GRIDVILLE Newsletter
Q1 2022
NEWS
GRIDVILLE IN THE MEDIA Podcast Last semester two of our members were guests in a podcast named ”Solsagt” by Solenergiklyngen. The episode discusses the GridVille project, with a focus on the use of solar power in microgrids and how solar energy can help provide electricity to areas that currently don’t have access to electric power. Click here to listen to the episode.
Article in Nidaros In January the newspaper Nidaros interviewed some of our members and published an article about the project on their webpage. Click here to read the article.
PHOTO: Sanna Drogset Børstad/Nidaros.
NEWS
Equinor At the beginning of this semester GridVille were selected for Equinor´s sponsorship program, Morgendagens helter, for 2021. The theme for that years competition was collaboration, and we were one of six recipients of NOK 100,000 in the region. In January they visited us at campus Gløshaugen where they got to see and hear about our project work. GridVille would like to thank Equinor for the trust and support of the project.
NEWS
GridVille’s new converter TEXT: Maurice Sudkamp
Over this first year, the electrical group has gone through a lot of changes. But It all started with the goal to design and build the required power electronic components required for the grid. In this article, I will summarize the work that has been done on power electronics, the lessons that have been learned, and the result of this first project year.
Based on the grid topology and some research, it became clear that the following converters were needed.
It became quite early clear that we had aimed too high with the goal to finish designing and building the power electronic in one year. The goal changed to having a finished converter design at the end of the year.
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Wind turbine to Bus; Rectifier and DCDC buck converter PV to Bus; DCDC buck converter Battery to Bus; DCDC Bidirectional buck-boost converter Bus to Load; DCDC boost and inverter
Even though three different DCDC buck converters were to be designed, they all had some common problems. The first was that they all had a very low duty cycle, which was in the region from 0.2 During the autumn semester, we consulted with to 0.3. The issue with such low-duty cycles is that the professors and PhD students at NTNU on how there is not much room for regulation. Ideally, a the topology of the grid should be formed. Here duty cycle of 0.4 up to 0.6 is desired. Another issue we got the opportunity to present our problems was high currents, since a buck converter reduces for the research Groups Electricity Markets and voltage the current will rise. A duty ratio of 0,25 Energy System Planning (EMESP) and Power will increase the current around 4 times its input. Electronic Systems and Components (PESC). Some issues we discussed and concluded on were. These high currents made it challenging to find suitable inductors and capacitors. The reason for this was the combination we required for • How to design a load profile our converters. We need high inductive and • The size of production and storage capacitive components, the reason behind this lies • DC- or AC-Microgrid in the ripple of the output current. Reducing a high • Control hierarchy current ripple requires high values of inductance, The result of this was the prototype grid, which the inductance selected will also affect the is illustrated below. What can be seen is that capacitance. The selected components would also we decided on a DC-microgrid, with a 48 Volt require withstanding high currents and voltages. bus. The reason for this was based on simplicity Based on the components we were able to choose and costs for the prototype. If an AC-microgrid from, we discovered that there was a correlation had been chosen, more converters would have that an increase in inductance or capacitance been required, which would make control would lead to a decrease in the component’s rated and communication between them more value for currents and voltages. To solve this issue, complicated. A higher bus voltage would have multiple inductors and capacitors need to be required more batteries in series, which will connected in series and parallel. have resulted in higher expenditure for batteries.
NEWS
A lot of time during the design process was used to find the optimal switching frequency for the DCDC converters. And an iteration algorithm was made, where the losses for different frequencies and duty cycles were compared. The result of this iterative cycle was that a switching frequency of 100 kHz would lead to the least losses and highest efficiency. During this process, we looked at frequencies between 25 kHz up to 1000 kHz.
The duty ratio for the converter becomes Vout = N2/N1 Vin D (1) This solves the problem with the low duty cycles, for an input off 300 V, and output off 48 V an duty cycle off 0.48 can be achieved with an transformation relation of N1:N2=3:1. This converter fixes also the problems with high currents and inductance through the first parallel connection. The CBC has another advantage compered with a typical flyback converter, which is that during the state where switch S1 and S2 are closes, S3 is open; this way the inductor L1 will discharge. In a normal Fly back in the same time period no current flows and the voltage over the load becomes zero. The discharging inductor helps stabilize output to a more continuous wave form.
