Sinusoidal Input Current Research Articles

(Invited) Nonlinear Frequency Response Analysis – Basics and Application for Battery Analysis

Nonlinear frequency response analysis (NFRA), also known as nonlinear impedance spectroscopy is the younger, less well-known sibling of impedance spectroscopy (EIS). In contrast to EIS, a large sinusoidal current or potential input is used; the output signal then contains higher harmonics, which are a nonlinear fingerprint of the electrochemical system under investigation. Why is this nonlinear response of practical relevance? Because electrochemical reactions have typically a nonlinear relation of current and potential. NFRA thus allows to discriminate between different reactions that give a similar linear response (i.e. EIS), to identify and parameterise reaction kinetics or surface/degradation changes, or to simply check if a process in EIS is nonlinear. Recent applications comprise batteries, electrosyntheses, and fuel cells. [1] This talk thrives to make NFRA more accessible to the electrochemistry and battery community. It introduces the NFRA technique (left Fig.) and its application to Li-ion batteries [3-6]. It gives an insight how to conduct reliable measurements, and which nonlinearities can be expected from reaction and transport processes [2]. Applied to Li-ion batteries, i.a. the potential for state-of-health estimation [3], for uniquely detecting Li-Plating (right Fig) or in-depth analysis on the impact of particle size on aging [5] is demonstrated. Models are shown to aid interpreting the NFR spectra. [6] Figure. Illustration of nonlinear frequency response analysis [2] (left) and spectra showing clear changes between plating (-10°C) vs. classical aging (25°C) [4](right).

A dSPACE-based implementation of ANFIS and predictive current control for a single phase boost power factor corrector

This paper presents an innovative control scheme designed to significantly enhance the power factor of AC/DC boost rectifiers by integrating an adaptive neuro-fuzzy inference system (ANFIS) with predictive current control. The innovative control strategy addresses key challenges in power quality and energy efficiency, demonstrating exceptional performance under diverse operating conditions. Through rigorous simulation, the proposed system achieves precise input current shaping, resulting in a remarkably low total harmonic distortion (THD) of 3.5%, which is well below the IEEE-519 standard threshold of 5%. Moreover, the power factor reaches an outstanding 0.990, indicating highly efficient energy utilization and near-unity power factor operation. To validate the theoretical findings, a 500 W laboratory prototype was implemented using the dSPACE ds1104 digital controller. Steady-state analysis reveals sinusoidal input currents with minimal THD and a power factor approaching unity, thereby enhancing grid stability and energy efficiency. Transient response tests further demonstrate the system’s robustness against load and voltage fluctuations, maintaining output voltage stability within an 18 V overshoot and a 20 V undershoot during load changes, and achieving rapid response times as low as 0.2 s. Comparative evaluations against conventional methods underscore the superiority of the proposed control strategy in terms of both performance and implementation simplicity. By harnessing the strengths of ANFIS-based voltage regulation and predictive current control, this scheme offers a robust solution to power quality issues in AC/DC boost rectifiers, promising substantial energy savings and improved grid stability. The results affirm the potential of the proposed system to set new benchmarks in power factor correction technology.

Design and Implementation of Robust H∞ Control for Improving Disturbance Rejection of Grid-Connected Three-Phase PWM Rectifiers

In response to the high performance requirements of pulse width modulation (PWM) converters in grid-connected power systems, H-Infinity (H∞) control has attracted significant research interest due to its robustness against parameter variations and external disturbances. In this work, an advanced robust H∞ control is proposed for a grid-connected three-phase PWM rectifier. A two-level control strategy is adopted, where cascaded H∞ controllers are designed to simultaneously regulate the DC bus voltage and input currents even under load disturbances and non-ideal grid conditions. As a result, unit power factor, stable DC bus voltage, and sinusoidal input currents with lower harmonics can be accurately achieved. The design methodology and stability of the proposed controller are verified through a comprehensive analysis. Simulation tests and experimental implementation on a dSPACE 1103 board demonstrate that the proposed control scheme can effectively enhance disturbance rejection performance under various operating conditions.

