Series Voltage Research Articles

A single switch high step-up DC-DC converter derived from coupled inductor and switched capacitor for a photovoltaic system.

This study suggests a single switch high step-up DC-DC Converter derived from coupled inductor and switched capacitor used in Grid-Connected Photovoltaic systems. In the suggested converter, a part of the yield voltage is produced by parallel charging of the capacitors on the side of the secondary winding and their series discharge together with the secondary winding. The other part of the output voltage is obtained by simultaneously charging the boost and buck-boost capacitors and discharging them in series with the input voltage source. Finally, these two parts make the output voltage in series, so that high voltage gain with proper duty cycle is obtained. In addition, boost and buck-boost capacitors absorb leakage inductance energy leading to a reduction of the switch voltage stress. As a result, switching losses are reduced and by choosing a switch with lower RDS(ON), conduction losses are also reduced. Finally, a prototype with an output power of 200 Watts, and a voltage conversion of 24-400 Volts was made to confirm the performance in the laboratory, which has the highest efficiency of 95.89%.

Determination of Coefficients of Decomposition of a Nonlinear Characteristic into a Power Series

The problem of monitoring the parameters of nonlinear elements included in various electrical devices is considered. A new algorithm for reproducing the nonlinear current-voltage characteristic of a device based on the measurement results has been proposed and investigated, which has several advantages over the known ones, allowing, in particular, to obtain an analytical representation of the current-voltage characteristic in real time. The proposed algorithm is based on the direct determination of the coefficients of the polynomial approximation of the current-voltage characteristic. A review of scientific research done to date by other authors dealing with this problem has also been carried out. Formulas for determining the amplitudes of current harmonics through power series coefficients and voltage amplitudes on a nonlinear element are obtained. Binomial coefficients are used to facilitate intermediate calculations. The relations for the zero, odd and even harmonics of the current are obtained, as well as analytical expressions for the coefficients of the polynomial approximation. An experimental study of the proposed method was carried out, according to the results of which an assessment of its accuracy was made. The use of the proposed method significantly simplifies the processing and reduces the measurement time of nonlinear VAC.

Design and Control of DVR Based on Adaptive Bateman Polynomial for Power Quality Improvement

ABSTRACTPower quality issues encompass a spectrum of disturbances that affect the stability and reliability of the power supply. This study explores voltage‐related anomalies, including sags, surges, flickers, unbalances, harmonics, interruptions, and swells, examining their origins, characteristics, and repercussions. These issues arise from a myriad of sources, such as load fluctuations, equipment malfunctions, and grid dynamics. The ramifications of these disturbances extend to equipment malfunctions, reduced operational efficiency, and financial losses. Dynamic voltage restorer (DVRs) are series custom power devices for mitigating these voltage‐related anomalies and use real‐time monitoring and control to quickly inject exact voltages into the grid during disruptions, restoring voltage levels to acceptable levels. This study demonstrates the capacity of DVRs to successfully alleviate power quality concerns, hence improving equipment dependability and system stability by analyzing case studies and simulation findings. The control system used to supply switching signals to the voltage source converter (VSC) of the DVR is based on adaptive Bateman polynomial (ABMP). Traditional DVR control techniques often rely on fixed or linear control strategies, which may not adequately handle varying load conditions and disturbances. ABMP offers an adaptive approach where the control parameters can adjust dynamically based on real‐time system conditions. This adaptive capability enhances the accuracy of voltage restoration, ensuring that the DVR responds optimally to varying loads and disturbances. During voltage sag and swell conditions at the grid side, the VSC injects the compensating voltage in series with the feeder with a constant switching frequency. A battery energy‐supported system (BESS) based DVR is considered for the proposed system. The supply is connected to the critical and sensitive loads. The proposed control scheme is validated through extensive simulation and experimental results.

Redundant series cell voltage measurement circuit design of battery management system for functional safety

