WindAid is also electronics

Posted on April 25, 2018 by Roberto Weiser 

Back in the summer of 2014 I had one of the best experiences of my life (sounds cheesy and the start of a teenage girl movie doesn’t it?). I was just finishing university and graduating with an electronics engineering bachelor degree at the university of Plymouth and before getting hooked into a 9-5 job I was looking to have an experience where I could combine three different factors:

  1. Traveling
  2. Engineering (in particular electronics and renewable energies)
  3. Helping other people

After a long web search I applied to and contacted different organizations and companies. After a few months I had the opportunity of either going to Peru with WindAid or Rwanda with Practical Action. To be honest I got scared with the Rwanda opportunity as I had to travel the country on my own going from village to village assessing them energetically. The work was very interested but I got scared given its recent history :), therefore, I decided to go to Peru. Best decision ever!

With that said, one of the best things I did at WindAid was to use my skills as an electronics engineer to create a device that could actually make a difference. After analyzing the electronic devices WindAid uses for its electricity generation system (battery charge controller and inverter), it was obvious that they could benefit from having their own devices custom made and locally built, after talking to the WindAid Team and understanding what they were looking for I decided to take on  the design of the first WindAid battery charge controller; let me tell you how did I arrive to that conclusion:

  • WindAid was paying a high cost to import the device. The controller itself wasn’t that expensive but the shipping and customs made the overall cost quite high.
  • Because the model used was a generic cheap controller from the far east, there was no documentation available. Meaning that if there was an issue with the controller there was no contact point to ask for help.
  • No capability of repairing: because the circuit was unknown and there was no local technical support. A lot of the controllers ended up in the bin if they suddenly stopped working.
  • Controller had no Maximum Power Point Tracking (MPPT) function: this optimization has the potential of making the energy conversion process more efficient. Since this was a simple controller it didn’t feature this function.

The team was excited to have me undertake the project since that meant it would be highly beneficial for the organization to have its own controller. After the initial R&D costs, the controller production cost would be half the price compared to the current one. Also, by having the knowledge of the insides of the controller it would make it enormously easier to repair in case of malfunction.

What’s the battery charge controller for?

The main purpose of the battery charge controller is to monitor the voltage levels of the battery and make sure they are not too high or too low, and in case they are, take actions such as disconnecting the turbine from the battery.

Controller Development

Requirements

  1. Must be easy to assemble for people without previous experience
  2. Must be easy to repair
  3. Must protect the battery from overcharge and undercharge
  4. Must show the user the battery level
  5. Must convert the AC generated voltage from the turbine to DC voltage
  6. The controller must be designed so it works with a 12V battery
  7. Must be compatible and able to work with WindAid 1.7 wind turbine model
  8. Must have an MPPT stage to improve the energy conversion and extraction process
  9. Must be robust and have a fail safe mode in case of failure
  10. Components must be able to be sourced from local suppliers
  11. Materials selected for the enclosure must be sustainable (low embodied, energy, local, recyclable)

Electronics design

The proposed design for the controller was the following depicted in the block diagram below:

Circuit elements and components

Series capacitors

Experimental use as it has the possibility of increasing the efficiency of the energy extraction process as described “Analysis of wind power for battery charging” by E. Mulijadi.

Power rectifier

This element converts (rectifies) the sinusoidal voltage from the wind turbine generator into a DC voltage in order to charge and work with the 12V battery.

Voltage sensors

Measure the battery voltage to determine under and over voltage conditions. It is also used in the MPPT algorithm calculations

Current sensors

Measure the output current of the generator that goes into the battery. It is used to determine if the charge must be stopped in case of over current and for the MPPT algorithm calculations.

Relays (switches) for battery protections and DC/DC bypass

The relay close to the generator is used in case of overcharging and it connects a load to the generator so most of the current is drawn that way. The other relay is used to disconnect the battery from the inverter, this is used in case of undercharging so the battery is not used in case it is near the under voltage level. Also a switch was placed in order to bypass the DC/DC converter in case this fails.

