scholarly journals A Low-Power Setup Proposal for Power Transformer Loading Tests

Energies ◽  
2019 ◽  
Vol 12 (21) ◽  
pp. 4133
Author(s):  
Thiago Galvão ◽  
Domingos Simonetti
Keyword(s):  
Low Power ◽  
Power Distribution ◽  
Power Level ◽  
Fractional Power ◽  
Voltage Regulation ◽  
Power Converter ◽  
Operating Conditions ◽  
Voltage Source ◽  
Total Power ◽  
Distribution Grid

A setup for testing transformers under load through low power converter is presented in this paper. This setup is used for testing power transformers as it allows to verify their performance under operating conditions regarding aspects such as heating, voltage regulation, and mounting robustness. The main goal of the study is centered on replacing a full power Back-to-Back converter (1 pu) by a fractional power one (less than 0.1 pu). The converter, a Voltage Source Inverter (VSI), is a series connected between two equally sized transformers and controls the current flowing in the system. Load profile configurations set according to power factor, current harmonics, or even power level can be imposed to evaluate the performance of the Transformer Under Test (TUT) and the entire system. Theoretical analysis, and simulation results employing Matlab/Simulink platform, considering a typical transformer of a 75 kVA power distribution grid with 13.8 kV/220 V voltage are presented to corroborate the proposal. The required VSI power achieved in the simulations is a fraction of the total power of transformer under test, and the grid power consumed is also of small order justified by losses.

Adaptive SRF-PLL Based Voltage and Frequency Control of Hybrid Standalone WECS with PMSG-BESS

2018 ◽  
Vol 19 (6) ◽  
Author(s):  
Anjana Jain ◽  
R. Saravanakumar ◽  
S. Shankar ◽  
V. Vanitha
Keyword(s):  
Reactive Power ◽  
Frequency Control ◽  
Storage System ◽  
Synchronous Generator ◽  
Energy Storage System ◽  
Voltage Regulation ◽  
Operating Conditions ◽  
Voltage Source ◽  
Voltage Source Converter ◽  
Control Scheme

Abstract The variable-speed Permanent Magnet Synchronous Generator (PMSG) based Wind Energy Conversion System (WECS) attracts the maximum power from wind, but voltage-regulation and frequency-control of the system in standalone operation is a challenging task A modern-control-based-tracking of power from wind for its best utilization is proposed in this paper for standalone PMSG based hybrid-WECS comprising Battery Energy Storage System (BESS). An Adaptive Synchronous Reference Frame Phase-Locked-Loop (SRF-PLL) based control scheme for load side bi-directional voltage source converter (VSC) is presented for the system. MATLAB/Simulink model is developed for simulation study for the proposed system and the effectiveness of the controller for bi-directional-converter is discussed under different operating conditions: like variable wind-velocity, sudden load variation, and load unbalancing. Converter control scheme enhances the power smoothening, supply-load power-matching. Also it is able to regulate the active & reactive power from PMSG-BESS hybrid system with control of fluctuations in voltage & frequency with respect to varying operating conditions. Proposed controller successfully offers reactive-power-compensation, harmonics-reduction, and power-balancing. The proposed scheme is based on proportional & integral (PI) controller. Also system is experimentally validated in the laboratory-environment and results are presented here.

scholarly journals A Novel Hybrid Converter Proposed for Multi-MW Wind Generator for Offshore Applications

Energies ◽  
2019 ◽  
Vol 12 (21) ◽  
pp. 4167 ◽  
Author(s):  
Muhammad Luqman ◽  
Gang Yao ◽  
Lidan Zhou ◽  
Tao Zhang ◽  
Anil Lamichhane
Keyword(s):  
Power Distribution ◽  
Semiconductor Devices ◽  
Power Converter ◽  
Offshore Wind ◽  
Total Power ◽  
Power Devices ◽  
Electric Grid ◽  
Current Stress ◽  
Wind Generator ◽  
Three Phase

