scholarly journals Quasi-Z Source T-Type Power Converter for PV Based Commercial and Industrial Nanogrids with Active Functions Strategy

Electronics ◽  
2020 ◽  
Vol 9 (8) ◽  
pp. 1233
Author(s):  
Fermín Barrero-González ◽  
Carlos Roncero-Clemente ◽  
María Isabel Milanés-Montero ◽  
Eva González-Romera ◽  
Enrique Romero-Cadaval ◽  
...  
Keyword(s):  
Reactive Power ◽  
Power Converter ◽  
Electrical Network ◽  
Distribution Grid ◽  
Industrial Facilities ◽  
Pv Inverter ◽  
Three Phase ◽  
The One ◽  
Grid Side ◽  
Type Power

Since most power electronics used in photovoltaic (PV) inverters at commercial and industrial facilities exhibit behavior as non-linear loads from the grid side, these high-power demand installations are expected to have a major impact on the network’s power quality. In an attempt to facilitate their integration into the distribution grid, this paper presents a comprehensive control strategy for Quasi-Z Source T-Type PV inverters inside a facility, which performs active and reactive power control, and harmonic and imbalance compensation at expenses of the spare inverter power capacity. Unlike other approaches, the one proposed here operates properly under distorted and unbalanced grid voltages. The electrical network structure inside a commercial and industrial facility is considered, analyzing the operation of the proposed strategy on three-phase PV inverters. The power topology used has voltage boosting ability, which eliminates the requirement for both an additional DC-DC converter and/or a step-up transformer commonly used in PV inverter systems. The proposed strategy performance is demonstrated on a 50 kW converter model under a disturbed grid environment and changing load conditions.

Design and implementation of FLC system for fault ride-through capability enhancement in PMSG-wind systems

2020 ◽  
pp. 0309524X2098177
Author(s):  
Mohamed Metwally Mahmoud ◽  
Hossam S Salama ◽  
Mohamed M Aly ◽  
Abdel-Moamen M Abdel-Rahim
Keyword(s):  
Fuzzy Logic Controller ◽  
Synchronous Generator ◽  
Electrical Network ◽  
Electricity Grid ◽  
Wind Energy Generation ◽  
Fault Ride Through ◽  
Three Phase ◽  
Hybrid Solution ◽  
Pi Controllers ◽  
Grid Side

Fault ride-through (FRT) capability enhancement for the growth of renewable energy generators has become a crucial issue for their incorporation into the electricity grid to provide secure, reliable, and efficient electricity. This paper presents a new FRT capability scheme for a permanent magnet synchronous generator (PMSG)-based wind energy generation system using a hybrid solution. The hybrid solution is a combination of a braking chopper (BC) and a fuzzy logic controller (FLC). All proportional-integral (PI) controllers which control the generator and grid side converters are replaced with FLC. Moreover, a BC system is connected to the dc link to improve the dynamic response of the PMSG during fault conditions. The PMSG was evaluated on a three-phase fault that occurs on an electrical network in three scenarios. In the first two scenarios, a BC is used with a PI controller and FLC respectively. While the third scenario uses only FLC without a BC. The obtained results showed that the suggested solution can not only enhance the FRT capability of the PMSG but also can diminish the occurrence of hardware systems and reduce their impact on the PMSG system. The simulation tests are performed using MATLAB/SIMULINK software.

scholarly journals Attenuation of DC-Link Pulsation of a Four-Wire Inverter during Phase Unbalanced Current Operation

2021 ◽  
Vol 11 (3) ◽  
pp. 1322
Author(s):  
Dariusz Zieliński ◽  
Karol Fatyga
Keyword(s):  
Energy Storage ◽  
Control Algorithm ◽  
Reactive Power ◽  
Lithium Ion ◽  
Power Converter ◽  
Dual Active Bridge ◽  
Three Phase ◽  
Ion Storage ◽  
Energy Store ◽  
Phase Converter

