Technical Challenges and Solutions of a three-phase bidirectional two stage Electric Vehicle charger

The sustainability of the power grid owing to the building strain of the ever-growing demand for electrical energy urges innovative and more practical solutions that enable active participation of end-users in stable and reliable management of power systems. One of the emerging projections of such a two-way exchange of electrical power between the grid and consumers is the developing field of bidirectional energy trade between power providers and electric vehicle owners. A bidirectional, three-phase, two-stage off-board electric vehicle EV charger design is proposed in this research. The first stage acts as alternating current AC to direct current DC converter during charging operation and behaves as three phase inverter and power factor corrector when energy exchange is from vehicle to grid. The second stage is a bidirectional DC-DC level converter linked to the first stage by a DC bus. The grid side filter is designed to enable the grid interfacing without any significant power quality problems. The proposed design, topology and the devised control infrastructure are tested through simulations on MATLAB/Simulink platform by interfacing the charger to a three-phase AC microgrid and the results approve the performance of the proposed charging topology

Coordinated Volt-Var control in multiple smart inverters in Smart Distribution Networks for Voltage Regulation.

The inevitable growing demand for electrical power, depleting sources of conventional power generation, and world wide concern about global warming are major factors to boost the trend of renewable integration in grids. This rising trend is causing many technical and operational challenges where one of the most prominent problem is the overvoltage caused by distributed generation units, interfaced at the consumer end, and power injections at random nodes. This in contrast with predefined power flows of conventional grids gives rise to bidirectional power flows that demand for modern, coordinated and robust voltage regulation scheme with minimal communication infrastructure. A centralized, coordinated, differential evolution based Volt/VAR regulation scheme is proposed to eliminate the voltage deviations caused by excessive photovoltaic integration in distribution systems. Time step simulation utilizing OpenDSS interfaced with MATLAB on standard IEEE-123 feeder are implemented to test the effectiveness of the proposed scheme

Roach Infestation Optimization MPPT Algorithm of PV Systems for Adaptive to Fast-Changing Irradiation and Partial Shading Conditions

Of all the renewable energy sources, solar photovoltaic (PV) power is considered to be a popular source owing to several advantages such as its free availability, absence of rotating parts, integration to building such as roof tops and less maintenance cost. The nonlinear current–voltage (I–V) characteristics and power generated from a PV array primarily depends on solar insolation/irradiation and panel temperature. The power output depends on the accuracy with which the nonlinear power–voltage (P–V) characteristics curve is traced by the maximum power point tracking (MPPT) controller. A DC-DC converter is commonly used in PV systems as an interface between the PV panel and the load, allowing the follow-up of the maximum power point (MPP). The objective of an efficient MPPT controller is to meet the following characteristics such as accuracy, robustness and faster tracking speed under partial shading conditions (PSCs) and climatic variations. To realize these objectives, numerous traditional techniques to artificial intelligence and bio-inspired techniques/algorithms have been recommended. Each technique has its own advantage and disadvantage. In view of that, in this thesis, a bio-inspired roach infestation optimization (RIO) algorithm is proposed to extract the maximum power from the PV system (PVS). In addition, the mathematical formulations and operation of the boost converter is investigated. To validate the effectiveness of the proposed RIO MPPT algorithm, MATLAB/Simulink simulations are carried out under varying environmental conditions, for example step changes in solar irradiance, and partial shading of the PV array. The obtained results are examined and compared with the particle swam optimization (PSO). The results demonstrated that the RIO MPPT performs remarkably in tracking with high accuracy as PSO based MPPT. Last but not the least, I am very grateful to the Arctic Centre for Sustainable Energy (ARC), UiT The Arctic University of Norway, Norway for providing an environment to d

Study and Analysis of Alternative Power Switches with Reverse-Voltage Blocking Capability

The current source inverters are becoming competitors of the voltage source inverters largely due to the reduced complexity, improved reliability and potentially improved efficiency. This paper describes the functionality of current source inverters and why they’re becoming increasingly popular. It also discusses about the benefits of SiC over other semiconductors and the use of SiC MOSFETS with reverse voltage blocking capability in current source inverters. Double pulse testing is carried out through simulations on different switch configurations under different conditions using Ltspice, MATLAB and Simulink to determine the turn-on and turn-off switching losses. The tests are performed on a single MOSFET and also in the anti-parallel and half bridge scenario. Altium Designer is used for the PCB design in order to observe the behavior of C3M0075120K which is Cree’s 3rd Generation SiC MOSFET through hardware implementation

Wireless charging of offshore wind service vessels

This report discusses the possibility for wireless charging solutions for electric vessels, with a focus on offshore wind turbine service. Where the charging time is minimal and safety for crew is important. Different types of wireless technologies have been studied, where the Inductive power transfer (IPT) is shown to be the preferred technology. Inductive power transfer (IPT) grants a safe charging operation and provides high power density. Brief time between the turbines requires high power to extend the range for the vessel between the turbines. Technical design of inductive charging systems is discussed, and the general aspect of a solution developed for power transfer in the range of 4 kW to 110 kW is proposed. Various compensations were consulted from literatures on Electric boats and wireless power technology, Series-Series (SS) was adopted due to its high-power ability. The proposed wireless charging solution has been simulated and analyzed, a small-scale prototype has not been constructed due to Covid-19

