At the end of the 21st century approximately 10-12 billion people will live on the Earth. If we want to supply them with electricity, we have to think about the environment and the ecosystem of our planet.
To protect the environment, we can use renewable energy, which is not so polluting as the traditional power plants, like oil or carbon power plants.
Today, we use already large amounts of the renewable energy, and this sector is growing.
Hungary's most dynamically developing structures of the renewable energy source in the last nine years were the wind power plants. In 2003, six pieces of wind turbines were operating in the country, at the end of 2010 were already 155 pieces with 295 MW of total power in use.
We have a requirement for these power plants: they have to produce energy consistently, without pulsation. The pulsating energy is caused by the variable speed of the wind. The solution can be an internal energy buffer for the energy storage, for example a flywheel.
In my thesis I wrote about the investigation of flywheel drives for wind turbines. The flywheel with its spared energy compensates the pulsating energy caused by the turbulent wind of the wind power plant for the network.
In Matlab Simulink environment, I made basically two models: flywheel built with induction machine, and flywheel built with synchronous machines in normal operating range.
We assume the pulsating energy of the wind generator sinusoidal. I have made calculation for different phase positions and amplitudes of this sinusoidal pulsation energy. The flywheel, as all energy storage, has symmetric energy storage; it can also compensate negative and positive energy pulsations.
I have examined, in which cases we can reached a perfect compensation, and what are the extreme cases when we reached the limits of the compensation.
The calculations showed that the induction and the synchronous machine operating in the normal-mode models can achieve perfect power compensation.