Modern multi-MW wind generators have used multi-level converter structures as well as parallel configuration of a back to back three-level neutral point clamped (3L-NPC) converters to reduce the voltage and current stress on the semiconductor devices. These configurations of converters for offshore wind energy conversion applications results in high cost, low power density, and complex control circuitry. Moreover, a large number of power devices being used by former topologies results in an expensive and inefficient system. In this paper, a novel bi-directional three-phase hybrid converter that is based on a parallel combination of 3L-NPC and ‘n’ number of Vienna rectifiers have been proposed for multi-MW offshore wind generator applications. In this novel configuration, total power equally distributes by sharing of total reference current in each parallel-connected generator side power converter, which ensures the lower current stress on the semiconductor devices. Newly proposed topology has less number of power devices compared to the conventional configuration of parallel 3L-NPC converters, which results in cost-effective, compact in size, simple control circuitry, and good performance of the system. Three-phase electric grid is considered as a generator source for implementation of a proposed converter. The control scheme for a directly connected three-phase source with a novel configuration of a hybrid converter has been applied to ratify the equal power distribution in each parallel-connected module with good power factor and low current distortion. A parallel combination of a 3L-NPC and 3L-Vienna rectifier with a three-phase electric grid source has been simulated while using MATLAB and then implemented it on hardware. The simulation and experimental results ratify the performance and effectiveness of the proposed system.

scholarly journals Analysis of Synchronization Stability for Multi VSCs Parallel-Connected to Weak Grids by Improved Net Damping Criterion

Energies ◽  
2020 ◽  
Vol 13 (13) ◽  
pp. 3316 ◽  
Author(s):  
Dong Wang ◽  
Xiaojie Zhang ◽  
Lei Yang ◽  
Yunhui Huang ◽  
Wei Huang ◽  
...  
Keyword(s):  
Voltage Regulation ◽  
Operating Conditions ◽  
Voltage Source ◽  
Voltage Source Converter ◽  
Signal Model ◽  
Detailed Model ◽  
Weak Grid ◽  
Grid Connection ◽  
Sensitivity Studies ◽  
Stability Enhancement

Recent studies show that the loss of stability for a voltage-source converter (VSC) in weak-grid connection is largely related to its synchronization unit, i.e., the phase-locked loop (PLL). This paper studies the synchronization stability of a system comprised by two VSCs in parallel connection to a weak grid. A reduced transfer function based small-signal model, which can allow for the interactions between PLL and converter outer power controls, is first proposed. Then, an improved net damping criterion is used to analyze the damping and stability characters of such system under various operating conditions and different controller configurations. Compared to the conventional net damping criterion, the used criterion has wider applicability in terms of stability judgment. Case studies show that the studied system tends to be unstable at weak-grid or heavy-loading conditions. The instability can be in the form of oscillations or monotonic divergence, in which, the latter is more likely to occur for the converters without grid voltage regulation capabilities. Besides, the net damping-based sensitivity studies can provide guidance on control tuning or design for stability enhancement. Detailed model-based time domain simulations are conducted to verify the analysis results.

scholarly journals High Frequency Solid State Transformer Design Considerations for Power Systems Applications

2021 ◽  
Vol 2 (5) ◽  
Author(s):  
Raton Kumar Nondy ◽  
Md. Abul Bashar ◽  
Prema Nondy ◽  
M. Hazrat Ali
Keyword(s):  
Power Quality ◽  
Power Factor ◽  
Power Distribution ◽  
High Frequency ◽  
Low Voltage ◽  
Voltage Drop ◽  
Distribution Networks ◽  
Voltage Regulation ◽  
Power Converter ◽  
Voltage Sag

The conventional power frequency (50 or 60 Hz) transformers are economical, highly reliable and quite efficient but they suffer with certain drawbacks like sensitive to harmonics, voltage drop under load, no protection from system disruptions and overloads, poor performance under dc offset load unbalances and no scope to improve power factor. These transformers with copper wound wires on iron cores are unable to respond to control signals as power generations become distributed and intermittent. So, the need of electronic based regulated power supply with software based remote intelligence has become essential. Also, to easily connect the new energy sources to the grid and to improve the power quality by harmonic filtering, voltage sag correction and highly dynamic control of the power flow, a new type of transformer based on power electronics, known as SST has been introduced. The SST realizes voltage transformation, galvanic isolation, power quality improvements such as instantaneous voltage regulation, voltage sag compensation and power factor correction. It is a collection of high-powered semiconductor components, high frequency power transformer and control circuitry which is used to provide a high level of flexible control to power distribution networks. The SST is a high frequency switched Power Electronic Devices (PEDs) based transformer with high controllability that enables flexible connectivity between existing medium voltage power distribution network, low voltage AC residential system and envisioned DC residential system. In this paper a systematic constructional detail of a SST with a power rating of 2 kVA, operating frequency of 20 kHz and voltage rating of 600/60 V as a scaled-down prototype used for power converter topologies is presented. The design is simple and it avoids the difficulty of choosing massive amounts of empirical parameters.

scholarly journals Electric Vehicle–Grid Integration with Voltage Regulation in Radial Distribution Networks

