Feedback Linearization Sliding Mode Control Strategy for Three-Phase Voltage PWM Rectifier Based on New Variable Speed Reaching Law

In this chapter an adaptive sliding mode controller for the Furuta pendulum is proposed. The Furuta pendulum is a class of underactuated mechanical systems commonly used in many control systems laboratories due to its complex stabilization which allows the analysis and design of different nonlinear and multivariable controllers that are useful in some fields such as aerospace and robotics. Sliding mode control has been extensively used in the control of mechanical systems as an alternative to other nonlinear control strategies such as backstepping, passivity based control etc. The design and implementation of an adaptive sliding mode controller for this kind of system is explained in this chapter, along with other sliding mode controller variations such as second order sliding mode (SOSMC) and PD plus sliding mode control (PD \(+\) SMC) in order to compare their performance under different system conditions. These control techniques are developed using the Lyapunov stability theorem and the variable structure design procedure to obtain asymptotically stable system trajectories. In this chapter the adaptive sliding mode consist of a sliding mode control law with an adaptive gain that makes the controller more flexible and reliable than other sliding mode control (SMC) algorithms and nonlinear control strategies. The adaptive sliding mode control (ASMC) of the Furuta pendulum, and the other SMC strategies shown in this chapter, are derived according to the Furuta’s pendulum dynamic equations making the sliding variables, position errors and velocity errors reach the zero value in a specified reaching time. The main reason of deriving two well known sliding mode control strategy apart from the proposed control strategy of this chapter (adaptive sliding mode control) is for comparison purposes and to evince the advantages and disadvantages of adaptive sliding mode control over other sliding mode control strategies for the stabilization of the Furuta pendulum. A chattering analysis of the three SMC variations is done, to examine the response of the system, and to test the performance of the ASMC in comparison with the other control strategies explained in this chapter.

In order to improve the robustness of the sliding mode control algorithm of the four-phase interleaved parallel Buck converter, an improved adaptive non-singular terminal sliding mode PI (ANTSMC-PI) dual closed-loop control strategy based on linearly expanding state observer (LESO) is proposed in this paper. First, two LESO observers are designed to estimate the matched and mismatched disturbance in the system dynamic model, respectively. Second, the estimates of the observers are Integrationed into the outer-loop controller, and an improved sliding-mode controller is proposed to achieve error-free tracking of the output voltage to the reference voltage; while the PI controller is used for the current inner loop to ensure the equal current flow in each phase of the system. Finally, the stability of the designed controller is demonstrated by using the lyapunov stability principle. The simulation in Matlab/Simulink platform shows that the proposed scheme can effectively reduce the output ripple and improve the system dynamic performance compared with the traditional non-singular terminal sliding-mode PI control strategy.

Permanent Magnet Synchronous Motors (PMSMs) exhibit inherent symmetry in their electromagnetic structure yet behave as nonlinear and strongly coupled systems that are susceptible to internal parameter perturbations and external disturbances, posing challenges to effective control under dynamic operating conditions. To address these issues, this paper proposes a sliding mode control strategy for PMSMs that integrates a Novel Adaptive Reaching Law (NARL) and an Improved Terminal Fuzzy Sliding Mode Disturbance Observer (IFTSMDO), denoted as SMC-NARL-IFTSMDO. The NARL is designed with a state-dependent dynamic gain adjustment mechanism and terminal attractive factor characteristics: it increases the gain to ensure fast convergence when the system state is far from the sliding mode surface, and adaptively attenuates the gain to suppress chattering when approaching the sliding mode surface, thereby balancing the contradiction between convergence speed and chattering in traditional sliding mode control. The IFTSMDO constructs a composite sliding mode surface incorporating error derivatives, terminal power terms, and saturation functions, which enhances the sensitivity of disturbance estimation in the small-error stage, avoids high-frequency chattering caused by sign functions, and provides accurate feedforward compensation for the speed loop controller to improve the system’s anti-disturbance capability. Additionally, the asymptotic stability of the proposed control strategy is strictly proven using the Lyapunov stability theory, laying a solid theoretical foundation for its application. Experiments are conducted on a TMS320F28379D DSP-based platform, and quantitative results show that compared with the traditional sliding mode control (SMC-TRL), the proposed strategy reduces the no-load startup response time by 60%, the steady-state speed fluctuation by 60%, and the speed fluctuation under load disturbance by 81.5%, fully demonstrating its superiority in dynamic response and anti-disturbance performance.

