Synergetic Control Research Articles

A New combined MPPT-Pitch Angle control of a Large Variable Speed Wind Turbine in Different Operating Areas based on Synergetic control

The aim of this paper is to create a novel combination between two controls, maximum power point tracking (MPPT) and Pitch angle control system of a variable-speed wind turbine. The main objective sought is to achieve the maximization of the power produced by the fixed pitch angle turbine through the MPPT control in the zone 02 of operation. Then, limit the power to its nominal value by using the Pitch control with variable pitch angle in zone 03 of operation. Our contribution will be to propose strategies based on two types of controllers. The first is the control by the MPPT control, it is applied in light winds to extract the maximum power. The second is Variable Pitch Control, which is applied in strong winds to keep power constant at its nominal value, as well as protecting the wind turbine from high winds. For this, linear and non-linear control laws (PI, SC) respectively are implemented to achieve the defined objective. The simulation results show the feasibility and effectiveness of the techniques used.

Forced sliding mode control for chaotic systems synchronization

Synchronization of chaotic systems is considered to be a common engineering problem. However, the proposed laws of synchronization control do not always provide robustness toward the parametric perturbations. The purpose of this article is to show the use of synergy-cybernetic approach for the construction of robust law for Arneodo chaotic systems synchronization. As the main method of design of robust control, the method of design of control with forced sliding mode of the synergetic control theory is considered. To illustrate the effectiveness of the proposed law, in this article it is compared with the classical sliding mode control and adaptive backstepping. The distinctive features of suggested robust control law are the more good compensation of parametric perturbations (better performance indexes—the root-mean-square error (RMSE), average absolute value (AVG) of error) without designing perturbation observers, the ability to exclude the chattering effect, less energy consuming and a simpler analysis of the stability of a closed-loop system. The study of the proposed control law and the change of its parameters and the place of parametric perturbation’s application is carried out. It is possible to significantly reduce the synchronization error and RMSE, as well as AVG of error by reducing some parameters, but that leads to an increase in control signal amplitude. The place of application of parametric disturbances (slave or master system) has no effect on the RMSE and AVG of error. Offered approach will allow a new consideration for the design of robust control laws for chaotic systems, taking into account the ideas of directed self-organization and robust control. It can be used for synchronization other chaotic systems.

Machine learning elucidates the impact of short-term emission changes on air pollution in Beijing

The Chinese Spring Festival (CSF) is the most solemn traditional festival in China, and the substantial changes in anthropogenic activities in megacities provide a unique natural experiment to assess the influence of short-term emission changes on air quality. Here we applied a machine learning based random forest algorithm to six-year aerosol composition measurements in urban Beijing during the CSFs of 2012–2020 to quantify the relative contributions of meteorology and emission changes to air quality. Our results demonstrate large variabilities of air pollutants during the CSF due to the meteorological changes and holiday effect. By removing the meteorological effect, we found that the reduced emissions during CSF caused an average decrease of 5.1% for non-refractory PM2.5 with chloride and primary organic aerosol being the largest (8.8–18.7%) while the changes in secondary species were small. The COVID-19 lockdown during 2020 led to additional reductions of primary species by 16.3–36.8%, yet increases in nitrate and secondary organic aerosol due to enhanced secondary production. Our study has a significant implication that reducing local traffic and cooking emissions is far from enough for mitigating air pollution in winter in megacities due to the nonlinear effect of secondary production and regional transport. A synergetic control of multiple precursors, e.g., NOx and ammonia, is of great importance to reduce secondary aerosol and improve air quality.

