scholarly journals Control of MMC-Based STATCOM as an Effective Interface between Energy Sources and the Power Grid

Electronics ◽  
2019 ◽  
Vol 8 (11) ◽  
pp. 1264 ◽  
Author(s):  
Fatemeh Shahnazian ◽  
Ebrahim Adabi ◽  
Jafar Adabi ◽  
Edris Pouresmaeil ◽  
Kumars Rouzbehi ◽  
...  
Keyword(s):  
Reactive Power ◽  
Control Method ◽  
Second Harmonic ◽  
Power Grid ◽  
Harmonic Component ◽  
Current Control ◽  
Energy Sources ◽  
Stable Operation ◽  
Multilevel Converters ◽  
Steady State Operation

This paper presents a dynamic model of modular multilevel converters (MMCs), which are considered as an effective interface between energy sources and the power grid. By improving the converter performance, appropriate reactive power compensation is guaranteed. Modulation indices are calculated based on detailed harmonic evaluations of both dynamic and steady-state operation modes, which is considered as the main contribution of this paper in comparison with other methods. As another novelty of this paper, circulating current control is accomplished by embedding an additional second harmonic component in the modulation process. The proposed control method leads to an effective reduction in capacitor voltage fluctuation and losses. Finally, converter’s maximum stable operation range is modified, which provides efficiency enhancements and also stability assurance. The proficiency and functionality of the proposed controller are demonstrated through detailed theoretical analysis and simulations with MATLAB/Simulink.

The Filtering Device under Improved Direct Current Control

2012 ◽  
Vol 588-589 ◽  
pp. 433-437 ◽  
Author(s):  
Ying Zhao ◽  
Jin Shan Ji ◽  
Nai Cheng Du
Keyword(s):  
Direct Current ◽  
Reactive Power ◽  
Control Method ◽  
Low Voltage ◽  
Power Grid ◽  
Current Control ◽  
Filter Method ◽  
Elimination Method ◽  
Direct Current Control

This paper mainly describes the mechanism and elimination method of harmonic in low-voltage power grid. Improve direct current control method in the traditional filter method,filtering the harmonic and timely compensating reactive power in the grid. On this condition, it can make the power grid safe and stability. At the same time simulate the improved direct current control method, and the results verify the correctness and rationality of the control method.

scholarly journals Extended Permanent Magnet Synchronous Motors Speed Range Based on the Active and Reactive Power Control of Inverters

Energies ◽  
2021 ◽  
Vol 14 (12) ◽  
pp. 3549
Author(s):  
Pham Quoc Khanh ◽  
Viet-Anh Truong ◽  
Ho Pham Huy Anh
Keyword(s):  
Power Control ◽  
Permanent Magnet ◽  
Reactive Power ◽  
Control Method ◽  
Speed Control ◽  
Torque Ripple ◽  
Current Control ◽  
Permanent Magnet Synchronous Motors ◽  
Synchronous Motors ◽  
Speed Range

The paper proposes a new speed control method to improve control quality and expand the Permanent Magnet Synchronous Motors speed range. The Permanent Magnet Synchronous Motors (PMSM) speed range enlarging is based on the newly proposed power control principle between two voltage sources instead of winding current control as the conventional Field Oriented Control method. The power management between the inverter and PMSM motor allows the Flux-Weakening obstacle to be overcome entirely, leading to a significant extension of the motor speed to a constant power range. Based on motor power control, a new control method is proposed and allows for efficiently reducing current and torque ripple caused by the imbalance between the power supply of the inverter and the power required through the desired stator current. The proposed method permits for not only an enhanced PMSM speed range, but also a robust stability in PMSM speed control. The simulation results have demonstrated the efficiency and stability of the proposed control method.

scholarly journals Improving Power Quality by a Four-Wire Shunt Active Power Filter: A Case Study

Energies ◽  
2021 ◽  
Vol 14 (7) ◽  
pp. 1951
Author(s):  
Mihaela Popescu ◽  
Alexandru Bitoleanu ◽  
Mihaita Linca ◽  
Constantin Vlad Suru
Keyword(s):  
Power Quality ◽  
Quality Indicators ◽  
Reactive Power ◽  
Control Method ◽  
Active Power Filter ◽  
Active Power ◽  
Current Control ◽  
Shunt Active Power Filter ◽  
Power Filter ◽  
Unbalanced Load

