The Research Of Inverter Switching Based On The Microgird Of Multi-energy Ship

With the development of the power electronics technology,the energy storage devices,the technology of solar power,new energy ships were being applied more and more widely in the ship building industry.Due to the intermittent nature of solar power and the restrictions of ship space,it was not enough to only rely on new energy for the ship.Thus,the multi-energy ship composed of diesel generator and new energy will become the future direction of the development of the new energy ship.However,taking into account the complex working conditions in the process of the ship,the power supply mode of the ship micro-grid became diversified,such as only new energy supply,the new energy and diesel generator in parallel supply,etc.How to make the power AC stable output converted by new energy power unstable DC,and make the switching reliably in different power supply mode,the new inverter technology were required.It was also one of the key issues must be solved for the micro-grid technology applying on ships.Therefore,for the system of ship micro-grid with multi-energy,aiming at the problem of reliable switching in different modes of power supply and based on the analysis of the shortcomings of traditional switching technology,the research on switching technology of the inverter about the micro-grid of multi-energy ship was carried out to improve the dynamic performance and safety performance of inverter switching technology and to ensure that the system of the ship micro-grid operate reliably under the different conditions.The main tasks and responsibilities are followed.1.Domestic and foreign research data on inverter of multi-energy ship was collected.The topology of the inverter,the filter and the related modulation technology were analyzed.On this basis,the mathematical model of the inverter of the multi-energy ship was established and its simulation model of modulation technology was built.2.The droop control technology of the inverter was analyzed and its parameters were designed.Aiming at the proposed system of the ship micro-grid,based on the analysis of inverter droop control principle and related research results,the current loop,voltage loop and power loop of droop control were designed.The simulation model was established and the rationality of the design parameters of the droop control were analyzed and verified.3.Combined with the characteristics of ship micro-grid system,based on the structure andthe control strategy of existing dual-mode static switching technology,the reasons that it could not switch smoothly were analyzed and the requirements and standards of the corresponding smooth switching were put forward.Then the simulation model was built to show that the dynamic performance and safety performance of the micro-grid of the multi-energy ship could not be met by the existing dual-mode static switching technology.4.Based on the above analysis,the virtual switching technology based on improved droop control was proposed,through improving the power loop of the droop control by introducing a self-saturated PI controller.The proposed virtual switching technology and the system of the ship micro-grid were established.The feasibility of the virtual switching and the automatic change of ship micro-grid in different power supply modes were verified.