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This paper presents a dual active bridge (DAB) converter with reactive power control capability (Q-capability) for a battery energy storage system (BESS) or an electric vehicle (EV) to deliver vehicle-to-home (V2H) and vehicle-to-grid (V2G) services. The DAB topology is preferable for EV charging systems due to its galvanic isolation and bidirectional power flow capabilities. However, this topology increases reactive current peak and loses zero voltage switching (ZVS) operation at light loads if it is not controlled with improved modulation strategies and proper Q control. This paper proposes a mixed modulation method and a reactive power optimization (RPO) algorithm based on power system load flow concepts. Due to the complexities associated with the analytical solution using time domain analysis, this paper develops detailed universal expressions of a DAB converter using the harmonic analysis method. Analytical identification of ZVS boundaries and DSP implementation of the RPO algorithm become easier with these universal expressions. Multiple modes analysis for different operational states is no longer required. Simulation results have been shown for different modulation strategies of the DAB converters. The theoretical analysis of modulation strategies, RPO algorithm and ZVS operation are validated by experimental results on a DAB prototype. Results show that the proposed control strategy reduces the reactive power and provide ZVS operation over a wide ranges of voltages. [ABSTRACT FROM AUTHOR]

This article presents low-frequency ripple power steering control strategies for a power conversion topology that comprises a high frequency linked three-port converter (HFL-TPC) and a voltage source inverter (VSI) for PV-BESS/EV applications. The proposed topology has three interfaces, which can be connected with a photovoltaic (PV) port, battery energy storage systems (BESS) and/or electric vehicles (EVs) port, and a four-quadrant ac port. The proposed topology inherently exhibits double line frequency (DLF) power fluctuation that needs to be decoupled and steered away from the PV port. In this article, we have developed and demonstrated two control strategies to deal with the DLF ripple. The first control strategy utilizes loop gain of the closed loop control system to decouple the DLF power, however, a residual DLF power still exists at the ac port. To completely decouple the DLF fluctuations, an improved sequence-based control strategy is proposed where the DLF voltage components are converted into positive and negative sequence components and controlled separately on their respective synchronous reference frames. To verify the practical feasibility of the proposed low-frequency ripple power steering control strategies, a 40 V, 400 W HFL-TPC is built and tested. Experimental results show that the proposed methods decouple the DLF power fluctuation and selectively steer it to the BESS/EV port. Comparative results reveal that the sequence-based control strategy shows a higher degree of DLF ripple suppression. [ABSTRACT FROM AUTHOR]

Abstract In the past five years substantial amounts of rooftop photovoltaic (PV) generation have been installed across the low voltage distribution networks. These networks often have design lifetimes of 40 years. Most of the existing distribution networks were constructed, and the voltage profiles set, prior to the rapid uptake of PV. When power quality difficulties arise reconstruction or some other form of intervention is required. This review will focus on power electronic options for voltage profile management in networks with high penetrations of PV. A voltage profile improvement can be achieved with a range of series or shunt connected devices. The traditional voltage regulator adds a series compensation voltage and electronic and electro-mechanical variations exist. Shunt devices attempt to influence voltage with reactive or real power flows when storage is allowed. A shunt device is additionally capable of phase balancing which may substantially raise the allowable PV fraction. In addition to the topological choices, the converter choice will impact upon capability. This paper will examine full converter solutions which incorporate meaningful energy storage at a DC bus and reduced energy storage scenarios or storage free solutions such as matrix converter (MC) based devices. Highlights • Rooftop PV penetration. • distribution regulator topologies. • Voltage regulator. • MC based voltage regulator. • DSP-FPGA based control. [ABSTRACT FROM AUTHOR]

Renewable energy source (RES) based electrical power plants are widely considered green and clean due to their contribution to decarbonizing the energy sectors. It is apparent that RESs do not produce carbon dioxide, however their significant negative impacts on the environment are still found and cannot be ignored. In this paper, the environmental impacts of RES based power plants are analyzed through a comprehensive review considering solar thermal, solar photovoltaic, wind, biomass, geothermal, hydroelectric, tidal, ocean current, oceanic wave, ocean thermal, and osmotic effects. Solar thermal power is well known as concentrated solar power. A strength, weakness, opportunity, and threat (SWOT) analysis is carried out and discussed for all RES based power plants. Comparative SWOT analyses for solar photovoltaic and concentrated solar power plants are presented. The comparative environmental impact analyses for all existing RES based power plants are tabulated for various attributes. These attributes include but are not limited to human health, noise, pollution, greenhouse gas emission, ozone layer depletion, toxification, flooding, impact on inhabitants, eutrophication, dried up rivers, and deforestation. Based on the analysis, it is found that careful selection of RES for electrical power plants is necessary because improper utilization of RES could be very harmful for the environment. • A comprehensive review is presented that identifies the environmental impacts of each RES based power plants. • The detailed SWOT analysis is carried out for various RES based power plants. • The impacts along with its intensity of different water resource related RES based power plants are separately tabulated. • It is found that improper utilization of RES in power plants is harmful for the environment. • A recommended guideline is presented for the selection of appropriate RES based power plants. [ABSTRACT FROM AUTHOR]

In this paper, a proton exchange membrane fuel cell (PEMFC) is implemented as a grid-connected electrical generator that uses hydrogen gas as fuel and air as an oxidant to produce electricity through electrochemical reactions. Analysis demonstrated that the performance of the PEMFC greatly depends on the rate of fuel supply and air supply pressure. Critical fuel and air supply pressures of the PEMFC are analysed to test its feasibility for the grid connection. Air and fuel supply pressures are varied to observe the effects on the PEMFC characteristics, efficiency, fuel supply, and air consumption over time. The PEMFC model is then implemented into an electrical power system with the aid of power electronics applications. Detailed mathematical modelling of the PEMFC is discussed with justification. The PEMFC functions as an electrical generator that is connected to the local grid through a power converter and a transformer. Modulation of the converter is controlled by means of a proportional-integral controller. The two-axis control methodology is applied to the current control of the system. The output voltage waveform and control actions of the controller on the current and frequency of the proposed system are plotted as well. Simulation results show that the PEMFC performs efficiently under certain air and fuel pressures, and it can effectively supply electrical power to the grid. [ABSTRACT FROM AUTHOR]