scholarly journals Robust Sliding Mode Control of a Unipolar Power Inverter

Energies ◽  
2021 ◽  
Vol 14 (17) ◽  
pp. 5405
Author(s):  
Muhammad Awais ◽  
Abdul Rehman Yasin ◽  
Mudassar Riaz ◽  
Bilal Saqib ◽  
Saba Zia ◽  
...  

The key issue in the practical implementation of the sliding mode (SM) control–based power inverter is the variable switching frequency. This variable switching frequency not only induces electromagnetic interference (EMI) noise, but also reduces the efficiency of the inverter, as the size of the inductor and capacitor does not alter in tandem with this variable frequency. In this context, fixed switching frequency–based SM control techniques are proposed; however, some of them are too complex, while others compromise the inherent properties of SM control. In this research, a fixed frequency SM controller is proposed, which is based on the novel low-pass filter extraction of the discontinuous control signal. This allows the technique to be implemented with fewer hardware components, thus reducing the complications of implementation, while maintaining the robustness and parametric invariance of SM control. A simulation-based comparison with an existing pulse width modulated (PWM) SM controller is presented as the benchmark. In comparison with the sigmoid function SM controller, an improvement of 50% in the settling time along with zero steady-state errors and a further 37% and 42% improvement in the undershoot and overshoot, respectively, is reported in the simulation. A hardware setup is established to validate the proposed technique, which substantiates the simulation results and its disturbance rejection properties.

2014 ◽  
Vol 5 (1) ◽  
pp. 20-26 ◽  
Author(s):  
Saeed Masoumi Kazraji ◽  
Ramin Bavili Soflayi ◽  
Mohammad Bagher Bannae Sharifian

Abstract The paper presents a sliding-mode observer that utilizes sigmoid function for speed and position sensorless control of permanent-magnet linear synchronous motor (PMLSM). In conventional sliding mode observer method there are the chattering phenomenon and the phase lag. Thus, in order to avoid the usage of the low pass filter and the phase compensator based on back EMF, in this paper a sliding mode observer with sigmoid function for detecting the back EMF in a PMLSM is designed to estimate the speed and the position of the rotor. Most of conventional sliding mode observers use sign or saturation functions which need low pass filter in order to detect back electromotive force (back EMF). In this paper a sigmoid function is used instead of discontinuous sign function to decrease undesirable chattering phenomenon. By reducing the chattering, detecting of the back EMF can be made directly from switching signal without any low pass filter. Thus the delay time in the proposed observer is eliminated because of the low pass filter. Furthermore, there is no need to compensate phase fault in position and speed estimating of linear-PMSM. Advantages of the proposed observer have been shown by simulation with MATLAB software.


Author(s):  
Ali Karami-Mollaee ◽  
Hamed Tirandaz ◽  
Oscar Barambones

Purpose The purpose of this paper is position control scheme for a servo induction motor (SIM) with uncertainty has been designed using a new observer issue and a dynamic sliding mode control (DSMC). Design/methodology/approach In DSMC, the chattering is removed due to the integrator (or a low-pass filter) which is placed before the input control of the plant. However, in DSMC, the augmented system has one dimension bigger than the actual system (if integrator is used) and then, the plant model should be completely known. To solve this problem in SIM, the use of a new adaptive state observer (ASO) is proposed. Findings The advantage of the proposed approach is to maintain the system controlled under the external load torque variations. Then, the load variations do not affect the motor positioning. Moreover, it is demonstrated that the observer error converges to zero based on the Lyapunov stability theory. Originality/value The knowledge of the upper bound for the system uncertainty is not necessary in an adaptive state observer, which is important in practical implementation. Simulation results are presented to demonstrate the performance of the proposed approach.


2020 ◽  
Vol 17 (3) ◽  
pp. 172988142091698 ◽  
Author(s):  
Pengcheng Wang ◽  
Dengfeng Zhang ◽  
Baochun Lu

This article investigates a difficult problem which focuses on the external disturbance and dynamic uncertainty in the process of trajectory tracking. This article presents a robust adaptive fuzzy terminal sliding mode controller with low-pass filter. The low-pass filter can provide smooth position and speed signals. The fuzzy terminal sliding mode controller can achieve fast convergence and desirable tracking precision. Chattering is eliminated with continuous control law, due to high-frequency switching terms contained in the first derivative of actual control signals. Ignoring the prior knowledge upper bound, the controller can reduce the influence of the uncertain kinematics and dynamics in the actual situation. Finally, the experiment is carried out and the results show the performance of the proposed controller.


2014 ◽  
Vol 541-542 ◽  
pp. 1216-1221
Author(s):  
Lin Du ◽  
Fei Lei Jia

Using the bounded sigmoid function and two-order Butterworth low-pass filter, a self-controlling feedback method for regulate the motion of a chaotic system is presented in this paper. It is shown that such controller has the advantage of being easy to implement based on the measurable input signals. A rigorous stability proof is provided from LaSalle Invariance theorem. Furthermore, the effectiveness and efficiency of the proposed feedback control strategy is illustrated by means of the numerical simulations of two-well Duffing Vander Pol oscillator. Finally, the result reveals that the enough large maximum amplitude results in a more possible regular domain in parameter space of the controlled oscillator.


2016 ◽  
Vol 23 (3) ◽  
pp. 458-468
Author(s):  
Jinjin Shi ◽  
Jinxiang Wang ◽  
Fangfa Fu

The chattering phenomenon and a system with both matched and mismatched disturbances are the major difficulties in sliding mode control design. This paper presents an effective design procedure to alleviate these two difficulties for a class of second-order under-actuated mechanical systems. In the proposed design, new hierarchical sliding surfaces are designed and a modified disturbance observer is utilized to estimate the lumped disturbance which is a linear combination of the matched and mismatched disturbances. The chatter in control input is filtered out by an integrator, which acts as a low-pass filter. The asymptotic stabilities of the entire sliding surfaces are guaranteed. A design study considering lateral control of a vehicle with matched and mismatched disturbances demonstrates the effectiveness of the proposed design.


2014 ◽  
Vol 2014 ◽  
pp. 1-12 ◽  
Author(s):  
Suneel K. Kommuri ◽  
Kalyana C. Veluvolu ◽  
M. Defoort ◽  
Yeng C. Soh

This paper presents a speed and position estimation method for the permanent magnet synchronous motor (PMSM) based on higher-order sliding mode (HOSM) observer. The back electromotive forces (EMFs) in the PMSM are treated as unknown inputs and are estimated with the HOSM observer without the need of low-pass filter and phase compensation modules. With the estimation of back EMFs, an accurate estimation of speed and rotor position can be obtained. Further, the proposed method completely eliminates chattering. Experimental results with a 26 W three-phase PMSM demonstrate the effectiveness of the proposed method.


Author(s):  
Sheng-Tao Geng ◽  
Jie Zhang ◽  
Jing-Guang Sun

This paper studies the guidance scheme for the terminal guidance problem subject to input constraints, attack angle constraints, and second-order dynamics of missile autopilot. Firstly, the guidance system model with the above multi-constraint model is given. Secondly, an anti-saturation back-stepping guidance law which makes use of the low-pass filter to avoid the differential of the virtual control signals is designed based on the terminal sliding mode method, auxiliary system, and adaptive technique. Finally, Lyapunov theory and numerical simulations are utilized to prove that the states of the system under the proposed guidance law are uniformly ultimately bounded.


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