scholarly journals Highly reliable Coordinated Control Strategy for Static Frequency Converters applied to Large Synchronous Condensers

CONVERTER ◽  
2021 ◽  
pp. 646-657
Author(s):  
Xiangjian Shi, Et al.
Keyword(s):  
Control Method ◽  
Frequency Converter ◽  
Dynamic Change ◽  
Coordinated Control ◽  
Stable Operation ◽  
Peak Reduction ◽  
Frequency Converters ◽  
Grid Synchronization ◽  
Synchronous Condenser ◽  
Grid Side

A large synchronous condenser can quickly and flexibly implement various functions such as dynamic change in load tracking, realization of peak reduction and valley filling, emergency reserve, frequency modulation, and phase modulation. This type of condenser is typically started using a static frequency converter (SFC). Based on the analysis of the working principle of SFCs, this paper proposes a highly reliable coordinated control method with resynchronization criterion for an SFC. An auxiliary loop is introduced for voltage control at the SFC to realize feedforward of the trigger angle of the rectifier. This method can effectively improve the success rate of grid synchronization of the synchronous condenser and shorten the start-up time. Moreover, when the AC voltage on the grid side drops, the auxiliary ring can automatically reduce the terminal voltage to maintain a stable operation. A comparative experiment was conducted on an RTDS to verify the feasibility and effectiveness of the proposed method.

scholarly journals Approach Control of DFIG Rotor Side Converter Based on Grid Frequency Coordinated Control

2021 ◽  
Author(s):  
Zakieldeen M. E. Elhassan ◽  
Abusabah I. A. Ahmed ◽  
Othman Hassan Abdalla
Keyword(s):  
Case Studies ◽  
Reactive Power ◽  
Control Method ◽  
Coordinated Control ◽  
Wind Speeds ◽  
Speed Regulation ◽  
Doubly Fed ◽  
Grid Side ◽  
Rotor Side Converter ◽  
System Frequency

Abstract. This paper presents an approach frequency coordinated control of Doubly Fed Induction Generator (DFIG) applying in the Rotor Side Converter (RSC) using an order reference active power (Pref ). Pref is obtained from the frequency deviation, speed regulation and kinetic energy stored in the DIFG. The Pref is employed as a main controller parameter of the dq-axis currents in the RSC under two case studies. In case1 study, the Pref is used to regulate the q-axis reference current and the grid reactive power controlled d- axis reference current. Whilst in case2 study, the d- axis reference current is produced by Pref , and the rotormechanical speed responsible to generate the q-axis reference current. The modified vector control method is used to control the Grid Side Converter (GSC) in two case studies. The transient performance of two case studies is simulated by PSCAD/EMDTC program under constant, step and variable wind speeds. A comparative result between two case studies shown that the frequency coordinated control has an ability to control both rotor dq-axis currents, and it enhancing the system frequency as well as improved DFIG voltage stability.However, case2 study has a better response than case1 study during system operated under random wind speed.

scholarly journals Insulation Life Span of Low-Voltage Electric Motors—A Survey

Energies ◽  
2021 ◽  
Vol 14 (6) ◽  
pp. 1738
Author(s):  
Vanessa Neves Höpner ◽  
Volmir Eugênio Wilhelm
Keyword(s):  
Life Span ◽  
Electric Motor ◽  
Low Voltage ◽  
Frequency Converter ◽  
Rate Of Change ◽  
High Rate ◽  
Switching Frequency ◽  
Electric Motors ◽  
Frequency Converters ◽  
High Switching Frequency

