Quick Transient Response Research Articles

Deep-Learning Algorithmic-Based Improved Maximum Power Point-Tracking Algorithms Using Irradiance Forecast

Renewable energy is a key technology for achieving carbon-free energy transitions, and solar power systems are one of the most reliable resources for achieving this. Solar power systems have a simple structure and are inexpensive. However, depending on the input irradiance, the existing maximum output control algorithm (P&O) has disadvantages due to its slow transient response and steady-state vibration. Therefore, in this paper, we propose a maximum output control algorithm based on a deep learning algorithm that can predict the input irradiance. This can achieve a quick transient response and steady-state stability. The proposed method predicts the irradiance based on the output voltage/current and power of the photovoltaic (PV) system and calculates the duty ratio that can accurately follow the maximum output point according to the irradiance. The deep learning model applied in this study was trained based on the experimental results using a 100 W PV panel, and the performance of the proposed algorithm was verified by comparing its performance with that of the conventional algorithm under various input irradiance conditions. The proposed algorithm exhibits a maximum efficiency increase of 11.24% under the same input conditions as those of the existing algorithms.

Design and implementation of optimal controller for DFIG-WT using autonomous groups particle swarm optimization

<span>There are many types of generators used within wind energy such as doubly fed induction generator (DFIG). Particle swarm optimization (PSO) algorithm is simple, robust and easy to implement. In addition to the privilege of PSO, autonomous groups particle swarm optimization (AGPSO) has the advantages of using diverse autonomous groups which result in more randomized and directed search. Applying AGPSO to tune PI controller to control DFIG is proposed in this paper. An implemented laboratory prototype consists of brushless DC motor (BLDC) for simulating the various wind speeds. Wound rotor induction machine, working as DFIG. This system is a stand-alone system. System identification strategy was introduced in this work. In this study, AGPSO is suggested for tuning the PI controller. Different case studies are performed, such as step changes in both speed and electrical load for showing the effectiveness of the proposed algorithm. For comparison PSO is used to tune the PI controller. Results from experiments clarify the feasibility of the proposed methodology. It is approved that AGPSO achieves the prevalent control execution (quicker transient response and more modest steady state error (ess)) contrasted with the PSO in tuning PI controller when applied to be used with off-grid systems. </span>

A Comprehensive Review: Topology, Modeling and Control Techniques of Resonant Converter for Electric Vehicle Applications

This paper proposes the comprehensive review on the different resonant converter topologies, different modelling techniques, and different control techniques are being used in electric vehicle application. This paper also discusses the merits and demerits of different modulation/control techniques. The performance of variable frequency control technique can be improvised using SSPM is discussed in this paper. Optimal projectory control method has a quick transient response than SSPSM followed by SSOC, then PSM, and finally by VF controller are reviewed in detail in this study. Cyclic averaging is an accurate alternative method for state variable, this approach is used for time domain analysis of resonant dc-dc converter has been emphasized in this paper. Reverberation would be beneficial when series and parallel resonance converters combined are explained in this paper. LLC topology would be best suitable for electric vehicle applications are discussed and structure of the resonant converters, power efficiency, compatibility and its suitable applications are presented in this paper. A detailed study of modelling techniques to address the increasing demand for electric vehicles are presented.

Comparative Study of BLDC Motor Drives with Different Approaches: FCS-Model Predictive Control and Hysteresis Current Control

The control techniques of the brushless DC (BLDC) motor have gained a large amount of interest in recent years, with their use being implemented in order to achieve a high-performance drive, including quick transient response and high-quality waveforms at the steady state. This paper provides a comparative study between three control schemes of BLDC motors: the direct power control scheme using a finite control set model predictive control (FCS-MPC) approach, the stator current controlled scheme using an FCS-MPC approach, and the stator current controlled scheme using ON–OFF hysteresis current controllers. The three systems were studied and investigated under the same operating conditions. The comparative study included investigating the performance of the BLDC drive in both steady state and transient operations. Qualitative and quantitative analyses were performed on the results obtained with each control scheme. The obtained results demonstrate the validity and effectiveness of the three investigated schemes in controlling the motor speed to the desired value under sudden load changes and achieving satisfactory quick transient responses. However, the results indicate the superiority of the direct power control scheme using an FCS-MPC approach over the others in terms of its minimum torque ripple, lowest torque and speed pulsations, minimum active and reactive power ripples, and high-quality waveforms of the stator currents drawn by the motor with minimum THD.