This paper presents the use of a three-phase four-wire shunt active power filter to improve the power quality in the Department of Industrial Electronics of a large enterprise from Romania. The specificity is given by the predominant existence of single-phase consumers (such as personal computers, printers, lighting and AC equipment). In order to identify the power quality indicators and ways to improve them, an A-class analyzer was used to record the electrical quantities and energy parameters in the point of common coupling (PCC) with the nonlinear loads for 27 h. The analysis shows that, in order to improve the power quality in PCC, three goals must be achieved: the compensation of the distortion power, the compensation of the reactive power and the compensation of the load unbalance. By using the conceived three-leg shunt active power filter, controlled through the indirect current control method in an original variant, the power quality at the supply side is very much improved. In the proposed control algorithm, the prescribed active current is obtained as a sum of the loss current provided by the DC voltage and the equivalent active current of the unbalanced load. The performance associated with each objective of the compensation is presented and analyzed. The results show that all the power quality indicators meet the specific standards and regulations and prove the validity of the proposed solution.

scholarly journals Control Strategy Based on Arm-Level Control for Output and Circulating Current of MMC in Stationary Reference Frame

Energies ◽  
2021 ◽  
Vol 14 (14) ◽  
pp. 4160
Author(s):  
Waqar Uddin ◽  
Tiago D. C. Busarello ◽  
Kamran Zeb ◽  
Muhammad Adil Khan ◽  
Anil Kumar Yedluri ◽  
...  
Keyword(s):  
Reference Frame ◽  
Control Method ◽  
Second Harmonic ◽  
Harmonic Component ◽  
Effective Control ◽  
Level Control ◽  
Circulating Current ◽  
Stationary Reference Frame ◽  
Pr Controller ◽  
Dc Component

This paper proposed a control method for output and circulating currents of modular multilevel converter (MMC). The output and circulating current are controlled with the help of arm currents, which contain DC, fundamental frequency, and double frequency components. The arm current is transformed into a stationary reference frame (SRF) to isolate the DC and AC components. The AC component is controlled with a conventional proportional resonant (PR) controller, while the DC component is controlled by a proportional controller. The effective control of the upper arm and lower arm ultimately controls the output current so that it delivers the required power to the grid and circulating current in such a way that the second harmonic component is completely vanished leaving behind only the DC component. Comparative results of leg-level control based on PR controller are included in the paper to show the effectiveness of the proposed control scheme. A three-phase, five-level MMC is developed in MATLAB/Simulink to verify the effectiveness of the proposed control method.

scholarly journals Modeling of Multiple Master–Slave Control under Island Microgrid and Stability Analysis Based on Control Parameter Configuration

Energies ◽  
2018 ◽  
Vol 11 (9) ◽  
pp. 2223 ◽  
Author(s):  
Haifeng Liang ◽  
Yue Dong ◽  
Yuxi Huang ◽  
Can Zheng ◽  
Peng Li
Keyword(s):  
Reactive Power ◽  
Control Method ◽  
Mutual Influence ◽  
Renewable Energy Sources ◽  
System Stability ◽  
Voltage Source ◽  
Stable Operation ◽  
Parameter Configuration ◽  
Islanded Mode ◽  
Virtual Impedance

The stable operation of a microgrid is crucial to the integration of renewable energy sources. However, with the expansion of scale in electronic devices applied in the microgrid, the interaction between voltage source converters poses a great threat to system stability. In this paper, the model of a three-source microgrid with a multi master–slave control method in islanded mode is built first of all. Two sources out of three use droop control as the main control source, and another is a subordinate one with constant power control which is also known as real and reactive power (PQ) control. Then, the small signal decoupling control model and its stability discriminant equation are established combined with “virtual impedance”. To delve deeper into the interaction between converters, mutual influence of paralleled converters of two main control micro sources and their effect on system stability is explored from the perspective of control parameters. Finally, simulation and analysis are launched and the study serves as a reference for parameter setting of converters in a microgrid.

Control Method of Parallel Vanadium Batteries Operating in Energy Stored Wind Farm System

2012 ◽  
Vol 512-515 ◽  
pp. 1027-1031 ◽  
Author(s):  
Xu Dong Guo ◽  
Bao Ming Ge ◽  
Da Qiang Bi ◽  
Xin Yu Yang
Keyword(s):  
Wind Farm ◽  
Control Method ◽  
Power Grid ◽  
Storage System ◽  
Wind Farms ◽  
Energy System ◽  
Energy Storage System ◽  
Current Control ◽  
Farm Model ◽  
Battery Energy

Wind farms with vanadium battery energy storage system are recognized and welcomed. Against the phenomenon of current distribution unreasonable while vanadium batteries are directly paralleled, a control strategy of vanadium battery parallel based on the state of charge (SOC) is proposed. The current control formula is given in this paper. Vanadium batteries are paralleled to adjust the power grid at the exit of wind farms by the bidirectional DC/DC converter. A wind farm model with vanadium battery energy system is simulated on MATLAB/Simulink. The simulation results show that this system can adjust the power grid of wind farms and achieve the goal that the charging and discharging of vanadium batteries are determined by their SOC, avoiding the overcharge or over-discharge.