This paper proposes a control algorithm for a hybrid power electronic AC/DC converter for prosumer applications operating under deep phase current asymmetry. The proposed system allows independent control of active and reactive power for each phase of the power converter without current pulsation on the DC link connected to an energy store. The system and its algorithm are based on a three-phase converter in four-wire topology (AC/DC 3p-4w) with two dual-active bridge (DC/DC) converters, interfaced with a supercapacitor and an energy storage. The control algorithm tests were carried out in a Hardware in the Loop environment. Obtained results indicate that operation with deep unbalances and powers of opposite signs in individual phases leads to current oscillations in the DC link. This phenomenon significantly limits energy storage utilization due to safety and durability reasons. The proposed algorithm significantly reduces the level of pulsation in the DC link which increases safety and reduces strain on lithium-ion storage technology, enabling their application in four-wire converter applications.

scholarly journals Full-Observable Three-Phase State Estimation Algorithm Applied to Electric Distribution Grids

Energies ◽  
2019 ◽  
Vol 12 (7) ◽  
pp. 1327 ◽  
Author(s):  
Thiago Soares ◽  
Ubiratan Bezerra ◽  
Maria Tostes
Keyword(s):  
State Estimation ◽  
Real Time ◽  
Distribution Systems ◽  
Phase State ◽  
Reactive Power ◽  
Estimation Algorithm ◽  
Load Flow ◽  
Electrical Network ◽  
The Real ◽  
Three Phase

This paper proposes the development of a three-phase state estimation algorithm, which ensures complete observability for the electric network and a low investment cost for application in typical electric power distribution systems, which usually exhibit low levels of supervision facilities and measurement redundancy. Using the customers´ energy bills to calculate average demands, a three-phase load flow algorithm is run to generate pseudo-measurements of voltage magnitudes, active and reactive power injections, as well as current injections which are used to ensure the electrical network is full-observable, even with measurements available at only one point, the substation-feeder coupling point. The estimation process begins with a load flow solution for the customers´ average demand and uses an adjustment mechanism to track the real-time operating state to calculate the pseudo-measurements successively. Besides estimating the real-time operation state the proposed methodology also generates nontechnical losses estimation for each operation state. The effectiveness of the state estimation procedure is demonstrated by simulation results obtained for the IEEE 13-bus test network and for a real urban feeder.

scholarly journals Enhanced Control Scheme for a Three-Phase Grid-Connected PV Inverter under Unbalanced Fault Conditions

Electronics ◽  
2020 ◽  
Vol 9 (8) ◽  
pp. 1247
Author(s):  
Saeid Abbasi ◽  
Ali Asghar Ghadimi ◽  
Amir Hossein Abolmasoumi ◽  
Mohammad Reza Miveh ◽  
Francisco Jurado
Keyword(s):  
Reactive Power ◽  
Control Strategies ◽  
Active Power ◽  
Reactive Control ◽  
Pv System ◽  
Pv Inverter ◽  
Three Phase ◽  
Control Scheme ◽  
Double Grid ◽  
Unbalanced Grid

This paper presents an improved control strategy to cancel the double grid frequency oscillations in the active power, reactive power, and DC-link voltage of a three-phase grid-connected photovoltaic (PV) system under unbalanced grid condition. To achieve these goals, an enhanced positive–negative-sequence control (PNSC) to remove oscillations of active power and an instantaneous active–reactive control (IARC) to mitigate the fluctuations of active and reactive power, simultaneously, are suggested. These methods are also effective to reduce the oscillations of the DC-link voltage. To track the desired unbalanced or harmonic reference currents, improved proportional resonant (PR) current controllers have been designed using the Bode frequency analysis. Simulation studies are carried out via Matlab/Simulink® software to verify the effectiveness of the suggested control strategies.

scholarly journals Variable Structure Back-Stepping Control of Two-stage Three Phase Grid Connected PV Inverter

2020 ◽  
Author(s):  
Nasim Ullah ◽  
Ahmad Aziz Al Ahmadi
Keyword(s):  
Reactive Power ◽  
Control Method ◽  
Sliding Mode ◽  
Variable Structure ◽  
Control Approach ◽  
Control Loops ◽  
Pv Inverter ◽  
Voltage Variation ◽  
Three Phase ◽  
Back Stepping Control

