Industrial Grade Adaptive Control Scheme for a Micro-Grid Integrated Dual Active Bridge Driven Battery Storage System

Fractional order sliding mode control is studied in this paper. The control objectives are achieved by adopting the reaching law approach of sliding mode control. The main contribution of this work is to show that the philosophy of integer order sliding mode control is valid also for the systems represented by fractional order operators. A sufficient condition and its implications for stability are given. Matched and unmatched uncertainties are studied. The attractor nature of the switching manifold is analyzed together with a stable sliding subspace design condition. The claims are justified through a set of simulations and the results obtained are found promising.

At present, the power system is more inclined towards disturbances, such as voltage variations and unbalanced load conditions, due to the grid's complexity and load growth. These challenges emphasize the integration of the compensating devices, such as battery storage (BS) and D-STATCOMs. In this regard, this current paper exhibits a novel energy management system (EMS) of a combined BS and D-STATCOM to compensate the power system during disturbances. The EMS is based on a fractional order sliding mode control (FOSMC) to drive the voltage source converters (VSCs) such that the active power is independently absorbed/injected by the BS, whereas the reactive power is independently absorbed/injected by the D-STATCOM depending upon the disturbance situation. FOSMC is a robust non-linear controller in which the Riemann-Liouville (RL) function is employed to design the sliding surface and the exponential reaching law is used to minimize the chattering phenomenon. The stability of the FOSMC in the proposed EMS is proved using the Lyapunov candidate function. In order to validate the performance of the proposed EMS, a model of a 400 V, 180 kVA radial distributor along with a BS and D-STATCOM is simulated in MATLAB/Simulink environment in two test cases. The results prove that the proposed EMS with FOMSC effectively compensates the power system under voltage variations and unbalanced load conditions with rapid tracking, fast convergence and upright damping. Furthermore, the results have been compared with the classical proportional integral (PI) control and fixed frequency SMC (FFSMC), and they demonstrate the superiority of the proposed EMS with FOSMC in power system applications.

The main goal of vehicle active suspension system is to upgrade the ride quality and stability of heavy duty vehicle (HDV) regardless of road surface. The mathematical modelling of HDV with two degrees of freedom is developed and simulated in MATLAB/Simulink environment. The simple and effective control techniques such as proportional integral and derivative (PID) controller, sliding mode controller (SMC) and fractional order sliding mode controller (FOSMC) are designed to detach the vibration from the passenger under step, sinusoidal and random road profile. Literature reveals that the FOSMC can eliminate steady state error and chattering effect unlike SMC and PID. The dynamic analysis of designed controllers is examined in terms of time domain, frequency domain and ride comfort analysis as per ISO 2631. The stability of SMC and FOSMC is confirmed by Lyapunouv stability for three different road profiles. The FOSMC shows satisfactory simulation results than SMC, PID and passive suspension system in reducing suspension deflection and body acceleration of HDV to upgrade the ride quality. Further, the efficacy of proposed FOSMC is proved by comparing the simulation results against existing results of PID controller.

This article investigates a novel cooperative control system based on the sliding mode variable structure control theory for multi-missile formation flight. It is desired in practice to form and maintain the formation under the premise of uncontrollable missile speed. First, under the inertial coordinate system, we obtain the model of the formation control problem using the relative position of the leader to the follower. Then, we perform acceleration conversion and combine it to this model, getting the form of the formation problem model in the ballistic coordinate system. The finished model is useful for researchers to design the formation controller on this basis. Besides, the sliding mode variable structure control theory is used to design the formation controller for the system not considering disturbances and considering disturbances. Then we use the Lyapunov stability theory to analyze the stability of the formation control system. Finally, we compare our method with another method which requires controllable speed. According to numerical simulations, the method proposed in this article can achieve similar relative position errors under the condition of uncontrollable speed. And the robustness, versatility and formation adaptability of the method we propose are confirmed by simulation results.

In this paper a novel controller for a flexible link manipulator based on fractional calculus is proposed. A hybrid system that combines the advantages in terms of robustness of the fractional control and the sliding mode control is proposed. Due to adding the extra degree of freedom, the fractional order sliding mode controller can achieve better control performance than the integer order sliding mode controller. For the problem of determining the design parameters, the particle swarm optimization (PSO) algorithm is used. The proposed controller is applied for a single‐link flexible manipulator robot. Finally, the performance and the significance of the closed loop system are investigated. The simulation results signify the performance of the proposed controller.

Fixed wing Unmanned Aerial Vehicles (FWUAVs) are widely utilized in both military and civilian sectors due to their ability to perform risky, inaccessible operations. The mathematical model of FWUAVs is complex, incorporating physical laws and coordinate systems with transformation matrices. In addition, controlling FWUAVs is challenging due to their nonlinear and coupled dynamics. This paper focuses on tracking trajectories for fixed wing unmanned aerial vehicles (FWUAVs) using a Robust Fractional Order Sliding Mode Controller (RFOSMC). An RFOSMC, which combines a conventional Sliding Mode Controller (SMC) with flexible fractional calculus, is proposed in this paper. Particle Swarm Optimization (PSO) is used to tune the control gains of RFOSMC. External disturbances and parameter variation are added to evaluate the controller’s performance. Comparative studies have been done with Linear Quadratic Regulator (LQR), Fractional Order PID (FOPID), SMC, and robust FOSMC. RFOSMC performs better than LQR, FOPID, and SMC in tracking accuracy, response speed, and overshoot. In addition, the performance comparison of RFOSMC and conventional SMC has been done based on performance index values of errors (ITAE), and RFOSMC showed a 76.5918% improvement. For a step input, RFOSMC showed the smallest settling time of 0.835s compared with 2.724s for SMC and 4.8573s for FOPID. Open-loop model verification and overall control system of FWUAV are done using MATLAB/Simulink software.