Underwater Inductive Power Transfer with Wireless Charging Applications

Underwater wireless power transfer (UWPT) has become an area of great interest due to the advancement of autonomous underwater vehicles (AUVs) and electic boats. This paper seeks to investigate the variation of the coupling coefficient and power transfer in air versus in seawater. The design is based on a class E converter as it can achieve soft-switching inherently. I made the transmitter and receiver coils then measured self-inductance and parasitic resistance in air and in water. I noted that self-inductance increases when they are placed in water but the mutual inductance is lower. I then calculated the component values for the class E converter based on inductor values (140 μH and 105 μH) and simulated the circuit on LTspice. The power at the output was 74W which is lower than the required value. However, I noted that reducing the coils inductance values while maintaining the value of the other passive components increased the efficiency and power at the output upto four times (311W). The final value chosen for making the inductors was 115 μH and 75 μH as these values gave the maximum power at the output while achieving ZVS. I then designed the transmitter and receiver circuits on Altium and printed the PCBs. All the components were then soldered onto the board and the tests done

A proxy for reliable 5G (and beyond) mmWave communications. Contributions to multi-path scheduling for a reliability focused mmWave proxy

Reliable, consistent and very high data rate mobile communication will become especially important for future services such as, among other things, future emergency communication needs. MmWave technology provides the needed capacity, however, lacks the reliability due to the abrupt capacity changes any one path experiences. Intelligently making use of varying numbers of available mmWave paths, efficiently scheduling data across the paths, perhaps even through multi-operator agreements; and balancing mobile power consumption with path costs and the need for reliable consistent quality will be critical to attaining this aim. In this thesis, the multipath scheduling problem in a mmWave proxy when the paths have dynamically changing path characteristics is considered. To address this problem, a hybrid scheduler is proposed, the performance of which is compared with the Round Robin scheduler, Random scheduler and the Highest Capacity First scheduler. Forward error correction is explored as a means of enhancing the scheduling. Keywords:Multipath Scheduling, mmWave Proxy, Forward Error Correction, beyond 5G

Modeling and analysis of power system oscillations using real-time simulator.

In this thesis a version of the Kundur two-area model has been developed for Simulink and real time simulator software and hardware from OPAL-RT. This model should be used for testing the rotor angle oscillations load variations create. A review of the different control elements found in basic power systems has been reviewed and implemented. The main component that will be manipulated in the model is the active load, so a zip-load model had to be developed for Simulink to make the system work. It was necessary to build multiple models of the same figure in Simulink, one fixed step version to run in RT-lab, and one variable step to do Simulink tests on. Frequency and voltage stability are not a focus but are mentioned throughout because each of them do affect the system. The lack of secondary frequency reserves leads to never regain nominal rotor speed, and voltage stability affects the simulations done on the RT-lab model. Linear analysis of the stability was done using PST software. The linear results were compared to the variable step model. The results show that the different models behave similarly and manages to simulate what happens with the stability during load changes

Automated Tugboat Assisted Docking of Large Vessels

The main research aspect behind this project was the problem in docking the ship to the port with limited space and resources available, causing number of onsite accidents and loss of resources. The main objective is to increase safety on ports, reduce pollution and increase fuel efficiency, also reduce the docking time for the vessels, which can be achieved by developing an autonomous docking system involving automated operations of tugboats, the port, and the vessel itself using control systems with limited involvement from human. This requires the development of a predictive control path for each component involved in the process. This is a long-term goal and requires a lot of research work and prototyping. In this thesis work, some studies will be carried out from past research work related to the problems focused on this project and the solutions provided to tackle these problems. Further data will be extracted along with all the essential equations and based on it; mathematical model will be developed as well as the development of path trajectory algorithm will be carried out. Also, its feasibility will be tested using simulation-based prototyping

Study & Analysis of Power Switches with reverse voltage blocking capability

This thesis hovers over the basic introduction to Silicon Carbide (Metal Oxide Semiconductors Field-effect Transistor) MOSFET switches and the circuit designing of Current Source Invertors using SiC MOSFET switches. The thesis covers the basic grounds for all the steps needed in the implementation of hardware design for half bridge, full bridge and three phase CSIs in the future. Firstly, a detailed literature review is presented to give a deep knowledge about the importance and advantages of using SiC switches and CSIs. Furthermore, a comparison is taken between half bridge and full bridge voltage source converters alongside half and full bridge CSIs using (Physical security information management) PSIM software to model the circuits and analyze different aspects with respect to efficiency of both type of converters. The converters are compared with respect to different input voltages, frequency, and power. Afterwards, a fully working three phase Current Source Inverter is designed using Simulink platform and tested on different frequencies and the results are shown with the outputs of current and voltage waveforms. In the next step Simulations for the PCBs of half bridge, full bridge and three phase CSIs are simulated using LTspice software and examined with the desired output and then are designed in Easy EDA software ready to be printed. Lastly, an additional objective is achieved by testing the Cree's N-channel 3rd generation SiC MOSFETs (C3M0040120K) with Cree's gate driver CGD15SG00D2SiC in simple hardware circuits to observe their basic behavior. The results are shown using oscilloscope graphs against different voltages and currents. The whole dissertation is about the SiC switches, their working, specifications, usage, CSIs, and a lot more with simulations