Converter Parameters Research Articles

Frequency‐Power Coupling Dynamic Response and Regulation Characteristics of Variable Speed Pumped Storage Unit With Full‐Size Converter

ABSTRACTThis paper aims to study the frequency‐power coupling dynamic response and regulation characteristics of a variable speed pumped storage unit (VSPSU) with full‐size converter (FSC). Firstly, the mathematical model of VSPSU with FSC is established. Secondly, the dynamic response of VSPSU with FSC under power disturbance is simulated, and the effect of operating speed on dynamic response of VSPSU with FSC is analyzed. Then, the frequency‐power coupling regulation characteristics of VSPSU with FSC are revealed. Finally, the dynamic responses between VSPSU with FSC and fixed speed pumped storage unit (FSPSU) are compared. The results show that, with the same disturbance amplitude, the variation times of speed and output under positive power disturbance are longer than those under negative power disturbance. With a negative power disturbance of larger amplitude, the speed and output of VSPSU have a faster response. The regulation characteristics of VSPSU can be improved by adjusting both the parameters of governor and converter based on the operation requirements. Under both the positive and negative power disturbances, the dynamic response of active power of VSPSU is faster than that of FSPSU. Under the negative power disturbance, the dynamic response of speed of VSPSU is slightly slower than that of FSPSU.

Modified input-to-output and control-to-output transfer functions of a non-ideal buck converter working in discontinuous conduction mode

Small-signal models of a buck converter working in the discontinuous conduction.mode that are available in the literature usually can be divided into those which contain.a single pole and refer to non-ideal converters and those that describe ideal converters and.contain two poles. Even though the models are noticeably different they have been validated.through simulations and measurements, which suggests both of them are correct. The.purpose of this paper is to provide a comprehensive comparison of the existing models with.transient simulations done in OrCAD software and through measurements, to show that both.of the mentioned models are true for a specific set of converter parameters, and to propose.a two-pole, control-to-output and input-to-output transfer functions of a non-ideal buck.converter, that can be used in any buck converter working in discontinuous conduction mode.

Array Optimization for a Wave Energy Converter with Adaptive Resonance Using Dual Bayesian Optimization

A novel Dual Bayesian optimization strategy is formed for an array of wave energy converters with adaptive resonance to maximize the annual performance through the energy conversion processes from irregular waves to electricity. A wave energy converter with adaptive resonance changes the natural frequency of power take-off dynamics for varying irregular waves, resulting in the maximum annual energy production. The first step of the two-step Dual Bayesian optimization determines the geometric layout of the array, which maximizes the first energy conversion to the total array excitation for irregular waves occurring annually. The second step optimizes the operational parameters of individual wave energy converters in the optimized array to maximize the power generation in varying sea states through simultaneous conversion to mechanical and electrical energy. The coupled hydrodynamics are solved in the frequency domain, and the power performance is evaluated by solving the Cummins’ equation in the time domain extended for multiple floating bodies, each strongly coupled with nonlinear power take-off dynamics. The proposed method is applied to a surface-riding wave energy converter, already optimized for single unit operation at individual sea states. Investigating two array layouts, linear and random, the optimized arrays after Step 1 increase the excitation spectral area by up to 40% relative to the single unit operation, indicating the synergy enhancing the first energy conversion. Subsequently, the dual-optimized linear layout attained a q-factor up to 1.13 in commonly occurring sea states, achieving improved average power generation in 60% of the evaluated sea states. The performance of the random layout exhibited the average power fluctuating along the wave spectra with a peak q-factor of 1.07. The individual adaptive resonance is confirmed in the optimized arrays, such that each surface-riding wave energy converter of both layouts adaptively resonates with the peak of the wave excitation spectra, maximizing the power generation for the different irregular waves.

