Papers by Keyword: Sliding Mode Observer (SMO)

Abstract: In this paper, a new sensorless speed control strategy which is based on a new sliding-mode observer (SMO) is proposed for permanent-magnet synchronous motor (PMSM). The rotor position is estimated by the back electromotive force (EMF). In order to improve the estimation accuracy, the speed estimator is proposed, which replace the method of direct differential. The Lyapunov theory is applied to prove the stability of the designed system. The simulation results indicate that the proposed sensorless speed control system of permanent-magnet synchronous motor based on a new sliding-mode observer is effective and feasible.

Abstract: In order to achieve sensorless control for permanent magnet linear synchronous motor (PMLSM) direct drive system, speed and position of the motor must be estimated. A new high speed sliding mode observer (SMO) is proposed for a PMLSM based on the sliding mode variable structure theory. A Sigmoid function is used for the SMO as a switching function of the control law, eliminating sliding mode chattering and improving its response rate. Simulation results show that the proposed SMO based on Sigmoid function is capable of estimating speed and position of the motor accurately and rapidly, and the proposed PMLSM sensorless control system has a good dynamic response.

Abstract: According to the phase delaying question of estimated rotor position angle in traditional sliding mode observer, using fractional order calculus theory and singular perturbation two-time-scale decomposition theory, making up the parameter designing rules of fractional order PD sliding mode observer, proposed position sensorless control strategy for permanent magnet synchronous motor based on fractional order PD sliding mode observer. On one side, taking fast time-varying subsystem of singular perturbation two-time-scale decomposition theory to establish fractional order sliding mode observer; on the other side, taking slow time-varying subsystem of singular perturbation two-time-scale decomposition theory to obtain parameter of fractional order sliding mode observer. The results show that the method could not only making estimated rotor position angle follow actual rotor angle, but also establishing a global compensating control strategy of estimated rotor position angle effectively.

Abstract: This paper introduces an improved sliding mode observer for sensorless control of PMSM. In order to reduce the chattering phenomenon of traditional sliding mode observer, replace the ideal switching function with sigmoid function and use two-stage low frequency filter. At last, the simulation was done to verify the measures.

Abstract: A novel sliding mode observer(SMO) of PMSM(permanent magnetic synchronous motor) was presented, which estimated the rotor position and angular velocity accurately.The proposed SMO substitutes a sigmoid function for the conventional signum function with a variable boundary layer which is changed according to the rotational velocity.The dependence to motor parameters and chattering effects that is commonly found in signum function using for the switching function were overcome.By combining the model of PMSM under d-q coordinate,the convergence condition of observer was deduced.The convergence was verified by the Lyapunov theory.Simulation results show that the rotor position and velocity can be observed accurately,and also has good dynamic performance and robustness.

Abstract: The key issue of feedback torque calculation in BLDCM-DTC system is how to get the accurate estimation of back-emf. The influences form the deviation of resistance and inductance on traditional back-emf sliding mode observer (SMO) and relevant torque observation results are analyzed. To advance the accuracy of the torque estimation, an adaptive sliding mode observer is designed to estimate the back-emf of the BLDCM and then get torque estimation from the back-emf estimation. The proposed sliding mode observer can also implement the online identification of the stator resistance and inductance simultaneously. Simulation results demonstrate the proposed method is valid and effective.

Abstract: The study of the application of the sliding mode observer method that estimates the state of charge. Based on the state space model of battery established on the model of improved EMF equivalent circuit, a sliding mode state observer is designed to help improve the jitter problem. Considering the nonlinear terms in the model for the analysis of the stability of the observer and the characteristics of the industry under its derivative, and using Lagrange mean value theory to guarantee the convergence conditions of the observer, the design parameters of the observer can thus be determined .Then, this thesis compares the simulation of this method under Matlab environment with the extended Kalman filter method. The results show that the method has higher estimation accuracy in the case of the same battery modeling errors. Therefore, the SOC estimation of the sliding mode observer can effectively reduce the state of charge estimation error introduced by the model error.

Abstract: Direct torque control (DTC) which replaces the conventional current loop with torque loop can directly control the electromagnetic torque in order to reduce the torque error within the hysteresis bandwidth, and it can attenuated commutation torque ripple and the torque ripple of brushless DC (BLDC) motor with un-ideal back electromotive force (EMF) waveforms. Further, the key issue of feedback torque calculation in torque loop is the estimation of back-EMF in sensorless DTC of BLDC motor. So a sliding mode observer (SMO) is employed to estimate the back-EMF in real time. The torque and rotor speed can be derived from the estimated back-EMF. Simulation results demonstrate the proposed method is valid and effective.

Abstract: In order to improve the dynamic performance of PMLSM, an adaptive robust controller is presented. Meanwhile, the stability of the system is proved by Lyapunov stable theory. The presented controller contains no other motor parameters except state variables. S-function based sliding mode observer is proposed to achieve the estimation of motor speed. The introduction of S-function in the observer can solve the chattering phenomenon caused by traditional sliding mode observer, and solve the amplitude and phase error caused by low-pass filter. Finally, simulation results verify the effectiveness of the proposed control scheme.

Abstract: In order to improve the torque control performance of permanent magnet synchronous motor, variable frequency variable speed control technology, vector control technology, direct torque control technology and sensorless control technology were analyzed. The fuzzy + PID control technology used in permanent magnetic synchronous motor was introduced in detail. The conventional sliding mode observer based on the counter electromotive force estimate control technology and the structure of improved sliding mode observer was given separately. The fuzzy + PID control technology and improved sliding mode observer control technology proposed could improve the dynamic performance and static performance of the permanent magnet synchronous motor.