In most battery management system (BMS) circuit designs, the analog front end (AFE) chip is used to get the series cell voltage of the battery pack. However, it can lead to incorrect calculations by the BMS, causing errors in battery information, failures in protection control, and triggering a battery system fire accident if the AFE chip is abnormal. Unfortunately, the BMS will never know the correct of measured results if it is measured by a single AFE chip. This paper proposes a redundant series voltage measurement system (RSVMS) for the series cell voltage of the battery pack. The original AFE is referred to as the main AFE (m-AFE). The RSVMS can be regarded as redundant AFE (r-AFE). In this paper, the r-AFE consists of a series cell selector and an analog-to-digital (ADC) converter with an isolated communication function to transmit measurement results to the microcontroller unit (MCU) of the BMS. Due to the hardware requirements of functional safety, it does not allow using two identically designed hardware as redundant systems. To satisfy the hardware level of functional safety and to minimize the hardware cost and size, the series cell selector of r-AFE shares the same hardware circuit as the Active Hybrid Equalizer Circuit (A-HEC). The cell selector of A-HEC is composed of the back-to-back MOSFET switch array with a simple ON/OFF function. The MCU of BMS will identify the abnormal of voltage measurement results when the difference of m-AFE and r-AFE is over the threshold. In summary, r-AFE can ensure the accuracy of cell voltage measurement for m-AFE to avoid significant errors when estimating battery information and avoid disaster caused by failure or malfunction of protection functions. In addition, the m-AFE and r-AFE are two independent designs to avoid similar errors caused by identical circuit configurations.

A novel sequential estimation framework for battery state of health and remaining useful life based on sparse and limited data

Battery State of Health (SOH) estimation and Remaining Useful Life (RUL) prediction are significant for battery management systems in both electric vehicles and energy storage systems. Various battery Health Indicators (HIs) and abundant health information are generally utilized for SOH and RUL estimation. However, HIs and health information may not be available for various reasons such as sensor installation limitations, computational burden and communication delay of the system. To overcome the issue of sparse and limited data acquisition in real applications, this study proposed a novel battery SOH and RUL sequential estimation framework only utilizing sparse segments of time series voltage data. The Extreme Learning Machine (ELM) and Long Short Term Memory (LSTM) network are applied for SOH estimation and RUL prediction respectively. Locally Weighted Scatterplot Smoothing (LOWESS) is used for both data smoothing and sparse data reconstruction. Three common battery datasets are fully investigated for validation. The experiment results show well estimation accuracies in both battery SOH and RUL, demonstrating the effectiveness of the framework in limited data prediction. Several popular SOH and RUL estimation algorithms and two state-of-the-art works are compared to further elaborate the superiority of the proposed framework.

FRT Capability Enhancement of DFIG-based Wind Turbine with Coordination Control of MSVC and FCL

Objective: To address the problems of various FRT (fault ride through) schemes in DFIG (doubly fed induction generator) systems, especially their applicability under different voltage sags, a combination scheme of an MSVC (minimized series voltage compensator) and FCL (fault current limiter) is proposed. Methods: Based on the analysis of the mathematical model of the DFIG and considering the capacity and volume in the process of practical engineering, the application structure and specific control strategy of an MSVC in DFIG systems are designed on the stator side, and the application effect is analyzed theoretically. Simultaneously, the application structure and control strategy of the FCL is proposed on the rotor side, and the application effect of the combination scheme is theoretically deduced and analyzed. Moreover, the simulation model is built on the MATLAB/Simulink platform. Results: The simulation results show that the scheme can quickly and effectively recover the fault voltage of the DFIG under different voltage sag degrees and has better dynamic performance. At the same time, it can effectively limit the fault current and suppress the DC-link voltage of the rotor side, and the transition process is relatively stable. Conclusion: The purpose of improving the FRT capability of the DFIG system is realized.

Series Voltage Conditioner (SeVC) to Mitigate Commutation Failure in HVDC-LCC Systems

Series Voltage Conditioner (SeVC) to Mitigate Commutation Failure in HVDC-LCC Systems

Power quality and efficiency functionalities for a three-level Dynamic Voltage Restorer on low voltage grids

Back-to-back PWM inverter based bidirectional dynamic voltage restorers (DVR) may have worse efficiency than mechanical or SCR based solutions, but they are able to provide a continuously variable voltage in series with the grid. As the injected waveform does not need to be sinusoidal, additional features may also be implemented in software. In this paper it is shown that the compensation of voltage harmonics, flicker, and even voltage transients are all possible to some extent. The power required for the series voltage injection does not need to originate from the same phase where it is injected. Drawing power from the less problematic phases can also be used to increase the voltage symmetry on the unregulated side of the device. It is shown in the paper, that at partial load the complete deactivation of one phase in the active rectifier stage can not only help with asymmetry, but can also increase the efficiency of the system. A method is proposed for the seamless transfer in the active rectifier stage from 3-phase to 2-phase operation and back. It is also shown in the paper, that phase deactivation and electronic bypass of the injection transformer is possible in the output stage as well. The three level half bridge circuit configuration enables this without additional components.

