Output Transfer Function Research Articles

Automatic Voltage Regulator Control System for Synchronous Generator

Presented in this paper is Automatic Voltage Regulator (AVR) Control System for Synchronous Generator. A nonlinear model of synchronous generator was developed in Simulink and was later linearized as a single input single output (SISO) transfer function model. A Proportional Integral and Derivative (PID) controller was designed and by using the MATLAB/Simulink PID tuner, the gains of the proportional, integral and derivative parameters were obtained. A Low Pass Filter, F(s) was designed and introduced as part of the input signal to eliminate any noise effect that may be introduced into the AVR control system through the input. Simulations were carried out considering basically three scenarios viz: the AVR control system without the proposed PIDf + F(s) control scheme, the AVR with the proposed technique, and the AVR with the PIDf + F(s) with the introduction of disturbance in form of load variation at 25 seconds. The performance of the proposed scheme was compared with conventional PID control AVR system without F(s). The results of the comparison indicated that the proposed technique provided superior performance in terms of percentage overshoot and settling time. Generally, the PIDf with F(s) control scheme was more stable than the conventional PID controller as indicated by the percentage overshoot, which was 4.58% for PIDf and 4.28% for PIDf + F(s).

Automatic Voltage Regulator Control System for Synchronous Generator

Presented in this paper is Automatic Voltage Regulator (AVR) Control System for Synchronous Generator. A nonlinear model of synchronous generator was developed in Simulink and was later linearized as a single input single output (SISO) transfer function model. A Proportional Integral and Derivative (PID) controller was designed and by using the MATLAB/Simulink PID tuner, the gains of the proportional, integral and derivative parameters were obtained. A Low Pass Filter, F(s) was designed and introduced as part of the input signal to eliminate any noise effect that may be introduced into the AVR control system through the input. Simulations were carried out considering basically three scenarios viz: the AVR control system without the proposed PIDf + F(s) control scheme, the AVR with the proposed technique, and the AVR with the PIDf + F(s) with the introduction of disturbance in form of load variation at 25 seconds. The performance of the proposed scheme was compared with conventional PID control AVR system without F(s). The results of the comparison indicated that the proposed technique provided superior performance in terms of percentage overshoot and settling time. Generally, the PIDf with F(s) control scheme was more stable than the conventional PID controller as indicated by the percentage overshoot, which was 4.58% for PIDf and 4.28% for PIDf + F(s).

A novel modulation for four‐switch Buck‐boost converter to eliminate the right half plane zero point

AbstractThe four‐switch Buck‐Boost (FSBB) converter are widely used in combination with other isolated converter to extend the voltage range capability of the overall structure. When the converter operates in buck‐boost mode and boost mode, it exhibits a right half plane zero (RHPZ) in the control to output transfer function. This characteristic would cause negative impact to stability of the converter. In order to eliminate the RHPZ, a novel modulation method is proposed in this paper. The buck mode is introduced to the modulation to adjust the voltage gain, and the corresponding average state space modeling for the FSBB with the proposed modulation is established. The simulation of the converter with the proposed modulation method and traditional modulation are presented. Finally, experiment results by hardware in the loop (HIL) platform is employed to verity the correctness of theoretical analysis results.

Polarization-independent edge detection based on the spin–orbit interaction of light

In previous edge detection schemes based on the spin-orbit interaction of light, the direction and intensity of the edge-enhanced images are influenced by the incident polarization state. In this study, we develop an edge detection strategy that is insensitive to changes in both the incident polarization and the incident angle. The output intensity and transfer function remain entirely impervious to changes in incident polarization, being explicitly formulated as functions of the incident angle, specifically in terms of cot2⁡θ i and cot⁡θ i , respectively. This behavior is attributed to the opposing nature of the polarization components E~ r H−H and E~ r V−V in the x-direction after undergoing mapping through the Glan polarizer, while the sum of polarization components E~ r H−V and E~ r V−H in the y-direction can be simplified to terms independent of incident polarization. Furthermore, we propose a metasurface design to achieve the required optical properties in order to realize the derived edge detection scheme.