Congestion tracking control for wireless TCP/AQM network via immersion and invariance

AbstractThis paper deals with an immersion and invariance (I&I) control design for wireless Transmission Control Protocol (TCP) network to solve Active Queue Management (AQM) problems. With the help of this strategy, the developed control law can be used to cope with congestion tracking problems for a nonlinear wireless network model. Besides, the nonlinear congestion control law is proposed to assure that the queue length is able to track the desired queue length despite having sudden changes. The developed control design is validated in the MATLAB environment. The effectiveness of the developed control is verified through a simulation and compared with integral backstepping design, backstepping design, sliding mode design, and synergetic control design. The simulation results demonstrated that the presented strategy is not only able to solve the desired congestion tracking control problem but also provide improved transient performances.

Fast Terminal Synergetic Control of PMVG-Based Wind Energy Conversion System for Enhancing the Power Extraction Efficiency

This study presents a fast terminal synergetic control (FTSC) scheme to investigate the nonlinear control problem of permanent magnet vernier generator (PMVG)-based variable-speed wind energy conversion systems (WECSs). In wind turbines, better speed tracking and fast dynamic behavior is required to achieve the maximum power extraction. To do this, the FTSC method is firstly proposed to improve the dynamic performance of tracking the speedby, addressing the turbulent wind and uncertainties in the PMVG system, which improves the wind energy extraction efficiency and alleviates mechanical stress over the turbine. Next, the closed-loop FTSC with a macro variable and novel reaching law is presented to enhance the convergence of the speed error signal when it is far from equilibrium in finite time. At this time, the controller’s output is a zero chattering generator torque reference that can operate the system in both below- and above-rated wind conditions, in addition to pitch control. Then, the proposed control method is verified for its effectiveness in energy capture through numerical simulation and experimental verification of a 5 kW direct drive PMVG-based WECS. Finally, comparative results confirm the better performance of the proposed system under transients than other controllers considered in this analysis.

Robust Adaptive Fuzzy Control of Nonlinear Systems

In this paper, an adaptive Fuzzy Fast Terminal Synergetic Controller (FFSC) for a certain class of SISO unknown nonlinear dynamic systems is proposed, that uses the concept of terminal attractor design, adaptive fuzzy synergetic control scheme, and Lyapunov synthesis approach. In contrast to the existing adaptive fuzzy synergetic control design, where the fuzzy systems are used to approximate the unknown system functions while the synergetic control guarantees robustness and achieves the asymptotic stability of the closed-loop system, in our technique both the continuous synergetic control law and the fuzzy approximator are derived to ensure finite-time convergence. Lyapunov conditions for finite-time stability and accuracy proofs in mathematics are presented to prove that the proposed adaptive scheme can achieve finite-time stable tracking of reference input and guarantee of the bonded system signals. Simulation results illustrate the design procedures and demonstrate the performance of the proposed controller.

A New Synergetic Scheme Control of Electric Vehicle Propelled by Six-phase Permanent Magnet Synchronous Motor

Electric Vehicles (EVs) are a promising alternative to conventional vehicles powered by internal combustion motors, of fering the possibility of reducing CO2, pollutants, and noise emissions. As known, the control of such an electric vehicle takes into account several phenomena governing its behavior, which is a complicated problem because of the non-linearities, unmeasured disturbance, and parameters uncertainty of this system. This problem is one of the important challenges facing controller designers. Various control techniques have been proposed to enhance EV’s performance. On this basis, in this research, a new synergetic scheme of electric vehicles propelled by Six-Phase Permanent Magnet Synchronous Motor (PMSMs) is developed. The synthesis of the proposed Synergetic Controller (SC) is based on the selection of four-manifolds of stator current of PMSMs. The SC provides fast response, asymptotic stability of the closed-loop system in wide range operating condition, and decrease the size of modeled system. Also, the principal feature of SC is that it supports parameters variation. Furthermore, to illustrate the improvements and the performances of the proposed controller, a comparison study between various nonlinear controllers such as Integral Action in Sliding Mode (ISMC), Super Twisting Sliding Mode (STSM), using a dynamic model of the lightweight vehicle under New European Driving Cycle (NEDC) was done. The obtained simulation results under several operating conditions show the efficiency and superiority of the proposed control compared with nonlinear controllers; also, it demonstrates the feasibility of the proposed control approach for real systems.