Research on Self-Adaptive Algorithm of Transient Performance Analysis for DC Electronic Instrument Transformer Calibration

DC electronic instrument transformers (DCEIT) are widely used in the voltage source converter based high voltage direct current transmission (VSC-HVDC) system to measure the bus voltage or current, and should be of accurate and quick transient response. The transient performance of the DCEIT need to be calibrated using a calibrator. The existing schemes are difficult to recognize different transient step responses automatically, and usually require human intervention, which limits their flexibility and applicability. Besides, the accuracy of the calculated results is affected by human factors. A self-adaptive algorithm of transient performance analysis is proposed. It recognizes the characteristics of the transient step response based on wavelet analysis, and distinguishes the steady-state and step intervals automatically. Then it evaluates and finds the stable data segments in the steady-state intervals adaptively to calculate the high and low steady-state values. Finally, the data in the step interval are interpolated to search the feature points of the waveform, and then the transient response parameters are calculated according to the coordinates of feature points. In the validation stage, six kinds of step response waveforms are generated by MATLAB to test the performance of the proposed algorithm. Compared with the boundary window method, the proposed algorithm could recognize the characteristics of the tested waveforms automatically and achieve a more accurate analyses of transient performance. In addition, a calibrator prototype based on the proposed algorithm is developed, and some tests are carried out at the National Center for High Voltage Measurement (NCHVM) in China, whose results verify the feasibility of the algorithm.

Singularity-Free Fixed-Time Fuzzy Control for Robotic Systems With User-Defined Performance

In this article, the singularity-free adaptive fuzzy fixed-time control problem is studied for an uncertain n-link robotic system with the position tracking error constraint. The controlled robotic system can be described as a multiple-input-multiple-output system.To implement the user-defined performance, an improved error conversion mechanism based on performance functions is presented such that the converted error is limited to an interval greater than zero, and an appropriate barrier Lyapunov function (BLF) is constructed to avoid the breach of position tracking error constraint. The fuzzy approximator is utilized to estimate the unknown functions. The significance and challenges of this article are to establish a new error conversion mechanism and design corresponding BLF that can be integrated into fixed-time control design to present a singularity-free adaptive fuzzy fixed-time control scheme. Benefits of the proposed adaptive fixed-time controller in comparison to the current approaches are that it cannot cause the singularity issue appearing in backstepping-based fixed-time control design and ensures quick transient response. Combining with Lyapunov stability theory, the boundedness of the closed-loop signals is ensured, and the position tracking error can be constrained in the user-defined performance boundaries. Finally, simulation results demonstrate the feasibility of the proposed control strategy.

Fixed-Time Third-Order Super-Twisting-like Sliding Mode Motion Control for Piezoelectric Nanopositioning Stage

This paper presents a novel third-order super-twisting-like integral sliding mode controller (3-ISMC) for trajectory tracking of nanopositioning applications. Different from traditional sliding mode control methods presenting with chattering problems, the proposed approach provides continuous control inputs, which brings much convenience for practical applications. Moreover, the fixed-time convergence of the proposed 3-ISMC is guaranteed independently of initial conditions. The estimation of the fixed convergence time and stability are derived based on the Lyapunov method. Simulation results demonstrate that the proposed controller exhibits chattering free and quick transient response performance for a piezoelectric nanopositioning system under model uncertainties and external disturbances.

Simulation based of DC-DC Converter for AVR System and PID Controller with Tree Seed Algorithm based AVR System for Synchronous Generator

The voltage is supervised by AVR an automatic voltage regulator. It transforms the varying voltage into a constant voltage. The most prevalent cause of voltage fluctuation is changes in load on the supply system. An excitation system is a system that provides the necessary field current to the synchronous machine's rotor winding. The most important characteristics of an excitation system are dependability under all operating circumstances, ease of control, and ease of maintenance, stability, and quick transient response. In the literature, several control systems, such as in the literature, PID controllers, adaptive control methods, and intelligent control methods have all been suggested. On the one hand to get an accurate and quick generator terminal voltage control, the usage of a step down chopper in the exciter circuit is suggested in this study. DC-DC converters are also called as Choppers. The Step down chopper, It changes a given DC input voltage into a determined DC output voltage The input voltage source is tie up with governable solid state device that acts as a switch. Switches can be made using metal oxide semiconductor field effect transistors (MOSFETs) or insulated gate bipolar transistors (IGBT). The field circuit of the generator is associated to the chopper and a Praportional-Intigral controller deviates the converter duty cycle to vary the generator's terminal voltage. to regulate the generator field voltage. On the other hand, Tree-Seed Algorithm (TSA) algorithm based PID controller is put forward for automatic voltage regulator system. The suggested approach calculates PID coefficients to the best of its ability. The execution of this TSA-based optimum PID controller is compared to that of various PID controllers produced in the literature utilizing different meta-hermetic optimization techniques. Comparative research in for the suggested schemes has a superior transient response and is more resistant to fluctuations in Generator load and DC input voltage.