DC/DC converter

A DC/DC converter of SEPIC topology was used to implement the MPPT optimization. The DC/DC converter acts as an element that changes the impedance seen by the source from the load, therefore has the ability to change the rotation speed of the generator thus allowing it to reach the maximum power point.

Microcontroller

The device needs a MCU to perform all the MPPT algorithm calculations, sense and calculate the battery voltage and current, drive the DC/DC converter control signal and open/close the protection relays.

LCD screen

A LCD screen was added to display useful information such as voltage, current, power and battery level.

 

Circuit schematics

From the block diagram, commercial components and detailed design was done producing the schematics:

Printed Circuit Board design

After finishing the circuit diagram and schematics a PCB was designed taking into account the following considerations:

  • Similar size as commercial options
  • Components must be THT so they can be easily soldered and unsoldered
  • Labels with important information must be added
  • Holes for M3 screws must be placed

 

Software design

The MCU was programmed with a custom made code written in C following a finite state machine topology:

 

State Functions Conditions
Initialization I/O config, peripherals initial setup, check state of sensors Only happens once when device is powered up
Read sensors Sensors are read and next state is decided according to the readings Always comes back after another state has completed its routine
Simple Charge Direct connection from generator to battery without using the DC/DC converter VBATT < 14.5V

IGEN < 7.8A

BYPASS SW = HIGH

MPPT Charge MPPT algorithm is executed VGEN > 4V

BYPASS SW = LOW

VBATT < 14.5V

IGEN < 7.8A

No Charge Battery charging is interrupted and the parallel resistance is connected to the generator VBATT > 14.5V

VGEN > 4V

IBAT > 7.8A

 

Mechanical design

Unfortunately there was no enclosure made for the controller and it was delivered as in the following picture:

If you are an enclosure designer or you just like to make boxes we need your help!

The controller will be on a harsh environment so it needs a good enclosure that can withstand sand, dust, moisture and also dissipate heat or ventilate. Ideally will be made of steel as it can be easily found in the region (lots of mines around) and can be reused with other controllers. The initial enclosure concept was the following:

Current state and what’s next

After assembling the whole device, initial testing was made to validate its core functions with satisfactory results. These initial test consisted in measuring the accuracy of sensors, opening/closing of relays and correct functioning of the DC/DC converter.

The project is currently still in development and being tested with real turbines. Also a modular version was designed in order to increase its repairability and ease of teaching for the volunteers and local communities.

The next step is to do a vast amount of testing with real systems to validate the functionality of the controller. Particularly the MPPT feature.

After finishing with testing and validation, the boards can be mass produced and distributed around the communities. Because this is not a commercial product and it is not next to communication infrastructure, EMC compliance will not be necessary (yet).

Are you interested in developing electronic devices? Do you think we should include sustainable design principles in the development process? Do you agree that engineers should only create devices to improve human existence?

If these questions resonate with you please visit Developpa and join its mailing list to learn about electronics development, sustainable design and create stuff for good! Also you will be able to access all the design worksheets and resources to help you complete your product development.

Kickstarting an Energy Revolution!

For many years, WindAid Institute has been installing wind turbines in rural communities here in Peru that have no grid electricity.  We now have over 50 functioning turbines across north-west Peru, clustered in geographical areas with up to 15 (and counting) in each area. We need to ensure all these turbines can be properly maintained and we can install new ones as the communities need them (and subsequently maintain those), while continuing with research and development on improving turbine technology. 

These factors, along with the need for the communities to be fully engaged and have autonomy over their energy supply, came together into a new strategy: Community Wind Workshops. These fully outfitted facilities would be built within each cluster area, providing an electronics room, a test turbine for developing technology in real environmental conditions, training facilities for community members, local technicians, and volunteers, and living space for volunteers.  After considering the strategy from all angles, WindAid identified the fishing village of Playa Blanca as the first site for a Community Wind Workshop and set about planning it.  The community set aside some land for us to use, we worked with a university in the UK to design the building with as many green facilities (grey water reuse, composting toilet, roof garden…) as we could identify, and we were all set to go!