Performing Wind System with Rectifier with Near Sinusoidal Input Current

The RNSIC-1 (rectifier with near sinusoidal input currents converter), is the foundation of a wind generator system that is presented. The three inductances that make up a traditional RNSIC–1 converter are eliminated in the proposed arrangement, and the SCIG generator's leakage inductances fill their place. This is what makes it new. The wind system's role in the load currents is discussed. Lower power losses, smaller harmonic input currents, fewer EMI issues, excellent dependability, and cheaper costs are characteristics of the new wind system. This new wind system could be used for partial variable speed wind turbines (usually 70% to 100% synchronous speed) and lower hydro connector squirrel cage induction generators (SCIG).

Implementation of Power Factor Correction using Asynchronous Boost Converter on Single Phase Full-Bridge Diode

In various industrial applications, the use of a power supply that uses a conventional diode single-phase rectifier topology results in high harmonic values in the electricity distribution system. One of the real impacts of this harmonic value is the heating of the electric power system equipment and power losses. High rms current values due to harmonics often cause problems in protection settings in addition to efficiency problems. The percentage value between the total harmonic component and the fundamental component is called THD (Total Harmonic Distortions). Therefore, in this study an asynchronous dc-dc boost converter is connected to the output side of a single-phase diode rectifier which is capable of improving power factor and low harmonics. So that a THD value of less than 15%, PF (Power Factor) = 0.92-1 and a sinusoidal input current can be obtained. The implementation results show that the PFC (Power Factor Correction) method can work well on single-phase diode rectifiers.

A Review on Recent Advances in Matrix Converter Technology: Topologies, Control, Applications, and Future Prospects

Matrix converters (MCs) are AC-AC power conversion topologies widely explored and applied in the industry for their attractive features of sinusoidal input and output currents, considerable size reduction, and reliable operation due to the omission of bulky passive components. Considerable research has made this technology a serious contender to the indirect AC-DC-AC topologies in industrial applications. This paper comprehensively reviews the state-of-the-art MC technology and its prospects. Furthermore, it presents the advancements in the topological structures of direct/indirect MCs and their modulation and control algorithms over the past decade. It also reports the recent progress in multiphase direct/indirect MC structural and control structures. This paper is aimed at providing comprehensive information to the researchers and engineers on MC technology’s current industrial applications and the research scope as the world moves towards AI and digitalization.

A Matrix-Type Back-to-Back Converter With Single-Arm Current Injection

A matrix-type back-to-back converter (MT-BBC) with single-arm current injection, consisting of a three-phase rectifier with a small film dc-link capacitor and a three-phase inverter, is proposed in this paper. A clamped modulation strategy is applied to the rectifier, which is featured by only one high-frequency switching bridge arm, reduced switching losses, and enhanced input reactive power control range. By controlling and injecting the quasi-third harmonic current into the phase with a high-frequency switching bridge arm of the rectifier, sinusoidal input currents and controllable input power factor are achieved. A carrier modulation strategy with variable carrier is applied to the inverter to compensate for the time-varying six-pulse dc-link voltage. The presented converter inherits the advantages of both the conventional voltage-source back-to-back converter (V-BBC) and the matrix converter (MC) including simple main circuit structure, sinusoidal inputs and outputs, bidirectional power flow capability, potentially high power density, high reliability, high efficiency, and direct ac-ac conversion. Additionally, the input reactive power control range is extended significantly. The effectiveness of the proposed methods is verified by a 6-kW experimental prototype.

Control Scheme Based on Improved Odd-Harmonic Repetitive Control for Third-Harmonic Injection Two-Stage Matrix Converter

The third-harmonic injection two-stage matrix converter (3TSMC) not only inherits the advantages of the conventional two-stage matrix converter (TSMC), but also has simple modulation strategy and low switching losses. The injection current control is the key to achieving sinusoidal input currents of 3TSMC. The injection current reference consists of the third harmonic and its odd harmonics, making it difficult to obtain high control accuracy with a proportional integral (PI) controller. In this paper, a control scheme is proposed for the injection current of 3TSMC, which consists of an improved odd-harmonic repetitive controller (IORC), a PI controller and a feedforward controller. Compared with the conventional repetitive controller (CRC) and existing odd-harmonic repetitive controllers (ORC), the IORC has the highest gains and bandwidths at odd-harmonic frequencies, offering the proposed control scheme high control accuracy and fast transient response. The stability conditions of the system with the proposed control scheme are analyzed, and the design guidelines for the control parameters are provided on this basis. The experimental results demonstrate the effectiveness of the proposed control scheme.

