scholarly journals Validation of Novel PLL-driven PI Control Schemes on Supporting VSIs in Weak AC-Connections

Energies ◽  
2020 ◽  
Vol 13 (6) ◽  
pp. 1373 ◽  
Author(s):  
Panos C. Papageorgiou ◽  
Konstantinos F. Krommydas ◽  
Antonio T. Alexandridis
Keyword(s):  
Power Systems ◽  
Stability And Convergence ◽  
Voltage Source ◽  
Phase Locked Loops ◽  
System Management ◽  
Long Distance ◽  
Voltage Source Inverters ◽  
Power Extraction ◽  
Control Schemes ◽  
Stable Performance

The integration of distributed energy resources (DERs) in modern power systems has substantially changed the local control capabilities of the grid since the majority of DERs are connected through a controlled dc/ac inverter interface. Such long-distance located DER installations, usually represented by current regulated dc sources, can inject large amounts of power into the main ac grid at points where the strength of the ac connection is low. The efficient and stable performance of such a power scheme is related to the capability of the control applied to retain the power extraction close to the maximum and simultaneously to regulate the dc-side voltage as well as the ac-side voltage magnitude at the weak ac connection point. This is implemented by designing the controllers of the voltage source inverters (VSIs) in a manner that reliably satisfies the above tasks. To this end, decentralized cascaded control schemes, driven by novel, locally implemented phase locked loops (PLLs), suitable to work in weak ac connections, are proposed for the VSI performance regulation by using new fast inner-loop proportional-integral (PI) current controllers. A decisive innovation is proposed by inserting an extra damping term in the inner-loop controllers to guarantee stability and convergence to the desired equilibrium. This is analytically proven by a rigorous analysis based on the entire nonlinear system model, where advanced Lyapunov-based methods are deployed in detail. As a good transient response of the VSI interface is indeed critical for the energy and grid system management, the conducted simulation and experimental results confirm that the proposed scheme efficiently supports the ac- and dc-side voltages of the VSI under different varying conditions in the power production or any voltage changes of the main grid.

scholarly journals Operation and Challenges of Multi-Infeed LCC–HVDC System: Commutation Failure, AC/DC Power Flow, and Voltage Stability

2021 ◽  
Vol 11 (18) ◽  
pp. 8637
Author(s):  
Bilawal Rehman ◽  
Atiq ur Rehman ◽  
Waqar Ahmad Khan ◽  
Irfan Sami ◽  
Jong-Suk Ro
Keyword(s):  
Power Systems ◽  
Power Flow ◽  
Voltage Stability ◽  
Power Transmission ◽  
Voltage Source ◽  
Future Research ◽  
Long Distance ◽  
Hvdc System ◽  
Dc Power ◽  
Commutation Failure

This paper presents a detailed analysis of commutation failure, AC/DC power flow, and voltage stability of multi-infeed high-voltage direct current (HVDC). The use of HVDC power transmission technology has become common in modern power systems. During the past two decades, HVDC technology has been extensively used for long-distance bulk power transmission to remote areas. Throughout the world, the demand for power has drastically increased in recent years due to industrialization; such situations make HVDC an economic candidate because the distance between power generation plants and load areas is significantly very long. The line-commutated converter (LCC) technology-based HVDC system is well more mature than other available conversion schemes (i.e., voltage source converters), and it is widely used in high-power projects. China had approximately 50 HVDC–LCC links in 2020, and a single LCC-based link with the highest capacity is 12 GW. The installation of several HVDC links in an existing power network has led to a situation where two or more HVDC links terminate in the electric vicinity of each other’s AC network or even in same AC busbar. Such scenarios are termed multi-infeed HVDC system. Multi-infeed HVDC systems bring various challenges related to voltage stability, local and concurrent commutation failure, and AC/DC power flow. Here, the literature available on these phenomena of LCC-based HVDC is discussed for future research. The assumptions and drawbacks of various techniques used for investigating the mentioned phenomena are also highlighted.

scholarly journals Design and implementation of DPFC for multi-bus power system

2018 ◽  
Vol 7 (2.8) ◽  
pp. 18
Author(s):  
B Vijaya Krishna ◽  
B Venkata Prashanth ◽  
P Sujatha
Keyword(s):  
Power Systems ◽  
Power System ◽  
Power Quality ◽  
Power Flow ◽  
Pulse Width Modulation ◽  
Voltage Source ◽  
Voltage Sag ◽  
Voltage Source Inverters ◽  
Interconnected Power System ◽  
Simulink Model

