Ancillary services provided by photovoltaic inverters: Single and three phase control strategies

2018 ◽  
Vol 70 ◽  
pp. 102-121 ◽  
Author(s):  
Lucas S. Xavier ◽  
Allan F. Cupertino ◽  
Heverton A. Pereira
Keyword(s):  
Control Strategies ◽  
Phase Control ◽  
Ancillary Services ◽  
Three Phase

scholarly journals Possible Power Quality Ancillary Services in Low-Voltage Grids Provided by the Three-Phase Damping Control Strategy

2020 ◽  
Vol 10 (21) ◽  
pp. 7876
Author(s):  
Dimitar V. Bozalakov ◽  
Joannes Laveyne ◽  
Mohannad J. Mnati ◽  
Jan Van de Vyver ◽  
Lieven Vandevelde
Keyword(s):  
Power Quality ◽  
Control Strategy ◽  
Distribution System ◽  
Low Voltage ◽  
Control Strategies ◽  
Ancillary Services ◽  
Phase Damping ◽  
Damping Control ◽  
Three Phase ◽  
System Operator

The share of renewable energy is increasing because of environmental concerns and favorable economic conditions. The majority of the distributed energy resources, connected to the low-voltage grid, are inverter-connected units. These inverters are controlled by using specially developed control strategies to determine the power injection between the primary source and the grid. In the past, the connection of distributed energy resources was based on the connect-and-forget principle, but this approach leads to severe power quality problems. Nowadays, more sophisticated control strategies need to be developed, so that ancillary services can be provided to the distribution system operator, which will allow further increase of renewable share in the distribution grids. This article examines the technical capabilities of the three-phase damping control strategy to provide ancillary services to the distribution system operator. Besides the three-phase damping control strategy, the article also compares the classical positive-sequence control strategy. Active power drooping and reactive power exchange are combined with these control strategies and the effect on the annual energy production, power quality, and grid performance is assessed. The simulations are conducted on a Matlab/OpenDSS platform in a time series simulations.

scholarly journals Impedance Matching-Based Power Flow Analysis for UPQC in Three-Phase Four-Wire Systems

Energies ◽  
2021 ◽  
Vol 14 (9) ◽  
pp. 2702
Author(s):  
Xiaojun Zhao ◽  
Xiuhui Chai ◽  
Xiaoqiang Guo ◽  
Ahmad Waseem ◽  
Xiaohuan Wang ◽  
...  
Keyword(s):  
Power Flow ◽  
Control Strategies ◽  
Impedance Matching ◽  
Flow Analysis ◽  
Point Of View ◽  
Impedance Model ◽  
Power Flow Analysis ◽  
Three Phase ◽  
System Node ◽  
Power Quality Conditioner

Different from the extant power flow analysis methods, this paper discusses the power flows for the unified power quality conditioner (UPQC) in three-phase four-wire systems from the point of view of impedance matching. To this end, combined with the designed control strategies, the establishing method of the UPQC impedance model is presented, and on this basis, the UPQC system can be equivalent to an adjustable impedance model. After that, a concept of impedance matching is introduced into this impedance model to study the operation principle for the UPQC system, i.e., how the system changes its operation states and power flow under the grid voltage variations through discussing the matching relationships among node impedances. In this way, the nodes of the series and parallel converter are matched into two sets of impedances in opposite directions, which mean that one converter operates in rectifier state to draw the energy and the other one operates in inverter state to transmit the energy. Consequently, no matter what grid voltages change, the system node impedances are dynamically matched to ensure that output equivalent impedances are always equal to load impedances, so as to realize impedance and power balances of the UPQC system. Finally, the correctness of the impedance matching-based power flow analysis is validated by the experimental results.

scholarly journals Numerical Modal Analysis of Vibrations in a Three-Phase Linear Switched Reluctance Actuator

2017 ◽  
Vol 2017 ◽  
pp. 1-18
Author(s):  
José Salvado ◽  
Maria do Rosário Calado ◽  
António Espírito Santo ◽  
Anna Guerman
Keyword(s):  
Control Strategies ◽  
Mode Shapes ◽  
Audio Signals ◽  
Structural Vibrations ◽  
Significant Information ◽  
Switched Reluctance ◽  
Three Phase ◽  
Linear Configuration ◽  
Analytical Approaches

This paper addresses the problem of vibrations produced by switched reluctance actuators, focusing on the linear configuration of this type of machines, aiming at its characterization regarding the structural vibrations. The complexity of the mechanical system and the number of parts used put serious restrictions on the effectiveness of analytical approaches. We build the 3D model of the actuator and use finite element method (FEM) to find its natural frequencies. The focus is on frequencies within the range up to nearly 1.2 kHz which is considered relevant, based on preliminary simulations and experiments. Spectral analysis results of audio signals from experimental modal excitation are also shown and discussed. The obtained data support the characterization of the linear actuator regarding the excited modes, its vibration frequencies, and mode shapes, with high potential of excitation due to the regular operation regimes of the machine. The results reveal abundant modes and harmonics and the symmetry characteristics of the actuator, showing that the vibration modes can be excited for different configurations of the actuator. The identification of the most critical modes is of great significance for the actuator’s control strategies. This analysis also provides significant information to adopt solutions to reduce the vibrations at the design.

scholarly journals Review of three-phase inverters control for unbalanced load compensation

2019 ◽  
Vol 10 (1) ◽  
pp. 242 ◽  
Author(s):  
Raef Aboelsaud ◽  
A. Ibrahim ◽  
Alexander G. Garganeev
Keyword(s):  
Power Quality ◽  
Control Strategies ◽  
Power Electronic ◽  
Distributed Energy ◽  
Nonlinear Loads ◽  
Load Compensation ◽  
Research Areas ◽  
Three Phase ◽  
Unbalanced Load ◽  
Three Phase Inverter

<span>In the microgrid systems, three-phase inverter becomes the main power electronic interface for renewable distributed energy resources (DERs), especially for the islanded microgrids in which the power quality is easily affected by unbalanced and nonlinear loads, this is due to the fact that the voltage and frequency of the microgrid are not supported by the main power grid but determined only by the inverters. Therefore, the compensation of the load unbalances and harmonics in autonomous microgrid inverters are getting more attention in power quality research areas. The main purpose of this paper is to represent an overview of the control strategies of various inverters for unbalanced load compensation</span>

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