Synergetic Control Strategy of Front-End Speed Regulation Wind Turbine (FESRWT) for Fault Ride through

A synergetic control method is proposed to improve the fault ride through capability of front-end speed regulation wind turbine (FESRWT). In case of three-phase short-circuit fault and single-phase grounding fault, this method can accelerate the attenuation of stator flux transient component and restrain the fluctuation of rotor speed, make generator produce large reactive power which will provide more reactive power support for power grid, and improve the fault ride through capability of FESRWT. By dynamic analysis of the proposed algorithm, the large range stability constraint condition satisfying the fault ride through is obtained, and the parameter range satisfying the condition is solved by Monte Carlo method. Taking 2 MW FESRWT as an example, the control strategy is verified and analyzed. Simulation results show that the proposed method can improve the fault ride through performance of FESRWT.

Procedures for cognitive and synergetic observation and proactive control of power capacity of nickel-hydrogen storage batteries onboard a geostationary spacecraft

The paper presents methods of providing power resources for the mission of the Yamal-100 spacecraft from the secondary onboard power supply sources — nickel-hydrogen storage batteries. For the first time in the world practice of using metal-hydrogen electrochemical batteries installed in a common gas manifold a ~10-years operational life in orbit has been achieved for batteries operated onboard a geostationary satellite. A decline in power capacity of storage batteries could result in early termination of the spacecraft mission. Therefore, the energy resource of the storage battery was maintained through proactive management consisting of prediction and active control. The methods that were developed for continuous observation in the form of monitoring and diagnostics of the storage batteries status including estimation of the current discharge energy capacity made it possible to predict further degradation loss under conditions of insufficient power for the storage batteries cooling equipment. The active control consisted in using methods aimed at providing optimal operating conditions, fending off a potential development of an anomalous thermal situation within the electrochemical reaction zone, and regenerating the energy capacity. The control furthermore used the synergy effect produced by secondary energy interrelationships between onboard systems. This made it possible to meet the batteries operational life requirements under exposure to an unfavorable external factor in the form of an increasing heat impact on the batteries temperature control equipment. The increase in thermal load was caused by re-reflection of a portion of the luminous flux from structural elements of the spacecraft and an increase in solar absorption factor (aging) of thermal control coatings. Key words: spacecraft, control process, nickel-hydrogen battery, provision of resources, energy capacity, proactive control, synergy.

Synergetic promoting/inhibiting mechanisms of copper/calcium compounds in the formation of persistent organic pollutants and environmentally persistent free radicals from anthracene

Copper compounds are considered the strongest promotors of unintentional persistent organic pollutants (POPs) formation, while calcium compounds are widely used to inhibit this process. Understanding the mechanisms underlying these processes is important for synergetic control of multiple POPs. Herein, the promoting ability of CuCl2 on the synergetic formation of POPs from anthracene and the underlying mechanisms were clarified. During thermochemical reaction with CuCl2, Cu2+ was first reduced to Cu+, and finally oxidized to CuO. Furthermore, CuCl2 promoted the formation of environmentally persistent free radicals (EPFRs) during thermochemical reaction. The formed EPFRs were identified as anthrone-type and anthraquinone-type radicals using electron paramagnetic resonance spectroscopy and gas chromatography/quadrupole time-of-flight mass spectrometry. Synergetic inhibition of POPs and EPFRs was achieved using CaO. The inhibiting mechanism of CaO was attributed to the absorption of chlorine originating from CuCl2 through the formation of CaClOH and the inhibition of free radical intermediates for POPs formation.