Modulation of electrodes on the sensitivity of the Pockels effect

In order to improve the sensitivity of the system in the Pockels effect, a design scheme for adding antennas at both ends of the crystal is proposed. Firstly, the influence of the applied electric field on the refractive index of the crystal is explored, and the relationship between the applied electric field and the output of the system is deduced. Secondly, two different antenna models are designed (one is to connect the antenna directly to both ends of the crystal, and the other is to connect the antenna after coating on the crystal), the distribution of the applied electric field in the internal field of the crystal under different models is studied, and the corresponding input and output transfer functions are analyzed. The analysis shows that the sensitivity of the system is improved in different antenna modes, and the crystal coating has little effect on the sensitivity. In addition, the antenna model without coating is simple to install, but the internal field strength of the crystal shows a tendency to be large in the middle and small at both ends, so it is easier to produce electric field breakdown effect in the strong field. The internal field strength distribution of the coated crystal is approximately uniform field, and the field strength maximum is smaller than that of the non-coated antenna model, so crystal breakdown is not easy to occur in the strong field. Finally, the effectiveness of the theoretical analysis is verified by experiments.

Prediction of Cutting Forces Obtained through Cryo-Treated and Untreated Cutting Tools Using Optimum ANN Determined by Taguchi Design

This experimental and statistical study addresses the prediction of cutting forces by using the optimum Artificial Neural Network employed by Taguchi design. For this purpose, input and output transfer function and training algorithm were selected as control parameters, while Mean Square Error was chosen as output parameters for evaluating optimum ANN structure with S/N ratios. ANN structure was optimized through Taguchi L9 orthogonal design, which occurred 5 set-up for utilizing all training function. According to MSE values of S/N ratios, each set-up was compared with the obtained prediction of making values of cutting forces to the optimal result. For each set, the hidden transfer function, output transfer function and training function used in the optimal ANN structure were determined. The optimal ANN structure for cutting forces obtained in turning experiments were logsig transfer function in hidden layer, Tlm training function and pureline transfer function in output layer, while R square was at 0.999945. It was found that ANN based Taguchi orthogonal design was successful in evaluating the experimental results.

Analysis of a DC converter working on a plasma arc

Introduction. The article is devoted to the analysis of a stabilized direct current converter operating on a plasma arc. Electroplasma technologies of the new generation cause the need to design workable systems that provide control of technological processes and their dynamic optimization in real time. The improvement of any electroplasma technology begins with the improvement of the operating parameters of the main element of plasma installations - the power source. Goal is to build and study a continuous model of a pulsed source of secondary power supply, which works on an electric welding and plasma arc. Methodology. In the work, a mathematical description of the converter was performed. The continuous model of the system is substantiated, taking into account its features, namely, the load (gas-discharge gap) is a source of voltage and dynamic resistance. The parameters of the constant part during circuit synthesis are determined: the components of the gain of the constant part, the relative signal coefficient of the current sensor and the PWM gain. Studies of the open system «power source - arc» have been carried out. Results. MATLAB objects were created - continuous mathematical models of the object in the form of transfer functions. The obtained transient characteristics for different options: «arc current - control signal» and « inductor current - control signal» showed that open systems are unstable. It was found that in the case of instability, the filling frequency of self-oscillations occurring in the linear mode is close to the frequency of natural oscillations of the circuit. The dependence of the module and the argument of the input resistance of the power part of the pulsed power supply with parallel capacitance to the electric arc and without it, which have matching frequency characteristics, is established. The circuit considered with the initial data adopted in this article has a frequency transfer coefficient of the same type as the first-order non-minimum-phase (phase-shifting) link. Frequency response graphs for the output impedance of the power unit show that this power unit is a broadband frequency-selective system with a bandwidth of B0.707 = 100 kHz. Originality. Expressions for the frequency transfer function, input and output resistance of the pulse voltage converter operating on an arc load were obtained by the method of averaging and linearization. The frequency amplitude and phase characteristics for the pulse voltage converter with an LC filter and the output according to the arc current and the choke current were studied. The transfer functions of the continuous model in terms of arc current and choke current at the specified parameters are the same, which must be taken into account when designing regulators. Practical significance. The frequency characteristics of the input and output resistances and transfer functions can be used when forming a technical task for designing a power source to assess the stability of the «pulse converter - arc» system and rational calculation of input filters.