Analysis and Fuzzy Neural Networks‐Based Inertia Coefficient Adjustment Strategy of Power Converters

ABSTRACTWith the development of new energy generation technology and power electronic technology, power electronic equipment occupies an increasing proportion of the power system, and its control flexibility makes the power system complicated, bringing problems such as low inertia, low damping, high harmonics, low reliability, and weak anti‐interference ability. Especially the influence of converter on inertia of power system, even causing excessive frequency fluctuations, leading to the collapse of the power system. In view of the inertia problem of converters, this article starts with the principle of converters and analyzes the inertia transmission characteristics of different types of converters in power systems by three types of control strategies. Based on the influence of the inertia parameters of converters on system frequency and power, a converter inertia target function is established, and a neural network adaptive adjustment strategy for converter inertia coefficient is proposed to achieve self‐adaptive optimization of converter output power and system frequency. The corresponding converter model is established, and the simulation circuit and control model are built by Simulink to verify the inertia transfer characteristics. The simulation results show the correctness of the relevant theories and provide theoretical support for the inertia design of high‐proportion power electronic systems.

Determination of converter parameters for high-voltage electromechanical systems of stationary installations of industrial fans

Purpose. To study the electromagnetic processes in the circuit of the phase rotor of a high-voltage induction motor connected to the network through a step-up converter, to determine the parameters of the converter and their relationship with the voltage gain to ensure the optimal level of energy efficiency of the electromechanical system. Methodology. Methods of theoretical electrical engineering for the construction of a rotor circuit replacement scheme for an induction motor with a step-up converter, methods for solving a system of first-order differential equations, analytical methods. Findings. The expediency of using a converter that combines the rotor circuit of a high-voltage induction motor with the power supply network and provides regulation of the rotor EMF with the recovery of the slip energy of the induction motor rotor to the power supply network has been proved. This will ensure speed control of powerful high-voltage induction motors on the rotor side with an EMF of up to 600 V and significantly reduce the cost of a high-voltage electromechanical system. A methodology for determining the converter gain and the parameters of the rotor circuit of the electromechanical system is proposed, which allows determining the transformation ratio of the matching transformer at the optimal value of the voltage gain. The conditions of trouble-free operation of the inverter at the moment of start-up of the electromechanical system are determined. Achieving these conditions is ensured by determining the delay of the control signal to the power keys of the inverter of a step-up converter. The correlation between the voltage gain and the equivalent resistance of the rotor circuit of the electromechanical system is established. Originality. The ratio of the voltage gain to the equivalent resistance of the rotor circuit of the electromechanical system is established, which will ensure the matching of the rotor EMF with the voltage of the power supply network while maintaining a high level of energy efficiency. Practical value. A methodology for determining the gain and parameters of a step-up converter is proposed, which allows determining the transformation ratio of a matching transformer at the optimal value of the voltage gain. The proposed methodology can be applied to the modelling of complex powerful high-voltage electromechanical systems, especially for stationary installations of industrial fans.

Adaptive output feedback control of a bidirectional AC/DC totem‐pole PFC converter for wireless charging of electric vehicles

AbstractThis paper deals with the control problem of a single‐phase bidirectional alternating current/direct current (AC/DC) totem‐pole power factor correction (PFC) converter intended to be used in wireless power transfer (WPT) chargers for electric vehicles (EVs). The converter is operating as a bridgeless boost rectifier with the PFC functionality during grid to vehicle (G2V) mode and as a PFC inverter during vehicle to grid (V2G) mode. Firstly, the operating principle is presented. Secondly, an overall mathematical model governing all the operating modes of the converter is elaborated. Thirdly, due to the nonlinearity of the studied system, a nonlinear controller–based Lyapunov technique is designed to achieve the following control objectives: (i) unity power factor (UPF) during both power transfer modes G2V and V2G, (ii) regulation of the DC‐link voltage, and (iii) asymptotic stability of the closed‐loop system. Further, as the developed control law requires the measurement of all voltages and currents, an adaptive observer–based Kalman‐like technique is designed to estimate all the required signals and parameters. The performances of the proposed output feedback control technique are validated through several simulation scenarios showing that all control objectives are achieved. It should be noted that the use of the Kalman observer reduces the complexity of the systems as it requires only two measurements (grid voltage and current) making it an advantageous solution over existing solutions where three measurements are generally used. Furthermore, due to the low‐pass filtering behavior of the observer and its susceptibility to estimate the converter's parameters, the robustness of the controller and its insensitivity to the parameter uncertainties are greatly improved.

