A fault ride through strategy of multi-ports DC transformer

2020 ◽  
Author(s):  
Hao Wu
Keyword(s):  
Fault Ride Through ◽  
Dc Transformer

scholarly journals Dynamic grid fault analysis in wind power plant with DFIG by using supervisory control and data acquisition (SCADA) viewer

2020 ◽  
Vol 181 ◽  
pp. 03006
Author(s):  
Nduwamungu Aphrodis ◽  
Ntagwirumugara Etienne ◽  
Utetiwabo Wellars ◽  
Mulolani Francis
Keyword(s):  
Power Systems ◽  
Power Flow ◽  
Control Strategies ◽  
Electrical Power ◽  
Fault Analysis ◽  
Operational Mode ◽  
Electrical Power Systems ◽  
Fault Ride Through ◽  
Before And After ◽  
Clearing Time

Faults in electrical power systems are among the key factors and sources to network disturbances, however control strategies are among key faults clearing techniques for the sake of safe operational mode of the system.Some researchers have shown various limitations of control strategies such as slow dynamic response,inability to switch Off and On network remotely and fault clearing time. For a system with wind energy technologies, if the power flow of a wind turbine is interrupted by a fault, the intermediate-circuit voltage between the machine-side converter and line-side converter will fall in unacceptably high values.To overcome the aforementioned issues, this paper used a Matlab simulations and experiments in order to analyze and validate the results.The results showed that fault ride through (FRT) with SCADA Viewer software are more adaptable to the variations of voltage and wind speed in order to avoid loss of synchronism. Therefore at the speed of 12.5m/s a wind produced a rated power of 750W and remained in synchronization before and after a fault created and cleared but worked as generator meanwhile at speed of 3.4m/s wind disconnected from grid and started working as a motor and consumed active power (P=-25watts) and voltage dip at 100% .For the protection purpose, the DC chopper and crowbar should be integrated towards management of excess energy during faults cases.

Design and implementation of FLC system for fault ride-through capability enhancement in PMSG-wind systems

2020 ◽  
pp. 0309524X2098177
Author(s):  
Mohamed Metwally Mahmoud ◽  
Hossam S Salama ◽  
Mohamed M Aly ◽  
Abdel-Moamen M Abdel-Rahim
Keyword(s):  
Fuzzy Logic Controller ◽  
Synchronous Generator ◽  
Electrical Network ◽  
Electricity Grid ◽  
Wind Energy Generation ◽  
Fault Ride Through ◽  
Three Phase ◽  
Hybrid Solution ◽  
Pi Controllers ◽  
Grid Side

Fault ride-through (FRT) capability enhancement for the growth of renewable energy generators has become a crucial issue for their incorporation into the electricity grid to provide secure, reliable, and efficient electricity. This paper presents a new FRT capability scheme for a permanent magnet synchronous generator (PMSG)-based wind energy generation system using a hybrid solution. The hybrid solution is a combination of a braking chopper (BC) and a fuzzy logic controller (FLC). All proportional-integral (PI) controllers which control the generator and grid side converters are replaced with FLC. Moreover, a BC system is connected to the dc link to improve the dynamic response of the PMSG during fault conditions. The PMSG was evaluated on a three-phase fault that occurs on an electrical network in three scenarios. In the first two scenarios, a BC is used with a PI controller and FLC respectively. While the third scenario uses only FLC without a BC. The obtained results showed that the suggested solution can not only enhance the FRT capability of the PMSG but also can diminish the occurrence of hardware systems and reduce their impact on the PMSG system. The simulation tests are performed using MATLAB/SIMULINK software.

scholarly journals Optimal Design of LLC Resonant DC Transformer under Adaptive Frequency Tracking Strategy

Electronics ◽  
2020 ◽  
Vol 9 (12) ◽  
pp. 2160
Author(s):  
Yu Tang ◽  
Dekai Kong ◽  
Chenxu Duan ◽  
Hao Sun
Keyword(s):  
Working Condition ◽  
Transmission Efficiency ◽  
Switching Frequency ◽  
Optimal Operating ◽  
Frequency Tracking ◽  
Zero Current ◽  
Llc Resonant Converter ◽  
Dc Transformer ◽  
Zero Voltage ◽  
Tracking Strategy

In recent years, the LLC (inductor–inductor–capacitor) DC transformer has been widely used in communication and computer power supply because of its advantages of zero voltage conduction of primary switch and zero current turn off concerning the output rectifier diode. To obtain higher transmission efficiency and make the LLC DC transformer always run at the optimal operating point, the switching frequency of the LLC DC transformer should work at the resonance frequency of the circuit. In actual conditions, the optimal operating frequency of the LLC DC transformer will be changed due to the influences of the working condition on the circuit parameters and the load change. Therefore, the LLC DC transformer controlled by the fixed frequency mode will not be in the best working condition. In this paper, an adaptive frequency tracking method is used to control the circuit; when the circuit parameters change, the LLC DC transformer can always be in the best working state. Then, the influence of circuit parameters such as output power and excitation inductor on the optimal working point of the LLC DC transformer is analyzed in detail. Finally, a 1 kW LLC resonant converter prototype is designed under laboratory conditions to verify the feasibility of the control strategy.

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