Development of small-scale wind energy systems adaptable to climatic conditions using chattering torque control - PI pitch control and CAES strategy

Abstract

Small wind turbines are commonly single-turbine installations owned by individual homeowners or farmers for on-site electricity consumption, and are becoming an attractive alternative for off-grid electrification and water pumping, both as stand-alone applications and in combination with other energy technologies such as photovoltaic, small hydro or diesel engines. The cost of energy alone is not the only criterion to consider, other aspects like system performance, suitability for a given wind regime, reliability under normal and extreme wind conditions, efficiency in energy storage and exploitation, and overall system life are often equally important. This research deals with the development of small-scale wind energy systems for increasing the productivity of wind power and achieving the better exploitation of generated energy. The proposed wind turbine controller is based on the variable-speed variable-pitch power regulation strategy, using the combination of chattering torque control and PI pitch control. The hardware-in-the-loop (HIL) simulation and on-site experimental testing in rural area are presented. Compressed air energy storage (CAES) strategy for the energy exploitation is also discussed.

A parametric model for wind turbine power curves incorporating environmental conditions

“…Firstly, while an optimal operation requires the rotational speed to be proportional to the wind speed, the speed of rotation is bounded by lower and upper limits. Secondly, at high wind speeds, the turbine can sometimes be deliberately operated at lower power to reduce rotor torque and noise levels [25].…”

“…If we assume that the wind turbine is designed to achieve its maximum efficiency in region II, the blade pitch angle can be set to zero between the cut-in and the nominal wind speed. Indeed, it is usually assumed that the blade pitch is only used to limit the power production to the nominal power in region III [10,2,25] and our modelling assumption seems therefore reasonable. That said, pitch angle can be also used in regulation strategies that aim to limit noise emissions or mechanical effects on the turbine structure within region II [25].…”

“…Indeed, it is usually assumed that the blade pitch is only used to limit the power production to the nominal power in region III [10,2,25] and our modelling assumption seems therefore reasonable. That said, pitch angle can be also used in regulation strategies that aim to limit noise emissions or mechanical effects on the turbine structure within region II [25]. Such strategies are not considered in the present work and their integration in our modelling approach may be the subject of future developments.…”

A parametric model for wind turbine power curves incorporating environmental conditions

“…Firstly, while an optimal operation requires the rotational speed to be proportional to the wind speed, the speed of rotation is bounded by lower and upper limits. Secondly, at high wind speeds, the turbine can sometimes be deliberately operated at lower power to reduce rotor torque and noise levels (Luo et al, 2017).…”

“…If we assume that the wind turbine is designed to achieve its maximum efficiency in region II, the blade pitch angle can be set to zero between the cut-in and the nominal wind speed. Indeed, it is usually assumed that the blade pitch is only used to limit the power production to the nominal power in region III (Dai et al, 2016;Avossa et al, 2017;Luo et al, 2017) and our modelling assumption seems therefore reasonable. That said, pitch angle can be used in regulation strategies that aim to limit noise emissions or mechanical effects on the turbine structure within region II as well (Luo et al, 2017).…”