But as a non-profit organisation, funding is always a challenge.  We’d never undertaken this kind of project before, and needed an upfront sum to buy the materials to do the build and fit out the workshop.  Crowdfunding is an increasingly popular way for individuals and small organisations to raise money for projects; we investigated and decided to try it out for the Community Wind Workshop.  We chose theKickstarter platform, as although it has a strict rule that you only get the funds if you exceed your target, it has a very structured approach, great support and guidance, and a solid reputation.  ‘Backers‘ pledge a certain amount to get a ‘reward‘, so we carefully picked a whole range of items that backers may like, from a keyring up to a trip out to Peru do a program and see the workshop completed in January 2017.  We researched how to run a crowdfunding campaign and planned to launch on 8 June – it was all systems go, and we sent out a series of teaser messages to get our supporters excited for the start of our energy revolution!

Prepping for the Lima auction fundraiser

Prepping for the Lima auction fundraiser

We started off very strongly, with over $1,000 raised in the first 24 hours.  Pledges came in steadily throughout the whole month, as past volunteers and other contacts signed up to back us.  Kickstarter chose us as a ‘Project We Love’ which attracted interest from regular Kickstarter backers who support projects that catch their eye, and we had great feedback that our story was inspiring people!

We held auctions and sporting polladas (traditional Peruvian BBQ), sent out press releases and ran a competition for who could bring in the most backers, we posted regular updates on our progress on Kickstarter and across social media.  But unfortunately it was not enough…  Of our $35,000 target we got $22,000 of pledges, so we ended up with nothing…  Except actually we ended up with so much more than we could have imagined!

Prepping for the Pollada

Prepping for the Pollada

Not only have we reached out to many new supporters and reconnected with old friends, we had lots of likes and shares on social media – spreading information far and wide about WindAid and our work.  We’ve had articles published in renewable energy and sustainability magazines, and linked with a journalist who writes for a major UK newspaper on sustainability; we’ve learnt a lot about fundraising and marketing in general.  And most important of all, we’ve ended up with around $8,000 (to date) in donations from our hugely generous backers who still wanted to support us outside of Kickstarter.  This is more than we’ve ever raised before, and is enough to continue with the next stage of the build in Playa Blanca!  Plus we had a lot of fun!

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Local football at the Pollada

Will we do crowdfunding again in the future?  Maybe; it was a big investment of time and energy and there are things we’d do differently if there is a next time.  But given our ambitious plans for future projects like the Community Wind Workshops, we will need dedicated fundraising events.  So watch this space for new projects Lighting up Lives here in Peru!  A huge thank you to all our Kickstarter backers and our many generous supporters – without you our work would not happen!

The Windaid Pollada Football team. June 2016

The Windaid Pollada Football team. June 2016

A first month`s experience  (February 2016)

Posted by Beth Brown on June 17th, 2016

Settling In

My trip to Peru had been planned for months, so it was extremely exciting to land for the first time in South America.  I spent a few days in Lima acclimatizing then got the most luxurious bus I´ve ever taken for the 10 hour journey to Trujillo – reclining wide leather seat, three action movies and a hot lunch, all for under 15 pounds sterling!  The views out the windows were fascinating – varied districts of Lima, huge sand dunes in the desert, the fishing communities living next to the waves crashing onto the coastline, and the sunset over the ocean.

Two of the WindAid team met me from the bus in the famous Beast, and the welcome presentation told me all about WindAid with plenty of opportunity to ask questions.  The four storey volunteer house is in a nice neighbourhood with all amenities – shops, banks, laundry: I quickly felt at home.

Starting Work

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During my first month there was another volunteer like me and the WindAid team – a mix of Peruvian and international staff.  As it was a smaller group, we didn’t do a full installation project, instead we visited several sites to do maintenance.  In between, we were in the workshop making a 500W turbine blade from scratch.

I got to do so many things I´ve never done before!  Safely wrapped up in gloves, mask, goggles and very elegant heavy denim overalls, I mixed chemicals, cut fiberglass, prepared moulds, done sealing, gluing, drilling and sanding, even soldering.  All under the watchful eye of Señor Abel and the team.  It’s safe to say I’m more comfortable with a tool kit than ever before!

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Although most of the team speaks English, having some Spanish is helpful and there are plenty of opportunities to learn the vocabulary of the workshop and the basics of day to day life.  

