Nonlinear robust sliding mode - Backstepping hybrid control for WECS -theoretical design and experimental evaluation.

This paper proposes a new contribution in the field of optimizing control techniques for wind systems to enhance the quality of the energy produced in the grid. Although the Sliding Mode control technique, whether classical or involving the use of artificial intelligence, has shown interesting results, its main drawback lies in the oscillation phenomenon commonly referred to as "chattering." This phenomenon affects the accuracy and robustness of the system, as well as the parametric variation of the system. In this work, we propose a solution that combines two nonlinear techniques based on the Lyapunov theorem to eliminate the chattering phenomenon. It is a hybrid approach between the Backstepping strategy and the Sliding Mode, aiming to control the active and reactive powers of the doubly fed induction generator (DFIG) connected to the electrical grid by two converters (grid side and machine side). This hybrid technique aims to improve the performance of the wind system in terms of precision errors, stability, as well as active and reactive power. The proposed solution has been validated in the Matlab & Simulink environment to assess the performance and robustness of the proposed model, as well as experimentally validated on a test bench using the DSPACE 1104 card. The obtained results are then compared with other techniques, demonstrating a significant improvement in performance.

Analysis and Compensation of Phase Current Measuring Error Caused by Sensing Resistor in PMSM Application.

Field Oriented Control (FOC) effectively realizes independent control of flux linkage and torque, and is widely used in application of Permanent Magnet Synchronous Motor (PMSM). However, it is necessary to detect the phase current information of the motor to realize the current closed-loop control. The phase current detection method based on a sampling resistor will cause a measurement error due to the influence of parasitic parameters of the sampling resistor, which will lead to the decrease in PMSM control performance. This paper reveals the formation mechanism of the current sampling error caused by parasitic inductance and capacitance of the sampling resistor, and further confirms that the above error will lead to the fluctuation of the electromagnetic torque output by simulation. Moreover, we propose an approach for online observation and compensation of the current sampling error based on PI-type observer to suppresses the torque pulsation of PMSM. The phase current sampling error is estimated by the proportional and integral (PI) observer, and the deviation value of current sampling is obtained by low-pass filter (LPF). The above deviation value is further injected into the phase current close-loop for error compensation. The PI observer continues to work to keep the current sampling error close to zero. The simulation platform of Matlab/Simulink (Version: R2021b) is established to verify the effectiveness of online error observation and compensation. Further experiments also prove that the proposed method can effectively improve the torque fluctuation of the PMSM and enhance its control accuracy performance of rotation speed.

Safety-oriented automated vehicle longitudinal control considering both stability and damping behavior.

Extensive research has examined the potential benefits of Automated Vehicles (AVs) for increasing traffic capacity and improving safety. However, previous studies on AV longitudinal control have focused primarily on control stability and instability or tradeoffs between safety and stability, neglecting the importance of vehicle damping characteristics. This study aims to demonstrate the significance of explicitly considering safety in addition to stability in AV longitudinal control through damping behavior analysis. Specifically, it proposes a safety-oriented AV longitudinal control and provides recommendations on the control parameters. For the proposed AV control, an Adaptive Cruise Control (ACC) model is integrated with damping behavior analysis to model AV safety under continuous traffic perturbations. Numerical simulations are conducted to quantify the relationship between mobility and safety for AVs considering both damping behavior and control stability. Different ACC control parameters are evaluated in terms of damping and stability properties, and their safety impacts are assessed based on various surrogate safety measures such as Deceleration Rate to Avoid Crash (DRAC), Crash Potential Index (CPI) and Time-Integrated Time-to-collision (TIT). The results indicate that an underdamped state (ACC damping ratio < 1) is less safe than the critically damped state (ACC damping ratio = 1) and the overdamped state (ACC damping ratio > 1). Furthermore, given the same AV car-following time lag, ACC with a damping ratio between 1 and 1.2 provides better safety performance. Increasing the AV car-following time lag can improve both safety and stability when the remaining ACC control parameters are kept the same. In this case, the optimal safety-oriented ACC regions also increase. The findings of this study provide important insights into designing safe and stable AV longitudinal control algorithms.

