Nemudriy I. Improving the efficiency of Electromechanical system of wind power plants with wind multiplication

Thesis deals with the peculiarities of the electromechanical system (EMS) of wind power plants (WPP) with wind multiplication (WM) and the construction of rational schemes of energy conversion in EMS WPP WM for the purpose to increase in its effectiveness. Resulting from the analysis the effect of maximum power take-off of the wind flow at fixed rotational frequency of the wind turbine at variable rotational speed of the wind wheel as function of the wind flow speed is found. It is demonstrated that at low wind flow speeds (below 5 m/s) the disagreement between maximum possible and actual power take-off up to 0.1Pn is evident. For the purpose to clear this effect the decrease in rotational frequency of the wind turbines by 2-3 times is required. To realize this operation is possible, when additional frequency converter with the power by approximately 0.2 Pn is integrated into the EMS. The control characteristics of the PDCVC that enable to determine requirements imposed upon control algorithms of the PDCVC and parameters of internal impedance of the EMS are derived. Distinctive features to construct the circuits for energy conversation in the high power WPP WM are discussed. The advisability to use DNI with PDCVC, high-frequency inductor generators is proved. These generators provide increase in capacity of DNI per unit up to 2000 kW and above while the generator mass is the same, higher efficiency and minimal cost for the frequency converter and transmission line of the DNI WM as the part of the wind plants providing stable operation of the DNI with power system. To realize the off-line operation of the ТГ-1000 type WPP the frequency converter with three-level voltage inverter is proposed, rational algorithm for the control by the frequency converter providing electromagnetic compatibility is justified. The results of practical application of the experimental studies are represented.