Double-current feedback control method applied to bidirectional grid-connected converter

Abstract

The invention discloses a double-current feedback control method applied to a bidirectional grid-connected converter. The method specifically comprises the steps that firstly, according to the principle that the power of the alternating-current side and the power of the direct-current side of a three-phase AC / DC converter are equal, the mathematic relation between the direct-current bus voltage Udc and the alternating-current side current iL of the three-phase AC / DC converter is established and substituted into a droop control equation, and a calculation equation of the alternating-current side current iL of the three-phase AC / DC converter is obtained; and then an active damping feedback loop is added in the control of the bidirectional grid-connected three-phase AC / DC converter to eliminate the resonance influence generated by the LCL filter. According to the method, the traditional droop control is improved, so that the direct-current bus voltage control effect is optimized. A grid-connected current feedback active damping method is adopted to suppress resonance, and system robustness is improved while grid-connected current harmonics are reduced. Through combination of improveddroop control and active damping feedback control, bidirectional control over the alternating current side and the direct current side of the grid-connected converter is formed.

Description

technical field [0001] The invention belongs to the technical field of grid-connected current control, and in particular relates to a dual current feedback control method applied to a bidirectional grid-connected converter. Background technique [0002] With the extensive exploitation and use of primary energy, not only the earth's environment is seriously polluted, but also conventional energy sources such as coal, oil, and natural gas are increasingly depleted. Therefore, a variety of renewable clean energy sources such as solar energy, wind energy, etc. focus on. Based on the rapid development of distributed power generation technology, it provides important power support for large power grids. However, due to the intermittence and volatility of renewable energy, there are certain challenges in the process of direct grid connection of distributed power generation. A microgrid is a small power generation, distribution, and consumption system composed of distributed power...

AI Technical Summary

Problems solved by technology

Compared with L and LC filters, the LCL filter is small in size and has good high-frequency filtering effect, which can reduce the cost in practical applications, but its own high-order characteristics will cause resonance phenomenon, which will increase the grid-connected current at a specific frequency. Harmonic amplitude, affecting the stable operation of the system

Images