scholarly journals A control method for parallel inverters in Microgrid based on sliding mode and droop controls

2016 ◽  
Vol 19 (1) ◽  
pp. 40-50
Author(s):  
Hoa Thi Xuan Pham ◽  
Huy Minh Nguyen
Keyword(s):  
Closed Loop ◽  
Control Method ◽  
Sliding Mode ◽  
Tracking Error ◽  
Harmonic Component ◽  
Voltage Control ◽  
Nonlinear Loads ◽  
Proportional Integral ◽  
Pr Controller ◽  
Islanded Microgrid

Robust control and flexible operation are the major objectives of islanded microgrid. A microgrid can have different configurations with linear loads and nonlinear loads. The harmonic current caused by nonlinear loads make Proportional Integral (PI) or Proportional Integral Derivative (PID) voltage controller far beyond excellent performance in case of microgrid operating in islanded mode. Additionally, the robustness of the PID closed loop system can not be guaranteed. The voltage control by using Proportional resonant (PR) controller are recommended. Although PR controller has the ability to sinusoidal signals. However, PR controller has a slight deviation of the frequency of selected harmonic component. This paper presents a Sliding Mode Control (SMC) for voltage control of parallel inverters operating in islanded microgrid. This controller can enhance the robustness of control system and reduced-state tracking error. The stability of the closed-system is verified by means of Lyapunov stability criterion. The control structure is based on the inner sliding mode closed-loop and the outer droop control loop. The main aim of this paper is to design inner controllers to enhance the dynamics of the microgrid. The results obtained from the simulation of Matlab.

The Simulation Analysis of Semi-Active Suspension System in Vehicle Based on Sliding Mode Control with Varying Structure

2011 ◽  
Vol 216 ◽  
pp. 96-100
Author(s):  
Jing Jun Zhang ◽  
Wei Sha Han ◽  
Li Ya Cao ◽  
Rui Zhen Gao
Keyword(s):  
Control Method ◽  
Simulation Analysis ◽  
Reference Model ◽  
Sliding Mode ◽  
Tracking Error ◽  
Active Suspension ◽  
Suspension System ◽  
Sliding Mode Controller ◽  
Error Dynamics ◽  
Dynamic Quality

A sliding mode controller for semi-active suspension system of a quarter car is designed with sliding model varying structure control method. This controller chooses Skyhook as a reference model, and to force the tracking error dynamics between the reference model and the plant in an asymptotically stable sliding mode. An equal near rate is used to improve the dynamic quality of sliding mode motion. Simulation result shows that the stability of performance of the sliding-mode controller can effectively improve the driving smoothness and safety.

scholarly journals Control Strategy Based on Arm-Level Control for Output and Circulating Current of MMC in Stationary Reference Frame

Energies ◽  
2021 ◽  
Vol 14 (14) ◽  
pp. 4160
Author(s):  
Waqar Uddin ◽  
Tiago D. C. Busarello ◽  
Kamran Zeb ◽  
Muhammad Adil Khan ◽  
Anil Kumar Yedluri ◽  
...  
Keyword(s):  
Reference Frame ◽  
Control Method ◽  
Second Harmonic ◽  
Harmonic Component ◽  
Effective Control ◽  
Level Control ◽  
Circulating Current ◽  
Stationary Reference Frame ◽  
Pr Controller ◽  
Dc Component

This paper proposed a control method for output and circulating currents of modular multilevel converter (MMC). The output and circulating current are controlled with the help of arm currents, which contain DC, fundamental frequency, and double frequency components. The arm current is transformed into a stationary reference frame (SRF) to isolate the DC and AC components. The AC component is controlled with a conventional proportional resonant (PR) controller, while the DC component is controlled by a proportional controller. The effective control of the upper arm and lower arm ultimately controls the output current so that it delivers the required power to the grid and circulating current in such a way that the second harmonic component is completely vanished leaving behind only the DC component. Comparative results of leg-level control based on PR controller are included in the paper to show the effectiveness of the proposed control scheme. A three-phase, five-level MMC is developed in MATLAB/Simulink to verify the effectiveness of the proposed control method.

scholarly journals A stable proportional–proportional integral tracking controller with self-organizing fuzzy-tuned gains for parallel robots

2019 ◽  
Vol 16 (1) ◽  
pp. 172988141881995
Author(s):  
Francisco G Salas ◽  
Jorge Orrante-Sakanassi ◽  
Raymundo Juarez-del-Toro ◽  
Ricardo P Parada
Keyword(s):  
Stability Analysis ◽  
Performance Index ◽  
Closed Loop ◽  
Tracking Error ◽  
Parallel Robots ◽  
Control Loop ◽  
Closed Loop System ◽  
Proportional Integral ◽  
The Stability ◽  
Self Organizing

