Energy storage inverter PQ control method under grid-connected state

Abstract

The invention relates to a three-phase inverter control technology, and provides an energy storage inverter PQ control method under a grid-connected state. The method mainly includes the steps of collecting three-phase output voltage and output current of an LCL output port of an energy storage inverter, and carrying out closed loop control on the output voltage and the output current of the energy storage inverter by means of an obtained inner-loop voltage reference value d-axis component, an inner-loop voltage reference value q-axis component and a phase angle, so that output active power and reactive power are equal to an instruction value and a power instruction can be tracked through output power of the inverter. The method integrates island droop control and grid-connected PQ control, and simplifies control of the energy storage inverter. In the control mode switching process, the probability of failed switching is beneficially lowered, and overvoltage and overcurrent phenomena can be obviously reduced. When a microgrid is disconnected with a power grid abnormally and the energy storage inverter enters an island to operate, the energy storage inverter can operate according to a preset rated point, and stability of the microgrid can be improved.

Description

technical field [0001] The invention relates to a PQ control method of an energy storage inverter in a grid-connected state, which belongs to the three-phase inverter control technology in the power electronic power conversion technology. Background technique [0002] With the increasing energy consumption, countries all over the world pay more and more attention to the development of new energy. Distributed new energy is connected to the large power grid in the form of a microgrid, which is an effective means to realize the large-scale application of distributed power generation. The microgrid operates in grid-connected state most of the time. When the large power grid fails or is planned for maintenance, the microgrid is disconnected from the large power grid and turns into an island mode of operation. At this time, the energy storage in the microgrid adopts droop control as the support of the internal voltage and frequency of the microgrid. When the large grid returns t...

AI Technical Summary

Problems solved by technology

[0004] The technical problem to be solved by the present invention is to overcome the deficiencies in the prior art and provide a PQ control method for energy storage inverters in the grid-connected state to solve the problem of energy storage between the island droop control and grid-connected PQ control modes. Switching failure or overvoltage and overcurrent problems that may be caused by switching

Images