基于虚拟直流电机控制的船舶高频高峰值脉冲负载冲击平抑控制策略研究

Study on Virtual DC Generator-Based Ship High-Frequency and High-Peak Power Pulsed Loads Impact Damping Control Strategy

高频高峰值脉冲负载对具有弱惯量特性的船舶电力系统呈现较大的功率冲击影响,严重时会造成船舶发电机组振荡停机。针对这一问题,该文首先建立典型脉冲负载的数学模型,研究脉冲负载功率特性及其对船舶电力系统冲击机理。根据研究结果,提出采用超级电容冲击平抑装置平抑脉冲功率。其次,通过分析虚拟直流电机(VDG)运行机理,确定通过VDG控制提升双向DC-DC变换器惯量的可行性。基于以上研究,推导双向DC-DC变换器的小信号模型及系统传递函数,分析虚拟转动惯量及虚拟阻尼对平抑装置稳定性的影响。然后,提出一种适用于脉冲负载稳态运行和暂态突变的平抑装置控制策略。最后,基于RT Box 3半实物仿真平台,搭建了具有平抑装置的船舶电力系统模型,验证了所提控制策略的有效性。

Various pulsed loads are widely used in modern ship power systems.Herein,radar pulsed loads have high-frequency and high-amplitude power characteristics.The loading-unloading and frequent-state switching cause severe impacts on the ship power system with weak inertia and even cause the diesel generator set to oscillate and stop.However,more research is still needed on the impacts of high-frequency and high-peak pulsed loads on the stability of ship power systems and the disturbance mechanism.Furthermore,the problems of traditional passive suppression strategies,such as ship space waste,short service life,and lack of pulsed load multi-mode suppression capability,should be solved urgently.This paper designs a multi-mode pulsed disturbance suppression strategy based on virtual dc motor control(VDG)by analyzing the disturbance mechanism of high-frequency and high-peak pulse loads on ship power systems.Firstly,this paper establishes a mathematical model of typical pulsed loads.The power characteristics and their impacts of pulsed loads on ship power system stability and impact mechanism are analyzed.A supercapacitor shock suppression device is suggested to suppress pulse power.The feasibility of this suppression strategy is derived,and the structure and related parameters of the suppression device are designed.Secondly,by analyzing the operation mechanism of the virtual DC motor,the feasibility of improving the inertia of the bidirectional DC-DC converter by VDG control is determined.The small signal model and system transfer function of the bidirectional DC-DC converter are derived,and the effects of virtual rotational inertia and virtual damping on the stability of the suppression device are analyzed.Then,a suppression device control strategy suitable for steady-state operation and transient sudden changes of pulsed loads is proposed.Finally,based on the RT Box 3 semi-physical simulation platform,a ship power system model with a suppression device is built to verify the proposed control strategy.The simulation results show that:(1)the high-frequency and high-amplitude pulsed load is manifested as a high-amplitude long-term pulsating power on the generator side.Its loading,switching,unloading,and steady-state operation cause different degrees of power impacts on the ship power system,and its sudden addition and subtraction of load have the greatest impact on the ship power system.(2)Compared with the energy storage system with the traditional DC-DC converter,the supercapacitor shock suppression device based on VDG control has flexible and adjustable virtual rotational inertia and output power.Therefore,the energy storage system enhances the ship power system's ability to resist impact disturbances.(3)The proposed suppression strategy has a good suppression effect when the pulsed loads run in the full range of operating conditions.Especially in the case of sudden addition and unloading of pulsed loads,it can prolong the steady-state time of the generator.As a result,its power can be slowly increased to the rated value,and its speed and line voltage amplitude fluctuations are significantly reduced.