Out and About

I´ve done some exploring of the local area including the bustling city markets selling EVERYTHING, the surfing beaches of Huanchaco and Pacasmayo and the archaeological sites of theHuacas del Sol y de la Luna and Chan Chan.  It’s also easy to venture further afield for long weekends; there is so much to see within a few hours.  

  • Cajamarca is a pretty cheese-making hill town with some archaelogical sites nearby.
  • The northern beaches around Màncora have rolling waves perfect for learning or perfecting your surfing.
  • The Cordillera Blanca mountain range has many hiking routes through stunning scenery.

The two maintenance trips were to Huamachuco and Huaraz:

Huamachuco 

The Democratic School of Huamachuco is following an unusual concept, where the children decide what and how to learn.  There are assistants rather than teachers, who facilitate exploratory play in carpentry, art, reading (on every subject from The Little Prince to Gabriel García Márquez to the Koran) and textiles.  Maths is learnt on table football!  There is a great vibe, all the kids were active, doing something, being creative.

The main school building is now connected to the grid, but they want the turbine ready again to power a new building.  So we removed the turbine to repair and test back in Trujillo.

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Huaraz

Our installation is at the Pastoruri glacier, a popular tourist attraction near Huaraz city in the Cordillera Blanca mountains.  We hold a Guinness World Record for the highest turbine in the world at almost 5000m! (to put it in perspective, Mont Blanc in the French Alps is lower at 4810m). Since 2013, the WindAid turbine has been powering a group of wood and tarpaulin huts selling visitors drinks, food and souvenirs.  The huts have now been replaced by proper buildings which don’t yet have the wiring to connect to the turbine.

We retrieved the data logger and electronics, which took a while for a seemingly simple task, and everyone was wet and cold by the end.  Luckily a friendly Señora was on hand with steaming cups of matè tea (from cocoa leaves to help with the altitude).  After, we walked up to the glacier, a stunning sight, plunging down into a black lake dotted with icebergs.  However it has receded significantly in the last few decades – climate change right in front of our eyes…

We saw more evidence of climate change inthe Trujillo suburb ofBuenos Aire.  Just a few years ago it was a popular beach, lined with restaurants.  Due to climate change and a nearby large commercial shipping port, the currents have changed and the beach is totally eroded, replaced by a high stone wall that prevents the few remaining open restaurants and occupied houses being washed away.

Daily Life in Trujillo

A medium sized city, it’s easy to get to know the main routes and neighbourhoods, which are generally safe and well looked after with lots of green spaces.  I have travelled locally by taxi and public buses – both plentiful and cheap.  For longer distances there are many bus services to suit every budget (though you get what you pay for in terms of comfort and leg room).

Although Peru isn’t a “first world” country, it´s not a backwater either.  There are big houses, shiney cars, supermarkets and clothes shops stocking branded goods you’d recognise.  Everyone has a smart phone and wifi is easy to find.

It´s a lively country with noise everywhere – barking dogs, beeping taxis, crowing roosters, latin and folk music blaring, children playing in the streets and parks.  Life is lived on a relaxed “Peru Time”, except when driving, when everyone goes at top speed!

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People really appreciate you trying to communicate in Spanish and I´ve found everyone friendly and helpful.

It has been an amazing experience.

Redesigning the wind turbine tower assembly

Posted by Bryce Alsten on June 2016

University of Florida and WindAid volunteer

Research and design; it’s the meat and potatoes of any engineering project. It is also an ongoing process, because no matter how good you think your product or system is, there’s always room for improvement.

The collective understanding that our wind turbine systems need continuous development is what makes working at WindAid a truly immersive learning experience. Volunteers from all over the world with a myriad of skills and experiences come together to learn from each other and contribute their own unique knowledge towards the ultimate goal of improving the way we empower developing communities by providing them with electricity.

