Microgrid secondary control clock synchronization method with delay robustness

Abstract

The invention relates to the technical field of micro-grid operation control, and discloses a micro-grid secondary control clock synchronization method with delay robustness. The method comprises the following steps: establishing a local hardware clock model of each distributed power supply, and introducing a correction coefficient to obtain a corrected logic clock reading; transmitting local information to a neighbor node, when a certain node receives neighbor node information, sampling the local information, estimating the relative frequency of a local clock and a neighbor clock by applying a random approximation method, calculating auxiliary variable information, and on the basis, if the neighbor clock is faster than the local clock or is closer to the same reference node, and when an event triggering condition is met, updating a local clock correction coefficient to realize synchronization with a neighbor clock, and finally, determining a secondary control moment according to the corrected logic clock, and establishing the distributed secondary control, so the control performance is improved, and safe and stable operation of the system is guaranteed.

Description

technical field [0001] The invention relates to the technical field of micro-grid operation control, in particular to a time-delay robust micro-grid secondary control clock synchronization method. Background technique [0002] With the depletion of the earth's resources and people's attention to environmental issues, the access to renewable energy has attracted more and more attention from all over the world. Microgrid is an emerging energy transmission mode that increases the penetration rate of renewable energy and distributed energy in the energy supply system, and its components include different types of distributed energy resources (DER, including micro gas turbines, wind turbines, Photovoltaic, fuel cells, energy storage equipment, etc.), user terminals of various electrical loads and / or thermal loads, and related monitoring and protection devices. [0003] The power supply inside the microgrid is mainly responsible for energy conversion by power electronic devices a...

AI Technical Summary

Problems solved by technology

However, since the droop control is a proportional difference control, it will cause a steady-state deviation of the voltage, and the effect of the current distribution is not ideal. Therefore, it is necessary to adopt coordinated control to assist in voltage recovery and current economical optimal distribution.

The traditional distributed cooperative control is realized by applying the consistency theory, which has a strong dependence on the synchronous communication between neighbor nodes. However, in the actual distributed communication, due to the lack of a centralized clock to send the global control trigger signal, each distributed power supply will The control operation is independently triggered based on the local clock, and considering that the working conditions of each clock are not exactly the same, there are inevitably differences between the frequencies of different clocks and the initial time setting values, and the corresponding secondary control sampling time determined by the local clock is not synchronized , which leads to asynchronous information interaction and eventually leads to the generation of steady-state deviation of the state quantity, and even causes system instability in severe cases

Images