This work presents a detailed analysis of a three phase grid tied photovoltaic inverter with variable structure back-stepping control approach. A nonlinear model of the system is derived and presented in rotational frame using the direct quadrature zero transformation (DQ). For the derivation of active and reactive power loops of the inverter, nonlinear back stepping approach is used. Moreover, sliding mode control method is used to derive the inner current loops while for the outer loop a virtual controller is derived using the Lyapunov function. The control loops are implemented in MATLAB/Simulink environment. To test the controller performance, active power variation, DC link voltage variation and reactive power variations are inflicted. The obtained results under the proposed control scheme are compared with boundary layer design based sliding mode controller. From the comparative analysis it is concluded that the proposed controller exhibit superior and robust performance under all test conditions.

scholarly journals Static Reactive Power Compensator Design, Based on Three-Phase Voltage Converter

Energies ◽  
2021 ◽  
Vol 14 (8) ◽  
pp. 2198
Author(s):  
Manuel Ayala-Chauvin ◽  
Bahodurjon S. Kavrakov ◽  
Jorge Buele ◽  
José Varela-Aldás
Keyword(s):  
Reactive Power ◽  
Electrical Network ◽  
Operating Modes ◽  
Power And Control ◽  
Current Voltage ◽  
Three Phase ◽  
Direct Current Voltage ◽  
Control Circuits ◽  
And Control ◽  
Reactive Power Compensator

At present, electrical network stability is of the utmost importance because of the increase in electric demand and the integration of distributed generation deriving from renewable energy. In this paper, we proposed a static reactive power compensator model with common direct current voltage sources. Converter parameters were calculated and designed to fulfill specifications. In order to ascertain the device response for different operating modes as reactive power consumer and generator, we developed the model’s power and control circuits in Matlab Simulink. Simulations were performed for different conditions, and as a result, the current and voltage waveforms and the circular power chart were obtained. This paper has theoretically proven it is possible to achieve the consumption or generation of purely active or reactive power by implementing a static reactive power compensator with common DC voltage sources.

A new discrete‐time PI‐RMRAC for grid‐side currents control of grid‐tied three‐phase power converter

2021 ◽  
Author(s):  
Paulo Jefferson Dias de Oliveira Evald ◽  
Guilherme Vieira Hollweg ◽  
Rodrigo Varella Tambara ◽  
Hilton Abílio Gründling
Keyword(s):  
Discrete Time ◽  
Power Converter ◽  
Three Phase ◽  
Grid Side

scholarly journals Assessment Indexes for Converter P-Q Control Coupling

Energies ◽  
2020 ◽  
Vol 13 (5) ◽  
pp. 1144
Author(s):  
Panagis N. Vovos ◽  
Ioannis D. Bouloumpasis ◽  
Konstantinos G. Georgakas
Keyword(s):  
Power Control ◽  
Reactive Power ◽  
Relevant Literature ◽  
Testing Procedure ◽  
Power Converter ◽  
Distribution Grid ◽  
Reactive Power Control ◽  
Power Coupling ◽  
Active And Reactive Power ◽  
The Impact

This work presents a concise methodology for the calculation of assessment indexes regarding the coupling between active and reactive power control observed on distribution level converters. First, the reader is introduced to the concept of power coupling; when, where and how it appears in power control of converters. A brief summary of the theory and formulation behind it is also included, together with relevant literature. Then, the methodology for the assessment of active and reactive power control performance of any grid-connected converter is presented. The impact of small control disturbances during a testing procedure is monitored, analyzed and converted to meaningful indexes, so that the type and level of coupling is quantified without putting the converter or the grid at risk. The efficiency of the methodology to assess the type and level of coupling is verified experimentally. This is done by assessing several power control approaches with different level of decoupling efficiency on the same power converter connected to a distribution grid. While the assessment is performed with safe, minimal disturbances, its exceptional accuracy is later confirmed by the level and type of coupling observed during significant power step changes.

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