Research Of Energy Storage Control Strategy And Capacity Allocation Of Ship Electric Propulsion

With the continuous exploitation and use of petrochemical energy,the petrochemical energy will be exhausted in the future.Therefore,the internal combustion engine driven by petrochemical energy as fuel will exit from the stage of history and turn into an electric propulsion system driven by electric energy.Electric propulsion ships will have the advantages that traditional power ships do not have.The characteristics of electric propulsion ships,such as large driving force,large speed range,easy installation and maintenance,low noise and low environmental pollution,are widely applied in the world.Therefore,the research on the ship electric propulsion system will be of great value to the theoretical development and practical significance of the ship.During the operation of a ship,stopping and reversing,encountering heavy load pulse and power failure will cause undervoltage and overvoltage to the DC busbar,which will seriously damage the stable operation of the ship power system.Based on this,this paper designs a hybrid energy storage device to suppress the fluctuation of DC bus voltage and power,and improve the stability of the ship power system.In this paper,the main modules of ship electric propulsion system are modeled mathematically,including prime mover and its speed regulation module,generator module,propulsion motor module and propeller module.To establish the model of super capacitor hybrid energy storage lithium battery in the ship electric propulsion system basic,respectively for the two order RC model of lithium battery and super capacitor equivalent model is analyzed and built,the charge discharge curves and charge discharge curves of the simulation model and the actual storage element is verified.Secondly,the lithium battery and super capacitor hybrid energy storage is a kind of MMC-BDC control strategy design model,the control method of series voltage,the series group N half bridge circuit under the bridge,is controlled by the control strategy on the switch,the storage capacity and voltage balance element group.In order to prevent overcharge and overcharge of supercapacitors and lithium batteries and damage the life of energy storage components,we need to design charging and discharging rules and energy management strategies for energy storage systems.The control model of the energy storage element is established in Matlab/Simulink,and the effectiveness of the mean voltage control strategy is verified by simulation.Then,the particle swarm algorithm of chaotic hybrid energy storage capacity allocation and optimization,the constraints of energy storage system,determine the total amount of energy storage element to consider life relations as the objective function of lithium batteries and super capacitors in parallel and serial number group group number allocation optimization and simulation.Finally,the simulation study on the ship motion in the process of common conditions and fault analysis of propeller reverse,sudden impulse load,single-phase grounding short circuit fault and three-phase short circuit fault,and the simulation,analysis the influence of motor speed,stability of the DC bus voltage and the propulsion motor speed and torque.After adding the hybrid energy storage system,the function of the DC bus voltage,the generator and the propulsion motor after the energy storage system is added.