Energies ◽  
2020 ◽  
Vol 13 (7) ◽  
pp. 1802 ◽  
Author(s):  
Chong Cao ◽  
Zhouquan Wu ◽  
Bo Chen
Keyword(s):  
Electric Vehicle ◽  
Power Distribution ◽  
Distribution System ◽  
Distribution Networks ◽  
Voltage Regulation ◽  
Grid Integration ◽  
Distribution Grid ◽  
Voltage Compensation ◽  
Control Schemes ◽  
Grid Level

In this paper, a vehicle–grid integration (VGI) control strategy for radial power distribution networks is presented. The control schemes are designed at both microgrid level and distribution level. At the VGI microgrid level, the available power capacity for electric vehicle (EV) charging is optimally allocated for charging electric vehicles to meet charging requirements. At the distribution grid level, a distributed voltage compensation algorithm is designed to recover voltage violation when it happens at a distribution node. The voltage compensation is achieved through a negotiation between the grid-level agent and VGI microgrid agents using the alternating direction method of multipliers. In each negotiation round, individual agents pursue their own objectives. The computation can be carried out in parallel for each agent. The presented VGI control schemes are simulated and verified in a modified IEEE 37 bus distribution system. The simulation results are presented to show the effectiveness of the VGI control algorithms and the effect of algorithm parameters on the convergence of agent negotiation.

A Novel Power Factor Correction Rectifier for Enhancing Power Quality

2015 ◽  
Vol 6 (4) ◽  
pp. 772 ◽  
Author(s):  
Bindu K V ◽  
B Justus Rabi
Keyword(s):  
Power Factor ◽  
High Power ◽  
High Efficiency ◽  
Power Level ◽  
Harmonic Distortion ◽  
Voltage Regulation ◽  
Total Power ◽  
Front End ◽  
Sinusoidal Input ◽  
Bidirectional Switches

In this paper, the disturbances in power system due to low quality of power are discussed and a current injection method to maintain the sinusoidal input current which will reduce the total current harmonic distortion (THD) as well as improve the power factor nearer to unity is proposed. The proposed method makes use of a novel controlled diode rectifier which involves the use of bidirectional switches across the front-end rectifier and the operation of the converter is fully analyzed. The main feature of the topology is low cost, small size, high efficiency and simplicity, and is excellent for retrofitting front-end rectifier of existing ac drives, UPS etc. A novel strategy implementing reference compensation current depending on the load harmonics and a control algorithm for three-phase three-level unity PF rectifier which draws high quality sinusoidal supply currents and maintains good dc link- voltage regulation under wide load variation. The proposed technique can be applied as a retrofit to a variety of existing thyristor converters which uses three bidirectional switches operating at low frequency and a half-bridge inverter operating at high frequency .The total power delivered to the load is processed by the injection network, the proposed converter offers high efficiency and not only high power factor but also the Total Harmonic Distortion is reduced. Theoretical analysis is verified by digital simulation and a hardware proto type module is implemented in order to confirm the feasibility of the proposed system. This scheme in general is suitable for the common variable medium-to high-power level DC load applications.

scholarly journals A Survey on Bidirectional DC/DC Power Converter Topologies for the Future Hybrid and All Electric Aircrafts

Energies ◽  
2020 ◽  
Vol 13 (18) ◽  
pp. 4883
Author(s):  
Álvaro Ojeda-Rodríguez ◽  
Pablo González-Vizuete ◽  
Joaquín Bernal-Méndez ◽  
María A. Martín-Prats
Keyword(s):  
Power Density ◽  
Power Distribution ◽  
Distribution Systems ◽  
High Efficiency ◽  
Low Voltage ◽  
Power Level ◽  
Power Converter ◽  
Dc Power ◽  
Converter Topologies ◽  
Converter Topology

DC-DC isolated converters allowing a bidirectional flow of energy between High-Voltage DC and Low-Voltage DC networks have been proposed to be integrated in future on board power distribution systems. These converters must meet the specially stringent efficiency and power density requirements that are typical of the aeronautic industry. This makes it specially challenging to determine which converter topology is best suited for each particular application. This work presents a thorough review of several topologies of bidirectional DC-DC power converters that are considered good candidates to meet certain important aeronautic requirements, as those related with high efficiency and high power density. We perform simulations on virtual prototypes, constructed by using detailed component models, and optimized following design criteria that are in accordance with those typically imposed by aeronautic requirements. This comparative analysis is aimed to clearly identify the advantages and drawbacks of each topology, and to relate them with the required voltage and power levels. As an outcome, we point out the topologies that, for the required power level at the chosen switching frequencies, yield higher efficiency in the whole range of required operation points and that are expected to allow more important weight reductions.

