Simulation of Electric Part of Six-Phase Ag in Matlab Simulink Environ-ment

Abstract

It is known that asynchronous generators with capacitor excitation are widely used, especially in renewable energy power plants. With a constant frequency of rotation, for example, at hydroelectric power stations, you can use the classic model of an asynchronous machine with capacitor self-excitation. Stator windings of this machine are connected in parallel with the battery of the capacitors.

Mathematical modeling on a computer is reduced to a numerical solution of the system of differential equations describing the investigated object, resulting in the dependence of the coordinates of the object that are of interest to the researcher in the transitional and steady modes of its operation, in the function of time or other coordinates. As a result, a complete mathematical description of the object is formed: the nonlinear dependence of the mutual inductance on the current of magnetization, a system of linear equations for the determination of currents through flow coupling and inductance.

The use of modern software visual block simulation for scientific and technical calculations in electrical engineering and power engineering, such as MATLAB and its expansion packets Simulink and SimPowerSystems, significantly increases the efficiency of research in the presence of appropriate standard blocks. The existing standard Asynchronous Machine unit from the Machines library of the SimPowerSystems expansion pack does not allow full investigation of the process of capacitor self-excitation. This is due to the fact that when connecting to the Asynchronous Machine's standard unit of excitation and activating the Simulate saturation option, the machine cannot be converted to capacitor self-excitation mode. Also, the outputs of the windings in this block are not available. It should be noted that when the Simulate saturation option is turned off, self-excitation occurs, but in the absence of nonlinearity, the amplitude of oscillations goes to infinity, which is unacceptable.

In this paper a mathematical model of a six-phase asynchronous machine in the generator mode is proposed. The simulation was performed in Matlab Simulink environment and the value of the generator voltage at the calculated power of the reactive source was obtained. The transition to the generator mode is in accordance with the calculated value of the reactive power of the capacitor battery.