Envelope-Detection-Based Accurate Small-Signal Modeling of Series Resonant Converters

Resonant converters have many desirable characteristics such as high efficiency, low component count and low electromagnetic interference production. The resonance phenomenon that enables this also makes their design and control a challenging process. Attempts have been made to determine the small signal control to output dynamics for resonant converters, however they either involve complex mathematics or numerical solutions which do not provide much insights and make it difficult to design controllers. This paper uses Fundamental Harmonic Approximation to model the different stages of Series Resonant Converter. Herein the small signal perturbations in control variable i.e. the switching frequency, result in perturbations in inductor current envelop that is analysed in the Laplace Domain. This current envelop is then used to analytically derive the control to output transfer function for the Series Resonant Converter. The modeling process is verified and validated by comparing the analytical frequency response with that obtained from Simulink simulation and experimental results. For wide output voltage application designs, the system performance and stability vary with the changing operating point. An example demonstrating the utility of the developed model in analysing such systems is also presented.

A Generalized Block-Matrix Circuit for Closed-Loop Analog In-Memory Computing

Matrix-based computing is ubiquitous in an increasing number of present-day machine learning applications such as neural networks, regression and 5G communications. Conventional systems based on von-Neumann architecture are limited by the energy and latency bottleneck induced by the physical separation of the processing and memory units. Inmemory computing (IMC) is a novel paradigm where computation is performed directly within the memory, thus eliminating the need for constant data transfer. IMC has shown exceptional throughput and energy efficiency when coupled with crosspoint arrays of resistive memory devices in open-loop matrix-vector-multiplication and closed-loop inverse-matrix-vector multiplication (IMVM) accelerators. However, each application result in a different circuit topology, thus complicating the development of reconfigurable, general-purpose IMC systems. In this paper, we present a generalized closed-loop IMVM circuit capable of performing any linear matrix operation by proper memory remapping. We derive closed-form equations for the ideal input/ output transfer functions, static error, and dynamic behavior, introducing a novel continuous-time analytical model allowing for orders-of-magnitude simulation speedup with respect to SPICE-based solvers. The proposed circuit represents an ideal candidate for general-purpose accelerators of machine learning.

Adaptive Control Algorithm for Two-Stage Integrated DC Transformer in DC Microgrid Applications

This paper presents the Two-Stage integrated DC Transformer (TSDCT) for DC Micro-Grid (MG) applications based on the Adaptive Control Algorithm (ACA). The prevailing control methods and design constraints employed in the DC transformer (DCT) do not consider the influence of the circuit's structural elements with their parasitic components on its performance. Consequently, it devalues the control variables that fail to achieve indispensable control features in the DC micro-grid network. Therefore, the proposed ACA is employed in the TSDCT, which improves the performance of TSDCT in comparison to the other control techniques in the DC micro-grid network. The proposed ACA includes the effect of the resonant tank circuit's parameters and converter's structural elements. Thereby, it defines the design constraints that significantly improve the performance of TSDCT in terms of efficiency and a wide range of voltage regulation at different buses. The detailed modeling and analysis are carried out at each stage to describe the principle and evolution of critical components involved in the ACA. Further, the control to output transfer functions are determined towards the implementation of the proposed ACA in the TSDCT. As a result, it exhibits voltage regulation in a wide range, soft-switching operation, high control resolution, and better performance under different operating conditions. Finally, a 4 kW laboratory platform is built, and test results validate the performance of the proposed TSDCT based on the proposed ACA for DC micro-grid applications.

