Synchronous Control Method Research Articles

Research on the proportional-integral-derivative synchronous control method of the marine spherical isolation plug in the rotation process

The emergency pipeline repair technology is crucial to the maintenance and safety of pipelines under the emergency condition. In the offshore industry, the marine spherical isolation plug, a novel active plug device, is a significant emergency repair equipment of the hot tapping and line stop operation. In this article, the structure scheme and operation process of the marine spherical isolation plug are designed. A mathematic model is extracted from the proposed structure, and then the coordinates of the center of the spherical plug head is calculated using the D–H method. The displacements of the inserting hydraulic cylinder and the rotation hydraulic cylinder are investigated to provide the remote control data for the upper computer controller during the torsion process of the plug head. Moreover, a proportional-integral-derivative (PID) synchronous control method simulated by MATLAB is presented to reduce the rotation error of the plug head. To discuss the control strategy, a numerical model using ADAMS software is built. The results show that the error of the PID synchronous control method is more precise than that of the signal step-by-step control method; the number of steps of 90 is recommended in the actual operation. This article will provide theoretical guidance for the optimization design of the marine spherical isolation plug system.

Finite-time function projective synchronization control method for chaotic wind power systems

Wind power is a rapidly growing renewable energy source that plays an increasingly important role in power systems. However, its dynamic behaviors are complex because of the instability of wind speed, strong coupling, highly nonlinear subsystems, and mass grid connections. Chaotic oscillation is one of the most typical complex dynamic behaviors of wind power systems. This behavior can seriously influence the stable operation of wind power systems and cause great harm. This study proposed a control method for finite-time function projective synchronization on the basis of the chaos synchronization principle and finite-time theory for wind power systems. Wind power systems with or without uncertain parameters were considered. First, we built a high-dimensional wind power system and analyzed its chaotic behaviors. Lyapunov exponents were derived to prove the existence of chaos and bifurcation. Second, we aimed to increase the robustness of the controller by adding parameter observers to the controller. The result helped solve the problem of unknown parameters. If a wind power system comprises unknown parameters, the unknown parameters can be defined as the system's states. An unknown parameter observer was designed to realize the identification of unknown parameters. Third, we proposed a control method for finite-time function projective synchronization. Finite-time stability theory and function projective synchronization theory were used to construct the controller. These theories can ensure the quick synchronization of a chaotic wind power system with a stable wind power system in finite time. Finally, the mathematical proof of the stability theorem was derived, and a corresponding numerical simulation was performed to validate the chaos control method for wind power systems.

Research and experiment of a novel flower transplanting device using hybrid-driven mechanism

Aiming at decreasing the component complexity and cost of flower transplanting machine, an integrated transplanting method for picking and planting flower seedlings was proposed, and a hybrid-driven five-bar parallel mechanism was designed. A “beak-shaped” trajectory was designed for integrated transplanting requirements, and meantime, either the posture requirements of transplanting claw were determined. Based on the transplanting trajectory of the mechanism, a corresponding mathematical model for solving the link parameters was established, and then the five-bar mechanism was divided into two bar groups, optimization was conducted in two steps based on genetic algorithm and NSGA-II algorithm. Consequently, the optimal solution of the hybrid-driven five-bar parallel mechanism for flower seedling transplanting was obtained. Compared with similar designs, the trajectory displacement of the proposed mechanism is larger in the condition of smaller link size, which indicates that the mechanism can effectively decrease the machine size. The real-time controllable motor angular acceleration fluctuation is smaller and the commutation times are less, which has the advantage of reducing the difficulty of the mechanism control system. Subsequently, the correctness of the design method is verified by kinematics simulation. Finally, the synchronous linkage motion control methods of the two motors were designed, a transplanting experiment of the prototype was carried out, the picking success rate had reached 90%-93.4% and transplanting success rate was 80.5%-86.9% during experiment, which showed that the integrated operation of picking and planting flower seedlings can be realized by the proposed mechanism. Keywords: hybrid-driven mechanism, mechanism optimization, integrated operation of picking and planting, synchronous linkage motion control DOI: 10.25165/j.ijabe.20201302.5187 Citation: Zhao X, Zhang X S, Wu Q P, Dai L, Chen J N. Research and experiment of a novel flower transplanting device using hybrid-driven mechanism. Int J Agric & Biol Eng, 2020; 13(2): 92–100.