Series Voltage Injection Impedance Measurement Device With Resonance Shunt

Series Voltage Injection Impedance Measurement Device With Resonance Shunt

A DC Bus Oscillation Suppression Strategy Based on Series Voltage Compensator for Diode Rectifier

A DC Bus Oscillation Suppression Strategy Based on Series Voltage Compensator for Diode Rectifier

Computational Performance Analysis of an Electromagnetic Dynamic Voltage Restorer: Physical Conception and Operational Approaches

The present paper focuses an electromagnetic device to restore busbar voltages to acceptable limits using an electromagnetic arrangement conception. The new device has been called by electromagnetic dynamic voltage restorer (EDVR) due to its physical structure. As for the insertion of the degree of the series voltage compensation, two approaches are considered. The first can be recognized as a discrete procedure as the restoring voltage procedure makes use of electronically switched tap changers. The second relies on a continuous voltage variation offered by a single tap supply and a controllable electronic device. It is shown that the overall compensator idea lies on positive or negative insertion of a variable voltage in series with de feeder so as to achieve a consumer supply voltage in accordance with acceptable levels. The device comprises a traditional shunt autotransformer linked to a series transformer which provides the necessary restoring property. The paper highlights the EDVR physical structure, the control units, the ATP platform models and results associated to case studies to show the overall compensation equipment and control performance offered by the given solutions.

DFT-based controller for sag and harmonic mitigation with a series-connected compensator

Voltage-quality problems in power distributionnetworks include harmonics, voltage sags and swells andunbalances. These problems may seriously affect sensitiveindustrial loads causing production interruption or equipmentdamage. Now-a-days series voltage compensation using powerelectronics devices is a promising solution for these problemsand the design, control and application of this type of deviceshave drawn much attention in the literature. In fact, compre-hensive controllers for power electronics series compensatorhave already been proposed in the literature to tackle all thoseproblems simultaneously. For example, repetitive controllersshow very promising performance although several aspectsstill need closer attention. This paper proposes a differenttype of controller based on a Discrete Fourier Transform tominimise voltage harmonic pollution using power electronicsseries devices. The design process of this type of controlleris straightforward regardless of the number of harmonics tobe tackled. In addition, the proposed controller uses a slowsampling rate and its computational effort is relatively low. Themain contributions of this paper are illustrated by simulation.

A Computational and Experimental Performance Analysis of an Electromagnetic Voltage Regulator Proposal throughout Controlled Series Voltage Injection

Power quality problems related to short or long time voltage variation have motived the search for voltage compensator techniques capable to provide dynamic voltage regulation to accomplish voltage supply levels in accordance with electrical energy agencies acceptable levels. Although one could recognize that a variety of products already offered in the market are capable of attending general electrical power system requirements the available technology comprises quite simple devices till very sophisticate ones. Having in mind the combination of simplicity, competitive cost, low maintenance need and an attractive performance at recovering the voltage deviations, then an electromagnetic concept to restore the desirable voltage within the established voltage levels is here proposed. The control strategy to be used can provide properties that enable this new device at proving the time response in accordance with the needs for long term and short term voltage variations. Concerning the proposed compensator physical topology it consists in extracting the necessary electrical power throughout a shunt transformer and the injection via a series unit. Besides the arrangement, the paper goes further by establishing a computational time domain model and a laboratory experiment to highlight the overall structure effectiveness at compensating voltage changes.

Phyto-inspired sustainable and high-performance fabric generators via moisture absorption-evaporation cycles.

Collecting energy from the ubiquitous water cycle has emerged as a promising technology for power generation. Here, we have developed a sustainable moisture absorption-evaporation cycling fabric (Mac-fabric). On the basis of the cycling unidirectional moisture conduction in the fabric and charge separation induced by the negative charge channel, sustainable constant voltage power generation can be achieved. A single Mac-fabric can achieve a high power output of 0.144 W/m2 (5.76 × 102 W/m3) at 40% relative humidity (RH) and 20°C. By assembling 500 series and 300 parallel units of Mac-fabrics, a large-scale demo achieves 350 V of series voltage and 33.76 mA of parallel current at 25% RH and 20°C. Thousands of Mac-fabric units are sewn into a tent to directly power commercial electronic products such as mobile phones in outdoor environments. The lightweight (300 g/m2) and soft characteristics of the Mac-fabric make it ideal for large-area integration and energy collection in real circumstances.

Simulation of a Hybrid System Wind Turbine-Battery-Ultracapacitor.