A new step-up-down quadratic dc–dc converter with a single active switch

A novel step-up-down quadratic dc–dc topology is proposed. After performing the dc analysis, it is found that the proposed converter has a wide dc conversion ratio. The current and voltage stresses and ripples are determined alongside the continuous conduction mode (CCM) operation conditions. The correct converter operation is verified by simulation and then through the measurements on an experimental prototype. Additionally, a design algorithm is proposed together with an example of applying it for building a practical prototype. The design algorithm is implemented in a numeric computing platform. The state–space model is derived for both for the ideal case as well as considering the conduction losses. The control to output transfer function and the audiosusceptibility are computed. It is shown how the fourth order control to output transfer function can be well approximated by a second order transfer function. This approximation brings the advantage of simple controller design based on classical techniques. Both classical operational amplifier (Op. Amp.) based controllers and widely available controllers in the form of integrated circuits (ICs) can be used for the implementation, requiring only the calculation of elements in the feedback loop of the error amplifier. Based on the transfer functions of the converter and of the Laplace domain controller, a digital controller may also be derived. An example is presented and simulated to prove the correct operation of the closed-loop system.

On the zeros of three-DoF damped flexible systems

This paper presents an investigation of the non-minimum phase (NMP) zeros in the single input single output (SISO) transfer function of three-DoF (degrees of freedom) damped flexible linear time-invariant (LTI) systems under the assumption of classical damping. It is well-known that when all the modal residue signs of any multi-DoF damped flexible LTI system are the same, NMP zeros never occur in the system dynamics for any value of system parameters including modal residue, modal frequency and modal damping ratio. However, when all the modal residue signs are not the same, then additional conditions in terms of the system parameters are required to guarantee the elimination of NMP zeros. In this paper, the zero loci of a three-DoF damped flexible LTI system are developed to derive the sufficient and necessary conditions for the elimination of all NMP zeros. These conditions can be employed in the robust physical design of flexible systems, i.e., as long as these conditions are satisfied, the elimination of NMP zeros is guaranteed even when the system parameters undergo variations.

Educational aid for dynamic study of DC converter with Leverrier's and Pole clustering technique using simulation software

Abstract : In this paper, the dynamic analysis of the dc-dc converter is proposed with an educational aid to ease the process in which the study is carried out. This study's primary importance is that it can be added to the curriculum of Master's program in Electrical Engineering. This article mainly focuses on the mathematical modelling of the dc-dc converter with which the dynamic analysis is carried out to regulate the load and line condition. The main problems in the analysis of higher-order dc-dc converter is addressed with techniques available in the literature. A quadratic boost converter with DCL cell is chosen for studying the dynamic analysis with the flow of the technique proposed. The solution to the resolvent matrix of the converter is obtained using Leverrier's algorithm. The higher-order system's transfer function is reduced using the pole clustering technique to ease the controller design. Finally, the PI controller is tuned with Ziegler-Nichols tuning and it is incorporated with the converter using the reduced-order transfer function. The input to output transfer function is analyzed with the step response in MATLAB software and compared with the full order transfer function to validate the reduced-order transfer function. The closed-loop response is also validated both with full order and reduced-order system. Keywords : Bloom's taxonomy, Leverrier's algorithm, Pole clustering, DC-DC converter, dynamic, reduced-order, controller

Study of Capacitive Coupling Sensor Fused With High Voltage XLPE Cable Joint

A capacitive coupling sensor for partial discharge detection with the fusion of high voltage XLPE cable joint is designed in this paper. The sensor is to address partial discharge signals leading to transmission attenuation and external interference causing poor field detection sensitivity. First, a coaxial waveguide transmission model was established of high-frequency electrical signals in the body and joint. The result showed that the signal transmission attenuation was minimized while the sensor electrodes were closely attached to the outer semi-conductive layer of the body. Second, the equivalent circuit model was constructed of the capacitive coupling sensor fused with the 110 kV straight passing joint. The specific installation location, main structure size, detection bandwidth, and sensitivity of the sensor in the joint area were determined, which was to maximize the coupling output signal amplitude and transfer function amplitude. Finally, a lightning surge voltage test was carried out with the integration of the fusion of the joint voltage thermal cycling. Simulation and measurement show the following: while the sensor is installed in the cable metal sleeve break and the electrodes are closed to the overall semi-conductive layer, there is excellent performance for partial discharge detection in the frequency range of 1–300 MHz, with a sensitivity of 5 pC.