Improved fractional order speed controller with non-linear VSI-IM model to enhance the load disturbance capability.

The conventional PI-based speed controllers are susceptible to speed tracking error and limited load rejection capability. This paper presents the high-performance fractional-order PI speed controller (FOPI) for field oriented control of induction motor (FOC-IM) drives with enhanced disturbance rejection capability. The design of FOPI involves third-order voltage source inverter fed induction motor (VSI-IM) model identification, fitting it into the required phase margin and gain margin constraints and Oustaloups fractional element approximation. The identification algorithm using the hardware-in-loop system is provided. The non-linear integer order VSI-IM model improves the tracking and dynamic performance of the drive. The designed FOPI speed controller performance is compared with the literature's existing FOPI controller design methods. The experimental analysis found that, in terms of speed tracking, parameter variations, inertia variations, and disturbance rejection capabilities, the suggested controller is more effective and resilient than existing tuning approaches.

Influencia del control orientado del balón con la planta del pie en el futsal infantil / Influência do controlo orientado da bola com a sola do pé no futsal infantil / Influence of oriented control of the ball with the sole of the foot in children's futsal

RESUMEN La investigación se desarrolló en niños de 1012 años de edad del combinado deportivo "Pueblo Nuevo" del municipio de Holguín. Tuvo como con el objetivo demostrar la influencia que tiene la técnica control orientado del balón con la planta del pie en los practicantes de Futsal, categoría infantil del combinado "Pueblo Nuevo" de Holguín, para desarrollar el juego rápido. Se utilizaron métodos y técnicas de nivel teórico y empírico; dentro de estos últimos se trabajó con la observación, la entrevista, la encuesta y la medición, que permitieron elevar el rigor científico de los elementos analizados procesados. Los resultados obtenidos permitieron demostrar por qué es de vital importancia utilizar durante el juego la técnica control orientado del balón con la planta del pie en el juego de futsal y, específicamente, desarrollarla desde edades tempranas. La investigación, además, realiza un análisis de esta técnica, atendiendo a las reglas y sistemas de juegos, basada en la revisión y análisis de investigaciones anteriores, en la observación directa en los entrenamientos y juegos de la categoría infantil del combinado deportivo "Pueblo Nuevo" del municipio de Holguín.

RESUMO A investigação foi realizada com crianças de 10-12 anos do complexo desportivo "Pueblo Nuevo", no município de Holguín. O seu objectivo era demonstrar a influência da técnica de controlo orientado da bola com a sola do pé em jogadores de futsal, categoria infantil da equipa "Pueblo Nuevo" em Holguín, a fim de desenvolver um jogo rápido. Foram utilizados métodos e técnicas teóricos e empíricos; dentro destes últimos, a observação, entrevista, inquérito e medição foram utilizados para aumentar o rigor científico dos elementos analisados processados. Os resultados obtidos permitiram demonstrar porque é de importância vital utilizar a técnica do controlo orientado da bola com a planta do pé no futsal durante o jogo e, especificamente, desenvolvê-la desde uma idade precoce. A investigação realiza também uma análise desta técnica, tendo em conta as regras e sistemas dos jogos, com base na revisão e análise de investigações anteriores, na observação direta em sessões de treino e jogos na categoria infantil da equipa desportiva "Pueblo Nuevo" no município de Holguín.

ABSTRACT The research began with children 10-12 years of age from the "Pueblo Nuevo" sports complex in the municipality of Holguín. It had as the objective: to demonstrate the influence that the oriented control technique of the ball with the sole of the foot has on Indoor football practitioners, a children's category of the Holguín "Pueblo Nuevo" team, to develop fast play. Theoretical and empirical methods and techniques were used; within the latter, observation, interview, survey and measurement were worked on, which allowed raising the scientific rigor of the elements analyzed and processed. The results obtained allowed to demonstrate why it is vitally important to use the oriented control technique of the ball with the sole of the foot during the game in the game of indoor football and, specifically, to develop it from an early age. The research, in addition, performs an analysis of this technique, taking into account the rules and game systems, based on the review and analysis of previous research, on direct observation in the training and games of the children's category of the sports team " Pueblo Nuevo ". " of the municipality of Holguin.

