Research On Inverter Dual-mode Control Of Solar Hybrid Ship

Photovoltaic power generation is one of the most widely used and mature technologies in new energy ships.Integrating photovoltaic power generation into the traditional ship power system powered by diesel generators can reduce fuel consumption and environmental pollution.However,the equivalent grid impedance of grid connected inverter access point often changes with the changes of line impedance,number of grid connected units,load and system operation mode,which reduces the stability of the system.At the same time,the ship’s navigation at sea is changeable,which requires a certain flexibility in the operation of photovoltaic inverter,which can operate stably under off/grid conditions and switch smoothly between working modes.In addition,considering the harm caused by the islanding effect of photovoltaic grid connected power generation system,it is necessary to deeply study the islanding detection strategy.Therefore,this paper studies the above problems,and the specific research contents are as follows:Firstly,based on the ship power system with solar energy,the ship power system model of photovoltaic inverter and diesel generator is constructed,and the independent and parallel simulation operation of photovoltaic inverter and diesel generator is carried out,which lays a foundation for subsequent research.Secondly,in view of the problem that the equivalent grid impedance of the grid connected inverter access point in the marine power system often changes with the changes of line impedance,number of grid connected units,load and system operation mode,in order to make the inverter operate stably within a wider range of grid impedance,A dual-mode control strategy based on grid impedance identification is constructed.Thirdly,considering the variable operating conditions of ship power system,in order to make the operation mode of photovoltaic inverter flexible,a seamless switching algorithm based on model predictive control is constructed to realize the stable operation of inverter in island and grid connected mode and smooth transition between the two modes.Fourthly,aiming at the disadvantages of traditional islanding detection strategies based on communication,passive and active,such as large investment,large detection blind area and reducing power quality,an islanding detection strategy based on adaptive neuro fuzzy reasoning is constructed to overcome the shortcomings of traditional detection strategies.