A SWISS-Rectifier-Based Single-Stage Three-Phase Bidirectional AC–DC Inductive-Power-Transfer Converter for Vehicle-to-Grid Applications

Three-phase bidirectional ac–dc inductive power transfer (IPT) systems for vehicle-to-grid applications are conventionally based on a two-stage architecture. However, poor conversion efficiency, high component counts, and high control complexity are distinct disadvantages. Even though a few single-stage ac–dc IPT systems based on matrix-type converters were proposed, it remains a challenge for achieving sinusoidal input current, zero-voltage switching, and high efficiency simultaneously. In this article, a new single-stage three-phase bidirectional ac–dc IPT converter is proposed. The proposed converter is based on a newly proposed multi-active-bridge converter coupled to a SWISS front end. As a result, the proposed converter inherits not only the merits of low distortion of input current, high efficiency, and output short-circuit protection, but also achieves soft-switching operation resulting from the proposed modulation strategy and the property of the double-sided <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$LCC$</tex-math></inline-formula> compensation network. The operating principle and mathematical analysis of the proposed converter are discussed. Experimental results are presented to verify the performance of the converter.

Reconstructed Phase Voltages Based Power Following Control for Three-Phase Buck Rectifier Under Unbalanced Phase Voltages and Wide AC Input Frequency

In wide ac input frequency applications, such as more electric aircraft, ac input frequency of the three-phase buck rectifier varies in the range of 360–800 Hz. In this article, a reconstructed phase voltages based power following control for the three-phase buck rectifier under unbalanced input phase voltages in wide ac input frequency application is proposed. The input phase voltages are reconstructed to get more balanced modulation signals compared with the input phase voltages. The input currents are controlled to be in proportion to the reconstructed phase voltages to mitigate the imbalance of the input currents. The control strategy is simple and easy to be realized in digital. The analysis and design of the proposed control strategy and digital implementation are illustrated. An experimental prototype with 1.5 kW is built. The experimental results show that the sinusoidal input currents can be obtained when input phase voltages are unbalanced in wide ac input frequency application.

A Comparative Analysis of Numerical Methods for Solving the Leaky Integrate and Fire Neuron Model

The human nervous system is one of the most complex systems of the human body. Understanding its behavior is crucial in drug discovery and developing medical devices. One approach to understanding such a system is to model its most basic unit, neurons. The leaky integrate and fire (LIF) method models the neurons’ response to a stimulus. Given the fact that the model’s equation is a linear ordinary differential equation, the purpose of this research is to compare which numerical analysis method gives the best results for the simplified version of this model. Adams predictor and corrector (AB4-AM4) and Heun’s methods were then used to solve the equation. In addition, this study further researches the effects of different current input models on the LIF’s voltage output. In terms of the computational time, Heun’s method was 0.01191 s on average which is much less than that of the AB-AM4 method (0.057138) for a constant DC input. As for the root mean square error, the AB-AM4 method had a much lower value (0.0061) compared to that of Heun’s method (0.3272) for the same constant input. Therefore, our results show that Heun’s method is best suited for the simplified LIF model since it had the lowest computation time of 36 ms, was stable over a larger range, and had an accuracy of 72% for the varying sinusoidal current input model.

Variable Pulse Density Modulation for a Buck-Type Three-Switch Current Source Rectifier

With flexible voltage adjustment without an intermediate DC/DC converter, short-circuit protection, self-starting, high reliability, and three-phase current source rectifiers (CSRs) are being widely used in high-power medium-voltage applications and low-power low-voltage applications. Modulation methods significantly affect the performance of CSRs and can be categorized into offline modulation methods, such as selective harmonic elimination/compensation pulse width modulation (SHE/SHC-PWM), and online modulation methods, such as space vector pulse width modulation (SV-PWM) and carrier-based pulse width modulation (CB-PWM). The SHE/SHC-PWM is popular in high-power medium-voltage applications that do not require a fast dynamic response and have a low switching frequency. Online modulations considerably improve the dynamic response and performance of the CSR; however, high computational power, such as digital signal processors (DSPs), is required at higher switching frequencies, leading to greater system complexity and cost. In this paper, an offline method based on variable pulse density modulation (VPDM) of power switches to synthesize sinusoidal input currents and control power transfer with pulse width modulation (PWM) is proposed. The proposed modulation is applicable to the three-switch buck-type VIENNA rectifier, showing the capability of improving the input current total harmonic distortion (THD) with respect to the SHE-PWM and is comparable to online modulations at a sufficiently high switching frequency. The simulation and experimental results basically prove the feasibility of the proposed modulation.

