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As more number of distributed generators like PV are penetrated into the power system network, the interaction of the filter elements associated with PV inverter and rest of the distribution system elements on network resonance needs to be investigated. Although the recent investigation of network resonance is focusing only on distributed generators like PV, the impact from distribution lines coming...
The increase in penetration levels of distributed generators like PV and Wind in a distribution system makes the IEEE 519 standard to be a vital aspect towards power quality. The network resonance has been described by IEEE 519 as a major contributor towards the harmonic distortion. Non-linear loads such as transformers, machines, silicon-controlled rectifiers (SCRs), solid state devices, power transistors,...
In this work an ac-dc-ac multilevel power converter is investigated. The developed configuration is composed of one single-phase ac-dc-ac three-leg module and two H-bridges, one of them connected in the shared part of the system to employ multilevel voltages to input and output converter, and the other one connected on the grid side for input overvoltage. The converter is employed in applications...
This paper presents dynamic analysis of a Modular Multi-Parallel Rectifier (MMR) based on state-space modelling. The proposed topology is suitable for high power motor drive or multi-parallel AC-DC applications, which can reduce line current harmonics emissions significantly. However, a proper controller is required to share and control current through each rectifier. Mathematical analysis and simulations...
This paper presents theoretical and experimental discussions on low-voltage-ride-through (LVRT) operation of a modular multilevel single-delta bridge-cell (SDBC) inverter intended for utility-scale photovoltaic (PV) systems. As the penetration of distributed generation from renewable energy sources connected to medium- and high-voltage grids increases, grid-tied inverters progressively need to abide...
At present, the research on the quality of micro-grid power at home and abroad is still at the initial stage, which focuses on the study of the power quality characteristics of micro-sources. There is little research on the quality control of micro-grid power and the power quality adjustment device for microgrid. In particular, there is no literature on the power quality of the microgrids containing...
Transformerless photovoltaic (PV) inverters offer several advantages in terms of weight and cost reduction as well as a higher efficiency compared to the topologies with transformers. However, the removal of transformers results in the establishment of a direct connection between the PV panels and the electrical grid which, consequently, leads to the generation of a leakage current. This current is...
A three phase to five phase configured twenty pulse AC-DC converter fed 3-level modular multilevel inverter (MMLI) based vector controlled induction motor drive (VCIMD) is presented in this work. To limit the total harmonic distortion (THD) in the utility current as per IEEE-519 standard, a twenty pulse AC-DC converter is used at the input end of the proposed drive. A three phase system is converted...
This paper presents a DC microgrid integrated dynamic voltage restorer (DVR) system to mitigate the grid voltage sag and swell. The DC source of the DVR is the DC microgrid, including the PV array and hybrid energy storage system consisting of lithium-ion battery and supercapacitor. Compared to the conventional DVR supplied by pure energy storages, the DC microgrid will prolong the operation the DVR...
Capacitor-switching operation can be used to measure network harmonic impedance. Via the transient components of voltage and current after capacitor switching, the harmonic impedance of PCC (Point of Common Coupling) can be calculated. To improve measurement accuracy, the TLS-ESPRIT algorithm is introduced in this paper to filter out noise and fundamental components in voltage and current signals...
This paper proposes a dual output Luo converter fed SRM (Switched Reluctance Motor) drive. The proposed converter generates two symmetrical output voltages. In order to obtain PFC (power factor correction) operation drive is operated in DCM (discontinuous conduction mode). The current through two output inductor is discontinuous in each switching period. The converter provides high efficiency, high...
The benefits of using grid connected Voltage Source Converters (VSC) related to processing and improving of electrical power quality in distribution grid heavily depends on current control (CC) method. Research in this field are mainly focused on response dynamics, stability and accuracy of reference current tracking under strongly distorted grid voltage conditions with variable grid impedance in...
Harmonic resonance problems can be aroused in the industrial power system in the presence of both nonlinear loads and shunt capacitors. This paper investigates the harmonic resonance problem by case-studying of a copper smelting plant low voltage power distribution system. A flexible selective harmonic compensation and resonance damping algorithm for shunt active power filter (SAPF) is proposed to...
This paper presents a comprehensive study about a Simplified Rail Power Conditioner (SRPC) based on a half-bridge indirect AC/DC/AC Modular Multilevel Converter (MMC) and a V/V traction power transformer. The proposed system with a half-bridge MMC can decrease the costs, reduce the control complexity, and require less hardware devices in comparison with the rail power conditioner based on a full-bridge...
A novel approach for mitigation of power quality issues have been presented in the paper. This paper introduces a Center-Point-Clamped AC-AC Buck-Boost Converter based power quality device for industrial and residential customers at the leaf end of the distribution network. This converter utilizes the principle of center-point-clamping to reduce the voltage stress on the power semiconductor switches...
This paper extensively analyzes the operation limits, system stability and disturbance rejection capability of the voltage control loops used in master-slave AC and DC Microgrids (MGs). Two different control schemes are studied analytically, simulated and experimentally tested, focusing on Constant Power Loads (CPL). Additionally, the use of the virtual capacitance (VC) as a tool for response enhancement...
A grid-connected inverter with energy storage and active DC-link voltage balancer circuit is presented. The system is implemented with two identical 100kW three-phase converters. The operating limits of the system under asymmetric grid currents with the given hardware architecture are considered and solutions for symmetrisation of the DC-link are proposed.
Two-phase residential installations have become very common in Ecuador since different policies prompt the users to replace gas stoves and water heaters by electric appliances. The addition of a second phase to the originally installed single-phase wiring is required to obtain 220Vrms. This fact carries an intrinsic unbalance since single- and two-phase loads coexist. In this paper a topology for...
The problems associated with the harmonics needs more attention as more number of distributed generators like PV and wind are integrated into a distribution system. Although the integration presents a lot of benefits, satisfying the needs of local load requirements by reducing the line losses and facilitating congestion management, the problems of power quality that impact the distribution system...
Aiming at the problems of slow dynamic response and high harmonic content for single phase magnetically controlled reactor (MCR), a comprehensive compensation system based on MCR and active power filter (APF) is proposed and the system topology is introduced. In the system, MCR is taken to compensate reactive power, while APF is taken to compensate harmonics generated by both load and MCR. Meanwhile,...
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