Dynamic Voltage Restorer (DVR) with a novel robust control strategy

With the advancement of technology, electric equipment and loads have become more sensitive to problems related to power quality, such as voltage sag, swell, imbalances, and harmonics. To detect faults and to protect sensitive loads from these voltage distortions, a Dynamic Voltage Restorer (DVR) series compensator is among the best available cost-effective solutions. One of the main goals of the DVR is to achieve a control structure that is robust, stable, and can handle properly the disturbances (e.g., grid voltage issues, load current, and fluctuations at the DC link voltage) and model uncertainties (e.g., inverters and filter parameters). In this work, a novel framework control strategy based on Uncertainty and Disturbance Estimator (UDE) is proposed to improve the response of the DVR to properly compensate the load voltage under a variety of power quality issues, particularly the ones associated with the grid voltage disturbances. Additionally, the stability of the proposed control system is analyzed and validated using the Lyapunov stability theory. The advantages of the new control system are robustness, simplified design, good harmonic rejection, low tracking error, fast response, and sinusoidal reference tracking without the need for voltage transformations or specific frequency tuning (e.g., abc-dq0 and Proportional-Resonant). This research uses the MATLAB/Simulink software to validate the effectiveness of the proposed scheme under a diverse set of conditions with no control limitations. Moreover, the designed controller is tested under real conditions using Hardware-In-the-Loop (HIL) validation with OPAL-RT real-time simulator coupled with a TI Launchpad microcontroller. The results demonstrate a good performance of the proposed control strategy for a quick transient response and a great harmonic rejection when subject to grid voltage distortions.

Adaptive nonsingular proportional–integral–derivative-type terminal sliding mode tracker based on rapid reaching law for nonlinear systems

This article deals with a novel adaptive robust controller for uncertain nonlinear systems relying on a proportional–integral–derivative-type nonsingular fast terminal sliding mode control. In this nonsingular proportional–integral–derivative-type terminal sliding mode controller nonsingular fast terminal sliding mode control, the nonsingular fast terminal sliding mode control sliding surface is modified with integral to match with the proportional–integral–derivative-type structure to obtain the essential attributes, namely, quick transient response, finite-time convergence, negligible steady-state error, and chattering cancellation. Furthermore, a novel rapid reaching law is also suggested with dynamic proof for providing the robustness during transient phase. The controller stability and convergence is mathematically analyzed using the Lyapunov theory. The overall control structure is simulated on MATLAB® software and tested for trajectory tracking of a two-degree-of-freedom revolute–prismatic joint industrial robotic manipulator. The rigorous test results show the performance efficacy of the innovative controller.

Teager Energy Operator for Fast Estimation of Three-Phase Grid Frequency

This article proposes a fundamental frequency estimation technique for three-phase voltage systems under unbalanced and harmonic conditions. It is based on the Clarke transformation, recursive discrete Fourier transform, and Teager energy operator. The proposed technique is computationally efficient and relatively simple to implement, thus suitable for low-cost applications. It does not require real-time evaluation of the computationally demanding inverse trigonometric functions. The proposed method does not suffer from the accumulation error and is also not affected when the voltage signal is sampled at zero or close to zero. It is immune to various voltage harmonics and can produce quick transient response with a time of less than 75% of one fundamental period. When compared with the competing techniques based on phase-locked loops and three consecutive samples, the proposed method can produce faster response under dynamic conditions. The advantages of the proposed technique are confirmed by simulated and experimental results in the laboratory.

High-voltage power supply for x-ray computed tomography and time-delay compensation of cockcroft-walton circuit

In recent years, an image diagnostic apparatus using X-ray is intensively investigated to reduce the radiation exposures amount. Above all, high-speed control of the high voltage generator to control the X-ray output is a very important issue. A Cockcroft-Walton circuit (CW circuit) is one of the method to generate the high voltage output. However, it has problem of the long time delay in the output response due to the huge capacitive component of the CW circuit. Therefore, it is required to achieve the stable output voltage with a quick transient response, which can be obtained by the time delay compensation technique of the CW circuit. This paper proposes an application of a Smith method to compensate for the time delay of the CW circuit output to reduce the undesirable excessive radiation exposure. AS a result of verification through the computer simulation, it has been confirmed that the overshoot of the output voltage can effectively be suppressed and that the optimal response can be realized without sacrificing the high-speed response. The paper indicates some possibilities of further improvement of the CW circuit output response by introducing the more precise compensation technique to the X-ray computed tomography.

