Research On Inverter Control Technology In Multi-Energy Ship Micro-Grid

To build light/diesel/storage multi-energy ship used AC micro-grid can effectively overcome the shortcomings of solar power generation to provide sufficient impetus for ships.Nevertheless,many working conditions in ship electric system and frequent switch overs of load caused the poor stability of ship network voltage and frequency,which indicate that,how to track the wide-range fluctuation of ship network voltage and frequency rapidly as well as accurately is the priority of applying inverter to ship electric system,and phaselock technique is the key to tracking.Aimed at the characteristic of poor voltage and frequency stability of ship electric system,this paper researched the highly stable as well as efficient inverter in light/diesel/storage multi-energy ship used AC micro-grid,including power circuit and control circuit;meanwhile,it emphatically researched self adaptive phaselock technique in wide-range frequency;the specific research contents are as follows:Firstly,specific to the characteristic of multi-energy ship micro-grid system,the inverter topological structure was selected,the design plan for outputting LCL filter parameter was rendered,and inverter full decoupling mathematical model was built up so as to realize full decoupling of ship used grid-connected inverter based on LCL filter under dq axis.Secondly,according to the characteristics of ship electric system such as larger load and strong coupling,combining with photovoltaic power technology used on land,the follow-up control strategy of inverter current was proposed to research the parallel power supply technology of inverter and synchronous generator in ship multi-energy power supply system.The methods of controlling strategy realization and parameter determination were obtained,based on theoretical derivation and mathematical modeling as well as simulation.The research results showed that,the parallel power supply system consisting of inverter controled by the follow-up control strategy and synchronous generator proposed in this paper carries that excellent performance of high stability,better dynamic characteristic,superior power supply quality and high electric generator utilization.Such new inverter control strategy provided new research thought for the application of new energy resources to ship hybrid power supply system,which has good application prospect in Multi-energy Ship Micro-grid.Thirdiy,large variation scope of voltage amplitude and frequency,high harmonic content and three-phase imbalance load cause many problems in multi-energy ship micro-grid,so the Double Second-order Generalized Integrator-Frequency and Phase Locked Loop(DSOGI-FPLL)applied to the ship was put forward by improving Double Second-order Generalized Integrator-Frequency Locked Loop(DSOGI-PLL)and Synchronous Reference Frame Phase Locked Loop(SRF-PLL),and gives theoretical analysis and simulation verification.At last,this paper applied the improved phase-locked loop DSOGI-FPLL to ship micro-grid inverter control strategy,the simulation result indicated that,the network voltage will fall when ships increase load.The improvement of phaselock technique can enable inverter output current to track ship network voltage phase fastly and realize stable operation of grid-connected system.