In order to improve the predictability of power generation from wind, short term energy storage in batteries combined with ultra capacitors (UCaps) is proposed. The system is simulated with SIMULINK and contains detailed models of a lead acid battery pack and a simple model of the UCap bank. The wind energy conversion system (WECS) is simulated by measured time series with a time resolution of one second. The objective of the simulation is to determinate the system configuration that is able to guarantee a predictable energy output to the grid during a given time interval. Within this time, the storage system should be able to compensate all type of rapid changes originated by wind speed fluctuations. Another important issue is the integration of an ultra capacitor bank. It is investigated its influence on the charge and discharge stress of the battery. It is demonstrated that quick changes in wind power generation can be covered by a reasonable size of battery capacity for a prediction time interval of 10 min. Very short transients in energy flow (1-10 s) are absorbed by the UCap bank which minimizes the deterioration of the battery because important current peaks do not reach the battery. The final system design is based on measurements at a 600 kW constant speed WECS. Its typical, very sharp changes in power output (more than 200 kW/s possible) are smoothed by a 500 Ah lead acid battery with 300 cells in series (voltage range: 480 – 720 V). In parallel to the battery a 10 F UCap bank is connected. To hold 720 V, the bank consists of 240 UCaps connected in series (3 V / 2400 F each).

Design of Dynamic Voltage Restorer for Power Quality Improvement

Solutions for customers with delicate loads and quick voltage regulation are essential. Protect important loads from supply-side voltage disturbances with a power electronic converter-based Dynamic Voltage Restorer (DVR). In the case of severe sag and swell, DVR is a well-known, low-cost therapy option. On the basis of its maximum voltage injection and active power contribution, a DVR's mitigation ability is determined. Standard DVRs use batteries as their DC input, but batteries are cumbersome, expensive, and hazardous to dispose of after they've been used. This limits compensation for DVRs. It is recommended to increase the DVR's VA rating by 1.5 times by increasing the DC connection voltage to 1.5 times the micro grid voltage regulation and quality improvement methods are proposed in this study. As a series voltage compensator, these solutions incorporate a Dynamic Voltage Restorer (DVR) for regulation, quality improvement, and reduction of harmonic distortion. Continuous adjustment of the DVR output voltage is proposed to reduce harmonic distortions while minimizing network bus voltage changes. As a result of this strategy, the peak demand voltage loss is compensated for. In constant impedance loads, voltage rise reduces network demand, resulting in lower branch currents and losses

Silicon distyryl-BODIPY hybrid photodiode: moving a step ahead from organic interface layer to type II band alignment

Organic-inorganic heterojunctions are becoming an attractive topic of research for their applications in hybrid photodetectors, solar cells, resistive switching memory devices etc. The easy chemical synthesis and low-cost fabrication for organic thin films come with the benefit of high light absorptivity, high fluorescence quantum yield and band gap tunability along with high charge carrier lifetime that could be combined with the existing silicon-based technology. In this aspect, various organic dyes utilised as an interfacial layer with silicon Schottky junction are reported earlier. However, the photo responses are quite limited. Here, in this report, a Type II Silicon/Distyryl-BODIPY p-n junction has been proposed as an organic-inorganic hybrid photodetector which has not been explored extensively yet. The transformation from a mere organic interfacial layer to band aligned junction enhances the charge carrier separation providing higher photo-responsive behaviour. With the simple spin-coating technique, the Distyryl-BODIPY derivative with phenolic functionalities is coated to fabricate the p-n junction diode. To further improve the performance, pyramidal surface texturization on silicon is deployed using wet chemical etching that supplements the light absorption with internal reflections. Both the devices have been investigated for their photo-response characteristic where a high photo-responsivity of 4353 A W−1 is attained for the textured device as compared to 118 A W−1 for the planar silicon device at a − 3 V bias with an ultra-high specific detectivity of 1012 Jones and 1010 Jones respectively. The behaviours of interfacial states have been demonstrated using the capacitance (C), conductance (G) and series resistance (RS) vs voltage (V) curves at different frequencies. Further calculations of interfacial state density revealed the existence of 1000 times higher interfacial states in planar device leading to lower performance as compared to pyramidal device. The findings in this report suggest that dye-based organic-inorganic heterostructures find potential applications in photodetectors and other optoelectronic devices.

