Hybrid terminal sliding mode observer design method for permanent magnet synchronous motor control system
ABSTRACT This paper proposes a hybrid terminal sliding mode observer based on the nonsingular terminal sliding mode and the high-order sliding mode for the rotor position and speed estimation in the permanent magnet synchronous motor control system. A nonsingular terminal sliding mode manifold is utilized to realize both fast convergence and better tracking precision. Meanwhile, a high-order sliding mode control law is designed to guarantee the stability of the observer and eliminate the chattering. Therefore, the smooth back electromotive force (EMF) signals can be obtained without a low pass filter. According to the back EMF equations, the rotor position and speed can be calculated. Simulation results show that, compared to the conventional sliding mode observer, the hybrid terminal sliding mode observer avoids the phase lag in the back EMF signals, and improves the estimation precision of the rotor position and speed.
- SourceAvailable from: Jia-Jun Wang05/2011; 6(5):819-825. DOI:10.4304/jsw.6.5.819-825
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ABSTRACT: In this paper, we develop a fuzzy sliding mode technique to control the field-oriented synchronous machine and to estimate the motor speed. The sliding mode controller (SMC) is designed for a class of non linear dynamic systems to tackle the problems with model uncertainties, parameter fluctuations and external disturbances. In SMC, the high frequency chattering phenomenon results from the discontinuous term in traditional sliding mode control is highly undesirable. In this paper we use the fuzzy logic to reduce the chattering phenomena. The system stability analysis is carried out using Lyapunov stability theorem. An asymptotically stable observer is designed to overcome the problem of speed sensor and is obtained without affecting the overall system response. The simulation results show the effectiveness of the proposed control strategy with desired tracking accuracy and robustness.
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ABSTRACT: In objectbased video representation, video scenes are composed of several arbitrarily shaped video objects (VOs), defined by their texture, shape and motion. In errorprone communications, packet loss results in missing information at the decoder. The impact of transmission errors is minimised through error concealment. In this paper, we propose a spatial error concealment technique for recovering lost shape data. We consider a geometric shape representation consisting of the object boundary, which can be extracted from the -plane. Missing macroblocks result in a broken boundary. A Bspline curve is constructed to replace a missing boundary segment, based on a T spline representation of the received boundary. We use Tsplines because they produce shapepreserving approximations and do not change the characteristics of the original boundary. The representation ensures a good estimation of the first derivatives at the points touching the missing segment. Applying smoothing conditions, we manage to construct a new spline that joins smoothly with the received boundary, leading to successful concealment results. Experimental results on object shapes with different concealment difficulty demonstrate the performance of the proposed method. Comparisons with prior proposed methods are also presented.IEEE Transactions on Image Processing 04/2012; 21(8). DOI:10.1109/TIP.2012.2192850 · 3.11 Impact Factor