Improvement of the Control of a Grid Connected Photovoltaic System Based on Synergetic and Sliding Mode Controllers Using a Reinforcement Learning Deep Deterministic Policy Gradient Agent

This article presents the control of a grid connected PV (GC-PV) array system, starting from a benchmark. The control structure used in this article was a cascade-type structure, in which PI or synergetic (SYN) controllers were used for the inner control loop of id and iq currents and PI or sliding mode control (SMC) controllers were used for the outer control loop of the udc voltage from the DC intermediate circuit. This paper presents the mathematical model of the PV array together with the main component blocks: simulated inputs for the PV array; the PV array itself; the MPPT algorithm; the DC-DC boost converter; the voltage and current measurements for the DC intermediate circuit; the load and connection to power grid; the DC-AC converter; and the power grid. It also presents the stages of building and training the reinforcement learning (RL) agent. To improve the performance of the control system for the GC-PV array system without using controllers with a more complicated mathematical description, the advantages provided by the RL agent on process controls could also be used. This technique does not require exact knowledge of the mathematical model of the controlled system or the type of uncertainties. The improvement in the control system performance for the GC-PV array system, both when using simple PI-type controllers or complex SMC- and SYN-type controllers, was achieved using an RL agent based on the Deep Deterministic Policy Gradient (DDPG). The variant of DDPG used in this study was the Twin-Delayed (TD3). The improvement in performance of the control system were obtained by using the correction command signals provided by the trained RL agent, which were added to the command signals ud, uq and idref. The parametric robustness of the proposed control system based on SMC and SYN controllers for the GC-PV array system was proven in the case of a variation of 30% caused by the three-phase load. Moreover, the results of the numerical simulations are shown comparatively and the validation of the synthesis of the proposed control system was obtained. This was achieved by comparing the proposed system with a software benchmark for the control of a GC-PV array system performed in MATLAB Simulink. The numerical simulations proved the superiority of the performance of control systems that use the RL-TD3 agent.

Shared network and supply chain features for synergetic control of carbon and air pollutant emissions

The synergetic control of carbon and air pollutant emissions will be an unflagging effort for China in its dual pursuit of air quality improvement and carbon neutrality. The shared features of sectoral emissions from network and supply chain perspectives, as well as the evolution of these features under policy intervention remain to be investigated. This study develops four ecological networks for CO2 and SO2 emissions targeting the period 2010–2015 with strengthened emission control implemented. By fusing input-output analysis, Ecological Network Analysis and Structural Path Analysis, the shared intersectoral linkages of emissions are examined, and the key supply chains are identified. The results indicate that most sectors have control over Transportation Equipment, Electronic Equipment, and Construction, and almost all sectors have dependence on Power and Heat. Exploitative relationships induced by emission flows along supply chains are predominant, accounting for over 60% for four emission flow networks. Eight shared supply chains are identified among the top 20 that generally induce larger than 50% emissions in both 2010 and 2015. The one with the largest emissions is “Total capital formation → Construction → Nonmetals”. During 2010–2015, the critical evolution of network features is the decrease in the economy's control over Construction, dependence on Fossil Energy Mining, and emissions contained in the paths associated with exports. The findings help to more pertinently strategize on prescient regulation of key supply chains for a more effective carbon-pollution synergetic control.

Synergetic Synthesis of Nonlinear Laws of Throttle Control of a Pneumatic Drive

Currently, a significant trend in control in robotic systems is developing and improving linear and nonlinear control algorithms to improve the overall quality of production with high accuracy and adaptability. The present study considers a synergistic synthesis of throttle control of a pneumatic distributor valve and backpressure control for piston rod positioning. The article presents the synthesis of control laws for the position of a pneumatic cylinder piston using the method of analytical design of aggregated regulators (ADAR) of synergetic control theory (STC), which allows operation with nonlinear mathematical models, eliminating the loss of information about the object during linearization. A comparative calculation of the energy efficiency of backpressure control and throttle control methods was carried out, while the numerical value of the total airflow with throttle control is 0.0569 m3⁄s and, with backpressure control, it is 0.0337 m3⁄s. Using a P controller in a linear model gives a transient oscillatory process damped in 2–2.5 s. When using a PID controller, the process has an overshoot equal to 11.5%, while the synergistic controller allows you to smoothly move the drive stem to a given position without overshoot. The parametric uncertainty analysis of the considered mathematical model is carried out. The model’s main parameters are identified, which change the actual functioning of the system under study. The inconsistency of applying classical control laws based on typical controllers to parametrically indeterminate mathematical models is shown.

