This paper describes the structure of the vector control with an emphasis on rotor magnetic flux estimators. αβ coordinate system (coordinate system of stator) and the dq coordinate system (coordinate system of the rotor flux) are described. Mathematical model of squirrel cage induction motor in αβ koordiatnom system is derived. The importance of the coordinate system of the rotor flux for operations with rotating vectors is explained, and a mathematical model of squirrel cage induction motor in dq koordiatnom system is derived. From the model in αβ system a machine model with state variables in αβ coordinate system is designed. The principle of operation for voltage model of the rotor flux estimator is set forth in detail, and the principle for rotor flux angle and amplitude estimation in current model is explained. Parameters of the squirrel cage induction motor that was used in this study are given, and the control system is configured according to these values. Using the technical optimum method the parameters of PI controllers of the stator current are set. It is shown that the parameters of the speed controller can be adjusted using the symmetric optimum method and the process of optimization is set forth in detail. The practical method of determining the parameters of the regulator is described. The impact of the decoupling of the regulationlation circuits of d and q component of the stator current is explained, and various methods for compensation of undesirable impacts that occur due to decoupling are described. Simulations were performed in which the engine is idling, in which it is burdened with 50% of the rated load, and in which the sensitivity of the control loop to the change in value of the engine parameters is tested. In section 5.1. responses of current and voltage models of flux estimators in steady state are compared. With both models, a simulation of idling and a simulation in which the engine is burdened with 50% of the rated load are conducted. Section 5.2 examines the sensitivity of the current and voltage models to the change in the value of two engine parameters - stator resistance Rr and mutual inductance Lm. Responses with parameter value equal to the factory value, with 50% of the factory value, and with 150% of the factory value were compared. The results of simulations are analyzed in detail and compared with expectations based on the theoretical model.