There are many factors and constraints that go into the successful design of small wind turbines, but above all others, the most important factor is safety. Currently, one of our main focuses is on ensuring safety over the lifespan of our 500W WindAid 1.7 model turbine by analyzing and improving the structural integrity of the tower assembly.
During our most recent installation in one of our communities, Playa Blanca (on the northern desert coast, where there is little rain, strong sun and very sandy soil), we took note of some concerning levels of degradation in the towers and foundations of some previously installed turbines. The most concerning signs were structural cracks in the concrete foundations (pictured below).

Base crack

 

There are two types of cracks in concrete: structural cracks and non-structural cracks. Non-structural cracks are normal and to be expected. They are unavoidable and are often caused by variations in moisture and temperature. A common adage is that there are two guarantees with concrete: one, it will get hard and two, it will crack. Structural cracks on the other hand, are larger (generally wider than 1/8”, or the thickness of a credit card) and must be addressed before they become larger and propagate, leading to eventual structural failure. Structural cracks can be caused by many factors including improper mixing and pouring of concrete, as well as excessive forces acting on the concrete.

It is our opinion that these structural cracks are being caused by a combination of the two previously mentioned factors. Because of the concern over the long-term structural integrity and safety of the turbines that these cracks raise, we have begun the process of completely redesigning the way be build and install the towers. Wind turbines experience a variety of different forces (pictured below), and in general the stresses caused by these forces build up throughout the turbine’s tower, especially at the base of the tower where it is connected to the foundation.

Base Options

Our current tower design is simple – like the example depicted above minus the tension cables (guy wires). The tower shaft is a circular post that is approximately 8m long and 13cm in diameter made of eucalyptus wood. We use eucalyptus because it is low cost, relatively strong, and readily available in Playa Blanca. The actual turbine assembly is bolted onto the top of this post. We then place the bottom of the tower into a hole that is approximately 1.5m deep and 0.75m in diameter and backfill the hole with concrete.

Based on the evident structural cracking in the foundations, it is clear that we must design a new tower structure that provides more support than our current design does. There are three common types of tower structures used to support wind turbines: lattice, monopole, and guyed mast (all pictured below). Our current design is a monopole. After extensive research, we have decided that the best option to properly support our turbines is to use a guyed mast structure, the most commonly used type of support structure in smaller scale turbines.

bases

 

 

However, using guy wires in our redesign brings a new problem – a significant increase in the footprint area of the tower. This is a problem is because in Playa Blanca, the tower foundations for all the existing turbines are located within 0.5m from the walls of the owners’ houses. This means that a traditional guyed mast tower setup would require anchoring one or more of the guy wires inside of the owner’s houses, which is simply not a realistic option. This issue has forced us to get creative. We want to use guy wires but we don’t want to increase the size of the tower’s footprint.

Our preferred solution is to add horizontal crossbeams towards the top of the tower that allow us to redirect the guy wires back towards the tower’s base while still maintaining proper tension. Think of the new tower design as a lower case letter t. The guy wires are attached at the top of the t, then at the ends of the cross of the t, and then again at the bottom. The only difference between our theoretical design and this simplified letter t example is that there will be three guy wires spaced 120 degrees apart so there will also be three beams supporting them as opposed the two that you would visualize on the t –shape.

Decisions now must be made on several factors including but not limited to: how high up the guy wires should be installed, how long the cross beams should be, and how much pretension should be installed in the guy wires. We will be able to answer these questions when we finish analyzing the forces and moments experienced by our turbines in Playa Blanca. When we are confident with the accuracy of our numbers, we can begin optimizing the equations and running finite element analysis (FEA) on the new structure design in programs like SolidWorks so that we can be confident that our design will remain structurally safe and sound for the entire lifespan of the turbine.

If you have any comments or suggestions on this article, we would be interested to hear from you at [email protected]

 

Electrifying Playa Blanca and exploring Peruvian desserts…

Posted on June 9, 2016 by Katherine Guo

It’s been about a week and a half since I arrived in Trujillo, Peru. From sanding blades at the workshop to having celebratory barbecues at the house, I have not had much time to reflect on our project, its impact, and my time in Peru, in general. Unfortunately, I am currently sick with a cold and could not make it to the workshop today, but this opened up some quiet space to finally think.