Ripple of a DC/DC converter based on SEPIC topology

Mathematical models serve as the basis for unified methods for the calculation and designing of radio-electronic devices. The developed limiting continuous mathematical model of a DC/DC converter, built using SEPIC topology, allows to determine the range of changes in currents flowing through the inductor windings and voltages on the capacitor plates, as well as to determine their maximum and minimum values for various converter parameters, such as switching frequency of the power switch, fill factor, element ratings, etc. The research results have shown that the phase coordinates of the mathematical model tend to the real values of currents and voltages of the converter when the switching frequency of the power switch is more than 200 kHz. Correspondence is established between the calculated values of the pulsation ranges and the results obtained during modelling (with changes in the filling factor and switching frequency of the power switch).

New electric starter system based on on-board power network with hydrogen energy storage

Current trends in industries related to autonomous, mobile objects, such as aircraft manufacturing, are aimed at increasing the share of electrification or completely replacing all units in favor of electric ones. Replacing components and assemblies with fully electric ones corresponds to the concept of a fully electric aircraft, which is based on new power sources and sources of electric propulsion, such as lithium-ion batteries, hydrogen batteries, and sources based on renewable energy. At the same time, the requirements for energy efficiency and weight and size parameters of components and assemblies are increasing. These needs can be met through the multi-purpose use of equipment, as well as through new systems that combine a number of functions.The article discusses the use of an aircraft three-stage synchronous generator as a starting device for a gas turbine engine. The problems associated with the use of a three-stage generator are analyzed and a method for solving them is proposed. The article presents a method for creating a starting torque using the reactive component of the electromagnetic torque for a synchronous salient pole generator. The analysis was carried out from the point of view of the formation of electromagnetic torque in an aircraft generator using a voltage inverter. A generalized expression for the torque is obtained, regulated and controlled by the electrical parameters of the frequency converter.

DETERMINATION OF LOAD CHARACTERISTICS OF A LINEAR ELECTROMECHANICAL ENERGY CONVERTER FOR THE TILT SYSTEM OF RAILWAY ROLLING STOCK

The article discusses the prerequisites for selecting the parameters of a Linear Electromechanical Energy Converter (LEEC) for the tilt system of railway rolling stock. Special attention is given to determining the required force to tilt the body to a specified angle and the load characteristics of the LEEC. To achieve this goal, a simulation model has been created that allows for the variation of geometric and physical parameters to obtain load characteristics for different configurations of the tilt mechanism. The obtained load characteristics are used to find the optimal placement of linear actuators in the tilt system.

The Condition Number Perspective in Modeling and Designing an Electronic IDBIC Converter

This paper proposes a novel method of evaluating the Independent Double-Boost Interleaved Converter’s performance, which can offer an overview of its behavior and can enhance the design stage of the converter. The concept of “condition number” is utilized and applied to the converter’s model. Correlations between the condition number variation and the converter parameters lead to a qualitative assessment of the converter’s behavior and offer the possibility to anticipate aspects like the stability and response of the converter. An in-depth analysis is conducted, starting from the state matrix and continuing with a series of presumptions regarding the converter and its operating mode, obtaining a series of expressions that define the condition number for the converter.

A Critical Analysis of Quadratic Boost Based High-Gain Converters for Electric Vehicle Applications: A Review.

Conventional DC-DC boost converters have played a vital role in electric vehicle (EVs) powertrains by enabling the necessary voltage to increase to meet the needs of electric motors. However, recent developments in high-gain converters have introduced new possibilities with enhanced voltage amplification capabilities and efficiency. This study discusses and evaluates the state-of-the-art high-gain DC-DC converters for EV applications based on the Quadratic Boost Converter (QBC). Research into innovative topologies has increased in response to the increasing demand for efficient and high-performance power electronic converters in the rapidly expanding EV industry. Due to its ability to provide more significant voltage gains than conventional boost converters, the QBC has become a viable option for meeting the unique requirements of EV power systems. This survey focuses on the efficiency, power density, and overall performance parameters of QBC-based high-gain converters. The literature review provides a foundation for comprehending power electronics converters' trends, challenges, and opportunities. The acquired knowledge can enhance the design and optimization of high-gain converters based on the QBC, thereby fostering more sustainable and efficient power systems for the expanding electric mobility industry. In the future, the report suggests that investigating new high-gain converter design methodologies will reduce component stress and enhance the intact system efficiency.

