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How to build a hybrid solar/wind energy harvester?

DC motor control with the mosfet switch board

Although, there is no such thing as a general purpose mosfet switch board because of the wide variations in application specific load (resistive, capacitive, inductive or mixed) characteristics, we were able to investigate and demonstrate DC motor control with our prototype board. Then, we performed the same tests on the energy2switch board. The brushed DC […]

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Current limiting with PWM

For particular applications, such as our energy harvester or at least the battery charger part of it, the ability to control the current is an essential property. We must emphasize that the presented method will limit the average current; the instantaneous current might be higher. So, although it works well for our particular application, it […]

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Coming Soon

Finally, we are almost there. Our first product – a joint development result of cooperation between IACS and RTOS.BE – is about to be commercialized. The Energy2Switch is a DC switch board with 2 channels rated up to 50V and 40A. Continuous power is limited at 1500W per channel, which boils down to 40A @ […]

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To smarter battery charging

Each battery(bank) has properties such as voltage and maximum load amperage and It also behaves differently (in our context of energy harvesting) depending on its state of charge (empty, half, full). To charge a battery efficiently and safely the (average) voltage and (average) load current must be measured, filtered and checked continuously. First thing a […]

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Dual channel power switching: testing different PWM configurations

Switching power between battery and dump load is an important functionality of a charge controller. Switching fast by means of PWM allows for efficient battery charging: the battery (bank) is charged with an appropriate algorithm (bulk, absorption, float, pulse) while unnecessary energy is diverted to a dump load. Since relays are not well-suited for fast PWM switching, […]

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STM32F100: configuring two PWM channels, polarity and alignment

Introduction In our project one source supplies power to two different loads and we need to control how much power goes to which load. To achieve this, we use an STM32F100 processor to PWM high-power mosfets. These mosfet channels do or do not conduct green energy to the different loads which are a battery (bank) […]

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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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Investigating the Wind-turbine to dump load switching – part 2, going the PWM route

In part 1, we talked about the ‘contactor’. Relays also use power, and in this particular case, the relay coil could draw up to 2 watts according to its specification. In order to save power, there are a couple of things we can do. Using PWM is one of them. Every relay coil has a […]

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Pulse Width Modulation

A short definition Pulse-width modulation is commonly used in power-control or motor-control applications. Time is divided into periods. As always, the smaller the time periods, the higher the frequency. Within this time block a pulse signal is applied. The digital signal is logically active (“1”or ON) during a specified percentage of the time period, the […]

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