Analysis of Non-Minimum Phase System for AC/DC Battery Charger Power Factor Correction Converter

Electric mobility is nowadays one of the more important trends regarding pollution reduction and global warming due to fuel consumption. Big efforts are done in order to develop efficient and reliable power electronic systems for electric vehicles. In two stage on board-battery chargers, one way of improving efficiency is by means of ensuring the DC-DC isolated converter always operates in the nominal input/output voltage ratio, that could be achieved with a variable DC-link operation. In this paper, a four-switch buck-boost based AC/DC converter is deeply analyzed in order to improve its dynamic performance, the power factor and the total harmonic distortion. The converter suffers from a non-minimum phase characteristic in different input–output transfer functions, which reduces the closed-loop bandwidth of the system. Therefore, after a deep converter analysis has been done, different solutions have been evaluated and tested. Finally, a control to different output transfer functions of the converter become minimum phase, which allows us to increase the system bandwidth and, consequently, high power factor, low harmonics distortion, single control structure and fast dynamics for wide output voltage range are achieved.

Small-Signal Model of an Inductive Power Transfer System Using LCC–LCC Compensation

The LCC–LCC compensation is widely used in the inductive power transfer systems. However, there is no simple and accurate small-signal equivalent circuit model for this resonant converter. Based on the extended describing function method, this article proposed a full-order (17th-order) equivalent circuit model to accurately predict the small-signal behaviors. For simplification, the full-order model is gradually simplified to a ninth-order model and finally to a fifth-order model. The input to output transfer function are analytically derived for the first time. Both simulation and experimental results are presented to justify the effectiveness of the model, and the model is accurate up to one-fifth of the switching frequency.

Output Error Dynamic Models Identification and Transfer Function - A comparative study -

Output Error Dynamic Models Identification and Transfer Function - A comparative study -

Output Error Dynamic Models Identification and Transfer Function - A comparative study –

In this research, the transfer function models were diagnosed based on seasonal data represented by solar brightness as inputs and temperatures as outputs, where a double seasonal model was obtained which was used in diagnosing the transfer function models as well as diagnosing the output error models represented by the (OE) model and the (BJ) model and compared the results. Finding that the dynamic systems give a better diagnosis than the transfer function models, depending on some statistical criteria

Analytical tuning of 2‐DOF smith predictor control scheme for DC‐DC boost converter: A process control perspective

AbstractStringent voltage regulation in a DC‐DC boost converter is a classical engineering problems in theory of power conversion. Voltage Mode Control (VMC) of boost converter is difficult for two principal reasons. First and foremost, of these two reasons, is the converter's non‐minimum phase (NMP) behavior that arises due to the presence of the dynamic right half plane zero (RHPZ) in control to output (c2o) transfer function in VMC. Second reason is the presence of parametric uncertainties* in converter during its continuous conduction mode (CCM) operation. This paper combines theory of smith predictor with boost converter for (i) analytically computing gains of PID controller, (ii) design of a low pass filter to deal with challenges posed by dynamic RHPZ. This two degrees of freedom (2‐DOF) control scheme is analytically derived as a function of the converter's parameters. Gains of PID controller, deduced in terms of circuit's parameter, are used in sequel for extensive simulation analysis of the converter's control loop. Results in this paper establish that the proposed 2‐DOF‐SP outperforms certain well known control schemes used in regulating output voltage and disturbance attenuation in boost converter.

Large- and Small-Signal Average-Value Modeling of Dual-Active-Bridge DC–DC Converter With Triple-Phase-Shift Control

This article presents a novel reduced order average model for dual-active-bridge converter which can be applied to all modulation methods, such as single-phase-shift modulation, dual-phase-shift modulation, extended-phase-shift modulation and triple-phase-shift modulation. This model considers conduction, inductance, and transformer power losses. Furthermore, the input-output filters are suitable for system performance analysis. Based on the large-signal average model, the small-signal model and the output transfer function are derived. The detailed model for predicting the large-signal transient is established and the small signal analysis in frequency domain is carried out. This model can accurately predict the steady-state and transient-state response of the system. The experimental results agreed well with the simulation results which proved the accuracy and correctness of the model.