The use of static frequency converters, which have a high switching frequency, generates voltage pulses with a high rate of change over time. In combination with cable and motor impedance, this generates repetitive overvoltage at the motor terminals, influencing the occurrence of partial discharges between conductors, causing degradation of the insulation of electric motors. Understanding the effects resulting from the frequency converter–electric motor interaction is essential for developing and implementing insulation systems with characteristics that support the most diverse applications, have an operating life under economically viable conditions, and promote energy efficiency. With this objective, a search was carried out in three recognized databases. Duplicate articles were eliminated, resulting in 1069 articles, which were systematically categorized and reviewed, resulting in 481 articles discussing the causes of degradation in the insulation of electric motors powered by frequency converters. A bibliographic portfolio was built and evaluated, with 230 articles that present results on the factors that can be used in estimating the life span of electric motor insulation. In this structure, the historical evolution of the collected information, the authors who conducted the most research on the theme, and the relevance of the knowledge presented in the works were considered.

scholarly journals Emulation of grid-forming inverters using real-time PC and 4-quadrant voltage amplifier

2021 ◽  
Author(s):  
Wolf Schulze ◽  
Maurizio Zajadatz ◽  
Michael Suriyah ◽  
Thomas Leibfried
Keyword(s):  
Real Time ◽  
Control Method ◽  
Current Control ◽  
Control Methods ◽  
Test Bed ◽  
Test Scenario ◽  
Power Semiconductors ◽  
Voltage Amplifier ◽  
Grid Side ◽  
Virtual Synchronous Machine

AbstractA test bed for the evaluation of novel control methods of inverters for renewable power generation is presented. The behavior of grid-following and grid-forming control in a test scenario is studied and compared.Using a real-time capable control platform with a cycle time of 50 µs, control methods developed with Matlab/Simulink can be implemented. For simplicity, a three-phase 4‑quadrant voltage amplifier is used instead of an inverter. Thus, the use of modulation and switched power semiconductors can be avoided. In order to show a realistic behavior of a grid-side filter, passive components can be automatically connected as L‑, LC- or LCL-filter. The test bed has a nominal active power of 43.6 kW and a nominal voltage of 400 V.As state-of-the-art grid-following control method, a current control in the d/q-system is implemented in the test bed. A virtual synchronous machine, the Synchronverter, is used as grid-forming control method. In combination with a frequency-variable grid emulation, the behavior of both control methods is studied in the event of a load connection in an island grid environment.

scholarly journals Coordinated Control of RSC and GSC for DFIG System under Harmonically Distorted Grid Considering Inter-Harmonics

Energies ◽  
2019 ◽  
Vol 13 (1) ◽  
pp. 28 ◽  
Author(s):  
Bo Pang ◽  
Hui Dai ◽  
Feng Li ◽  
Heng Nian
Keyword(s):  
Theoretical Analysis ◽  
Control Strategy ◽  
Coordinated Control ◽  
Delay Compensation ◽  
Pass Filter ◽  
Grid Connection ◽  
Distorted Grid ◽  
Negative Impacts ◽  
Doubly Fed ◽  
Grid Side

For improving the performance of a doubly fed induction generator (DFIG) system under a harmonically distorted grid, this paper proposes a coordinated control strategy which is effective for grid inter-harmonics as well as grid integer harmonics. In order to suppress the negative impacts caused by grid harmonics, including inter-harmonics, this paper introduces an additional harmonics suppression controller, which contains a Chebyshev high-pass filter and a modified lead element considering the delay compensation. The proposed controller is employed in the rotor side converter (RSC) and grid side converter (GSC). Based on the proposed harmonics suppression controller, a coordinated control strategy between RSC and GSC is developed, in which the control targets, including the sinusoidal output current, constant power, or steady generator torque, can be achieved for DFIG, while GSC is responsible for maintaining the sinusoidal total current to guarantee the power quality of the grid connection. The effectiveness of the proposed method is verified by the theoretical analysis, and the experimental results derived using a 1 kW DFIG system validate the correctness of the theoretical analysis.

