Current Harmonics Compensation in Microgrids Exploiting the Power Electronics Interfaces of Renewable Energy Sources

Bouloumpasis, Ioannis; Vovos, Panagis N.; Georgakas, Konstantinos G.; Vovos, N.A.

doi:10.3390/en8042295

Cited by 21 publications

(12 citation statements)

References 16 publications

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“…The current motivation is to achieve that the microinverter technology play a new role in AC distribution systems complementing their main objective of real power injection with capabilities of power conditioning [7]- [9]. This new approach introduces the distributed generation-conditioning concept, taking full advantage of the converters on the microinverter devices [10].…”

Section: Introductionmentioning

confidence: 99%

Operation of a Photovoltaic Microinverter as Active Power Filter using the single phase P-Q Theory and Sliding Mode Control

López-Santos

Tilaguy-Lezama

Rico-Ramírez

et al. 2017

Ing.

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Context: Microinverters are widely used in modular photovoltaic installations but its operation with reduced power is limited to inject real power into the grid. One way to optimize the use of microinverters consist of providing them the Active Power Filtering (APF) capability, which allows its use as both distributed generation and compensation unit even under unfavorable conditions of insolation. With this approach, the output stage of the microinverter can provide reactive and distortive components of power in order to compensate power quality defects of a localized load. Method: This paper proposes a non-linear control strategy to integrate the APF function in a singlephase two-stage photovoltaic microinverter. The proposal involves the use of the single-phase P-Q theory to generate the current reference, sliding mode control to achieve a robust tracking of that reference and linear robust control to maintain the power balance regulating the DC-link voltage of the microinverter. The proposed control does not require the use of low-pass filters and in turn uses a recursive average computation improving the general performance of the system. Results: The theoretical approach is validated by means of simulation results in which appropriate levels of harmonic distortion are obtained in the grid-side current for different load types and power levels. The robustness of the control system is tested by applying disturbances in the harmonic content of the load current and its power level obtaining an appropriate dynamic performance adapted to the demands of the application. Conclusions: The main advantage of this proposal is the possibility to add the active filter function to coventional microinverters extending its capability to power conditioning only integrating some algorithms. A simple design method to ensure reliability, robustness and high power quality is detailed. ResumenContexto: Los microinversores son ampliamente utilizados en instalaciones fotovoltaicas modulares pero su operación con potencia reducida es limitada a inyectar potencia real en la red. Una forma de optimizar el uso de los microinversores consiste en proveerles la capacidad para realizar Filtrado Activo de Potencia (FAP), lo que permite su uso como una unidad tanto de generación como de compensación distribuida, incluso en condiciones desfavorables de irradiación solar. Con esta propuesta, la etapa de salida del microinversor puede suministrar componentes de potencia reactiva y de distorsión para compensar defectos en la calidad de energía de una carga localizada. Método: Se propone una estrategia de control no lineal para integrar la función FAP en un microinversor fotovoltaico monofásico de dos etapas. La propuesta involucra el uso de la teoría P-Q monofásica para generar la referencia de corriente, control en modo deslizante para conseguir un seguimiento robusto de dicha referencia y control lineal robusto para mantener el balance de potencia regulando el voltaje del bus DC intermedio del microinversor. El control propuesto no r...

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Section: Introductionmentioning

confidence: 99%

Operation of a Photovoltaic Microinverter as Active Power Filter using the single phase P-Q Theory and Sliding Mode Control

López-Santos

Tilaguy-Lezama

Rico-Ramírez

et al. 2017

Ing.