Film-penetrating transducers applicable to on-chip reservoir computing with spin waves

We have proposed a spin-wave transducer structure named film-penetrating transducers (FPTs). FPTs penetrate an on-chip magnetic film for a spin-wave transmission medium and allow flexible spatial arrangements of many exciters/detectors due to their zero-dimensional feature. We constructed four device models with different spatial arrangements of FPT/conventional exciters using a 10-nm-thick ferrimagnetic garnet film with a central FPT detector. We performed numerical experiments that combine electromagnetics with micromagnetics including thermal noise at 300 K. We evaluated important device features of FPTs, such as the signal-to-noise ratios (SNRs), input/output signal transmission efficiencies, and nonlinear phenomena of spin waves. We applied in-phase sinusoidal input currents with various amplitudes and frequencies and altered the damping strengths near the film boundaries. We obtained sufficient SNRs for the practical use of FPTs and revealed that FPTs have both higher transmission efficiencies and nonlinear strengths than conventional antennas, as the input frequency approaches the ferromagnetic resonance frequency of the film. Moreover, we observed and analyzed various nonlinear phenomena of spin waves, including beats in the time-domain waveform, components of integer harmonic frequencies, wide-range scatterings of inter-harmonic frequencies, and frequency doubling in spin precession. These characteristics probably originate from various device effects: FPTs effectively excite dipolar spin waves with large-angle precession, propagating spin waves reflect from the film boundaries, and spin waves dynamically and nonlinearly interfere with each other. This study demonstrated that FPTs have promising features for both their applications to reservoir computing and the studies on the physics of nonlinear and space-varying spin waves.

Rectifier with Near Sinusoidal Input Currents Vector-controlled for AC Motor Drive

This paper is presented a three – phase rectifier, which is able to assure a very low harmonic injection in the power supply (RNSIC converter = Rectifier with Near Sinusoidal Input Currents).

Three-Level Indirect Matrix Converter With Neutral-Point Potential Balance Scheme for Adjustable Speed Drives

To improve the performance and explore a new solution of adjustable speed drive systems, a T-type three-level indirect matrix converter (T3LIMC) topology and its modulation scheme are presented in this article. The presented topology is composed of an <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">LC</i> input filter, a current-source rectifier, and a T-type three-level inverter, where the split dc source voltage of the inverter is formed by two input line-line voltages and the neutral-point voltage. A multicarrier-based modulation scheme for the inverter and a specific zero-sequence voltage are also developed, and the desired neutral-point current of the inverter is constructed to compensate for the input currents. Consequently, the balanced neutral-point potential and symmetric sinusoidal input currents are achieved without additional control effort. In addition to advantages such as bidirectional power flow, sinusoidal input–output currents, controllable input power factor, no dc-link energy storage elements, and compact structure, the T3LIMC also improves the output waveform quality by generating the three-level output voltages. Meanwhile, the zero current switching (ZCS) operation of the rectifier helps to improve efficiency. Finally, the functionality and effectiveness of the presented topology and modulation scheme are verified by experimental results.

Design and Implementation of Input AC Filters and Predictive Control for Matrix-Converter Based PMSM Drive Systems

Matrix converters have many advantages, including high-efficiency, single-stage AC/AC energy conversion, bidirectional power flow, a near-unity input power factor, sinusoidal three-phase input currents, and sinusoidal three-phase output currents. However, matrix converters have 360 Hz voltage pulsations at the virtual DC-bus, which produce input harmonic currents and output harmonic currents, which cause unsatisfactory responses. To solve the problem of the input harmonic currents, a systematic design of an input three-phase current modulation method and an input three-phase AC filter that uses two different design methods are proposed. In addition, to improve dynamic responses, two predictive speed controllers are investigated and compared, and a predictive current controller is studied to reduce the output harmonic currents. A digital signal processor and an FPGA are used to execute the control algorithms. Several experimental results validate the theoretical analysis and show that the proposed methods effectively improve the power quality of the PMSM drive system and its input power-source quality.