A Bio-Inspired Global Finite Time Tracking Control of Four-Rotor Test Bench System

Introduction: We present a bio-inspired global finite time control using global fast-terminal sliding mode controller and radial basis function network to address the attitude tracking control problem of the three degree-of-freedom four rotor hover system. The proposed controller provides convergence of system states in a pre-determined finite time and estimates the unmodeled dynamics of the four rotor system. Methods: The dynamic model of the four rotor system is derived from Newton’s force equations. The unknown dynamics of the four rotor systems are estimated using Radial basis function. The bio-inspired global fast terminal sliding mode controller is proposed to provide chattering free finite time error convergence and to provide optimal tracking of the attitude angles while being subjected to unknown dynamics. The global stability proof of the designed controller is provided on the basis of the Lyapunov stability theorem. Results: The proposed controller is validated by (i) conducting an experiment through implementing it on the laboratory based hover system, and (ii) through simulations. Performance of the proposed control scheme is also compared with classical and intelligent controllers. The performance comparison exhibits that the designed controller has quick transient response and improved chattering free steady state performance. Conclusion: The proposed bio-inspired global fast terminal sliding mode controller offers improved estimation and better tracking performance than the traditional controllers. In addition, the proposed controller is computationally cost effective and can be implanted on multirotor unmanned air vehicles with limited computational processing capabilities.

Design and Experiment Evaluation of a Rotatable and Deployable Sleeve Mechanism Using a Two-DOF Piezoelectric Actuator

A rotatable and deployable sleeve mechanism using a longitudinal-bending composite piezoelectric actuator was designed, fabricated, and tested. A two-DOF piezoelectric actuator with single driving foot was designed to work as the driver of the deployable sleeve mechanism: it could push the inner sleeve with linear, rotary, or spiral stretching motions, which was controlled easily by applying different exciting signals. The stretching principles of the proposed deployable sleeve mechanism were illustrated in detail and verified by means of the finite element method. A prototype of the two-DOF piezoelectric actuator was fabricated and the deployable sleeve mechanism was assembled. The mechanical output characteristics of the inner sleeve were tested and discussed. The proposed deployable sleeve mechanism achieved the maximum linear and rotary stretching speeds of 530 mm/s and 240 °/s when the voltage amplitudes and exciting frequencies were $300\,\,V_{\mathrm {p-p}}$ and 22.35 kHz. The spiral stretching ability of the deployable sleeve mechanism was validated experimentally. The linear and rotary stretching displacement resolutions of the inner sleeve were tested to be about $2~\mu \text{m}$ and 0.0014°, respectively. The proposed deployable sleeve mechanism obtained quick transient response characteristics with a starting time of 28 ms and a stopping time of 20 ms.

Modified Single Phase SRF d-q Theory Based Controller for DVR Mitigating Voltage Sag in Case of Nonlinear Load

This paper mainly concentrates on design of improved controller and its implementation based on single phase synchronous reference frame theory (SRFT) for Dynamic Voltage Restorer (DVR) compensating voltage sag particularly for nonlinear load. In case of single phase distribution line with nonlinear load, the complexity of controller’s design becomes more serious issue. The present single phase and/or three phase theories applicable to DVR shows poor response to restore voltage sag in case of nonlinear load due to presence of harmonics. Hence restoration of voltage sag in single phase nonlinear load connected system has been a serious concern. Therefore, new controller for DVR has been proposed incorporating effective design concept for fundamental component extraction in case of nonlinear load. The single phase SRFT based main controller for DVR works on two separate closed path viz. feed forward path for quick transient response and feedback path for reducing the steady state error. Moreover, pre-sag mitigation strategy of DVR has been adapted through these two aforementioned paths. Complete design of proposed controller is based on phasor analysis. It also consist of proportional integral (PI) controller to reduce the error in the DC-link voltage during compensation time. The controller performance has been verified in MATLAB Simulink for both types (linear and nonlinear) of load. The results obtained indicates that the proposed controller is effective in its performance.

Online Computation of Hysteresis Boundary for Constant Switching Frequency Current-Error Space-Vector-Based Hysteresis Controller for VSI-Fed IM Drives

This paper proposes a current-error space-vector-based hysteresis controller with online computation of boundary for two-level inverter-fed induction motor (IM) drives. The proposed hysteresis controller has got all advantages of conventional current-error space-vector-based hysteresis controllers like quick transient response, simplicity, adjacent voltage vector switching, etc. Major advantage of the proposed controller-based voltage-source-inverters-fed drive is that phase voltage frequency spectrum produced is exactly similar to that of a constant switching frequency space-vector pulsewidth modulated (SVPWM) inverter. In this proposed hysteresis controller, stator voltages along α- and β-axes are estimated during zero and active voltage vector periods using current errors along α- and β-axes and steady-state model of IM. Online computation of hysteresis boundary is carried out using estimated stator voltages in the proposed hysteresis controller. The proposed scheme is simple and capable of taking inverter upto six-step-mode operation, if demanded by drive system. The proposed hysteresis-controller-based inverter-fed drive scheme is experimentally verified. The steady state and transient performance of the proposed scheme is extensively tested. The experimental results are giving constant frequency spectrum for phase voltage similar to that of constant frequency SVPWM inverter-fed drive.

