω r +…”

“…On the other hand, removing the speed sensors affects the IM observability property at very low speed. Important contributions in this direction have been reported in [9], where under some operating conditions (low speed) the IM is not observable. Furthermore, strategies based on IM spatial saliency methods with fundamental excitation and high frequency signal injection [12], extended Kalman filter techniques and adaptive system approaches [18] have been studied.…”

“…Furthermore, strategies based on IM spatial saliency methods with fundamental excitation and high frequency signal injection [12], extended Kalman filter techniques and adaptive system approaches [18] have been studied. The sensorless control of IM allowing operation at very low speed can also be found in [7], [8], [9], [10], [13], [21].…”

On sliding mode and adaptive observers design for multicell converter

“…We can remark that (13) is on the form of affine systems ( [7], [8]) where the matrix A(u) = A is constant.…”

“…The first one is based on the supertwisting algorithm ( [3], [10]) and the other one is based on an adaptive approach ( [7], [8]). Both observers allow to estimate the voltage across the capacitors in a multicell converter using only the current load and the voltage of the source.…”