Mechanism and Solutions for Control Fault of Multiple Converters Connected in Practical Engineering

In industrial engineering, application scenario with multiple converters connected to the power system is normal, however it is investigated at ports and container yards that converter control error occurs sometimes when more than 5 cable reel RTGs (rubber-tire gantry cranes) are running. This paper simulates and reproduces this special case, and analyzes the mechanism, which is the instability of the inner loop and over-limit modulation of converter when units feeding power to the grid. An equivalent analysis method of multiple converters connected is proposed, to theoretically analyze the modulation of converter, corresponding to the grid voltage, active power, reactive power and other factors. Some feasible solutions and advice are given, which provide reference for engineering operation and the distribution power system design, with a general significance to similar practical engineering of multiple converters paralleled.