Параметры и характеристики генераторов ветроэнергетических установок малой мощности на базе асинхронных двигателей с короткозамкнутым ротором

Abstract

The technical literature provides conflicting recommendations on the use of asynchronous machines witha short-circuited rotor of industrial production in wind power plants of low power when operating in parallel with the network. This is primarily due to the imperfection of the method of calculating the characteristics of asynchronous machineson the T-shaped equivalent circuit. Improving the automated method for calculating asynchronous machines with a squirrel-cage rotor in motor and generator modes, analyzing the operation of asynchronous generators of low-capacity wind turbines based on industrial-grade asynchronous motors when the network voltage changes, developing recommendations for improving the characteristics of wind turbines is the goal of the paper. In the developed method of calculation the characteristics of an asynchronous machine are determined by the T-shaped equivalent circuit taking into account the nonlinear changes in its parameters. In the calculation algorithm for a given slip, as an independent variable the value of the resulting electromotive force is applied, which is further corrected by the network voltage, turbine power or motor power specified in the task. According to the results of the research, it has been established: the calculation of an asynchronous generator of a wind power installation at nominal network voltage and constant parameters of the equivalent circuit can lead to a significant error in determining the calculated generator power; an increase in the network voltage within the limits provided for in the Standard may lead to a decrease in the generator power up to 50% of the rated power of the asynchronous motor. Technical and economic indicators of the installation can be significantly improved by increasing the number of turns of the stator windings of the asynchronous machine with the allowable fill factor of the slot. The developed technique can be applied when designing asynchronous machines.