Design And Control Of Virtual Synchronous Generators In New Energy Ship

The global energy crisis and environmental pollution are becoming more and more serious,and green environment protection will become the main direction for the future development of ships.New energy technology is developing rapidly and is widely used in ships,improving the diversity of power supply methods in the ship’s power system.However,as new energy generation has almost no inertia,the inertia of the whole ship power system will be greatly reduced when it is integrated into the ship power system,resulting in the weakened ability of the ship power grid to resist external interference or load fluctuations.In this paper,virtual synchronous generator(VSG)is introduced,technology based on the new energy generation system in the ship power system,study and improve its structure and parameters with the characteristics of the ship,and propose the adaptive control strategy of VSG parameters suitable for the ship power grid to improve the stability of the ship operation.Firstly,according to the components of the ship power system and their actual working mechanism,the mathematical model of the ship power system,including the power generation module and propulsion module,is constructed using the modular modelling idea,and the working principle of the photovoltaic power generation and hybrid energy storage system is studied to determine the mathematical model of the hybrid optical storage system applicable to the ship power system.Based on the operating topology of the power system containing optical storage,the individual models are encapsulated and coupled,so as to realise the construction of the ship power system simulation model.Secondly,the grid-connected inverter is taken as the object of study.According to the mathematical model of the grid-connected inverter,the parameters of the dual closed-loop control of the outer-loop voltage and inner-loop current are designed under the αβ coordinate system,and the working principles of the active-frequency control link and the reactive-voltage control link in the VSG are given on the basis of the analysis of the synchronous generator,and the VSG control output voltage is taken as the input value of the dual closed-loop voltage and current control,which together constitute the grid-connected inverter control strategy.The dynamic phase control model of the VSG is established,and the power decoupling of the activereactive coupling in the VSG control is carried out by using the method of series diagonal matrix compensation matrix,using the root trajectory method to analyse and determine the influence of inertia and damping parameters in the VSG on the transient and steady state of the ship’s power system,and verifying the parameter design through simulation.The correctness of the parameter design is verified by simulation.Finally,the variation characteristics of the power angle of the ship’s power system during oscillations are analysed,and the adaptive relationships between the rotational inertia and damping coefficients and frequency are constructed to suit the operating characteristics of the ship’s power system,so as to improve the stability of the system under various operating conditions of the ship and reduce the oscillation amplitude and dynamic response time when the system is subject to disturbances.The optimal values of the control parameters in the VSG are selected using chaotic particle swarm algorithms,and the advantages of the control strategy in optimising the stability of the ship power system are demonstrated using simulation experiments.