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How to build a hybrid solar/wind energy harvester?

Filtering sensor data

The ADC is a much used peripheral in embedded systems. This is not different in our project. We extensively use it to read out – for example – voltage and amperage data. Many people are still unaware of the fact that it is still just sampling: One gets a digital value which is the result […]

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Battery charging with the Wind-turbine simulator

In order to charge batteries with the wind turbine simulator, the setup already becomes quite elaborate. First, there is the brushed DC motor which drives the axial flux turbine. It has a 24V, 350W and maximum 19A rating. The DC motor drives the generator with a chain gear to step down the high RPM of […]

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Charging a deep-cycle battery via low-side mosfet switching: the hard way

Introduction The core of our charge controller (PMD2) is essentially two switchable mosfet channels: one channel to load a battery (bank) and another channel to divert abundant energy to a dump load. Both channels can be switched on/off by software controlled PWM, and by configuring different PWM duty cycle ratios, we should be able: to […]

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Building a wind-turbine simulator

One of the challenges involved in designing and developing the ‘energy harvester‘, is to work out how to design, prototype, test and evaluate software algorithms for managing power flow in the system. At first, we can use powerful lab power supplies: We have lab supplies capable of 900W, 1500W and 3000W DC power output. These […]

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How we work: one year retrospective

Introduction We started the energy harverster project about a year ago and we thought it might be interesting to our readers to explain how we work and how we get the job done. Of course, bringing the technical challenge to a good end is important but only part of our mission, which is to: demonstrate […]

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Charge controller high-side / low-side wiring diagrams – part 2

Connection scheme for low-side switching In comparison to the high-side wiring diagram we saw in part 1, the connections for low-side switching are the other way around: all ‘+’-s are connected (instead of all ‘-‘-s), and the (power) switching devices are ‘below’ the loads (instead of ‘above’). In order to better explain this diagram, we need […]

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Device-internal current and voltage sensing – part 2

Attopilot 50V 180A A few weeks ago we tested the Attopilot 50V 90A. Results were ok, we only noticed a small gap between measured and real amps. Today we show you the experimentation results of the 180A  Attopilot sensor board. Again, we used the Deans connectors and quite a lot of solder to connect the Attopilot device […]

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Charge controller high-side / low-side wiring diagrams – part 1

Introduction After exploring the relay solution space (read part1, part2 and part3), we decided to actually change the boundary of the system and move the relay outside of the energy harvester. Main reason is flexibility and scalability: one could choose a more optimal relay in terms of cost and power spec depending on the (maximum) […]

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Device-internal current and voltage sensing – part 1

The energy harvester application needs to be able to determine current flows and volt charges in order to take the right decisions about charging and dumping. The micro-controller’s ADC unit is able to translate the analogue signal from the sensor into a quantified entity, a number if you wish. Internally, the device current is limited […]

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Electrical direct current switching boards

Prototype building block While working on our energy harvester design, we have identified a couple of relatively independent building blocks that could also be interesting for other people doing projects and building prototypes. One building block is the switch: In its most basic form, it closes an electrical circuit after which a load can get […]

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