Parallel robots are nowadays used in many high-precision tasks. The dynamics of parallel robots is naturally more complex than the dynamics of serial robots, due to their kinematic structure composed by closed chains. In addition, their current high-precision applications demand the innovation of more effective and robust motion controllers. This has motivated researchers to propose novel and more robust controllers that can perform the motion control tasks of these manipulators. In this article, a two-loop proportional–proportional integral controller for trajectory tracking control of parallel robots is proposed. In the proposed scheme, the gains of the proportional integral control loop are constant, while the gains of the proportional control loop are online tuned by a novel self-organizing fuzzy algorithm. This algorithm generates a performance index of the overall controller based on the past and the current tracking error. Such a performance index is then used to modify some parameters of fuzzy membership functions, which are part of a fuzzy inference engine. This fuzzy engine receives, in turn, the tracking error as input and produces an increment (positive or negative) to the current gain. The stability analysis of the closed-loop system of the proposed controller applied to the model of a parallel manipulator is carried on, which results in the uniform ultimate boundedness of the solutions of the closed-loop system. Moreover, the stability analysis developed for proportional–proportional integral variable gains schemes is valid not only when using a self-organizing fuzzy algorithm for gain-tuning but also with other gain-tuning algorithms, only providing that the produced gains meet the criterion for boundedness of the solutions. Furthermore, the superior performance of the proposed controller is validated by numerical simulations of its application to the model of a planar three-degree-of-freedom parallel robot. The results of numerical simulations of a proportional integral derivative controller and a fuzzy-tuned proportional derivative controller applied to the model of the robot are also obtained for comparison purposes.

A sky-hook sliding mode semiactive control for commercial truck seat suspension

2020 ◽  
pp. 107754632094097
Author(s):  
Qiang Chen ◽  
Yong Zhang ◽  
Chengwei Zhu ◽  
Jinbo Wu ◽  
Ye Zhuang
Keyword(s):  
Nonlinear System ◽  
Phase Portrait ◽  
Control Method ◽  
Reference Model ◽  
Sliding Mode ◽  
Tracking Error ◽  
Magnetorheological Damper ◽  
Nonlinear Controller ◽  
Parameter Uncertainties ◽  
Seat Suspension

A semiactive seat suspension control method is proposed in this study and applied to attenuate the vibration of the commercial truck seat for enhancing its ride comfort. The semiactive seat suspension system with a magnetorheological damper behaves with undesirable nonlinear properties. The proposed controller is a typical nonlinear controller, which takes the ideal sky-hook controller as the reference model and forces the tracking error vector. The controller has achieved great performance of attenuating vibration and is robust to parameter uncertainties and external disturbances. The relaxation oscillation phenomenon and convergence were also analyzed by the contribution of the phase portrait. As the phase portrait depicted, the sky-hook controller, a weakly nonlinear system, could be approximated by the equivalent linear approximate model. However, the proposed controller, the sky-hook sliding mode controller, is a strongly nonlinear system, which could not be linearized by the regular perturbation theory, and the criterion is given by the phase portrait. The experiment results showed good agreement with the simulation results, and some other matters encountered were also analyzed in the process of application.

scholarly journals Adaptive Sliding Mode Control Method for Z-Axis Vibrating Gyroscope Using Prescribed Performance Approach

2020 ◽  
Vol 10 (14) ◽  
pp. 4779 ◽  
Author(s):  
Cheng Lu ◽  
Liang Hua ◽  
Xinsong Zhang ◽  
Huiming Wang ◽  
Yunxiang Guo
Keyword(s):  
Sliding Mode Control ◽  
Error Bound ◽  
Control Method ◽  
Sliding Mode ◽  
Tracking Error ◽  
Adaptive Sliding Mode Control ◽  
Performance Control ◽  
Prescribed Performance ◽  
Adaptive Sliding Mode ◽  
Mode Control

This paper investigates one kind of high performance control methods for Micro-Electro-Mechanical-System (MEMS) gyroscopes using adaptive sliding mode control (ASMC) scheme with prescribed performance. Prescribed performance control (PPC) method is combined with conventional ASMC method to provide quantitative analysis of gyroscope tracking error performances in terms of specified tracking error bound and specified error convergence rate. The new derived adaptive prescribed performance sliding mode control (APPSMC) can maintain a satisfactory control performance which guarantees system tracking error, at any time, to be within a predefined error bound and the error convergences faster than the error bound. Besides, adaptive control (AC) technique is integrated with PPC to online tune controller parameters, which will converge to their true values at last. The stability of the control system is proved in the Lyapunov stability framework and simulation results on a Z-axis MEMS gyroscope is conducted to validate the effectiveness of the proposed control approach.

scholarly journals Adaptive Sliding Mode Robust Control for Virtual Compound-Axis Servo System

2013 ◽  
Vol 2013 ◽  
pp. 1-9 ◽  
Author(s):  
Yan Ren ◽  
Zhenghua Liu ◽  
Le Chang ◽  
Nuan Wen
Keyword(s):  
Robust Control ◽  
High Frequency ◽  
Disturbance Observer ◽  
Position Control ◽  
Control Method ◽  
Sliding Mode ◽  
Tracking Error ◽  
Servo System ◽  
Adaptive Sliding Mode ◽  
Main System

