Desenvolvimento de um gerador de afundamentos de tensão (GAT) para testes de inversores trifásicos conectados à rede elétrica

Abstract

As the penetration of renewable energy into the grid has been increasing, modern network codes require the generators to possess low voltage ride-through (LVRT) capability. To evaluate the performance of a generator during grid faults, a voltage sag generator (VSG) is required to simulate grid fault conditions. This study presents a review of standards that addresses LVRT capability. Also, three VSG topologies are analyzed and a comparison is made between different types of switching devices. The development of a VSG based on impedance switching is shown, using contactor relays as switching devices. The project of the impedances and inductors used in it are described. A STM32F746-Discovery microcontroller is used to perform the control of the contactor switches, and through its LCD display it provides a graphical interface for the user to perform the desired tests. The microcontroller, the control logic and the software used to build the graphical interface are presented. A triphasic inverter setup is shown and its components and characteristics are detailed, aiming to perform tests in future works using the VSG proposed in this study. The theoretical behavior of the voltages and currents of the VSG is verified through the software PSIM, and then it is compared with the experimental results obtained in the laboratory, without load and with resistive load. To validate the VSG developed, a comparison was made between simulation and experiment, showing that the results obtained with the equipment are consistent.