An Induction Generator Scheme With Series-Compensation for Frequency Insensitive Loads

Induction generators (IG) are widely used in renewable energy systems, such as wind power, and micro/mini hydro-turbines. In applications, such as urban wind-energy systems, electric vehicles and more electric aircrafts, induction machines can be used to supply electrical power to auxiliary loads, deriving power from main engines. In this article, an IG system with open-end stator windings is proposed for simultaneous supply of regulated power to frequency insensitive ac-loads and dc-link loads for the first time. One end of the stator winding is connected to auxiliary loads while the other end is connected to a capacitor-fed voltage source inverter (VSI). In the proposed system, VSI is controlled to supply reactive power required by the IG while simultaneously regulating the dc-link voltage and ac load voltage at required level. The proposed method is based on scalar-control of the induction machine, thus making it a simple and robust system to supply active power demanded by ac and dc loads. The proposed control scheme has been simulated in MATLAB-Simulink and experimentally verified for steady state and transients with various ac loads including linear, nonlinear, and unbalanced loads.