Small-signal transmittances of the non-ideal flyback switch-mode DC–DC converter

Small-signal transmittances of the power stage of a flyback converter in continuous conduction mode are derived on the averaged model obtained by the separation of variables approach. The precise knowledge of these transmittances is necessary in the design process of the converter control circuit. Apart from mathematical formulas for transmittances, the numerical calculations of the frequency dependencies of the transmittances for the assumed set of the converter parameters are presented with the parasitic resistances of components taken into account. The results of the calculations are compared with the measurements performed on the laboratory model of the converter and a good consistency is observed. It is concluded, that the results of the paper may be useful in the designing process of a control circuit of the flyback converter.

Influence of quadrature transformation imbalance on the noise immunity of signal reception with amplitude-phase shift keying

Objectives. At the present time, amplitude-phase shift keyed (APSK) signals are actively used in satellite communication systems. In particular, they are applied in systems which operate in a limited radio frequency spectrum with increased data transmission quality requirements. Such systems use multi-channel type receivers with maximum likelihood decision on the received symbol (correlation receiver) or quadrature type receivers. The noise immunity of these receivers is directly dependent on the quality of the formation of reference oscillations. These oscillations are reference signals for correlation receivers and in-phase and quadrature components for quadrature receivers. The aim of the work is to analyze the influence of the amplitude and phase parameter spread of the in-phase and quadrature channels on the noise immunity of receiving APSK signals with a circular shape of the signal constellation.Methods. Methods of statistical radio engineering, theory of optimal signal reception, and computer simulation are used.Results. The study established the characteristics of noise immunity of the APSK signal reception depending on the spread of parameters of the quadrature converter. The theoretical calculations were confirmed by the results of modeling the transmission of APSK signals in a Gaussian communication channel. A comparison with systems using quadrature amplitude modulation (QAM) was carried out, in order to assess system stability in the presence of spread parameters among other similar systems.Conclusions. The studies enabled us to conclude that an imbalance of the quadrature reference oscillations can lead to a significant decrease in the noise immunity of radio systems using APSK signals. The minimum energy loss due to imbalance of quadrature reference oscillations is achieved when the imbalance value is less than 10% in amplitude and 2°–3° in phase. The amplitude imbalance of quadrature reference oscillations when receiving QAM signals is more pronounced than in the case of APSK signals. The phase imbalance affects approximately the same.

Integration of a proton exchange membrane fuel cell system for voltage and frequency stabilization in a micro hydro system

This work discusses the frequency and voltage stabilization in a stand-alone self-excited induction generator system (SEIGs) using a fuel cell (FC)-based generation unit. The proposed SEIG acts as the power generator in a microhydro system. Variations in load create fluctuations in voltage and frequency, which have to be stabilized. In this work, authors have proposed integrating a FC-based generation unit with the existing SEIGs to improve its voltage and frequency profiles. For this work, a proton exchange membrane fuel cell (PEMFC) has been considered. Modeling of a 36 kW PEMFC is taken for the proposed work, which has to be integrated with the 22 kW self-excited induction generator. The design of the system and converter parameters have also been included in the work. Authors have proposed an orthogonal current component-based controlstructure that provides independent control of active and reactive power in the system. Considering the FC system working conditions, this article aims to assure optimum power transfer capability between the self-excited induction generator, fuel cell system, and the time-varying loads. The system is exposed to time-varying RL loads dynamic load switching, and the performance is evaluated in real-time. OP 4510 real-time simulator verifies the proposed system's dynamic model created using Matlab/Simulink.