Highly Efficient Dual-Buck Structured Buck–Boost AC–AC Converter With Versatile Identical Inverting/Noninverting Operations

Single-phase dual-buck ac-ac (DBAC) converters are gaining attention due to their intrinsic protection from shoot-through and open-circuit problems of conventional ac-ac converters. However, researches on DBAC converters are mainly concentrated around unipolar topologies. In a few developed bipolar topologies till date, the inverting buck-boost operations (for series voltage injection and step-variable frequency outputs) are inefficient and burdened by large voltage and current stresses ( <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">v_in + v_o</i> and <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">i_in</i> + <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">i_o</i> ) of switching devices and ripples of passive elements. In this article, an efficient dual-buck structured buck-boost ac-ac converter is proposed, with the following features: no voltage source shoot-through and inductor open-circuit problems, natural attainment of safe-commutation without additional protection circuitry or complex control, no need of PWM dead-times, and elimination of high-frequency conduction of MOSFET's body diodes and related slow reverse recovery issues. The proposed converter provides distinct type efficient inverting and non-inverting buck (EINIBu) and boost (EINIBo) operations, with smaller switch voltage/current stresses ( <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">v_in</i> / <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">v_o</i> and <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">i_in</i> / <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">i_o</i> ) and passive component ripples. Combined inverting and non-inverting buck-boost (CINIBB) operations are also proposed with separate tuning of buck and boost voltage transfer ratios. A simple adaptable switching strategy provides the switch control pulses for all circuit operations by modulating the buck and boost control reference signals. The proposed converter provides sustained input/output currents and performs well with non-resistive loads. Extensive theoretical analysis is presented followed by practical verifications on a 400-VA laboratory circuit.

Control Strategies for Enhancing Power Quality with Unified Power Quality Conditioner in a Solar-PV Integrated Utility System

The electrical utility systems are well-liked as local energy systems because of their capacity to incorporate renewable energy, enhance energy effectiveness and strengthen the resilience of the power system. These benefits do, however, come with specific complications regarding control and power quality (PQ). PQ within a utility system is paramount to ensure the appropriate operation of connected devices and the well-being of the overall system. As a result, both voltage quality &amp; current quality are significant. Control strategies in conjunction with cutting-edge power electronics devices (PED) offer a solid framework to handle PQ challenges. Hence, this paper’s proposed work discusses the application of a Solar-Photovoltaic (PV) fed Unified Power Quality Conditioner (UPQC) for power quality enhancement towards the supply grid network. The Solar-PV fed UPQC enhances PQ and maximizes solar energy utilisation, leading to an eco-friendly and cost-effective solution while injecting clean, renewable energy into the grid. In this paper, the control strategies for UPQC are based primarily on the Adaptive Leaky Least Mean Square (AL_LMS) algorithm as compared with the Synchronous Reference Frame (SRF) based theory for switching of series and shunt active converters of UPQC. This AL_LMS approach extracts reference signals to switch UPQC’s shunt and series voltage source converters (VSCs) by iteratively updating the weights. Thus, the control strategy applied to Solar-PV fed UPQC mitigates voltage problems like voltage sag and swell, current harmonic distortions and other PQ issues. The work is done in MATLAB/ Simulation software and simulation outcomes show the effectiveness of Solar-PV fed UPQC in improving power quality by maintaining within the IEEE-519 Standards.

Novel approach for modeling and attenuation of power waves in large – scale power systems

In this paper modeling and attenuation of electromechanical power waves in large – scale power systems are discussed. Mathematical model of power wave is derived using Euler – Lagrange equation. The proposed modeling procedure is based on kinetic and potential energies of the system, as well as system’s dissipation power. A novel method for incorporation of spatially dependent power losses into Euler – Lagrange equation is defined as well. The obtained mathematical model is simple for derivation, straightforward and practical for use, so it can easily be applied to derive wave equation of other technical systems or natural phenomena as well, which is an additional advantage compared to the existing models. Based on the developed model, an appropriate control system is proposed. The main idea for control system synthesis is to reduce transmitted waves inside the system. It is shown that the series power line impedance and voltage amplitude have the greatest impact on the wave transmission coefficient. Since unified power flow controller (UPFC) is capable of simultaneously modulating both these parameters, this device is chosen to perform control tasks in proposed operation mode. The effectiveness of the proposed solution has been verified by thorough computer simulations on artificial generator array and IEEE benchmark simplified Australian system. The results show significant power wave reduction. Some future works such as derivation of the mathematical model of inverter array or incorporation of artificial intelligence algorithms in UPFC control system based on transmission coefficient reduction might rely on this work.