scholarly journals Controlled Intersystem Link Based on a "Hexagon" Scheme Converter

2021 ◽  
Author(s):  
Lev Kalinin ◽  
◽  
Dmitrii Zaitsev ◽  
Mihai Tirshu ◽  
Irina Golub ◽  
...  
Keyword(s):  
Power Systems ◽  
Control Strategy ◽  
Frequency Conversion ◽  
Frequency Converter ◽  
Harmonic Distortion ◽  
Input Voltage ◽  
Technical Solution ◽  
Operating Characteristics ◽  
Fine Control ◽  
And Control

The aim of the paper is to research possibility to use a "hexagon" scheme static frequency converter as controlled intersystem link for two parallel operating power systems with different operating frequencies, or standards for frequency stabilization. The paper aims to study the transformer device operating characteristics that implements the output voltage phase circular rotation principle relative to the input voltage and controlled by power electronics. This goal is achieved through the elaborated "rough" device control strategy, which made it possible to provide controlled AC intersystem link of asynchronous power systems without the use of additional harmonic filters and dampers. Two sectioning modes of adjusting windings were used to apply 24 and 48 position laws of the converter "fine" control. The most significant results are the new technical solution of the frequency converter, as well as the "rough" control strategy. To assess the conversion quality, indicators were used that characterize the degree of stability of the transmitted power and the harmonic distortion of the current. The computational experiments results have shown the effectiveness of the proposed "rough" control strategy. It is proved that 48-position sectioning of the "fine" regulation winding can significantly improve the quality of conversion compare to 24-position. The obtained results significance is that developed technical solution provides acceptable indicators of the frequency conversion quality and transmitted active power stability. In addition, the use of the proposed converter technical solution can significantly reduce the number of windings and control means compare to previously ones studied by the authors

scholarly journals Resonance overvoltage control algorithms in long cable frequency conversion drive based on discrete mathematics

Open Physics ◽  
2020 ◽  
Vol 18 (1) ◽  
pp. 408-418
Author(s):  
Yonghong Deng ◽  
Quanzhu Zhang
Keyword(s):  
Mathematical Model ◽  
Control Strategy ◽  
Frequency Conversion ◽  
Balance Control ◽  
Frequency Converter ◽  
Active Power ◽  
Drive System ◽  
Discrete Mathematics ◽  
Power Controller ◽  
Capacitor Voltage

AbstractIn order to solve the problem that the long cable variable voltage and variable frequency (VVVF) system does not adopt an effective capacitor voltage sharing control method, resulting in a poor effect of resonance overvoltage control, the resonance overvoltage control algorithm of the long cable VVVF system based on discrete mathematics is studied. First, the long cable frequency conversion drive system is established. In order to ensure voltage loss in the range of motor requirements, a frequency converter–cable–motor (ICM) system connection mode is used to maintain the system operation. Based on the research of the capacitor voltage balance control strategy of a long cable frequency conversion drive system, the discrete mathematical model of the AC side of the ICM system is established by using this control strategy. The improved constant active power controller is obtained by establishing the mathematical model, and the resonant overvoltage in a long cable frequency conversion drive is realized by using the constant active power controller. The experimental results show that the algorithm can effectively control the resonance overvoltage phenomenon in the long cable frequency control system, and the control accuracy is over 97%. It has good performance and can be applied in practice.

Improved Control Strategy of Wind Turbine with DFIG for Low Voltage Ride through Capability

2014 ◽  
Vol 707 ◽  
pp. 329-332
Author(s):  
Li Ling Sun ◽  
Dan Fang
Keyword(s):  
Wind Turbine ◽  
Control Strategy ◽  
Low Voltage ◽  
Induction Generator ◽  
Doubly Fed Induction Generator ◽  
Operating Characteristics ◽  
Low Voltage Ride Through ◽  
Doubly Fed ◽  
Rotor Side Converter ◽  
And Control

As the number of doubly fed induction generator (DFIG)- based wind-turbine systems continues to increase, wind turbines are required to provide Low Voltage Ride-Through (LVRT) capability, especially under the condition of grid voltage dips. This paper, depending on the operating characteristics of doubly-fed induction generator during grid faults ,deals with a protection and control strategy on rotor-side converter (RSC) to enhance the low voltage ride through capability of a wind turbine driven doubly fed induction generator (DFIG). The simulation and experiment studies demonstrate the correctness of the developed model and the effectiveness of the control strategy for DFIG-based wind-turbine systems under such adverse grid conditions.