Sustainability is Key

I, along with two other Duke students Danielle and Aashna, are working with WindAid Institute to help electrify Playa Blanca, a rural community where most residents do not have access to electricity. Although efforts have been made by the government to install solar panels in the homes in Playa Blanca, the solar panels have been proven to be unreliable, as many of them have broken down and can no longer generate electricity. Therefore, with the support of the community, WindAid has stepped in and offered to provide wind turbines for any household that wants one. WindAid has already electrified 15 houses with wind turbines, and over the next few months, we will construct the components (blades, rotors, stators, etc.) and install two more wind turbines for two families.
When learning about what WindAid does, my first thought was: Since Playa Blanca is quite far from Trujillo (where WindAid’s workshop is), so what happens if the turbines break? How would they be maintained?

After talking to Jessica, our point of contact at and co-founder of WindAid Institute, she explained that a project was underway to create a workshop in Playa Blanca, as a centre for wind turbine maintenance, as well as a space for providing educational sessions to the community about the wind turbines. The community members are ever so passionate about being environmentally friendly and preserving their home, making them excited to learn about renewable energy and the nooks and crannies of the wind turbine. Hopefully, with a more permanent space for WindAid in Playa Blanca, community members would be able to gain enough knowledge about the wind turbines to eventually be able to maintain the turbines on their own.

Side Note: WindAid is currently seeking funds for the construction for this Community Wind Workshop, check out the campaign here

For me, sustainability is arguably the most important component to any service project. I want to ensure that the impact we are making will last longer than when WindAid completes their project in Playa Blanca. The development of the test center drew me the most to our project, and is going to be my main focus during my time with WindAid.

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Reading to attentive kids at Playa Blanca!

Workshoppin’

During the weekdays since I’ve arrived in Trujillo, we go to the workshop to make the different components of the wind turbine. What I’ve enjoyed most is that the people at WindAid really wants us to learn. For example, welding is a technique that serves to bind pieces of metals together. It involves lots of sparks, and I have to admit, I was pretty terrified of it in the beginning (and still may be a little bit). After a long day working with sparks and trying to weld, I was ready to call it a day, but Ross, one of the founders of WindAid, made sure that I would not leave that afternoon without welding the two pieces of metal together. Ross gave me a demonstration and some tips on how to get the flame going. Thereafter, I was successfully able to make the welds. I am very grateful that instead of asking someone who was already adept at welding to combine the two metals, Ross was determined to assure that I was able to weld and comfortable with it.

Aside from welding, I have been making the blades of the wind turbine smooth by sanding and adding filler, constructing the tail, and making coils for the stator. As all the different parts of the turbine reach their final stages, it’s exciting to finally start to the wind turbine come together!

This Saturday, we are going to Playa Blanca to actually install two wind turbines, one for a family and the other one to be used at the test center. During the time in Playa Blanca, I will be able to work on the sustainability aspect of the project, by creating lesson plans for the community, building paper airplanes or boats with kids in schools, and talking to community members to understand their thoughts and feelings about the wind turbines. Interacting with the community is what I am most looking forward to doing in Playa Blanca!

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Assembling the stator onto its structure in the workshop

 

Work Aside

Peru is also really fun! To start, the people here are really nice- although I don’t know much Spanish, Peruvians still try making conversation with me and are always smiling at me even when we cannot understand each other. From the past week, I have picked up some Spanish that helps me get by, including how to catch a taxi and the numbers to buy things at the bodega (small neighborhood store). Hopefully, by the end of this trip I am able to actually have conversations in Spanish so I can learn more about Peruvian life and culture.

In Trujillo, there is a beautiful beach town called Huanchaco, where we went the past two weekends to eat ceviche (citrus infused fish) or to just admire the surfers in the ocean.

Finally, I have been eating so much dessert here! From palmier cookies to three milk cakes, all the options are so delicious and cheap. Luckily, one of the WindAid workers loves desserts as much as I do (maybe even more) so he can be my guide to all desserts Peruvian.
That’s all for now. Stay tuned for blog posts from Danielle and Aashna as well as more updates from me after we get back from Playa Blanca!

Hasta la vista,
Katherine

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Visiting the giant rock wall in Buenos Aires, Trujillo