Due to the advantages of multiple power supply points and multiple power receiving points, the multi-terminal direct current (MTDC) technology has gradually become the main trend in the future development of DC power grids. The coordinated control of a MTDC system is one of the key technologies to realize the stable operation of power systems. Droop control is an effective coordinated control method to maintain the power and voltage balance of a DC transmission system. However, improper selection of the droop coefficient leads to an imbalance of the power and voltage distribution. An improved coordinated control strategy based on an adaptive droop coefficient is proposed to realize a faster dynamic response and a more reasonable power distribution, which is applicable to all of the topologies of MTDC systems. The power and voltage deviation controls are added to prevent the output power and voltage from exceeding the range that a converter can bear. In addition, a lagging link is added in the current loop to compensate for the delay caused by the current loop and to improve the response speed of the system. Taking the MMC topology as an example, the dynamic characteristics of the proposed control strategy are analyzed, and a four-terminal MTDC simulation model based on the MATLAB/Simulink simulation platform has been established to verify the superiority of the proposed strategy under different disturbances.

由于多个供电点和多个受电点的优势，多端子直流电（MTDC）技术已逐渐成为直流电网未来发展的主要趋势。MTDC系统的协调控制是实现电力系统稳定运行的关键技术之一。下垂控制是一种有效的协调控制方法，可保持直流输电系统的功率和电压平衡。但是，下垂系数的选择不当会导致功率和电压分布的不平衡。提出了一种基于自适应下垂系数的改进协调控制策略，以实现更快的动态响应和更合理的功率分配，适用于MTDC系统的所有拓扑。添加了功率和电压偏差控件，以防止输出功率和电压超出转换器可以承受的范围。另外，在电流环路中添加了滞后链路，以补偿由电流环路引起的延迟并提高系统的响应速度。以MMC拓扑为例，分析了该控制策略的动态特性，建立了基于MATLAB / Simulink仿真平台的四端MTDC仿真模型，验证了该策略在不同干扰下的优越性。在电流环路中增加了一个滞后链路，以补偿由电流环路引起的延迟并提高系统的响应速度。以MMC拓扑为例，分析了该控制策略的动态特性，建立了基于MATLAB / Simulink仿真平台的四端MTDC仿真模型，验证了该策略在不同干扰下的优越性。在电流环路中增加了一个滞后链路，以补偿由电流环路引起的延迟并提高系统的响应速度。以MMC拓扑为例，分析了该控制策略的动态特性，建立了基于MATLAB / Simulink仿真平台的四端MTDC仿真模型，验证了该策略在不同干扰下的优越性。