Coordinated Control for Novel Full Hybrid Vehicles

2013 ◽  
Vol 860-863 ◽  
pp. 1073-1077 ◽  
Author(s):  
Zhi Guo Kong ◽  
Hong Wei Zhang ◽  
Zi Ning Tang
Keyword(s):  
Control Method ◽  
Dynamic Performance ◽  
Coordinated Control ◽  
Rate Of Change ◽  
Adjustment Process ◽  
Accelerator Pedal ◽  
Dynamic Constraints ◽  
Electric Bus ◽  
The Stability ◽  
Working Point

In order to improve the performance of a new type of full hybrid electric bus, this paper puts forward a set of coordinated control method to adjust the operation of the engine and two motors. In the engine start-stop logic control, comprehensive consideration of SOC, the speed of the bus and the accelerator pedal stroke are performed, while hysteresis control is introduced to improve the stability of the control; In the engine working point adjusting control, not only the engine speed command rate of change was optimized, but also the output torque rate was optimized to match the air injection and exhaust, etc. Further, the method based on dynamic constraints was used to optimize the working point adjustment process. At present, there are hundreds of busses operates in route. Results verify the feasibility and effectiveness of the control method. The vehicle has good fuel economy, and the dynamic performance and driving comfort are also greatly improved.

scholarly journals Control method for the stable operation of distributed inverters following the introduction of large-scale renewable energy to a remote island grid

Clean Energy ◽  
2021 ◽  
Vol 5 (2) ◽  
pp. 196-207
Author(s):  
Shoichi Sato ◽  
Yasuhiro Noro
Keyword(s):  
Renewable Energy ◽  
Large Scale ◽  
Control Method ◽  
Synchronous Generator ◽  
Stable Operation ◽  
Battery Energy Storage Systems ◽  
Simulation Results ◽  
Battery Energy ◽  
Systems Simulation ◽  
Different Characteristics

Abstract The introduction of large-scale renewable energy requires a control system that can operate multiple distributed inverters in a stable way. This study proposes an inverter control method that uses information corresponding to the inertia of the synchronous generator to coordinate the operation of battery energy storage systems. Simulation results for a system with multiple inverters applying the control method are presented. Various faults such as line-to-line short circuits and three-phase line-to-ground faults were simulated. Two fault points with different characteristics were compared. The voltage, frequency and active power quickly returned to their steady-state values after the fault was eliminated. From the obtained simulation results, it was verified that our control method can be operated stably against various faults.

scholarly journals A Fuzzy-ANP Approach for Comprehensive Benefit Evaluation of Grid-Side Commercial Storage Project

Energies ◽  
2021 ◽  
Vol 14 (4) ◽  
pp. 1129
Author(s):  
Huijia Yang ◽  
Weiguang Fan ◽  
Guangyu Qin ◽  
Zhenyu Zhao
Keyword(s):  
Energy Storage ◽  
Evaluation System ◽  
Large Scale ◽  
Stable Operation ◽  
Low Carbon ◽  
Profit Model ◽  
Benefit Evaluation ◽  
Comprehensive Benefit ◽  
Grid Side ◽  
Business Mode

With the increasing demand for clean and low-carbon energy, high proportion of renewable energy has been integrated into the receiving-end grid. The grid-side energy storage project can ensure the safe and stable operation of the grid, but it still faces many problems, such as high initial investment, difficult operation and maintenance, unclear profit model, lack of business mode. Therefore, it is of great significance to evaluate the comprehensive benefit of energy storage projects in order to guide the sustainable development of large-scale energy storage projects and power system. By studying the technical and economic characteristics of energy storage, this paper establishes a comprehensive evaluation system from four dimensions of energy efficiency, economic, social, and environmental benefit. Combined with typical business modes and determining the subdivision index system of different modes, the comprehensive benefit evaluation model of grid-side commercial storage project based on Fuzzy-Analytic Network Process (ANP) approach is established. Empirical analysis of a 100-megawatt storage project is carried out to evaluate the project benefits comprehensively, the potential problems of the market development and business mode of the grid-side large-scale storage project are discussed, and the future development orientation and suggestions are put forward.

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