液化天然气船舶动力系统加速性能优化策略研究

目的 针对船舶天然气发动机匹配定距桨直接推进加速速率慢动态性能差的缺陷,提出了一种系统级优化方案,设计并联型式气电混合动力系统,通过轴带电机辅助推进优化系统的加速性能。方法 建立船舶气电混合动力系统仿真模型,根据试验数据对LNG发动机的加速性能进行数据标定保证模型动态精度,以仿真手段分别验证混合动力系统使用变频器动态切换策略和变频器超前控制策略的加速优化效果。结果 综合考虑实际工程控制难度和加速过程优化效果,变频器动态切换策略优于变频器超前控制策略。结论 气电混合动力系统PTI模式使用变频器切换控制策略可达到较好的加速性能,在降低主机机械负荷和热力负荷的同时船舶快速性最大提升16%。PTO模式加速时轴带发电机负载转移至船舶辅机,稳定一段时间后切换至电动模式助推,加速性能可达到PTI模式加速水平。

Optimizing Strategies for Accelerating Performance of LNG Power System

Objective The target vessel power system uses LNG engine to match the fixed-pitch direct propulsion system. Aiming at the defects of slow system acceleration and poor dynamic performance, a system-level optimization scheme is proposed. Design a parallel type gas-electric hybrid power system, and optimize the acceleration performance of the system through the auxiliary propulsion of shaft motor. Methods Establish a simulation model of the gas-electric hybrid system, calibrate the acceleration performance of the LNG engine according to the test data to ensure the dynamic accuracy of the model, and verify the acceleration of the hybrid power system using the VDF dynamic switching strategy and the VDF advanced control strategy by simulation Optimize the effect. Results Taking into account the actual engineering control difficulty and the acceleration process optimization effect, the VDF dynamic switching strategy is superior to the VDF advanced control strategy. Conclusion The PTI mode of the gas-electric hybrid power system can achieve better acceleration performance by using the VDF switching control strategy, while reducing the mechanical load and thermal load of the main engine and increasing the vessel"s speed by up to 16%.