Indonesian Journal of Electrical Engineering and Computer Science Vol. 27, No. 3, September 2022, pp. 1185~1198 ISSN: 2502-4752, DOI: 10.11591/ijeecs.v27.i3.pp1185-1198  1185 Journal homepage: http://ijeecs.iaescore.com An accurate dynamical model of induction generator utilized in wind energy systems Bilal Abdullah Nasir Electrical Technologies Department, Hawijah Technical Institute, Northern Technical University, Kirkuk, Iraq Article Info ABSTRACT Article history: Received Dec 19, 2021 Revised Jun 14, 2022 Accepted Jul 4, 2022 Due to the advantages of a self-excited induction generator (SEIG), it plays a main role in sources of renewable energy, such as wind turbines (WT). The regulation of terminal voltage and frequency is poor under variable rotor speed and load conditions at stand-alone operation mode. The generator terminal voltage depends on the excitation capacitance which can be controlled by a capacitor bank and static voltage compensator. The dynamical model of the machine is described by differential equations in D- Q axes transformations of the synchronously rotating frame. Many models of analysis are proposed in the literature. In those models, several approximations are used to simplify the process of calculations, such as neglecting the iron core resistance, stray load resistance, stator and rotor leakage reactance, and magnetic saturation. In this work, a comprehensive dynamic model of the SEIG-WT is performed to analyze the system performance under transient and steady-state conditions. This dynamic model considers the effect of all machine parameters variation. New analytical formulas are used for to accurate calculation of minimum and maximum values of excitation capacitance and generator rotor cut-off and maximum speed. The dynamic model results are partially compared with experimental results, and accurate agreement is shown. Keywords: Cross-coupling magnetizing saturation Excitation-capacitance Self-excited induction generator Voltage-frequency regulation Wind turbine This is an open access article under the CC BY-SA license. Corresponding Author: Bilal Abdullah Nasir Electrical Technologies Department, Hawijah Technical Institute, Northern Technical University AlMinsaa St, Mosul City, Nineveh Governorate, Iraq Email: bilalalnasir@ntu.edu.iq 1. INTRODUCTION Due to the brushless construction of a self-excited induction generator (SEIG), it is also known as brushless asynchronous generator (BAG). This generator is a good candidate with the wind turbine for electric power generation, especially in an isolated and remote area as a stand-alone generation system with a self-excitation by a capacitors bank with the following advantages; brush-less construction, it can be excited without an extra power supply, easy to parallel operation, high reliability, and efficiency, no hunting, simple construction, and operation, it has a low unit cost, low running cost, low capital cost, ruggedness and robustness construction, better transient performance, absence of moving contacts, it has no DC power supply for field excitation, and low maintenance requirements. Although these are preferable features, induction generators have poor voltage and frequency adjusting on the generator terminal phases with the variation of load and speed. When the SEIG is directly connected to the national grid, it starts generating power when its shaft speed higher than the synchronous speed, which is limited by the grid frequency. The poor regulation of generator frequency may be adjusted by the speed-governor of the prime-mover. The blade pitch angle controller with the actuator adjusts shaft speed in the case of the SEIG-WT system. Generator terminal voltages can be regulated by excitation capacitances.