Doris B - Power Curve(1)

In order to match the rotor to the generator, it is necessary to understand the behaviour of both. The first step is to grab data, starting with the generator because this can be done on the workbench rather than the beach. Much the same solution can be used for both. Currently, the instrumentation is an Arduino Nano which provides analogue to digital conversion (ADC) and a Raspberry Pi for processing. Electricity and electronics were part of my OND but that was a long time ago, so setting up the tests involved a little vexation, but eventually a Python programme managed to capture a sample of the output of the generator.

Two things became apparent, first the output of the generator is complex and not a simple sine wave, Secondly the starting torque increased significantly from the open circuit value when a resistor was placed across the terminals.

The next step is to analyse the data, the plan is to use a Fourier transform to determine the rotational speed and the area under the curve will provide the energy generated, putting the two together will provide a power curve (I hope). The Ardunio is a brilliant tool and may offer a solution to the high starting torque. If pulse width modulation is applied to the load, the turbine can start with no load and as speed increases the load on it is increased, this in turn could provide a means of optimising performance.