In current days, the power quality issues in the interconnected power system are mainly happens due to the demand of electricity and utilization of large non-linear loads as well as inductive/capacitive loads. The power quality cries are voltage sag and swell in multi-bus power system (MBPS). In this article studies on a two bus, three bus and five bus power systems using DPFC. In order to eliminate the voltage sag and swell in the MBPS, a distributed power flow controller (DPFC) is designed. The structure of the DPFC consists of three-phase shunt converter and three single series phase converters. Both these converters are arranged in back-back voltage source inverters (VSIs). These converters are controlled with help of the pulse width modulation (PWM) scheme. The feedback controllers and reference signals are derived the PWM for DPFC to magnify the power quality problems in MBPS. The performance of the model is investigated at different loads by making of MATLAB/Simulink model. The simulation results are presented.

scholarly journals Grid Connected Energy System four leg Inverter for DC Voltage and Power Improvement

IJOSTHE ◽  
2018 ◽  
Vol 5 (4) ◽  
pp. 4
Author(s):  
Yogeeta Hurde ◽  
Nandkishor .
Keyword(s):  
Power Systems ◽  
Single Phase ◽  
Control Method ◽  
Energy System ◽  
Voltage Source ◽  
Construction Time ◽  
Voltage Source Inverters ◽  
Three Phase ◽  
And Performance ◽  
Electrical Loads

The first power systems were DG systems designed to meet the needs of local areas.Full load DG applications showed greater benefits in terms of power and performance as well as reducing transmission losses. GDs are very suitable for a specific location and for specific applications because they require a short construction time and require little investment. It is defined on the basis of the size of the plant, which can vary from a few KW to MW (10-50 MW). GD options can be classified as renewable or non-renewable sources from fuel sources. This study deals with a newly-conceived voltage control method for three-phase four-leg voltage source inverters (VSIs) which are being required in autonomous power generating units devoted to supply both three-phase and single-phase electrical loads

scholarly journals Multivariable Deadbeat Control of Power Electronics Converters with Fast Dynamic Response and Fixed Switching Frequency

Energies ◽  
2021 ◽  
Vol 14 (2) ◽  
pp. 313
Author(s):  
Jaime A. Rohten ◽  
David N. Dewar ◽  
Pericle Zanchetta ◽  
Andrea Formentini ◽  
Javier A. Muñoz ◽  
...  
Keyword(s):  
Dynamic Response ◽  
Power Systems ◽  
Power Converter ◽  
Current Control ◽  
Renewable Energies ◽  
Voltage Source ◽  
Switching Frequency ◽  
Control Loop ◽  
Voltage Source Inverters ◽  
Power Electronics Converters

Power converters have turned into a critical and every-day solution for electric power systems. In fact, the incorporation of renewable energies has led towards the constant improvement of power converter topologies and their controls. In this context, over the last 10 years, model predictive control (MPC) is positioned as one the most studied and promising alternatives for power converter control. In voltage source inverters (VSI), MPC has only been applied in the inner current control loop, accelerating and improving its dynamic response, but as mentioned, has been limited only to the current control loop. The fastest of the MPC techniques is the Deadbeat (DB) control, and in this paper, it is proposed to employ DB control on the entire system, therefore accelerating the time response not only for the current loops, but also for voltage loops. At the same time, this avoids overshoots and overpower in order to protect the power converter, leading to the fastest dynamic response according to VSI capabilities. For renewable energies, fast-dynamics entails fast maximum power tracking and therefore, maximizes energy harvesting, or in other words, reduces the losses due to the control dynamics. Thus, this paper gives a clear procedure and key points for designing a DB control for all the variables based on a mathematical model, which is corroborated by simulations and the experimental results.

scholarly journals Design of Inverter Voltage Mode Controller by Backstepping Technique for Nonlinear Power System Model

2021 ◽  
Vol 3 (4) ◽  
pp. 265-276
Author(s):  
P. Karuppusamy
Keyword(s):  
Power Systems ◽  
Output Voltage ◽  
Formal Analysis ◽  
System Model ◽  
Control Mode ◽  
Electrical Network ◽  
Voltage Source ◽  
Voltage Source Inverters ◽  
Voltage Mode ◽  
Voltage Control Mode

Modelling systems are a new sort of electrical network that can be easily adapted. Dispersed generators are linked to a microgrid using voltage source inverters. Nonlinear modelling systems are used in this study to create an inverter voltage mode controller for power systems to control power supply volatility. Controller for a nonlinear inverter that operates in voltage control mode is proposed. The primary goal is to ensure that the output voltage of the system matches a predetermined standard. Once the system model is completed, the controller is constructed using the backstepping method. After the control law is developed, several simulations are run to test the proposed controller's performance. According to simulation findings and formal analysis, the output voltage matches the reference voltage with global asymptotic stability. The accomplishment of this work is that the controller built, works in both grid-connected and inverter voltage modes of microgrid operation.

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