Combined voltage oriented control and direct power control based on backstepping control for four-leg PWM rectifier under unbalanced conditions

The present paper proposes a combined voltage-oriented control and direct power control (VOC-DPC) method associated with the backstepping control technique for a three-phase four-wire grid-connected four-leg rectifier in the synchronous rotating frame without using phase locked loop (PLL) and Parks transformation under balanced and unbalanced load and grid conditions. This control method is proposed in order to remove the drawbacks of the conventional VOC based on the PLL technique .The proposed control method is able to enhance the control performance and dynamic responses of the system when considering slow dynamics and instability issues of the PLL in several cases and can decrease the computational burden due to the absence of PLL and Park transformation. In addition, the performance of the proposed VOC-DPC method is enhanced by using backstepping control (BSC) based on Lyabonov theory for both the input currents and DC-bus voltage loops. As a consequence, constant DC-bus voltage, unit power factor, sinusoidal input currents, and neutral current minimization can be accurately carried out under both DC-bus voltage and load variations. Furthermore, robustness against filter inductance variations can also be achieved. The effectiveness, superiority, and performance of the proposed control method for a four-leg rectifier based on BSC in the dq0-frame are validated by several processor-in-the-loop (PIL) co-simulation tests sing the STM32F407 discovery development board.

Load response of magnetorheological (MR) plastomer dampers under applied magnetic fields

Magnetorheological plastomers (MRPs) are smart fluids whose rheological properties make them suitable for suspension systems, structural engineering, electrical transmission lines, medical applications, and agricultural engineering. In this paper, an integrated model of computational fluid mechanics (CFD) and finite element analysis (FEA) is used to investigate the dynamic characteristics and the controllable damping force of shear-mode MRP dampers. An MRP with 60% weight ratio of soft-magnetic carbonyl iron powder (CIP) to the prepared plastic polyurethane matrix (MRP60) is used in the analysis. First. the magnetic field-dependent shear stress of MRP60 is calculated based on the relationship between the shear stress and the magnetic strength. Next, the shear stress and the strain rate are used in the CFD analysis to determine the flow and pressure fields as well as the variation of the damping force with the piston displacement, the piston velocity and the time for different sinusoidal motion frequencies and input currents. The results indicate that MRP dampers have the capacity to be used in semi-active applications.

Control system design of a low‐frequency‐switchingsingle‐phase four‐quadrant PWMconverter

This work is focused on the control of low-frequency-switching single-phase four-quadrant pulse width modulation (PWM) converters used in grid-connected modern power electronics applications. The switching frequency is chosen to be lower than that used in industrial applications in order to use the designed control system in high-power applications such as railway electrical traction systems. The control system is designed under three main headings: grid synchronization, input current control, and voltage control, where grid synchronization is achieved by a single-phase phase-locked loop (PLL). The current loop is designed by using a proportional-resonant (PR) controller, and the classical proportional-integral (PI) controller is employed in the voltage control loop. The parameters of the PI controller are determined by using the coefficient diagram method (CDM). The control system is modelled as a discrete-time system to get the response closest to the actual system and to be easily implemented on the TMS320F28335 DSP platform. The performance of designed control system is tested on a 30-kW single-phase PWM converter test set-up, and experimental results show that bidirectional power flow, sinusoidal input current, power factor correction, and constant output voltage are achieved. This study is aimed to be a guide for the designers, from the selection of converter passive elements to controller design and experimental verification.

Cascaded Multilevel Rectifier with Common High Voltage Direct Current (HVDC) Bus and Its Control Method

In order to realize the voltage equalization and minimize the total harmonic distortion rate of current of cascaded multilevel rectifier with common high voltage Direct Current (HVDC) bus, the cascaded multilevel rectifier with common high voltage DC bus and its control method are studied. The output side DC voltage of the cascade multilevel rectifier with common high voltage DC bus is sampled, and the output DC current signal amplitude is obtained according to the calculated output side DC voltage signal. On this basis, the AC side voltage corresponding to the applied switching state and the switching state corresponding to the rectifier in the sampling period are solved. The driving signal of the switch device is generated and sent to the corresponding switch device to realize the active power factor correction and sinusoidal input current, so as to realize the balanced control of output DC capacitor voltage of cascaded multilevel rectifier with common High-Voltage Direct Current (HVDC) bus. The test results show that this method can effectively control the three-phase output current of the rectifier and ensure the maximum output of the current. The lowest total harmonic distortion rate of the output phase voltage is about 40%, which can effectively ensure the stability of the output phase voltage after control.