A New Application Research of Time-Base Following Control in Non-Circular Contour Turning Lathe

On the base of analyzing the kinematics equations of non-circular machine tool, a new control algorithm is created by lathe tool kinematics principle, which based on the time-base method, in the non-circular machine tool have been verified on the experimental results show that the machining accuracy can be improved effectively. In order to obtain non-circular turning function relative to traditional CNC system, a new Open CNC systems was designed based on PMAC (programmable multi-axes controller) and linear motor. The research focused on the time-base following control between the CNC system and the linear servo systems used for the non-circular section turning. The advantages of the linear motor system directly driven by simple structure, quick transient response, high velocity and acceleration, high accuracy, little vibration and noise etc, which meets the requirements of manufacturing parts with non-circular section, and has been widely applied in the CNC forming and machining. To fit the crank non-circular contour, uses the high frequency linear servo motor to drive the tool move to-and-fro with high frequency, so the tool will track the crank non-circular contour with real time. With the results of several experiments for time-base following control with displacement feedback, the feasibility and efficiency of Open CNC system are verified.

Composite nonlinear feedback based discrete integral sliding mode controller for uncertain systems

In this paper, a discrete integral sliding mode (ISM) controller based on composite nonlinear feedback (CNF) method is proposed. The aim of the controller is to improve the transient performance of uncertain systems. The CNF based discrete ISM controller consists of a linear and a nonlinear term. The linear control law is used to decrease the damping ratio of the closed-loop system for yielding a quick transient response. The nonlinear feedback control law is used to increase the damping ratio with an aim to reduce the overshoot of the closed-loop system as it approaches the desired reference position. It is observed that the discrete CNF-ISM controller produces superior transient performance as compared to the discrete ISM controller. The closed-loop control system remains stable during the sliding condition. Simulation results demonstrate the effectiveness of the proposed controller.

A stable adaptive flux observer for a very low speed-sensorless induction motor drives insensitive to stator resistance variations

In recent years, numerous attempts have been made to improve the performance of sensorless induction motor drives. However, parameter variations, low-speed and zero-speed operations are the most critical aspects affecting the accuracy and stability of sensorless drives. This paper presents a stable adaptive flux observer (AFO) for sensorless induction motor drives insensitive to stator resistance variations. Design of the observer feedback gain of AFO is proposed to guarantee the stability, especially at low speeds. The adaptive law parameters are designed to give quick transient response and good tracking performance. The sensitivity of AFO to stator resistance mismatch is studied. A stator resistance adaptation scheme for accurate speed estimation at low speeds is derived. The relation between the identification error of rotor speed and adaptive gains is clarified based on Lyapunov theory. Experimental setup using DSP-DS1102 control board is implemented. Simulation and experimental results confirm the efficacy of the proposed approach.

A Signal-Processing Adaptive Algorithm for Selective Current Harmonic Cancellation in Active Power Filters

Selective harmonic cancellation has become of primary importance in a wide range of power electronics applications, for example, uninterrupted power systems, regenerative converters, and active power filters (APFs). In such applications, the primary objectives are an accurate cancellation of selected harmonics and a quick speed of response under transients. This paper provides a novel signal-processing algorithm for selective harmonic identification based on heterodyning, average finite-impulse response filters, and phase-locked loop (PLL). The algorithm is applied over the current of a nonlinear load in the feedforward-based control of an APF. The PLL tracks the phase and frequency of the fundamental component. Then, the fundamental phase is multiplied by the order of the selected harmonic, and two random unitary orthogonal axis waves are generated. These unitary waves, rotating at the harmonic frequency, are multiplied by the input load current, thereby moving the Fourier series coefficients of the selected harmonic to DC (heterodyning). Moving average FIR filters are used to filter the harmonics generated in the heterodyning process from the DC signal; average FIR filters are very suitable for most of the power quality applications, thanks to their comb-type frequency response and their quick transient response. Experimental results confirm good performance for steady-state harmonic cancellation and an optimal system response to load transients. The theory of the algorithm has been developed for single- and three-phase systems.