Adaptive fractional-order sliding-mode disturbance observer-based robust theoretical frequency controller applied to hybrid wind–diesel power system

According to the requirements of the third phase project of Chinas lunar probe program, a six degrees of freedom (DOF) air-bearing spacecraft simulator was designed for the lunar orbiter docking with the sample transfer performance test system. A pose optimal sliding mode control strategy was proposed for the pose control of air-bearing table, which integrates sliding mode variable structure control and optimal control theory, through integral compensation term to enhance robustness of the optimal regulator, eliminate the approaching modal of sliding mode control, and solve the impact of large load inertia ratio and uncertainty factors of air-bearing pose control system on the control accuracy. Experimental results indicate that the control precision of the system meets the task requirements, and validate the correctness and feasibility of the scheme.

Underwater vehicle speed control methodology method is the focus of research in this study. Driven by a hydraulic flexible traction system, the underwater vehicle advances steadily on underwater guide rails, simulating an underwater environment for the carried device. Considering the influence of steel rope viscoelasticity and the control system traction structure feature, a mathematical model of the underwater vehicle driven by hydraulic flexible traction system is established. A speed control strategy is then proposed based on the sliding mode variable structure of fuzzy reaching law, according to nonlinearity and external variable load of the vehicle speed control system. Sliding mode variable structure control theory for the nonlinear system allows an improved control effect for movements in “sliding mode” when compared with conventional control. The fuzzy control theory is also introduced, weakening output chattering caused by the sliding mode control switchover while producing high output stability. Matlab mathematical simulation and practical test verification indicate the speed control method as effective in obtaining accurate control results, thus inferring strong practical significance for engineering applications.

To improve the performance of vehicle-grid system under multiple operation conditions and suppress the low-frequency oscillation (LFO) in electrified railways, this paper proposed a control strategy of electric multiple units (EMUs) traction line-side converter (LSC) based on sliding mode control (SMC). First, the accurate model of EMUs is established and then the mathematical model of it in the d-q frame is derived. Then, the application of sliding mode variable structure control strategy in the LSC of EMUs is presented in detail, which includes the design of outer loop voltage sliding mode surface and inner loop current control law. Moreover, the control performance for EMUs based on SMC and traditional linear proportional integral (PI) control is compared under multiple operation conditions in the case of one traction drive unit of EMUs and multi-EMUs, respectively. Finally, experiments are implemented on the hardware in the loop simulation platform based on software StarSim. The experiments results show that, compared with PI control, SMC owns better control performance, such as the lower total harmonic distortion of traction line-side current under multiple conditions, lower voltage fluctuation when braking occurs, better anti-interference ability with the change of system parameters, and can effectively suppress the LFO occurs under operation mode.

Adaptive fractional order sliding mode controller with neural estimator

Fractional order neural sliding mode control based on the FO-Hammerstein model of piezoelectric actuator

Fractional Order Sliding Mode Controller (FOSMC) is a hybrid one and has been integrated to escalate low voltage ride through (LVRT) during faults in a modular multilevel converter (MMC) based doubly fed induction generator (DFIG) connected wind energy conversion system (WECS). Voltage sag at grid directly affects stator of DFIG, due to its immediate connection. The machine’s rotor is joined to power electronic converters i.e. a rectifier (MSC) and an inverter (GSC) via a DC link. A Fractional Order Sliding Mode controller is used at Grid Side Converter to mitigate fault current and ameliorate parameters at stator, rotor terminals. This paper infers that proposed Fractional Order Super Twisting Algorithm (FOSTA) deployed Sliding Mode Controller (FOSMC) is the exceptional in dealing with symmetrical and asymmetrical faults by refining power quality parameters, LVRT problem. The fault ride capability with FOSMC is good compared to FOPI and SMC controllers.

ABS(antilock brake system) is one of the most important active safety technology for modern vehicles which could enhance vehicle active safety. In this paper, an improved sliding mode control method based on reaching law has been proposed to solve the vibration problem in traditional sliding mode control. The ABS control strategy has been designed based on the sliding mode variable structure control. On this basis, the ABS single wheel depending on control strategy has been designed to ensure the braking stability. By hardware-in-loop simulation, the results demonstrate that ABS sliding mode variable structure control could enhance braking stability performance and improve the control effect on high friction and low friction road.

The radiating power with sine waveform is required for modulated infrared thermography nondestructive testing. Sine voltage was applied by former authors for deriving sine power waveform. The theory mode of infrared lamp is proposed. According to numerical solution and FFT analysis, high frequency components are included in the radiating power waveform, when sine voltage is set to drive the lamp. A light intensity sensor was utilized for monitoring the real-time radiating power, and a close-loop power tracking system was constructed. Fractional order sliding mode controller was selected in the tracking system, for its robustness and flexibility property. The reachability of the controller is proved and the calculation formulas of reach time are given. In experiment, the tracking results with both PID and sliding mode controller were derived. Lower tracking overshoot and better robustness was derived through the sliding mode controller, compared with the PID counterpart.