Inertia Response Improvement in AC Microgrids: A Fuzzy-Based Virtual Synchronous Generator Control

The absence of rotational masses from synchronous generators in converter-interfaced microgrids leads to a lack of inertia. Consequently, the system exhibits steeper frequency variations and higher frequency nadir, which may degrade the dynamic performance and challenge the operation of sensitive equipment such as protective relays in the grid. Virtual synchronous generator is introduced as an effective solution to increase the inertial response of converter interfaced renewable energy sources. This article proposed a fuzzy controller, which is augmented on the virtual synchronous generator topology to damp the perturbation during transients by increasing the inertia of the system. The proposed fuzzy control adds a correction term to the governor's output power that increases the system inertia during transients. In order to compare the inertial response improvement, a comparison between proposed fuzzy control technique and cost function based inertia and damping coefficient optimization is done on a virtual synchronous generator platform. It is shown that online measurement based adaptive methods have a better inertial response against other time-consuming techniques. To further verification, a number of experiments are done, which confirm the merits of the proposed fuzzy based virtual synchronous generator control method.

Fixed-time synchronization control for a class of nonlinear coupled Cohen–Grossberg neural networks from synchronization dynamics viewpoint

This paper is mainly concerned with fixed-time synchronization control for a class of Cohen–Grossberg neural networks (CGNNs) with nonlinear coupling and time-varying delay based on synchronization dynamics. First, by using a derived sufficient condition of fixed-time synchronization (FTS) for nonlinear coupled CGNNs (NCCGNNs) with time-varying delay, a novel fixed-time synchronization controller with time-varying delay is designed. Second, by combining the synchronization dynamic viewpoint and the obtained fixed-time synchronization control rule, several useful fixed-time synchronization controllers (FTSCs) are derived. Third, comparisons with known conclusions are provided to show the innovation and feasibility of the proposed fixed-time synchronization control methods. Finally, two examples are given to verify the effectiveness of the theoretical results. Compared with related works, the advantages of this paper are as follows: (1) The designed novel FTSCs can scientifically and efficiently process the time-varying delay of the addressed coupled CGNNs; (2) The derived settling time of the FTS built on FTSCs can reflect the effect of the proposed system’s parameters on the synchronization convergence time.

Synchronization for the integer-order and fractional-order chaotic maps based on parameter estimation with JAYA-IPSO algorithm

To enrich the processing means of secure communication, a novel synchronization control method is proposed based on parameter estimation technology. Unlike the traditional synchronization method, it does not need the control law and is only implemented by the parameter estimation. To realize the synchronization between two chaotic maps, a hybrid algorithm combining the JAYA algorithm with an improved particle swarm optimization (IPSO) algorithm is proposed for parameter estimation. Because there is no mathematical reasoning process, the novel method’s realization is simple, and it can theoretically be utilized for synchronization of various chaotic maps. In addition, the synchronization with unknown master system structure is also studied. Numerical simulations are carried out in two classical chaotic maps and their fractional-order form. Detailed experimental results demonstrate the effectiveness of the novel synchronization control method.

PMSG Control for a Stand-Alone Gas Engine Generator Using Active Rectifier and VSG-Controlled Inverter

The engine generator system with a diode rectifier causes harmonic currents in the generator which can affect generator efficiency and may produce torque oscillations. Using an active rectifier instead of a diode rectifier helps us to improve the current waveforms. In this paper, an active rectifier is used for a stand-alone gas engine generation system with a permanent magnet synchronous generator (PMSG). The generator side converter and the load side converter can be controlled separately to achieve high performance and reliability of the system. In the proposed control framework, the generator side converter is controlled by means of a current vector control method in a cascade structure with the synchronous reference frame (dq- frame). In the proposed control scheme, the dc link voltage is controlled by the generator side converter. For load side converter control, the concept of virtual synchronous generator control method is adopted to support a smooth power transient during the load changes. To verify the usefulness of the proposed control structure, using PSCAD software (version 4.2.1), the system transient responses with both a diode rectifier and an active rectifier are investigated under loading and load removal cases. Moreover, for the system with an active rectifier, the transient response of the system with different vector control strategies of PMSG is also investigated.

