The Kuramoto model in complex networks

Synchronization of an ensemble of oscillators is an emergent phenomenon present in several complex systems, ranging from social and physical to biological and technological systems. The most successful approach to describe how coherent behavior emerges in these complex systems is given by the paradigmatic Kuramoto model. This model has been traditionally studied in complete graphs. However, besides being intrinsically dynamical, complex systems present very heterogeneous structure, which can be represented as complex networks. This report is dedicated to review main contributions in the field of synchronization in networks of Kuramoto oscillators. In particular, we provide an overview of the impact of network patterns on the local and global dynamics of coupled phase oscillators. We cover many relevant topics, which encompass a description of the most used analytical approaches and the analysis of several numerical results. Furthermore, we discuss recent developments on variations of the Kuramoto model in networks, including the presence of noise and inertia. The rich potential for applications is discussed for special fields in engineering, neuroscience, physics and Earth science. Finally, we conclude by discussing problems that remain open after the last decade of intensive research on the Kuramoto model and point out some promising directions for future research.

In this paper, a linear active disturbance rejection controller is applied for sensorless control of internal permanent-magnet synchronous motors. A hybrid position estimation strategy combining the high-frequency (HF) current injection for low-speed region with the electromotive force (EMF) estimation for high-speed region is presented. In contrast to conventional hybrid methods, the two schemes were integrated into the same control structure, and the position observer is embedded into the current controller. The high performance of position estimation was achieved using line extended state observers (ESOs). Compared with conventional sliding-model observer, the phase delay and speed chattering was obviously reduced. The robustness of the hybrid sensorless control system was well performed in the full-speed range. Experimental results were presented to verify the application of proposed method.

Application of Linear Active Disturbance Rejection Controller for Sensorless Control of Internal Permanent-Magnet Synchronous Motor

The most frequently used electrical machine in various modern high-performance drive applications is the induction motor (IM), especially its squirrel cage type rotor counterpart. The high-precision, efficient control of sensorless IM drives throughout its operating range demands an exact knowledge of a few of the IM parameters. The stator resistance, rotor resistances are such important IM parameters whose variations may lead to improper estimation of speed over the whole operating range in sensorless drives. Numerous methods for the estimation of speed of high-performance sensorless IM drives taking into account the effect of parameter variations have been developed. This paper aims at providing a review of the major model reference adaptive system (MRAS) based techniques applied for the estimation of speed of such sensorless drives. This paper is illustrated throughout with relevant mathematical equations, experimental and simulation results, associated to different MRAS-based sensorless vector control of the IM drive.

https://ietresearch.onlinelibrary.wiley.com/doi/pdf/10.1049/iet-epa.2014.0220

Review on model reference adaptive system for sensorless vector control of induction motor drives

Cascading failure analysis in power systems draws a wide attention from researchers due to frequent occurrence of blackouts all over the world during past decades. A variety of mathematical models and analysis tools have been proposed in order to better understand the complicated mechanisms during the cascading failure. This paper provides a brief overview on cascading failure analysis and categorizes the most relevant literatures and analysis models. Different features related to cascading failures have been demonstrated and discussed. Comparisons between different models have been presented. Advantages and disadvantages of these models are summarized. The paper also highlights the possible future trends.

A critical review of cascading failure analysis and modeling of power system

Permanent magnet synchronous motor (PMSM) will demonstrate chaotic phenomena when its parameters fall into a certain area. The performance of PMSM will degrade because of chaos. Therefore, chaos should be suppressed or eliminated. According to the features of this practical plant, the drawbacks of existing control methods are analyzed, and the nonlinear feedback control method is suggested to control the chaos in PMSM. The nonlinear feedback principle is developed using the direct axis and the quadrature axis stator voltage as manipulated variables. The control target will become a unique asymptotically stable equilibrium under the nonlinear feedback principle, by this way, the controlled states can reach the target and the control objective can be implemented. This method can be physically realized using nonlinear state feedback. The control forces can be put into effect at any time. The target of the method may be any point in the strange attractor. The influence of the model error and the measurement noise upon the control performance is studied via simulations. Simulation results show the effectiveness of this method under the presence of the model error and the measurement noise