Modified MPC based grid-connected five-level inverter for photovoltaic applications

2018 ◽  
Vol 37 (2) ◽  
pp. 971-985 ◽  
Author(s):  
Mohammad Maalandish ◽  
Seyed Hossein Hosseini ◽  
Mehran Sabahi ◽  
Pouyan Asgharian
Keyword(s):  
Control Method ◽  
Harmonic Distortion ◽  
Input Voltage ◽  
Modified Model ◽  
Content Type ◽  
Current Path ◽  
Voltage Stress ◽  
Photovoltaic Applications ◽  
Multi Level ◽  
And Control

PurposeThe main purpose of this paper is to select appropriate voltage vectors in the switching techniques and, by selecting the proper voltage vectors, be able to achieve a DC link with the same outputs and a symmetric multi-level inverter. Design/methodology/approachThe proposed structure, a two-stage DC–AC symmetric multi-level inverter with modified Model Predictive Control (MMPC) method, is presented for Photovoltaic (PV) applications. The voltage of DC-link capacitors of the boost converter is controlled by MMPC control method to select appropriate switching vectors for the multi-level inverter. The proposed structure is provided for single-phase power system, which increases 65 V input voltage to 220 V/50 Hz output voltage, with 400 V DC link. Simulation results of proposed structure with MMPC method are carried out by PSCAD/EMTDC software. FindingsBased on the proposed structure and control method, total harmonic distortion (THD) reduces, which leads to lower power losses and higher circuit reliability. In addition, reducing the number of active switches in current path causes to lower voltage stress on the switches, lower PV leakage current and higher overall efficiency. Originality/valueIn the proposed structure, a new control method is presented that can make a symmetric five-level voltage with lower THD by selecting proper switching for PV applications.

scholarly journals A stabilising control strategy for Cyber-Physical Power Systems

2018 ◽  
Author(s):  
Etinosa Ekomwenrenren ◽  
Hatem Alharbi ◽  
Taisir Elgorashi ◽  
Jaafar Elmirghani ◽  
Petros Aristidou
Keyword(s):  
Power Systems ◽  
Power System ◽  
Control Strategy ◽  
Physical Nature ◽  
System Stability ◽  
Wide Area ◽  
Equivalent Model ◽  
Communication Infrastructure ◽  
Damping Controllers ◽  
And Control

The cyber-physical nature of electric power systems has increased immensely over the last decades, with advanced communication infrastructure paving the way. It is now possible to design wide-area controllers, relying on remote monitor and control of devices, that can tackle power system stability problems more effectively than local controllers. However, their performance and security relies extensively on the communication infrastructure and can make power systems vulnerable to disturbances emerging on the cyber side of the system. In this paper, we investigate the effect of communication delays on the performance and security of wide-area damping controllers (WADC) designed to stabilise oscillatory modes in a Cyber-Physical Power System (CPPS). We propose a rule-based control strategy that combines wide-area and traditional local stabilising controllers to increase the performance and maintain the security of CPPS. The proposed strategy is validated on a reduced CPPS equivalent model of Great-Britain (GB).

scholarly journals The Design of Harmonic Simulator based on Hartley Transform

2018 ◽  
Vol 1 (1) ◽  
pp. 21-24 ◽  
Author(s):  
Fahri Vatansever ◽  
Nedim Aktan Yalcin
Keyword(s):  
Power Systems ◽  
Harmonic Analysis ◽  
Power Quality ◽  
Harmonic Distortion ◽  
Nonlinear Loads ◽  
Hartley Transform ◽  
User Friendly ◽  
And Control ◽  
Measurement And Control

Increase in the number of nonlinear loads and devices in energy and power systems have raised harmonic distortion on voltage and current signals. Harmonics are one of the primary factors in determining power quality. Therefore, measurement and control of harmonics are crucial. Many methods have developed for harmonic analysis. In this study, a simulator which uses Hartley transform for determining harmonics is designed. Harmonic distributions and parameters of loaded/defined signals can be calculated accurately and effectively and obtained results can be displayed numerically and graphically with developed systems which have user friendly interface.

scholarly journals Design and Analysis of the STATCOM Based on Diode Clamped Multilevel Converter Using Model Predictive Current Control Strategy

2021 ◽  
Vol 23 (3) ◽  
pp. 221-228
Author(s):  
Raaed Faleh Hassan ◽  
Suha Sabah Shyaa
Keyword(s):  
Power Systems ◽  
Power Quality ◽  
Control Strategy ◽  
Control Algorithm ◽  
Reactive Power ◽  
Current Control ◽  
Multilevel Converter ◽  
Static Synchronous Compensator ◽  
Multi Level ◽  
And Control