In this paper, we present a simulation study of a wind system with a doubly fed induction machine driven by a variable pitch wind turbine. The objective of the work is to design a control algorithm based on the sliding mode control strategy allowing the control of both active and reactive power independently. The main goal achieved by the control strategy is to control the amount of active and reactive power produced by the doubly fed induction generator and injected in the main grid according to the power references derived from turbine's mechanical power and the grid operator. The simulation results have shown good performances concerning the tracking of the references both in transient and steady state. A comparative study between the proposed control strategy and the well known vector control strategy has been carried out and has shown the superiority of sliding mode control to track the given references.

In this paper, a chatter free sliding mode control (SMC) strategy for chaos control is introduced to the nonlinear uncertain chaotic systems in the presence of unknown bounded uncertainties and external disturbances. The sliding mode surface with differential operators is proposed to divert the discontinuous gian function swith term into only one control input, and the control input is smooth and differentiable with respect to time. Based on the Lyapunov stability theory, SMC stability analysis is performed and a theorem serving as designing a chatter free sliding mode control input is also introduced. Finally, numerical simulations are presented to verify the usefulness of the proposed control strategy.

Super-twisting sliding mode control of grid-side inverters for wind power generation systems with parameter perturbation

Objective: This study proposes the application of optimized Sliding Mode Control (SMC) with Nonlinear Disturbance Observer (NDO) for the Inverted pendulum, which is subjected to mismatched disturbances. Methods/Statistical Analysis: Sliding Mode Control (SMC) with Nonlinear Disturbance Observer (NDO) solves the main problem of chattering present in traditional sliding mode controllers while retaining the nominal performance even with mismatched disturbances. Chattering defines the presence of finite frequency and finite amplitude oscillations in the control input. Genetic Algorithm is used for searching the optimal controller parameters, which includes switching function coefficient, switching gain and observer gain. Findings: Simulation results shows the advantages of NDO based SMC and proves that NDOSMC can observe the mismatched disturbances very effectively. The conventional SMC method is also used in the control design the Inverted pendulum for comparison studies. The two main issues to be tackled in conventional Sliding Mode Control (SMC) are convergence time and chattering. Chattering and convergence time can be reduced in SMC by getting the optimal values of controller parameters using intelligent optimization techniques such as Genetic Algorithm (GA). In the present study convergence time and chattering of the controlled system are considered as the performance index of objective function. Application/Improvements: This study can further be extended for Multi-Input Multi-Output (MIMO) systems subjected to mismatched disturbances and parametric uncertainties.

The single robot joint, which contains a DC torque motor and a harmonic reducer, was designed. And sliding mode control strategy by the self-adaptive adjustment of the sliding parameter e was proposed in this paper. This control strategy can adaptively adjust e by switching variables and their derivatives according to the system. It is applied in the control of robot joint to solve the contradiction between the exponential reaching law response speed and chattering. Simulation results show that the open-loop control response time of the parameter adaptive adjustment sliding mode control is 0.3s. The experiment results show that under the control of adaptive sliding mode with joint angle 45 and rise-time 0.23s, the maximum overshoot is 0.4%, with no chattering and a good dynamic quality.

In this paper, because a adaptive fuzzy control is incorporated into the sliding mode control (SMC) to adaptively regulate the adaptive law of SMC, an adaptive fuzzy sliding mode controller (AFSMC) for brushless doubly fed machine (BDFM) adjustable speed system is presented. The proposed controller for BDFM eliminates the average chattering encountered by most SMC schemes, and employs the robustness and excellent static and dynamic performances of SMC. Simulation results show that the proposed control strategy is of the feasibility, correctness and effectiveness.

