船舶岸电变流器用构网型电流矢量控制

Grid-Forming Vector Current Control of Ship Shore Converter

船舶岸电变流器作为靠港船舶新的供电电源,可极大地降低船舶靠港时船用同步发电机重质柴油燃烧所带来的NOx、SOx和柴油颗粒等污染物。为保证船舶供电的连续性,岸电侧与船电侧电源多采用预同步方式完成不断电切换,然而可能会因两侧电压非理想的相位差而诱发电流冲击,进而导致岸电与船电电源切换失败。因此,该文首先提出船舶岸电变流器用构网型电流矢量控制策略,其实施于锁相环确定的船电两相同步旋转坐标系中,可在无预同步的前提下完成岸电变流器无冲击自整步并入船电系统,同时通过幅频电压-矢量电流级联闭环完成对船舶岸电变流器输出电压幅值和频率的有效调控。然后,建立构网型电流矢量控制数学模型,并基于此分析控制带宽对控制系统相位稳定裕度、电压跟踪能力以及对负载电流的抗扰能力。最后,通过Satrsim MT 8020硬件在环测试,验证了所提构网型电流矢量控制策略的有效性。

As the available power supply for ships in seaports,the shore converter can replace the synchronous generator with heavy diesel,resulting in less NOx,SOx,and other pollutants.The pre-synchronization method is employed for the continuous power supply between the ship generator and the shore converter.However,due to the inrush connecting current produced by the undesired phase angle difference,the shore source fails to replace the ship source.This paper develops the grid-forming vector current control for the shore converter.The proposed control strategy is implemented in the synchronous reference frame of the ship power system determined by the phase-locked loop.The commanded current reference of the shore converter is produced by the voltage amplitude-frequency control loop,and the modulated converter voltage is obtained by the current control loop.With the pulse-width modulation,the seamless self-synchronization between the ship and the shore is achieved with the parallel connection and the voltage forming.On the one hand,the phase-locked loop is employed instead of the active power-frequency synchronization loop,which can generate the phase angle for the frame transformation and voltage modulation without power provision.The pre-synchronization for the quasi-synchronization with the voltage modulation and the parallel connection is avoided.On the other hand,the commanded current reference is generated from the measured voltage amplitude and frequency of the ship power system.This approach can provide the desired active and reactive power to maintain non-steady errors of the voltage amplitude and frequency during the load transfer and islanded supply.Consequently,the grid-forming capability of the ship power system is achieved.Then,a mathematical model of the grid-forming vector current control is established.Accordingly,the system stability,voltage tracking capability,and sensitivity against load variations are analyzed.With the larger equivalent bandwidth coefficient of the grid-forming vector current control,higher voltage tracking capability and minor sensitivity against load variations are achieved while maintaining a sufficient stability margin.Finally,hardware-in-loop tests are conducted in conditions of the shore-ship connection,shipload transfer,islanded power supply capability with load variations,and voltage amplitude and frequency regulation of the grid-forming vector current control.The proposed grid-forming vector current control achieves a seamless connection between the ship power system and the shore converter without pre-synchronization while maintaining the voltage amplitude and frequency stability of the ship power system.