scholarly journals Implementasi DC-DC Boost Converter Menggunakan Arduino Berbasis Simulink Matlab

2020 ◽  
Vol 1 (2) ◽  
pp. 144-149
Author(s):  
Muldi Yuhendri ◽  
Randy Setiawan
Keyword(s):  
Direct Current ◽  
Output Voltage ◽  
Input Voltage ◽  
Voltage Regulation ◽  
Power Converter ◽  
Boost Converter ◽  
Experimental Results ◽  
Voltage Source ◽  
Matlab Simulink ◽  
Dc Voltage

Direct current (dc) voltage sources are one of the voltage sources most widely used for various purposes. Dc voltage can be obtained from a dc generator or by converting an ac voltage into a dc voltage using a power converter. There are several dc voltage levels that are commonly used by electrical and electronic equipment. To get a dc voltage that can be used for various equipment, then a dc voltage source must be varied according to the required. One way to get a variable dc voltage is to use a dc-dc converter. This research proposes a dc-dc boost converter that can increase the dc voltage with varying outputs. The boost converter is proposed using Arduino Uno as a controller with an input voltage of 12 volts. The converter output voltage regulation is implemented through Arduino programming using Matlab simulink. The experimental results show that the boost converter designed in this study has worked well as intended. This can be seen from the boost converter output voltage which is in accordance with the reference voltage entered in the Matlab simulink program

scholarly journals RES and ES Integration in Combination with Distribution Grid Development Using MILP

Energies ◽  
2021 ◽  
Vol 14 (2) ◽  
pp. 383
Author(s):  
Mateusz Andrychowicz
Keyword(s):  
Energy Storage ◽  
Distribution System ◽  
Renewable Energy Sources ◽  
Power Level ◽  
Peak Load ◽  
Operating Conditions ◽  
Mixed Integer ◽  
Distribution Grid ◽  
Specific Level ◽  
Load Curtailment

In the paper, a new method of long-term planning of operation and development of the distribution system, taking into account operational aspects such as power flows, power losses, voltage levels, and energy balances, is presented. The developed method allows for the allocation and selection of the power of Renewable Energy Sources (RES), control of energy storage (ES), curtailing of RES production (EC), and the development of the distribution grid (GD). Different types of RES and loads are considered, represented by generation/demand profiles reflecting their typical operating conditions. RES allocation indicates the node in the distribution system and the power level for each type of RES that may be built. Energy storage (ES) allows generation to be transferred from the demand valley to the peak load. Curtailment of RES generation indicates the moment and level of power by which generation will be reduced, while the grid development (GD) determines between which network nodes a new power line should be built. All these activities allow to minimize the costs of planning work and development of the distribution system at a specific level of energy consumption from RES in the analyzed distribution system using a Mixed Integer-Linear Programming (MILP).

scholarly journals Hybrid Multimodule DC-DC Converters for Ultrafast Electric Vehicle Chargers

Energies ◽  
2020 ◽  
Vol 13 (18) ◽  
pp. 4949
Author(s):  
Mena ElMenshawy ◽  
Ahmed Massoud
Keyword(s):  
Power Density ◽  
High Power ◽  
High Efficiency ◽  
Controller Design ◽  
Power Level ◽  
Power Converter ◽  
Total Power ◽  
Switching Frequency ◽  
High Power Density ◽  
High Switching Frequency

To increase the adoption of electric vehicles (EVs), significant efforts in terms of reducing the charging time are required. Consequently, ultrafast charging (UFC) stations require extensive investigation, particularly considering their higher power level requirements. Accordingly, this paper introduces a hybrid multimodule DC-DC converter-based dual-active bridge (DAB) topology for EV-UFC to achieve high-efficiency and high-power density. The hybrid concept is achieved through employing two different groups of multimodule converters. The first is designed to be in charge of a high fraction of the total required power, operating at a relatively low switching frequency, while the second is designed for a small fraction of the total power, operating at a relatively high switching frequency. To support the power converter controller design, a generalized small-signal model for the hybrid converter is studied. Also, cross feedback output current sharing (CFOCS) control for the hybrid input-series output-parallel (ISOP) converters is examined to ensure uniform power-sharing and ensure the desired fraction of power handled by each multimodule group. The control scheme for a hybrid eight-module ISOP converter of 200 kW is investigated using a reflex charging scheme. The power loss analysis of the hybrid converter is provided and compared to conventional multimodule DC-DC converters. It has been shown that the presented converter can achieve both high efficiency (99.6%) and high power density (10.3 kW/L), compromising between the two other conventional converters. Simulation results are provided using the MatLab/Simulink software to elucidate the presented concept considering parameter mismatches.

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