Study Of The Hybrid Electric Power System On Container Crane

Rail-mounted Container Gantry Crane(RMG),is mainly used for container loading and unloading,handling and stacking operstion in large container rail transport and storage fields at home and abroad.Conventional container crane uses single diesel generator as the power source.This structure of power system has a large dieselgenerator and can-not absorb the energy generated in the process of container dropping,and has problems of low rate of energy utilization,large fuel consumption,and serious environmental pollution.To deal with these problems,in orderto meet the needs of container crane's power demand,the new system use supercapacitor and lithium iron phosphate to build hybrid electric power and access it to the DC bus.The newhybrid power system is combined with the hybrid electric power and the diesel generator sets.It can absorb feedback energy in the container dropping process and release energy when there is need.Thereby to achieve the purposes of improving energy efficiency and energy-saving.Firstly,through the establishment of a dual DC/DC structure of composite power and a modified two-channel DC/DC converter,the new system combines supercapacitor's majoritypower characteristics and lithium iron phosphate's majority energy characteristics,make the hybrid electric power having the performance of high-power and high-energy.By using supercapacitorto protectethe batteryin the purpose to prolong its service life and improve the overall performance.Then,based on the working characteristicsof the crane,the system set up different working modes of hybrid electric power and propose an improved power control strategy with power conditioning and handle signal.It solves the accumulator's malfunction caused by DC bus voltage fluctuation and system's real-time response problems.Then,in the optimization of energy control,fuzzy control strategy is used to work out energy distributionbetweenthe battery and supercapacitor in the composite drive mode.Through diesel generator's chargingand energy exchanging between the super capacitor and battery,thehybrid electric power maintained at the optimum charging and discharging state,ensuring efficiency and stability of the system.In coordination of the diesel generator and hybrid electric power,the diesel generator develops a "thermostat modewith power follow mode" control strategy.Adjusting the generator's output based on the state of the hybrid electric power and the need of system,make it work in the best workspace to save energy.Finally,this paper constructs a hybrid simulation model of the container crane and analyzes container's liftingand dropping,trolley's translation operation.By analyzing the simulation results,we come to the conclusion that the hybrid electric power is able to absorb feedback energy and the bus voltage is stable during theworking process.Lithium battery has less charge and discharge times and gets adequate protection.System has high energy efficiency.