The goal for the rest of this first project year is to make a simulation for the converter, and to see if At this point in the project, structural changes the theoretical expressions developed are the same were made. And focus were shifted to developing in the simulation. If the simulation are similar to one DC-DC converter which could handle the the theory, the next step for the converter would design challenges. What became clear was that be real life testing and troubleshooting. Which will a conventional buck or fly-back converter could be a task for the next GridVille power electronics handle the challenges. During the research for the team. right converter design, based on our knowledge, we came up with the idea for a new converter. Which we have called the Clean Buss Converter (CBC). This converter is a combination of a fly back converter in series with a buck converter.
NEWS
Eco Moyo GridVille’s group Education has lately been working on a project for the Education Centre Eco Moyo, a modern school in a rural village, located in Ezamoyo in Kilifi county, Kenya. The Eco Moyo Education centre is a unique school based on sustainable design where they catch and store rainwater, use solar power for their energy needs and compost their waste. In collaboration with two Meaningful Masters students, the education team has created a training program for the use, maintenance and repair of their solar power based microgrid. This experience has incredible relevance to the GridVille project, as one of our goals is to ensure that the people receiving the microgrid are equipped to handle it by themselves. By ensuring that they can manage the microgrid by themselves, we make sure the project is sustainable, as they will not be reliant on outside help to use the microgrid.
INTERVIEW
NAME: Andreas Hope Pedersen AGE: 23 STUDY: Mechanical egnineering, 4th year student POSITION: Chief Mechanical Engineer
NAME: Kristine de Boer AGE: 20 STUDY: Applied Physics and Mathematics POSITION: Education Group Leader
What is it like to be a leader for Mechanical in GV? It’s quite rewarding. I feel like I’m gaining leadership skills and can see that I’ve evolved though out this year, both as a person and a leader. The team is very social and enjoyable, so it’s very easy to communicate with them and they work quite well with each other.
What is it like to be a leader for Education in GV? It is exciting because I get to work on challenging tasks and learn to work together with other people towards the same goal. This inspires me and gives me new impulses besides my studies.
Why did you want to be a part of GV? After I heard about the organization and its vision, I thought this was a unique opportunity to combine my technical competence and aid. When I joined, this was a new organization who never had gone through a cycle, so I wanted to be a part of the foundation of this project and gain this ”founder” experience.
Why did you want to be a part of GV? I though it was a cool project that combined technology with aid. I also like to meet new people in new settings and work on a project that helps people in need. I hope this can be the start of combining my technical education with development work.
What are you working on now? We are currently finishing up our prototype wind turbine. This means that I supply the mechanical team with all the resources they need, everything from getting access to the workshop to ordering materials and tools.
What are you working on now? We have just finished a training program for a microgrid which two Master with Meaning students are producing for the education centre Eco Moyo in Kenya. We are now reviewing the whole prosess of making a training program, and summarising experiences and lessons learned.
Anything you want to say to the members of GridVille? It has been fun to meet so many different people from different fields of study with one common goal.
Anything you want to say to the members of GridVille? I am glad that I got the opportunity to be a part of GridVille and have got to know new people that share the same interests as me.
SPONSOR
The GridVille team is pleased to announce our partnership with 4Test Instrument AS and anticipate a fruitful collaboration! 4Test Instrument AS is a leader in measurement solutions and expertise, building on the foundation of Keysight Technologies measurement equipment and technology. Their mission is to provide customers with the best-fit measurement application to their electronics, wireless and photonic devices. Our association with 4Test ensures that the electrical team has all the equipment it needs to test, measure and validate the electrical components they are building. For more information about 4Test Instrument AS visit 4test.no
Facebook: 4Test Instrument AS LinkedIn: 4Test Instrument AS