Impact of Connecting Reactor on Stable Operation of Chain SVG Device

2014 ◽  
Vol 644-650 ◽  
pp. 794-797
Author(s):  
Zheng Dao Liu ◽  
De Sheng Xi ◽  
Qiang Liu ◽  
Lei Shi ◽  
Shu Han Wang ◽  
...  
Keyword(s):  
Electrical Property ◽  
Design Principle ◽  
Reactive Power ◽  
Power Grid ◽  
Stable Operation ◽  
Grid System ◽  
Reactive Compensation ◽  
Actual Operation ◽  
Design Requirements ◽  
The Impact

Chain SVG device is connected to the power grid via the reactor which is also referred to as connection reactor. Compared with other reactors of reactive compensation devices, It’s not like the serial filtering reactor which simply provides a specific quantity of inductive reactive power, or parallel phase control reactor which provides continuously adjustable inductive reactive power. The connection reactor in SVG is related to the impact of SVG on the power grid, the impact of the power grid system on SVG, and in particular, the compensation capacity and effect of SVG. Therefore, during design, requirements of SVG and electrical property of the compensated system should both be considered. In this paper, the impact of the connection reactor on SVG stable operation is analyzed in detail. The design principle that when choosing the reactor parameters, the impact on power unit DC side voltage should be prioritized is proposed, and simulation verification is conducted by using of PSCAD software. A reasonable reactor is selected for a 10kV SVG based on the conclusion. The actual operation result verifies the rationality of design.

The New Type of Reactive Power Compensation Device under Direct Current Control and Indirect Current Control

2013 ◽  
Vol 694-697 ◽  
pp. 826-829
Author(s):  
Yan Han ◽  
Xiaoming Zhang ◽  
Pan Pan Yang
Keyword(s):  
Direct Current ◽  
Reactive Power ◽  
Control Method ◽  
Reactive Power Compensation ◽  
Current Control ◽  
Instantaneous Reactive Power Theory ◽  
Direct Current Control ◽  
Indirect Current Control ◽  
The Difference ◽  
Compensation Device

This Paper Briefly Describes the Basic Principle of Reactive Power Compensation and Introduces the Indirect Current Control and Direct Current Control Method Based on Instantaneous Reactive Power Theory. Compare the Two Control Theory and Use the MATABLE Simulink Environment to Analyzing the Difference between the Two Methods

scholarly journals Control Method of Parallel Inverters with Self-Synchronizing Characteristics in Distributed Microgrid

Energies ◽  
2019 ◽  
Vol 12 (20) ◽  
pp. 3871 ◽  
Author(s):  
Yan ◽  
Cui ◽  
Cui
Keyword(s):  
Reactive Power ◽  
Control Method ◽  
Dynamic Performance ◽  
Synchronous Generator ◽  
Power Sharing ◽  
Control Mode ◽  
Stable Operation ◽  
Centralized Control ◽  
Local Data ◽  
Precise Control

The centralized control mode is no longer applicable for microgrid operation due to the high penetration rate of distributed energy, which is responsible for the widespread interest in the use of the distributed microgrid. Focusing on the issues of power coupling and uncontrollable droop coefficient at the terminal of the connecting line between the micro-source and AC bus, which is rarely considered, this paper proposes an improved virtual synchronous generator (VSG) control strategy based on local data considering precise control of the droop coefficient and realizing the power decoupling and the expected droop characteristics. Then, combined with the virtual rotor characteristic matching method, the reasonable active and reactive power sharing of the parallel microgrid inverters are realized in terms of static and dynamic performance without additional improvement of reactive power control. Finally, the effectiveness and feasibility of the proposed method are verified based on the MATLAB/Simulink simulation platform. The combination of the proved strategy and matching principle endows inverters with self-synchronization characteristics, forming the self-synchronizing voltage sources, which gives the distributed microgrid a higher self-stability, autonomy and robustness to ensure the stable operation of the microgrid.

Summary of Research Status of Active Power Filter

2014 ◽  
Vol 721 ◽  
pp. 587-590
Author(s):  
Hai Yang Wang
Keyword(s):  
Power Electronics ◽  
Reactive Power ◽  
Control Method ◽  
Rapid Development ◽  
Active Power Filter ◽  
Active Power ◽  
Current Control ◽  
Power Filter ◽  
Power System Harmonics ◽  
Working Principle

Due to the rapid development of modern rapid power electronics, power system harmonics are also increasingly serious harm, in order to effectively suppress harmonics to improve power quality, active power filter APF came into being, it can be effective for reactive power and frequency, amplitude harmonic changes are real-time tracking compensation. Currently, APF power electronics technology has become a major research topic. This article describes the basic working principle of harmonic current detection method and compensation current control method, the main circuit type of active power filter.

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