Synchronization Control of Complex Network Based on Extended Observer and Sliding Mode Control

The synchronization of complex networks is one of the key points to study the dynamic law of network. Due to the influence of external environment or physical conditions, nonlinear interference is inevitable. As a result, system parameters will not be obtained completely, which is not conducive to realize synchronization of network. In order to get system state variables and realize synchronization of complex networks with external interference. A synchronization control method is proposed based on the extended observer theory and sliding mode control theory in this paper. Firstly, aiming at the problem that the system state variables can’t be obtained accurately. A method of designing extended observer is proposed to observe the unknown state variables of system. Secondly, on the basis of getting the system state variables, in order to realize system synchronization control, the synchronization controller is designed based on the sliding mode control theory. And the correctness of this method is proved by Lyapunov stability theory. Finally, the validity of the proposed method is verified by simulation of Lorenz chaotic system of random 30-node and IEEE39-bus system.

Precise Linear-Motor Synchronization Control Via Cross-Coupled Second-Order Discrete-Time Fractional-Order Sliding Mode

This article presents a universal method of precise synchronization control for linear-motor-driven systems. The control method named cross-coupled second-order discrete-time fractional-order sliding mode control contains a cross-coupled control strategy to reduce the incoordination among driving linear motors. It also includes the second-order structure and fractional-order sliding mode surface to reduce the chattering phenomenon and improve the dynamic performance simultaneously, so that the precision is further enhanced. In particular, a universal definition of synchronization error is presented so that a better synchronization control performance can be achieved, especially in multidimensional systems. It is also compatible well with the contouring control, which extends the application further. Moreover, the stability of the controller is analyzed in this article. Finally, the proposed control method is conducted in simulations and experiments under various tasks, whose results have proved its effectiveness and advantages over conventional methods.

Research and experiment of a novel flower transplanting device using hybrid-driven mechanism

Aiming at decreasing the component complexity and cost of flower transplanting machine, an integrated transplanting method for picking and planting flower seedlings was proposed, and a hybrid-driven five-bar parallel mechanism was designed. A “beak-shaped” trajectory was designed for integrated transplanting requirements, and meantime, either the posture requirements of transplanting claw were determined. Based on the transplanting trajectory of the mechanism, a corresponding mathematical model for solving the link parameters was established, and then the five-bar mechanism was divided into two bar groups, optimization was conducted in two steps based on genetic algorithm and NSGA-II algorithm. Consequently, the optimal solution of the hybrid-driven five-bar parallel mechanism for flower seedling transplanting was obtained. Compared with similar designs, the trajectory displacement of the proposed mechanism is larger in the condition of smaller link size, which indicates that the mechanism can effectively decrease the machine size. The real-time controllable motor angular acceleration fluctuation is smaller and the commutation times are less, which has the advantage of reducing the difficulty of the mechanism control system. Subsequently, the correctness of the design method is verified by kinematics simulation. Finally, the synchronous linkage motion control methods of the two motors were designed, a transplanting experiment of the prototype was carried out, the picking success rate had reached 90%-93.4% and transplanting success rate was 80.5%-86.9% during experiment, which showed that the integrated operation of picking and planting flower seedlings can be realized by the proposed mechanism. Keywords: hybrid-driven mechanism, mechanism optimization, integrated operation of picking and planting, synchronous linkage motion control DOI: 10.25165/j.ijabe.20201302.5187 Citation: Zhao X, Zhang X S, Wu Q P, Dai L, Chen J N. Research and experiment of a novel flower transplanting device using hybrid-driven mechanism. Int J Agric & Biol Eng, 2020; 13(2): 92–100.

Sequence Impedance-Based Stability Analysis of AC Microgrids Controlled by Virtual Synchronous Generator Control Methods

In this paper, sequence impedance-based modelling is applied to two different grid-forming converters which are based on virtual synchronous generator (VSG) concepts including a dual loop voltage control. The considered controls only differ in the feedback design (PLL-driven or not) of the power-related control loop. In general, impedance modelling is a suitable method to analyse stability issues related to converter controls for use in larger power networks. In this work, the analytical model of a voltage-controlled converter is illustrated first. Sequence impedance models are then proposed, which do not only predict the effect of two different VSG controls on the systems stability, but also reveal its frequency coupling effect and analogy to the classical droop control. In addition, a small power system consisting of VSG-controlled converters is analysed by their equivalent output impedances. These models and the stability of the converter cluster are validated by time-domain simulations and laboratory experiments. The close correlation between sequence impedance model, time-domain simulation and experimental results confirms the effectiveness of the derived models.