Vanadium Redox Battery (VRB) has the advantages of large capacity, long life, safety and environmentally friendly. This paper proposes a double closed-loop charge-discharge control strategy of VRB based on cerebellar model arithmetic computer (CMAC) to ensure safe charge-discharge and shorten the charge-discharge time. The proposed control strategy consists of two main control loops: an outer voltage loop and an inner current loop. The outer control loop is designed as a voltage loop with CMAC controller which uses kernel voltage for feedback, and the inner current loop adopts PI regulator with amplitude limiting. In this paper, we first build a mathematical model of VRB of 5 kW/30kW· h. Then, the proposed control strategy and conventional PID control strategy are respectively applied to VRB model and comparisons are made. Results show that under the proposed control strategy, charging time of VRB shortened by 3.03%, discharging time of VRB shortened by 9.37% compared with conventional PID control strategy, and the terminal voltage can be guaranteed in a safe range, thus realizing fast and safe charge-discharge of VRB.

This paper proposes an adaptive second sliding mode (SOSM) control strategy to control the stabilized platform of rotary steering drilling tool. Stabilized platform is typical uncertain system, and using traditional sliding mode control (SMC) needs to know the upper bound of uncertainty firstly, which cannot be satisfied for stabilized platform under work condition. Meanwhile, the input chattering phenomenon exists inevitably. Therefore, using adaptive SOSM method can solve the two problems. SOSM controller eliminates the input chattering, and the design of adaptive tuning law for SOSM controller overcomes the limitation of prior knowledge about the uncertain upper bound. Simulation results show that the proposed control strategy can make stabilized platform achieve good control performance and robustness.

A model-free fractional-order sliding mode control (MFFOSMC) method based on a non-linear disturbance observer is proposed for the electric drive system in this paper. Firstly, the ultra-local model is established by using the mathematical model of electric drive system under parameter perturbation. Then, aiming at reducing the chattering of the sliding mode controller and improving the transient response, a model-free fractional-order sliding mode controller is designed based on fractional-order theory. Next, considering that the traditional sliding mode control can only suppress matched disturbance and that it is sensitive to mismatched disturbance, a non-linear disturbance observer is used to estimate disturbance, and the estimated variables are used in the design of a sliding mode surface to improve the tracking accuracy of the system. Finally, the experiment is completed on an asynchronous motor drive platform. Compared with the model-free integer-order sliding mode control (MFIOSMC), the results show that the proposed method has good dynamic response and strong robustness. Meanwhile, the proposed method reduces the dependence on mathematical models.

This paper considers an aeroelastic two-dimensional wing-flap system with uncertainty and external disturbance. Nonlinear stiffness in pitch is expressed as the second-order polynomial form. In the uncontrolled aeroelastic model, limit cycle oscillation (LCO) appears at postflutter speed. By utilizing leading-edge and trailing-edge control surfaces as the control input, a sliding mode control scheme using varying boundary layers based on backstepping design is developed to suppress aeroelastic vibration. The proposed control strategy combines the advantages of both sliding mode control with varying boundary layers and backstepping technique. In contrast to the conventional sliding mode control design, the proposed method not only avoids chattering but also obtains stronger robustness. The results of numerical simulation clearly demonstrate the effectiveness of the proposed control strategy for aeroelastic vibration suppression under saturated controller input.

In this article, the adaptive sliding mode (ASM) control scheme of half-car active suspension systems with prescribed performance is studied. Because of the affected by model uncertainty, time-varying parameter, pavement roughness excitation, etc., the study of suspension systems can be regarded as the multivariable nonlinear control problem. First of all, the prescribed performance function (PPF) is applied to constrain the displacement and pitch angle of the suspension systems to ensure the transient and steady-state suspension responses. Second, an integral terminal sliding mode control method with strong robustness is put forward, which can make the system converge rapidly in a finite-time when it is far from the equilibrium point, solve the singularity problem in the control process, and reduce the chattering phenomenon in the traditional sliding mode control. Then, the neural networks (NNs) approximation characteristics are used to deal with unknown items in the design of the controller, and the Lyapunov stability theory is employed to analyze the stability of the closed-loop system. In the end, the comparative simulation results demonstrate the feasibility and effectiveness of the proposed control scheme.

Robust internal model control of servo motor based on sliding mode control approach