In recent decades, multi-level converters have become popular and used in many power systems applications. Compared with conventional converters, multi-level converters contribute to reducing the voltage stress on the switching devices and enhancing the power quality delivered to the load. In this paper, the study of the five-level diode clamped multilevel converter based static synchronous compensator has been accomplished. Model Predictive current control strategy which a type of modern control algorithms was employed for driving the proposed compensator. The suggested five level converter controlled by model predictive current control is firstly examined to verify that this control algorithm is appropriate for achieving the desired performance. Then the proposed converter and control combination is employed and simulated as a static synchronous compensator in distributed power system. Moreover, in order to examine the robustness of this compensator, the load status is suggested to be heavy inductive. Simulation process has been performed using MATLAB – SIMULINK software package. The results show that the implemented configuration (converter and control algorithm) provides high power quality improvement with adequate reactive power compensation.

scholarly journals Research on the System and Control Strategy of an AC-DC Hybrid Single-Phase Electric Energy Router

Electronics ◽  
2019 ◽  
Vol 8 (9) ◽  
pp. 970
Author(s):  
Zhao ◽  
Jiang ◽  
Liu
Keyword(s):  
Power Systems ◽  
Control Strategy ◽  
Single Phase ◽  
Electric Energy ◽  
Electrical Equipment ◽  
Optimal Operation ◽  
Energy Sources ◽  
Hybrid Form ◽  
New Energy ◽  
And Control

With the extensive development and use of new energy sources, it has become an urgent issue to solve the problem how to effectively use such energy sources. This paper designs a single-phase electric energy router (SPEER) whose main goal is to solve the problem of optimal operation of the home power system under a high penetration rate of new energy. First, a SPEER structure is presented which has an AC-DC hybrid form to meet the power requirements of all household electrical equipment. Compared with the existing structures, its structural design is more suitable for small-capacity systems, such as home power systems. Next, a reasonable, detailed, and feasible control scheme was designed for each part of the SPEER, so that it has the functions of plug and play, power routing, island detection, and synchronous grid connection, and a seamless coordination management scheme between subsystems was designed. Complete functions make it more intelligent in response to various conditions. Finally, the correctness of the designed SPEER and control strategy was verified by experiment.

scholarly journals Demand Response Optimal Dispatch and Control of TCL and PEV Agents with Renewable Energies

2021 ◽  
Vol 5 (4) ◽  
pp. 140
Author(s):  
Jianqiang Hu ◽  
Jinde Cao
Keyword(s):  
Power Systems ◽  
Demand Response ◽  
Control Strategy ◽  
Programming Model ◽  
Response Strategy ◽  
Chance Constraint ◽  
Optimal Dispatch ◽  
Renewable Power ◽  
Power Injection ◽  
And Control

Demand response (DR) flexible loads can provide fast regulation and ancillary services as reserve capacity in power systems. This paper proposes a demand response optimization dispatch control strategy for flexible thermostatically controlled loads (TCLs) and plug-in electric vehicles (PEVs) with stochastic renewable power injection. Firstly, a chance constraint look-ahead programming model is proposed to maximize the social welfare of both units and load agents, through which the optimal power scheduling for TCL/PEV agents can be obtained. Secondly, two demand response control algorithms for TCLs and PEVs are proposed, respectively, based on the aggregate control models of the load agents. The TCLs are controlled by its temperature setpoints and PEVs are controlled by its charging power such that the DR control objective can be fulfilled. It has been shown that the proposed dispatch and control strategy can coordinate the flexible load agents and the renewable power injection. Finally, the simulation results on a modified IEEE 39 bus system demonstrate the effectiveness of the proposed demand response strategy.

Single-Primary-Winding Voltage-Fed Double-Input Push-Pull Converter

2012 ◽  
Vol 461 ◽  
pp. 241-245
Author(s):  
Qin Wang ◽  
Yuan Xu ◽  
Lan Xiao
Keyword(s):  
Theoretical Analysis ◽  
Control Strategy ◽  
Input Voltage ◽  
Experimental Results ◽  
Voltage Source ◽  
Multiple Primary ◽  
Combination Principle ◽  
Single Input ◽  
And Control

Multi-input push-pull converter with multiple-primary-winding is suitable in low and medium-power applications. However, with the increase of input sources, the number of the primary windings and switches increases as well. Based on Pulsating Voltage Source Cells (PVSCs) combination principle, this paper replaces the input voltage source of the single-input push-pull converter with the series or parallel-connected non-isolated pulsating voltage source cells (PVSCs). Thus a family of single-primary-winding (SPW) voltage-fed multi-input push-pull converters can be proposed. Compared with traditional multi-input converters, they have a form of single-Primary-Winding, and therefore we could greatly reduce the size and cost. Since the configuration of a double-input Buck dc/dc converter is very simple, it is chosen as an example in this paper to analysis this MIC. The operation principle and control strategy are illustrated. Finally, simulation and experimental results are presented to verify the correctness of theoretical analysis

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