Power Sharing and Synchronization Strategies for Multiple PCC Islanded Microgrids

Most of researchers have already studied and discussed the power sharing and synchronization of several generation systems connected to a unique point of common coupling (PCC) to which the loads are also connected. A high penetration rate of distributed generation systems (DGs) based on renewable energies has for logic consequence the development and setting up of networked multi-PCC microgrids. In this paper an improved droop control method for synchronization as well as active and reactive power sharing of different DGs in multiple PCC islanded microgrids is proposed while the real characteristics of the line feeders are taken into account. The simulation results confirm the feasibility and effectiveness of the proposed strategies for synchronization and interconnection of different microgrid DGs, while insuring accurate sharing of the DGs active and reactive powers. 

Disturbance Observer-Based Linear Matrix Inequality for the Synchronization of Takagi-Sugeno Fuzzy Chaotic Systems

This article presents a synchronization control method based on poles’ placement, disturbances, and uncertainty estimation (DUE) for a pair of Takagi-Sugeno fuzzy systems. First, a 3-D chaotic system was completely converted into a Takagi-Sugeno (T-S) fuzzy model by applying the nonlinearity sector method, which consists of if-then rules and sub-linear systems. Second, two identical T-S fuzzy systems with different initial conditions were synchronized by applying the linear matrix inequality (LMI) to place the eigenvalues of the state error equations in the stable region. Third, the sum of the time-varying disturbances and uncertainties of two nonidentical T-S fuzzy systems were deleted by a disturbance and uncertainty estimation. The given output signals confirmed that the proposed method is suitable and ideal for synchronizing T-S fuzzy systems. The ideas of control theory were implemented by using two experimental scenarios in MATLAB Simulink for two computers connected via an internet router and an electronics circuit’s communication.

Optimization of maximum torque output in the wide speed range of a PMSM traction control system

This paper introduces a permanent magnet synchronous motor maximum torque control method for the wide speed range of a traction control system. This method tracks the maximum torque per ampere operating point and generates a d-axis current command according to the injection of a high-frequency angle signal to the current. This method is parameter independent when looking for the maximum torque per ampere operating point. By not injecting any real signal to a permanent magnet synchronous motor, this method does not increase the amount of copper and iron losses resulting from real signal injection. To obtain a maximum torque output in a wide speed range, this method considers the maximum amplitude limits of voltage and current when the traction motor runs in a flux weakening control field. This method is also robust to current and voltage harmonics, speed mutations, and torque disturbances. Experiment and analysis are conducted on a permanent magnet synchronous motor traction control system prototype under various operating conditions to verify the effectiveness of this method.

An Unscented Kalman Filter-based Synchronization Control Approach for Communication-Based Train Control Systems

Communication-based train control (CBTC) system is an advanced train signalling and control technology which is developed using the moving block signalling (MBS) framework. The CBTC system has been shown to be capable of improving the operational efficiency, line capacity and safety of the railway operation. The main objective in implementing the MBS framework in CBTC system is to minimize the train headways through the utilization of an inter-train continuous communication system that determine and control the position of each train more precisely. One important challenge in such an implementation is the fulfillment of the necessary requirement of having highly accurate train localization method to ensure the safety of the short headway operation. This paper describes the results from experimental examination and application of a synchronization control strategy for the CBTC system using an unscented Kalman filter (UKF)-based sensor fusion approach as the localization method. In the proposed approach, the train localization task is performed using an UKF-based sensor fusion method which fuses measurement data from speed sensors and radio frequency identification tags. A synchronization control approach to ensure the safety movement of the train convoy in curved railway tracks under the MBS scheme is then proposed. The results presented in this paper show that the proposed localization and synchronization control methods can significantly improve the localization accuracy and reduce the inter-train headways.