Development and empirical research of the perioperative fine management evaluation scale for process control / 中华医院管理杂志

Objective:To design an evaluation scale of perioperative fine management, and test it in hospitals, for verifying its effectiveness and sorting out problems in such management.Methods:November 2020 to August 2021, the scale framework was designed by using the process management theories featuring process-oriented control; then the scale was built based on a risk measurement indicators pool created based on policies, literature, standards and expert interview results on perioperative management; an empirical study was made in the end.Results:The scale consists of 209 risk measurement indicators and Likert 5-level scoring method was adopted to measure the possibility of problems in each respect. A total of 99 experts from 31 hospitals participated in the trial of the scale in 2021, and Cronbach α coefficient was 0.997, indicating good consistency among risk measurement indicators. The median of the average scoring of respective risk measurement indicators was 1.69. The most common problems in the perioperative management process include: lack of analysis and countermeasure research on the perioperative fine management; insufficient medical staff; poor awareness of medical staff in standardized and fine management. Conclusions:This scale can quantitatively evaluate respective aspects of perioperative fine management.

The Impact of Accountability-Oriented Control Aspects of Variance Investigation on Budgetary Slack and Moderating Effect of Moral Development.

Variance investigation (VI) has been identified as an effective mechanism to reduce budgetary slack at the ex ante budgeting stage. This paper focuses on two further research questions: (1) the extent to which two different accountability-oriented control aspects (i.e., external investigation and self-reporting) of VI affect budgetary slack and (2) the extent of the moderating effect of moral development on the relationship between these two accountability-oriented control aspects and budgetary slack. Our experimental results show that both external investigation and self-reporting can reduce the propensity of creating slack at the ex ante budgeting stage. More specifically, the effect of external investigation on reducing the propensity of creating budgetary slack is greater than that of self-reporting. This study further reveals that moral development moderates the effect of external investigation on budgetary slack. When comparing subordinates with low moral development with those with high moral development, our results show that the effect of external investigation on budgetary slack is stronger among the former group than the latter group. This study does not find any moderating effect of moral development on the relationship between self-reporting and budgetary slack. Our study sheds some new light on varying effects of two accountability-oriented control aspects of VI on budgetary slack, which are also moderated by different levels of subordinates' moral development. These results may be considered in the design and implementation of management control systems.

A Visualization and Control Strategy for Dynamic Minimization of Chemical Process Releases.

Our societal needs for greener, economically viable products and processes have grown given the adverse environmental impact and unsustainable development caused by human activities, including chemical releases, exposure, and impacts. To make chemical processes safer and more sustainable, a novel sustainability-oriented control strategy is developed in this work. This strategy enables the incorporation of online sustainability assessment and process control with sustainability constraints into chemical process operations. Specifically, U.S. Environmental Protection Agency (EPA)'s GREENSCOPE (Gauging Reaction Effectiveness for the ENvironmental Sustainability of Chemistries with a multi-Objective Process Evaluator) tool is used for sustainability assessment and environmental release minimization of chemical processes. The multivariable GREENSCOPE indicators in real time can be represented using a novel visualization method with dynamic radar plots. The analysis of the process dynamic behavior in terms of sustainability performance provides means of defining sustainability constraints for the control strategy to improve process sustainability aspects with lower scores. For the control tasks, Biologically Inspired Optimal Control Strategy (BIO-CS) is implemented with sustainability constraints so that the control actions can be calculated considering the sustainability performance. This work leads to a significant step forward towards augmenting the capability of process control to meet future demands on multiple control objectives (e.g., economic, environmental, and safety related). The effectiveness of the proposed framework is illustrated via two case studies associated with a fermentation system. The results show that the proposed control strategy can effectively drive the system to the desired setpoints while meeting a preset sustainability constraint and improving the transient sustainability performance by up to 16.86% in terms of selected GREENSCOPE indicators.

