Business ship distributed energy pre-grid-connection method based on model-free adaptive control

Abstract

The invention discloses a commercial ship distributed energy pre-grid-connection method based on model-free adaptive control, and relates to the technical field of micro-grid control. The method comprises the steps of acquiring three-phase phase voltage of a ship virtual synchronous generator and shore power; performing park change on the three-phase phase voltage to obtain a voltage value under a two-phase rotating coordinate system; calculating the phase difference between the shore power and the ship virtual synchronous generator on line; establishing a virtual power equation between the shore power and the ship virtual synchronous generator; carrying out dynamic linearization treatment and obtaining a data model; calculating a virtual power pseudo partial derivative estimation rate; designing a virtual power model-free adaptive controller; and through model-free adaptive control, improving virtual synchronous generator pre-grid-connection control based on virtual power to realize commercial ship distributed energy pre-grid-connection. According to the invention, the response speed of the commercial ship distributed energy grid connection is optimized, the generation of grid connection impact current when the commercial ship distributed energy is connected to the shore power is improved, and the oscillation problem of active power and reactive power is reduced.

Description

technical field [0001] The invention belongs to the technical field of micro-grid control, and in particular relates to a method for pre-grid-connecting merchant ship distributed energy sources based on model-free adaptive control. Background technique [0002] A green port refers to a sustainable port or wharf that implements the concept of green development in the process of production and operation, fulfills social obligations and legal responsibilities, and achieves a good balance between environmental impact and economic interests. During the operation of ships entering the port, in order to maintain production and living needs, the main power source of the ship is provided by marine diesel generators. Due to the influence of factors such as poor quality of heavy oil on ships, serious pollution, and complex control mechanisms, traditional generators have Certain application limitations. Ship shore power technology uses shore power instead of ship auxiliary engines to p...

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Problems solved by technology

The difference between the reference value and the actual value is fed back to the virtual synchronous generator algorithm through the PI controller to form a closed loop, so as to realize the synchronization between the inverter and the grid frequency, voltage amplitude and phase, but the participation of the phase-locked loop not only takes time to Adjust the parameters of the phase-locked loop, and there is a problem of measurement data delay, so it is difficult to ensure accuracy and reliability in the environment of ship load switching

In addition, the existence of multiple phase-locked loops in the ship's virtual synchronous generator system will cause interlocking and reduce system stability, so it is difficult to apply to the grid-connected process of merchant ship distributed energy in the shore power connection environment; Wei Yalong of Xi'an University of Technology proposed the virtual power method to realize the pre-synchronization control of virtual synchronous generators, but because PID uses the idea of ​​"eliminating errors based on errors", there is a small oscillation in pre-grid-connection, which cannot meet the frequency requirements of ship sensitive loads, and the pre-connection The existence of synchronous enabling link in the synchronous control strategy will slow down the response speed of grid connection

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