Nonlinear feedback control of chaos in permanent magnet synchronous motor

The modern world fully relies on wireless communication. Because of intrinsic physical constraints of the wireless physical media (multipath, damping, and filtering), signals carrying information are strongly modified, preventing information from being transmitted with a high bit rate. We show that, though a chaotic signal is strongly modified by the wireless physical media, its Lyapunov exponents remain unaltered, suggesting that the information transmitted is not modified by the channel. For some particular chaotic signals, we have indeed proved that the dynamic description of both the transmitted and the received signals is identical and shown that the capacity of the chaos-based wireless channel is unaffected by the multipath propagation of the physical media. These physical properties of chaotic signals warrant an effective chaos-based wireless communication system.

Wireless communication with chaos

A novel robust control scheme employing three first-order auto-disturbance rejection controllers (ADRCs) is presented for the speed control of induction motor drives. Compared with the existing high-order ADRC-based speed control structures, the proposed method does not need to estimate the rotor flux. As a result, the implementation of the proposed scheme on a digital signal processor (DSP) is easier, and the runtime of the proposed ADRC control algorithm is shorter. The simulation results show that the proposed control scheme can cope with the internal disturbance and external disturbance, such as the motor's parameter variations, the load disturbances, etc. A TMS320F2812 DSP-based prototype using the proposed control scheme was developed. The comparative experimental results show that the robustness of the proposed ADRC system is obviously better than the conventional proportional–integral system when various disturbances occur, and the scheme is feasible and effective.

Robust Speed Control of Induction Motor Drives Using First-Order Auto-Disturbance Rejection Controllers

In this paper, a fractional-order model of pneumatic servo system is introduced by replacing the integer-order dynamic equation with the corresponding fractional order one. Then, a fractional-order proportional-integer-differential (FPID) controller is optimized for the servo system using an online multivariable multiobjective genetic algorithm (MMGA). The proposed MMGA searches in five-dimensional parameter space based on Pareto rank to balance multiobjectives. In order to provide a basis for comparison, the parameters of a integer order proportional-integer-differential (IPID) controller are also optimized using the same method. The performance indices defined for comparison are the steady-state tracking accuracy and the control energy consumption. Additionally, seven other methods from the literature are compared. The experimental results obtained show that the optimized FPID controller results in a better performance than the optimized IPID controller and the other existing approaches.

Optimal Design of a Fractional-Order Proportional-Integer-Differential Controller for a Pneumatic Position Servo System

The constraints of a wireless physical media, such as multi-path propagation and complex ambient noises, prevent information from being communicated at low bit error rate. Surprisingly, it has only recently been shown that, from a theoretical perspective, chaotic signals are optimal for communication. It maximises the receiver signal-to-noise performance, consequently minimizing the bit error rate. This work demonstrates numerically and experimentally that chaotic systems can in fact be used to create a reliable and efficient wireless communication system. Toward this goal, we propose an impulsive control method to generate chaotic wave signals that encode arbitrary binary information signals and an integration logic together with the match filter capable of decreasing the noise effect over a wireless channel. The experimental validation is conducted by inputting the signals generated by an electronic transmitting circuit to an electronic circuit that emulates a wireless channel, where the signals travel along three different paths. The output signal is decoded by an electronic receiver, after passing through a match filter.

/pdf/experimental-validation-of-wireless-communication-with-chaos-dlbkv8ovfs.pdf

Hai-Peng Ren

Papers

Nonlinear feedback control of chaos in permanent magnet synchronous motor

Wireless communication with chaos

Robust Speed Control of Induction Motor Drives Using First-Order Auto-Disturbance Rejection Controllers

Optimal Design of a Fractional-Order Proportional-Integer-Differential Controller for a Pneumatic Position Servo System

Experimental validation of wireless communication with chaos