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“…Then, using the information of two variables, namely load voltage and current, the DC component of the active power is extracted. Further, the required current reference to control the SAPF is generated using (1). However, an ideal positive sequence voltage can never be made at the PCC.…”

Section: Practical Issues and Proposed Solutionsmentioning

confidence: 99%

“…However, how to integrate these renewable sources into a power system, a challenging issue, has been attracting considerable attention [1][2][3][4][5].…”

Section: Introductionmentioning

confidence: 99%

A Wavelet-Based Unified Power Quality Conditioner to Eliminate Wind Turbine Non-Ideality Consequences on Grid-Connected Photovoltaic Systems

Rahmani

Liu

2016

Energies

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Abstract:The integration of renewable power sources with power grids presents many challenges, such as synchronization with the grid, power quality problems and so on. The shunt active power filter (SAPF) can be a solution to address the issue while suppressing the grid-end current harmonics and distortions. Nonetheless, available SAPFs work somewhat unpredictably in practice. This is attributed to the dependency of the SAPF controller on nonlinear complicated equations and two distorted variables, such as load current and voltage, to produce the current reference. This condition will worsen when the plant includes wind turbines which inherently produce 3rd, 5th, 7th and 11th voltage harmonics. Moreover, the inability of the typical phase locked loop (PLL) used to synchronize the SAPF reference with the power grid also disrupts SAPF operation. This paper proposes an improved synchronous reference frame (SRF) which is equipped with a wavelet-based PLL to control the SAPF, using one variable such as load current. Firstly the fundamental positive sequence of the source voltage, obtained using a wavelet, is used as the input signal of the PLL through an orthogonal signal generator process. Then, the generated orthogonal signals are applied through the SRF-based compensation algorithm to synchronize the SAPF's reference with power grid. To further force the remained uncompensated grid current harmonics to pass through the SAPF, an improved series filter (SF) equipped with a current harmonic suppression loop is proposed. Concurrent operation of the improved SAPF and SF is coordinated through a unified power quality conditioner (UPQC). The DC-link capacitor of the proposed UPQC, used to interconnect a photovoltaic (PV) system to the power grid, is regulated by an adaptive controller. Matlab/Simulink results confirm that the proposed wavelet-based UPQC results in purely sinusoidal grid-end currents with total harmonic distortion (THD) = 1.29%, which leads to high electrical efficiency of a grid-connected PV system.

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“…Current harmonics may result from nonlinear load operations produced by power electronic devices and applications which are injected into the supply network through a point of common coupling (PCC). Specifically, in smart grid systems, these problems may arise with involvement of multiple energy sources and systems which include photovoltaic (PV) grid connected systems [1][2][3][4][5][6]. Among the effects of current harmonics are capacitor blowing, equipment overheating, motor vibration and excessive neutral currents [7,8].…”

Section: Introductionmentioning

confidence: 99%

Fundamental Active Current Adaptive Linear Neural Networks for Photovoltaic Shunt Active Power Filters

et al. 2016

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This paper presents improvement of a harmonics extraction algorithm, known as the fundamental active current (FAC) adaptive linear element (ADALINE) neural network with the integration of photovoltaic (PV) to shunt active power filters (SAPFs) as active current source. Active PV injection in SAPFs should reduce dependency on grid supply current to supply the system. In addition, with a better and faster harmonics extraction algorithm, the SAPF should perform well, especially under dynamic PV and load conditions. The role of the actual injection current from SAPF after connecting PVs will be evaluated, and the better effect of using FAC ADALINE will be confirmed. The proposed SAPF was simulated and evaluated in MATLAB/Simulink first. Then, an experimental laboratory prototype was also developed to be tested with a PV simulator (CHROMA 62100H-600S), and the algorithm was implemented using a TMS320F28335 Digital Signal Processor (DSP). From simulation and experimental results, significant improvements in terms of total harmonic distortion (THD), time response and reduction of source power from grid have successfully been verified and achieved.

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Current Harmonics Compensation in Microgrids Exploiting the Power Electronics Interfaces of Renewable Energy Sources

Cited by 21 publications

References 16 publications

Operation of a Photovoltaic Microinverter as Active Power Filter using the single phase P-Q Theory and Sliding Mode Control

Operation of a Photovoltaic Microinverter as Active Power Filter using the single phase P-Q Theory and Sliding Mode Control

A Wavelet-Based Unified Power Quality Conditioner to Eliminate Wind Turbine Non-Ideality Consequences on Grid-Connected Photovoltaic Systems

Fundamental Active Current Adaptive Linear Neural Networks for Photovoltaic Shunt Active Power Filters

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