A Fast and Accurate Frequency Tracking Method for Ultrasonic Cutting System via the Synergetic Control of Phase and Current.

Ultrasonic cutting is a superior machining process for brittle materials, owing to its capability to reduce the cutting force and improve the surface quality. To avoid the destructive instability of ultrasonic vibration induced by the cutting force, the excitation frequency of the ultrasonic system must reliably track its resonance frequency. However, it remains challenging for the conventional frequency tracking methods via one parameter to simultaneously achieve both high response rate and high tracking accuracy. This study proposes that more than one parameter could be coupled to get advantages from each parameter. A frequency tracking method via the synergetic control of circuit phase and current of the ultrasonic system was proposed as an example. This method utilizes the phase to responsively determine the tracking direction and uses the characteristic current as the endpoint frequency to ensure accuracy. Theoretical analyses and numerical simulations were conducted to demonstrate that the proposed method can accurately track the frequency of maximum vibration amplitude with a higher response rate than conventional methods. Moreover, ultrasonic cutting tests were performed on Nomex composites to evaluate the machining performance of the ultrasonic system with the proposed method. The experimental results verify that the proposed frequency tracking method enables the ultrasonic system to reach a stable state with a shorter response time, which is beneficial for the reduction of cutting-induced defects.

The Implementation of Synergetic Control for a DC-DC Buck-Boost Converter

In order to solve the nonlinear control problem of DC-DC Buck-Boost converter in switching power supply, the synergetic control method is adopted and applied to DC-DC Buck-Boost converters. Firstly, according to the characteristics of DC-DC Buck-Boost converter, we choose an improved macro-variable during the design of synergetic controller, which reduces the dynamic response time of the system. The synergetic control law of the system is also derived. Then, considering of the system robustness to the input voltage changes, we add a compensation amount to the control law, which can improve the control precision and make the system a good inhibitory effect to parameter change. Finally, the simulation results show the effectiveness of the proposed method.

Robust Control based on Synergetic Theory for Transformable Quadrotor

In this paper, a Synergetic Control (SC) is proposed for a transformable quadrotor exposed to external disturbances. This control strategy has a simple structure, smooth dynamics and good tracking performance. The SC is applied to our system, which has the particularity of changing its morphology during the flight. Numerical simulations are performed to demonstrate the efficiency of the suggested control approach, of which a qualitative and quantitative comparison with respect to Sliding Mode Controller (SMC) is made. Overall, the investigations show that this control technique outperforms in terms of accuracy and robustness.

Fuzzy Synergetic Control for Dynamic Car-Like Mobile Robot

Abstract This paper aims to present the dynamic control of a Car-like Mobile Robot (CLMR) using Synergetic Control (SC). The SC control is used to make the linear velocity and steering velocity converge to references. Lyapunov synthesis is adopted to assure controlled system stability. To find the optimised parameters of the SC, the grey wolf optimiser (GWO) algorithm is used. These parameters depend on the best-selected fitness function. Four fitness functions are selected for this purpose, which is based on the integral of the error square (ISE), the integral of the square of the time-weighted error (ITSE), the integral of the error absolute (IAE) and the integral of the absolute of the time-weighted error (TIAE) criterion. To go further in the investigation, fuzzy logic type 2 is used to get at each iteration the appropriate controller parameters that give the best performances and robustness. Simulations results are conducted to show the feasibility and efficiency of the proposed control methods.