The Characteristics and Suppression of Common-Mode Current for Brushless Doubly Fed Generator System

Due to the cancellation of the brush and slip ring, the brushless doubly fed generator (BDFG) is more reliable than the doubly fed induction generator and it has wide prospect in the field of variable speed constant frequency power generation. However, the internal structure of BDFG is complex, which brings difficulties to the analysis of common-mode circuit and the suppression of common-mode current. Based on the structure of BDFG system, the common-mode voltage circuit paths are analyzed. The common-mode equivalent circuit model and the extraction method of equivalent common-mode impedance parameters are presented in this article. The characteristics of each common-mode circuit path are analyzed. The common-mode Path 3 (line-side converter-motor power winding-motor control winding-machine-side converter-line-side converter) is an important factor that affects the common-mode current characteristics of the BDFG system. The relationship between carrier difference and common-mode current characteristics of two pulsewidth modulation converters, in this path, is analyzed emphatically. In order to reduce the common-mode voltage, it is necessary to ensure the carrier synchronization between them. And the control method of carrier synchronization is provided. The experiment is designed based on the experiment platform of the BDFG system. The experimental results verify the correctness of the proposed model and theoretical analysis, as well as the effectiveness of the common-mode current suppression method.

Synchronous Commutation Control of Doubly Salient Motor Drive With Adaptive Angle Optimization

Due to the strong nonlinearity of the commutation process of doubly salient motors fed by square-wave currents, it is difficult to establish accurate models and design an appropriate commutation control strategy to achieve satisfactory commutation performance. The synchronous commutation control method is proposed to improve commutation control. By introducing an additional angle loop to synchronize the zero crossings of the phase current and the alignment of the core poles, the commutation angle can be adaptively optimized without requiring the accurate model. Also presented is a vector control scheme during the commutation process to shape the trajectory of the current vector into a regular hexagon. Based on the linearized model of the commutation process, the digital control law to synchronize the zero crossings is designed with robustness considered. Finally, simulations and experiments were conducted. The results show less commutation torque loss with the method. Ultimately, the method provides a high torque-to-current ratio and low-torque ripple at a wide range of speeds.

Synchronization Control and Circuit Implementation of Fractional-order Rabinovich Hyperchaotic System

In this paper, a synchronization controller is designed for fractional Rabinovich hyperchaotic system. The fractional Rabinovich hyperchaotic system is solved and the phase diagram is drawn by improved Adomian decomposition method. At the same time, an adaptive synchronization control method is proposed based on Lyapunov stability theory of fractional nonlinear system. Multisim software is used to simulate the synchronization controller. The simulation results show the effectiveness of the control strategy.

Synchronization Control Method of Information Flow in Coastal Logistics Supply Chain under Asymmetric Information

Wei, H., 2019. Synchronization control method of information flow in coastal logistics supply chain under asymmetric information. In: Guido-Aldana, P.A. and Mulahasan, S. (eds.), Advances in Water Resources and Exploration. Journal of Coastal Research, Special Issue No. 93, pp. 1087–1092. Coconut Creek (Florida), ISSN 0749-0208.Traditional methods have poor security and cannot solve the imbalance of benefit distribution caused by information flow sharing, and their overall performance is poor. Therefore, a new synchronous control method of information flow in construction supply chain under asymmetric information is proposed. According to the needs of participants in the construction supply chain for various information flows, the information in the central database is divided into blocks. Each participant and different information blocks correspond to each other. Each participant is provided with different rights. The corresponding information is obtained through user verification, and the data flow security control is realized. By calculating Shapley value, a Shapley value model of benefit distribution in information flow of construction supply chain under asymmetric information is constructed. Aiming at the disadvantage of ignoring the influence of other factors on benefit distribution under asymmetric information, this model comprehensively analyzed the four external factors of participant's benefit distribution: input proportion, risk sharing coefficient, performance degree value and participant's contribution value, completed the improvement of Shapley model, obtained benefit distribution value, and gave the process of determining risk sharing coefficient and contribution value. The experimental results show that the proposed method can guarantee the security of information flow synchronization control, and the results of benefit allocation are more balanced.

Chaotic synchronization based on fractional order calculus financial system

Abstract This paper uses the coupled synchronization control method to study the chaotic synchronization problem of fractional calculus financial systems. Firstly, the paper couples the control variables to each equation of the fractional financial system to synchronize the drive system and the response system. Secondly, the coupled control variables are added to each equation to synchronize the response system of the financial system. At the end of the thesis, the Laplace transform theory is used to prove the effectiveness of the method used in this paper.