Normalized Error-Based PI Controller and Its Application to the DC–DC Buck Converter

In this article, the structure of the normalized error-based proportional-integral (PI) controller is presented and its application to the DC–DC buck converter is discussed. The main motivation is to overcome the drawbacks of saturation and the limited range of controller gains offered by the traditional PI controller. Initially, the theoretical structure and advantages of an improved PI controller are shown. Next, the problem of regulation of the step-down DC–DC converter is addressed using the proposed controller. The objective is to keep the load voltage constant even when the converter parameters vary. The averaged state-space model of the converter is presented and a detailed stability analysis based on the Lypunov indirect method is carried out. The results show an improved range of controller parameters when the proposed controller is employed. Finally, some simulation results are shown to illustrate the effect of controller parameter variations on the output response. These results also verify the ability of the proposed controller to handle the changes in the load, input voltage, and reference voltage of the converter. Moreover, a comparative simulation study validates the superior transient response of the proposed normalized error-based PI controller over the traditional PI controller.

Modeling and Control of a 36-Phase Interleaved Buck Converter as an Ultrafast Battery Charger

This paper presents the dynamic modeling of a three-phase interleaved buck converter, and the design of a multiple loop controller in cascade configuration, to implement the constant-current constant-voltage (CC-CV) protocol for the ultrafast charging of an electric vehicle (EV) battery of 800 V from a 1500 V DC input. The designed controller is validated by PSIM simulations to put in evidence its robust performance in terms of input and load variations, and uncertainties in the converter parameters.

Study and Modeling of Nonlinear Dynamic Characteristics of DC-DC Converters with Amnesia Loads

Abstract The chaos phenomenon is a seemingly random irregular motion occurring in a deterministic system, which is an inherent characteristic and prevalent phenomenon of amnesia-loaded DC-DC converter nonlinear systems. Nonlinear dynamics and chaos theory guide the text, and we create an amnesia-loaded DC-DC converter system model using an amnesia resistor. We analyze the stability of the system using Filippov theory, and analyze the nonlinear dynamic characteristic behavior of the amnesia-loaded DC-DC converter using the time-domain waveform diagram, bifurcation diagram, and phase-track diagram. This paper talks about the slope compensation method and the parametric resonance perturbation method for control analysis. These methods are used to stop the chaotic behavior that happens in the amnesia-loaded DCDC converter. The system maintains a stable state when the reference current is less than 4.732A and the supply voltage exceeds about 17.966V, maintaining an amplitude of the maximum eigenvalue below 1. When the load resistance is 50Ω, the capacitance is 43 uF, the inductance is 2.8 mH, and the reference voltage is 2.05 volts, the amnesia-loaded DC-DC converter suffers from obvious chaos. To restore the system to a steady state by applying the ramp compensation method, the slope of the ramp signal will need to increase as the reference current increases. Loading amnesia onto the DC-DC converter achieves a stable cycle 1 state when the perturbation phase’s fluctuation range falls between 4.35 and 6.15. A nonlinear dynamic analysis of the amnesia-loaded DC-DC converter helps find the stable parameters of the amnesia-loaded DC-DC converter and improve the design of the converter.

Analysis of Stability Stationary Point for Virtual Parameters of Grid-forming Converter Integrated Power Systems Based on Small-signal Model

Analysis of Stability Stationary Point for Virtual Parameters of Grid-forming Converter Integrated Power Systems Based on Small-signal Model

Analysis and Optimization of Boost Converter Parameters in Internal Model Control for Voltage Source Converter-Based AC Microgrids

Analysis and Optimization of Boost Converter Parameters in Internal Model Control for Voltage Source Converter-Based AC Microgrids

Adaptive Control of a Boost DC/DC Converter based on Artificial Intelligence

The paper presents a solution to model and control the operation of DC/DC converters, in normal regime based on Artificial Intelligence. A solution is developed for simulating and controlling the performance of DC/DC converters, encompassing both normal and fault scenarios. The suggested model for the converter employs a transfer function mathematical model configuration with adaptable coefficients. To accommodate variable duty cycles, fully connected neural networks are utilized to determine the appropriate coefficients for the model. Additionally, a control framework capable of identifying faults and mitigating their impact is presented. This framework includes a compensator designed to prevent unstable conditions as the converter parameters deviate from their nominal values, serving as an effective fault tolerance mechanism. The proposed methodology is aimed at devising algorithms suitable for real-time execution on 32-bit ARM processors.