Improved Synergetic Current Control for Grid-connected Microgrids and Distributed Generation Systems

This paper presents the development of improved synergetic current control for the injected current of an inverter in the grid-connected microgrid and the distributed generation system (DGS). This paper introduces new formulas of the macro-variable functions for integral synergetic control (SC) and integral fast terminal SC, which both have an integral term to guarantee zero steady-state error. The proposed integral SC and integral fast terminal SC achieve a seamless performance such as the fast convergence, minimal overshoot, zero steady-state error, and chattering-free operation. To demonstrate the meritorious performance of the proposed scheme for injected current control, it is compared with the performance of a proportional-integral (PI) controller and advanced exponential sliding mode control (SMC). Finally, the practicality of the proposed scheme is justified by experimental results obtained through rapid control prototyping (RCP) using the dSPACE-SCALEXIO platform.

Synergetic Control Strategy for Water Hammer Wave and Mass Wave in Hydropower Station With Downstream Channel

This paper investigates the synergetic control strategy for water hammer wave and mass wave in hydropower station with downstream channel. Firstly, the mathematical model of hydropower station with downstream channel (HSDC) and hydropower station with downstream channel and surge tank (HSDCST) are established. Then, the controller formula of HSDC and HSDCST are derived on the basis of the synergetic theory. Furthermore, it is parsed that the dynamic characteristics of HSDC and HSDCST to various disturbances under synergetic control strategy. Finally, the robustness and applicability of synergetic control strategy for HSDC and HSDCST are analyzed. The results indicate that the macro variable is the linear combination of state variables and their derivatives based on feedback linearization of the state equation. For the hydropower station under the synergetic control strategy, it has excellent dynamic characteristics employing sensitive response, small overshoot, fast attenuation speed and no static error. The synergetic control strategy is superior to the PID control strategy under various disturbances in controlling the amplitude of water hammer wave in HSDC, which is down 12.5%. The attenuation of mass wave in HSDCST under synergetic control strategy is faster, and the settling time is 6.16s less than that of PID control strategy. The synergetic control strategy is superior to the PID control strategy under various disturbances in controlling the amplitude of water hammer wave in HSDC and the attenuation of mass wave in HSDCST. Compared with PID control strategy, it is the robustness of synergetic control strategy that are much more advantageous for HSDC and HSDCST. Specifically, RI value is about 1.65, 0.18 for HSDC and 2.21, 0.25 for HSDCST under synergetic control strategy, while it is about 3.05, 1.20 and 3.32, 1.30 under PID control strategy. Moreover, the synergetic control strategy has a wide applicability in controlling the water hammer wave in HSDC and mass wave in HSDCST.

Fixed-time command-filtered backstepping control design for hydraulic turbine regulating systems

A novel practical fixed-time command-filtered backstepping strategy for a hydraulic turbine regulating system (HTRS) is developed in this paper. The developed controller is designed with the help of a combination of command-filtered backstepping and practical fixed-time stability theory. Based on this scheme, the obtained control strategy is utilized to ensure that the equilibrium point is practically fixed-time stable, and all signals of the closed-loop system are bounded within a fixed time. The main contributions of this paper are threefold: (i) The control scheme for frequency regulation of the HTRS is proposed to deal with the problem of the “explosion of terms” caused by conventional backstepping design. (ii) The proposed practical fixed-time control law can guarantee superior stabilization with a more precisely bounded convergence time, and (iii) The proposed controller performs well, simultaneously offers better transient performance, and overcomes three important drawbacks arising in the current results of fixed-time synergetic controllers. The strategy's effectiveness and feasibility are validated in a nonlinear model of the HTRS connected to a single-machine infinite bus power system. The numerical simulation indicates that the frequency regulation and improved transient performances in fixed time are achieved based on the proposed strategy. Further, the presented control reduces the oscillations rapidly and performs better than fixed-time synergetic control and modified fixed-time synergetic control approaches.