Supervisory predictive control for wheel slip prevention and tracking of desired speed profile in electric trains.

This article presents a supervisory model predictive control system to track the desired speed profile and simultaneously prevent the wheels from slipping in acceleration mode of electrical trains. The proposed control strategy employs field-oriented control (FOC) to control the angular speed of the wheel. Model predictive control (MPC) is used to control the longitudinal velocity of the train to track the desired speed profile and prevent the wheels from slipping by generating the desired angular velocity for the FOC. Since, it is not possible to control the longitudinal velocity and slip ratio independently, a fuzzy supervisor system is proposed to control the train dynamics at the appropriate operating point. A method is presented to estimate train longitudinal velocity and the adhesion coefficient between the wheels and rail surface. These components are vital to implement the proposed method in a real train control system. The closed loop stability of the control system has been studied. Simulations were run under different friction coefficients corresponding to real train parameters to verify the effectiveness of the proposed re-adhesion control system. The simulation results have been compared with the results of other researches to show the feasibility and validity of the presented approach.

Modelling and comparative dynamic analysis due to demagnetization of a torque controlled permanent magnet synchronous motor drive for energy-efficient electric vehicle.

In this paper modelling and comparative dynamic analysis of a field oriented controlled permanent magnet synchronous motor (PMSM) torque drive employing a hysteresis current controller and a PWM (Pulse Width Modulation) operated current controller is presented. To illustrate the proposed concept in this torque controlled drive, torque and mutual flux linkages are applied as external inputs and speed of the machine is kept fixed. Moreover the magnitude of torque angle as well as stator current reference is controlled through the proposed machine dynamics. In fact a computation based on demagnetization of direct axis current to achieve the flux weakening in this proposed drive for current compensation is also introduced. To achieve the faster computation and accuracy Euler's integration technique is used to solve the proposed complex dynamics of the permanent magnet synchronous machine. In a hysteresis current, controllers with a large hysteresis band current ripple and the torque pulsations are prominent at higher carrier frequency of the inverter. Additionally, a relationship with the magnitude of torque pulsations, PWM carrier frequency and the hysteresis window size is also achieved through various case-studies. Furthermore, the presence of current ripple and the pulsations generate some noise as well as vibration in a typical electric propulsion system. Afterwards a PWM current controller with identical operating conditions is proposed for such reduction of torque pulsation as well as ripples in the current waveform. Finally various feasible results are presented through MATLAB simulation and necessary hardware implementation to justify the comparative assessment of the proposed controllers for dynamic performance analysis in energy-efficient electric vehicles.

Application of quadratic linearization state feedback control with hysteresis reference reformer to improve the dynamic response of interior permanent magnet synchronous motors.

Interior Permanent Magnet Synchronous Motors (IPMSMs) offer excellent features, however, the dynamic complexity of these motors has always caused a challenge to control them. In addition, Field Oriented Control (FOC) method developed using Proportional-Integral (PI) regulators, which is the most implemented approach to control the IPMSM, is associated with slow dynamic response and saturation in the controller. This paper presents a novel control algorithm based on State Feedback (SF) regulator for IPMSM drives. The focus of the paper is on simplifying the dynamic of the IPMSM using nonlinear analysis methods and enhancing the response of the designed control approach. The development of the control system starts with linearizing the dynamics of the IPMSM. A linearization approach based on Quadratic Linearization Method (QLM) is proposed and then the linear model is used for designing a state feedback controller optimized by Linear Quadratic Regulator (LQR) method. Applying control constraints is a challenge in systems controlled by state feedback theory. Hence, the proposed control method offers a novel solution based on hysteresis control theory. The proposed hysteresis technique offers several advantages such as lowering overshoot in speed step response in addition to applying constraints and it eliminates all drawbacks of hysteresis controllers. To control the IPMSM in the whole speed range (constant torque and constant power regions), the proposed approach adopts Maximum Torque per Ampere (MTPA) and Voltage Constraint Tracking (VCT) control strategies. Finally, simulations are carried out in MATLAB/SIMULINK environment to compare the performance of the proposed controller with the conventional FOC method.

