直流微电网分层分布式协同控制及稳定性研究

The dc microgrid has been a promising solution for interfacing the solar/wind renewable energy sources based distributed generation systems, energy storage systems, electric vehicles and other dc loads, with less energy conversion stages. So the system can operate with improved energy conversion efficiency, economy and reliability. Motivated by the development trend and the challenge of dc microgrid stable operation and control, research on the hierarchical distributed cooperative control and stability of dc microgrid will be carried on thoroughly in this project. Main works are as following:. 1) For the primary control layer, in order to suppress the transient impacts and fluctuations of dc bus voltage, improve the operation performance and stability margin of the dc bus voltage control system, a robust autonomous dc bus voltage method with the droop control, nonlinear disturbance observer and adaptive active damping method integrated application will be developed;. 2) In order to recover the dc bus voltage deviation and improve the load sharing performance, a plug-and-play based distributed cooperative control strategy will be proposed, which can avoid the centralized communication, control and a single failure fault on the secondary control layer;. 3) The stability analysis of the dc microgrid hierarchical distributed cooperative control considering time delays will be carried on deeply in this project, which can be very useful for optimization design of the communication architecture and the critical control parameters;. 4) Finally, a real-time digital simulator based digital-analog hybrid simulation experimental platform and an actual dynamic simulated system of dc microgrid will be built to verify the control method and theoretical results of this project. .Our research in this project will provide the theoretical and technical support for the development and the practical application of dc microgrid in the future.

直流微电网可更高效可靠地接纳风、光等分布式可再生能源发电系统、储能单元、电动汽车及其他直流用电负荷。本项目将针对直流微电网的发展趋势及稳定运行控制面临的挑战，拟深入开展直流微电网分层分布式协同控制及稳定性研究。首先研究直流微电网一次直流母线电压鲁棒自治控制方法，综合应用下垂控制、非线性干扰观测器和自适应有源阻尼方法以提高直流母线电压控制系统的自治运行性能及稳定裕度；其次，为避免集中通信和控制，提出即插即用型二次分布式协同控制方法，解决一次控制中存在的直流母线电压偏移及多源功率输出不合理分配等问题；然后，研究含时滞环节的直流微电网分层分布式协同控制系统稳定运行机理，为优化设计控制系统的通信架构及关键控制参数提供指导和理论依据；最后，构建直流微电网实时数模混合仿真平台和动态模拟实验系统，验证上述控制方法和理论成果。本项目研究成果将为直流微电网的发展和实际工程应用提供理论支撑与技术保障。

本项目研究主要围绕直流微电网稳定控制关键技术展开，取得了如下几方面的研究成果。1） 揭示了大功率扰动下直流微电网在主从控制和对等下垂控制两类控制模式下的直流母线电压波动快速平抑机理，提出了基于干扰观测器的功率扰动前馈控制方法，并成功应用于直流微电网主从控制和对等下垂控制策略中。2）建立了下垂控制直流微电网的小扰动稳定性分析模型，揭示了下垂控制直流微电网谐振失稳机理，提出了基于扰动前馈和低通滤波两种有源阻尼控制方法。3） 提出了基于一致性控制策略的直流微电网二次电压恢复及多源均流性能改善控制方法，解决了直流电压下垂控制所面临的电压变化、多源功率分配不合理等问题。4）提出了面向柔性互联装置的统一控制方法，首次实现了柔性互联装置在互联功率支撑、直流电压控制或交流电压/频率控制等多种控制模式上的统一，实现了多微电网间互联功率快速主动支撑和紧急工况下的多运行模式无缝切换，使得交直流微电网集群从物理层面和控制层面真正融合成为一个统一的整体。5）提出了多直流有源滤波器和多电压平衡器协调控制策略，有效解决了直流微电网内电压纹波及正、负极功率不平衡问题。6）研发了高频隔离双向DC-DC变流器、直流电压平衡器、交直流功率转换装置等关键设备，并构建了交直流微电网动态模拟实验系统。. 相关研究成果为实现交直流微电网及集群的安全稳定运行控制提供了重要的理论与方法支撑，具有重要的科学意义与应用价值。上述研究成果均在我们自己构建的交直流微电网实验系统进行了实验验证，部分成果已用于相关合作单位的微电网实验室或示范工程中。