Decentralized Unified Control Strategy for Medium and Low Voltage DC Distribution Power System

2019 ◽  
Author(s):  
Pengpeng Pan ◽  
Wu Chen ◽  
Han Mu
Keyword(s):  
Power System ◽  
Control Strategy ◽  
Low Voltage ◽  
Dc Distribution

scholarly journals Transient Stability Enhancement of a Grid-Connected Large-Scale PV System Using Fuzzy Logic Controller

Electronics ◽  
2021 ◽  
Vol 10 (19) ◽  
pp. 2437
Author(s):  
Md. Rifat Hazari ◽  
Effat Jahan ◽  
Mohammad Abdul Mannan ◽  
Narottam Das
Keyword(s):  
Fuzzy Logic ◽  
Power System ◽  
Control Strategy ◽  
Computer Aided Design ◽  
Large Scale ◽  
Transient Stability ◽  
Fuzzy Logic Controller ◽  
Reactive Power ◽  
Low Voltage ◽  
Pv System

This paper presents a new intelligent control strategy to augment the low-voltage ride-through (LVRT) potential of photovoltaic (PV) plants, and the transient stability of a complete grid system. Modern grid codes demand that a PV plant should be connected to the main power system during network disturbance, providing voltage support. Therefore, in this paper, a novel fuzzy logic controller (FLC) using the controlled cascaded strategy is proposed for the grid side converter (GSC) of a PV plant to guarantee voltage recovery. The proposed FLC offers variable gains based upon the system requirements, which can inject a useful amount of reactive power after a severe network disturbance. Therefore, the terminal voltage dip will be low, restoring its pre-fault value and resuming its operation quickly. To make it realistic, the PV system is linked to the well-known IEEE nine bus system. Comparative analysis is shown—using power system computer-aided design/electromagnetic transients including DC (PSCAD/EMTDC) software—between the conventional proportional–integral (PI) controller-based cascaded strategy and the proposed control strategy to authenticate the usefulness of the proposed strategy. The comparative simulation results indicate that the transient stability and the LVRT capability of a grid-tied PV system can be augmented against severe fault using the proposed FLC-based cascaded GSC controller.

scholarly journals A DC-side fault-tolerant bidirectional AC/DC converter for power system in integration of low-voltage DC distribution systems

2021 ◽  
Author(s):  
Nikoo Kouchakipour
Keyword(s):  
Mathematical Model ◽  
Power System ◽  
Power Distribution ◽  
Distribution Systems ◽  
Low Voltage ◽  
Short Circuit ◽  
Power Converter ◽  
Software Environment ◽  
Medium Voltage ◽  
Dc Distribution

With the rising potential for the employment of low- and medium-voltage direct-current (dc) electric power distribution systems, most notably for a more efficient integration of plug-in electric vehicles and such other distributed energy resources as photovoltaic (PV) panels, there is a need for robust ac/dc electronic power converters that can interface such dc distribution systems with the legacy alternating current (ac) power system. Thus, this thesis proposes a new single-stage low-voltage three-phase ac-dc power converter that is simple structurally, en- ables a bidirectional power exchanges between the ac and dc distribution systems, and can handle short-circuit faults at its dc as well as ac sides. The proposed converter consists of three legs, corresponding to the three phases of the host ac grid, each of which hosting two full-bridge submodule (FBSM), in an architecture that can be regarded as a special case of the so-called modular multi-level converter (MMC). Thus, at the dc port each FBSM is connected in parallel with a corresponding capacitor, while the ac voltage of each phase is synthesized by the coordinated sinusoidal pulse-width modulation (SPWM) of the two corresponding FBSMs. This architecture allows the generation of low-distortion ac voltage while it also provides the converter with the very important dc fault current blocking capability since, upon the detection of a short circuit across the converter dc port, the switches of the FBSMs are turned off and disallow the flow of any dc current. The thesis also presents a mathematical model for the converter, for analysis and control design purposes. Thus, the control for the regulation of the overall dc-side voltage, as well as those for the regulation of the dc voltages of the FBSMs are devised based on the aforementioned mathematical model and presented with details. It is further shown that the voltage conversion ratio of the proposed converter is the same as that offered by a conventional voltage-sourced converter (VSC), whereas the VSC is vulnerable to dc- side shorts. The proposed converter can be extended to medium-voltage levels by multi- plying the number of FBSMs in each leg. The effectiveness of the proposed converter and its controls is demonstrated through time-domain simulation studies conducted on a topological model of the converter in PSCAD/EMTDC software environment.

scholarly journals A DC-side fault-tolerant bidirectional AC/DC converter for power system in integration of low-voltage DC distribution systems

2021 ◽  
Author(s):  
Nikoo Kouchakipour
Keyword(s):  
Mathematical Model ◽  
Power System ◽  
Power Distribution ◽  
Distribution Systems ◽  
Low Voltage ◽  
Short Circuit ◽  
Power Converter ◽  
Software Environment ◽  
Medium Voltage ◽  
Dc Distribution

With the rising potential for the employment of low- and medium-voltage direct-current (dc) electric power distribution systems, most notably for a more efficient integration of plug-in electric vehicles and such other distributed energy resources as photovoltaic (PV) panels, there is a need for robust ac/dc electronic power converters that can interface such dc distribution systems with the legacy alternating current (ac) power system. Thus, this thesis proposes a new single-stage low-voltage three-phase ac-dc power converter that is simple structurally, en- ables a bidirectional power exchanges between the ac and dc distribution systems, and can handle short-circuit faults at its dc as well as ac sides. The proposed converter consists of three legs, corresponding to the three phases of the host ac grid, each of which hosting two full-bridge submodule (FBSM), in an architecture that can be regarded as a special case of the so-called modular multi-level converter (MMC). Thus, at the dc port each FBSM is connected in parallel with a corresponding capacitor, while the ac voltage of each phase is synthesized by the coordinated sinusoidal pulse-width modulation (SPWM) of the two corresponding FBSMs. This architecture allows the generation of low-distortion ac voltage while it also provides the converter with the very important dc fault current blocking capability since, upon the detection of a short circuit across the converter dc port, the switches of the FBSMs are turned off and disallow the flow of any dc current. The thesis also presents a mathematical model for the converter, for analysis and control design purposes. Thus, the control for the regulation of the overall dc-side voltage, as well as those for the regulation of the dc voltages of the FBSMs are devised based on the aforementioned mathematical model and presented with details. It is further shown that the voltage conversion ratio of the proposed converter is the same as that offered by a conventional voltage-sourced converter (VSC), whereas the VSC is vulnerable to dc- side shorts. The proposed converter can be extended to medium-voltage levels by multi- plying the number of FBSMs in each leg. The effectiveness of the proposed converter and its controls is demonstrated through time-domain simulation studies conducted on a topological model of the converter in PSCAD/EMTDC software environment.

Formulated Representation for Upper Limitation of Deliverable Power in Low-Voltage DC Distribution System

2011 ◽  
Vol 131 (4) ◽  
pp. 362-368 ◽  
Author(s):  
Yasunobu Yokomizu ◽  
Doaa Mokhtar Yehia ◽  
Daisuke Iioka ◽  
Toshiro Matsumura
Keyword(s):  
Distribution System ◽  
Low Voltage ◽  
Dc Distribution
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