Virtual Current Sensor in the Fault-Tolerant Field-Oriented Control Structure of an Induction Motor Drive.

Designing electrical drives resistant to the failures of chosen sensors has recently become increasingly popular due to the possibility of their use in fault-tolerant control (FTC) systems including drives for electric vehicles. In this article, a virtual current sensor (VCS) based on an algorithmic method for the reconstruction of the induction motor (IM) phase currents after current sensor faults was proposed. This stator current estimator is based only on the measurements of the DC-bus voltage in the intermediate circuit of the voltage-source inverter (VSI) and a rotor speed. This proposal is dedicated to fault-tolerant vector controlled IM drives, where it is necessary to switch to scalar control as a result of damage to the current sensors. The proposed VCS allows further uninterrupted operation of the direct rotor-field oriented control (DRFOC) of the induction motor drive. The stator current estimator has been presented in the form of equations, enabling its practical implementation in a microprocessor system. Simulation studies of the proposed algorithm in an open and closed-loop DRFOC structure are presented under different operation conditions of the drive system. The experimental verification of the proposed method is also presented and the accuracy of the stator current estimation algorithm is analyzed under various operating conditions of the drive system.

Artificial Neural Network Application for Current Sensors Fault Detection in the Vector Controlled Induction Motor Drive.

This paper describes a Fault Tolerant Control structure for the Induction Motor (IM) drive. We analyzed the influence of current sensor faults on the properties of the vector-controlled IM drive system. As a control algorithm, the Direct Field Oriented Control structure was chosen. For the proper operation of this system and for other vector algorithms, information about the stator currents components is required. It is important to monitor and detect these sensor faults, especially in drives with an increased safety level. We discuss the possibility of the neural network application in detecting stator current sensor faults in the vector control algorithm. Simulation and experimental results for various drive conditions are presented.

Real time PI-backstepping induction machine drive with efficiency optimization.

This paper describes a robust and efficient speed control of a three phase induction machine (IM) subjected to load disturbances. First, a Multiple-Input Multiple-Output (MIMO) PI-Backstepping controller is proposed for a robust and highly accurate tracking of the mechanical speed and rotor flux. Asymptotic stability of the control scheme is proven by Lyapunov Stability Theory. Second, an active online optimization algorithm is used to optimize the efficiency of the drive system. The efficiency improvement approach consists of adjusting the rotor flux with respect to the load torque in order to minimize total losses in the IM. A dSPACE DS1104 R&D board is used to implement the proposed solution. The experimental results released on 3kW squirrel cage IM, show that the reference speed as well as the rotor flux are rapidly achieved with a fast transient response and without overshoot. A good load disturbances rejection response and IM parameters variation are fairly handled. The improvement of drive system efficiency reaches up to 180% at light load.

Stabilization of Structured Populations via Vector Target-Oriented Control.

In contrast with unstructured models, structured discrete population models have been able to fit and predict chaotic experimental data. However, most of the chaos control techniques in the literature have been designed and analyzed in a one-dimensional setting. Here, by introducing target-oriented control for discrete dynamical systems, we prove the possibility to stabilize a chosen state for a wide range of structured population models. The results are illustrated with introducing a control in the celebrated LPA model describing a flour beetle dynamics. Moreover, we show that the new control allows to stabilize periodic solutions for higher-order difference equations, such as the delayed Ricker model, for which previous target-oriented methods were not designed.

Non-linear backstepping control of five-phase IM drive at low speed conditions-experimental implementation.

In this paper non-linear backstepping control (BSC) is employed for high performance five-phase induction motor drive for low speed operation. The traditional control approaches such as direct torque control and indirect rotor field oriented control introduces stability problem at low speed. The proposed BSC is shown to offer stable operation in the sense of Lyapunov and high dynamics at low speed. Experimental results are provided to present the proprieties of the proposed approach at low speed in terms of stability, torque ripple, desired control performance, achievable dynamics and complexity of implementation etc.