A structure mode of virtual compound-axis servo system is proposed to improve the tracking accuracy of the ordinary optoelectric tracking platform. It is based on the structure and principles of compound-axis servo system. A hybrid position control scheme combining the PD controller and feed-forward controller is used in subsystem to track the tracking error of the main system. This paper analyzes the influences of the equivalent disturbance in main system and proposes an adaptive sliding mode robust control method based on the improved disturbance observer. The sliding mode technique helps this disturbance observer to deal with the uncompensated disturbance in high frequency by making use of the rapid switching control value, which is based on the subtle error of disturbance estimation. Besides, the high-frequency chattering is alleviated effectively in this proposal. The effectiveness of the proposal is confirmed by experiments on optoelectric tracking platform.

scholarly journals Adaptive Sliding Mode Control for a Class of Manipulator Systems with Output Constraint

Complexity ◽  
2021 ◽  
Vol 2021 ◽  
pp. 1-7
Author(s):  
Guangshi Li
Keyword(s):  
Sliding Mode Control ◽  
Control Method ◽  
Sliding Mode ◽  
Tracking Error ◽  
Lyapunov Stability Theory ◽  
Adaptive Sliding Mode Control ◽  
Compact Set ◽  
Adaptive Sliding Mode ◽  
Mode Control ◽  
System Output

In this paper, an adaptive sliding mode control method based on neural networks is presented for a class of manipulator systems. The main characteristic of the discussed system is that the output variable is required to keep within a constraint set. In order to ensure that the system output meets the time-varying constraint condition, the asymmetric barrier Lyapunov function is selected in the design process. According to Lyapunov stability theory, the stability of the closed-loop system is analyzed. It is demonstrated that all signals in the resulted system are bounded, the tracking error converges to a small compact set, and the system output limits in its constrained set. Finally, the simulation example is used to show the effectiveness of the presented control strategy.

scholarly journals Proportional-Integral Sliding Mode Control with an Application in the Balance Control of a Two-Wheel Vehicle System

2020 ◽  
Vol 10 (15) ◽  
pp. 5087
Author(s):  
Chien-Hong Lin ◽  
Fu-Yuen Hsiao
Keyword(s):  
Sliding Mode Control ◽  
Control Method ◽  
Sliding Mode ◽  
Balance Control ◽  
Successful Implementation ◽  
Integral Sliding Mode Control ◽  
Integral Sliding Mode ◽  
Proportional Integral ◽  
Mode Control ◽  
Vehicle System

A balance control method, the proportional-integral sliding mode control (PISMC), is proposed to control the tilt attitude of an experimental two-wheel vehicle system (TWVS). Based on our previous work of implementing a generalized PISMC to control a linearized dynamical system, this paper extends the algorithm to a wider range: First, the control design of a weighted-control system is proposed. Secondly, our algorithm was realized and verified in a TWVS using its original nonlinear model. Thirdly, a systematical way to tune parameters are presented. The robustness of the proposed algorithm is also discussed in this paper. The simulation results of this work validate that the PISMC has better robustness to counteract the external disturbances than the conventional sliding mode control (SMC) does. Additionally, the experimental results show that the PISMC is capable of autonomously balancing the TWVS more effectively than the conventional SMC. The successful implementation of our algorithm potentially extends the implementation of the PISMC to various nonlinear and emerging systems.

scholarly journals Torque control of bolt tightening process through adaptive-gain second-order sliding mode

2020 ◽  
Vol 53 (7-8) ◽  
pp. 1131-1143
Author(s):  
Zhimin Wu ◽  
Guigang Zhang ◽  
Wenjuan Du ◽  
Jian Wang ◽  
Fengyang Han ◽  
...  
Keyword(s):  
Closed Loop ◽  
Control Method ◽  
Sliding Mode ◽  
Nonlinear Process ◽  
Second Order ◽  
Torque Control ◽  
Sliding Mode Controller ◽  
Tightening Torque ◽  
Bolt Preload ◽  
Second Order Sliding Mode

Bolts constitute a very important subset of mechanical fasteners. In order to tighten bolts, a degree of bolt preload scatter is to be expected. Since the torque control of tightening bolts is the most popular means of controlling the preload, an appropriate tightening torque becomes pivotal. This paper investigates the torque control problem of bolt tightening process. This process is not as simple as it looks because the inherently nonlinear process contains many uncertainties. To conquer the adverse effects of the uncertainties, this paper designs an adaptive-gain second-order sliding mode controller. Theoretically, such design can guarantee that the bolt tightening process has the closed-loop stability in the sense of Lyapunov. From the aspect of practice, the control method is carried out by a platform. Some comparisons illustrate the feasibility and effectiveness of the designed controller.

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