Full-order Luenberger observer based on fuzzy-logic control for sensorless field-oriented control of a single-sided linear induction motor.

This paper investigates sensorless indirect field oriented control (IFOC) of SLIM with full-order Luenberger observer. The dynamic equations of SLIM are first elaborated to draw full-order Luenberger observer with some simplifying assumption. The observer gain matrix is derived from conventional procedure so that observer poles are proportional to SLIM poles to ensure the stability of system for wide range of linear speed. The operation of observer is significantly impressed by adaptive scheme. A fuzzy logic control (FLC) is proposed as adaptive scheme to estimate linear speed using speed tuning signal. The parameters of FLC are tuned using an off-line method through chaotic optimization algorithm (COA). The performance of the proposed observer is verified by both numerical simulation and real-time hardware-in-the-loop (HIL) implementation. Moreover, a detailed comparative study among proposed and other speed observers is obtained under different operation conditions.

Fault ride-through enhancement using an enhanced field oriented control technique for converters of grid connected DFIG and STATCOM for different types of faults.

With increase in electric power demand, transmission lines were forced to operate close to its full load and due to the drastic change in weather conditions, thermal limit is increasing and the system is operating with less security margin. To meet the increased power demand, a doubly fed induction generator (DFIG) based wind generation system is a better alternative. For improving power flow capability and increasing security STATCOM can be adopted. As per modern grid rules, DFIG needs to operate without losing synchronism called low voltage ride through (LVRT) during severe grid faults. Hence, an enhanced field oriented control technique (EFOC) was adopted in Rotor Side Converter of DFIG converter to improve power flow transfer and to improve dynamic and transient stability. A STATCOM is coordinated to the system for obtaining much better stability and enhanced operation during grid fault. For the EFOC technique, rotor flux reference changes its value from synchronous speed to zero during fault for injecting current at the rotor slip frequency. In this process DC-Offset component of flux is controlled, decomposition during symmetric and asymmetric faults. The offset decomposition of flux will be oscillatory in a conventional field oriented control, whereas in EFOC it was aimed to damp quickly. This paper mitigates voltage and limits surge currents to enhance the operation of DFIG during symmetrical and asymmetrical faults. The system performance with different types of faults like single line to ground, double line to ground and triple line to ground was applied and compared without and with a STATCOM occurring at the point of common coupling with fault resistance of a very small value at 0.001Ω.

Flux-torque cross-coupling analysis of FOC schemes: Novel perturbation rejection characteristics.

Field oriented control (FOC) is one of the most successful control schemes for electrical machines. In this article new properties of FOC schemes for induction motors (IMs) are revealed by studying the cross-coupling of the flux-torque subsystem. Through the use of frequency-based multivariable tools, it is shown that FOC has intrinsic stator currents disturbance rejection properties due to the existence of a transmission zero in the flux-torque subsystem. These properties can be exploited in order to select appropriate feedback loop configurations. One of the major drawbacks of FOC schemes is their high sensitivity to slip angular velocity perturbations. These perturbations are related to variations of the rotor time constant, which are known to be problematic for IM control. In this regard, the effect that slip angular velocity perturbations have over the newly found perturbation rejection properties is also studied. In particular, although perturbation rejection is maintained, deviations to the equilibrium point are induced; this introduces difficulties for simultaneous flux and torque control. The existence of equilibrium point issues when flux and torque are simultaneously controlled is documented for the first time in this article.

Analysis of field-oriented controlled induction motor drives under sensor faults and an overview of sensorless schemes.

To obtain high dynamic performance on induction motor drives (IMD), variable voltage and variable frequency operation has to be performed by measuring speed of rotation and stator currents through sensors and fed back them to the controllers. When the sensors are undergone a fault, the stability of control system, may be designed for an industrial process, is disturbed. This paper studies the negative effects on a 12.5 hp induction motor drives when the field oriented control system is subjected to sensor faults. To illustrate the importance of this study mine hoist load diagram is considered as shaft load of the tested machine. The methods to recover the system from sensor faults are discussed. In addition, the various speed sensorless schemes are reviewed comprehensively.