It is well-recognized that a transfer system response delay that reduces the test stability inevitably exists in real-time dynamic hybrid testing （RTDHT）. This paper focuses on the delay-dependent stability and adde...It is well-recognized that a transfer system response delay that reduces the test stability inevitably exists in real-time dynamic hybrid testing （RTDHT）. This paper focuses on the delay-dependent stability and added damping of SDOF systems in RTDHT. The exponential delay term is transferred into a rational fraction by the Pad6 approximation, and the delay-dependent stability conditions and instability mechanism of SDOF RTDHT systems are investigated by the root locus technique. First, the stability conditions are discussed separately for the cases of stiffness, mass, and damping experimental substructure. The use of root locus plots shows that the added damping effect and instability mechanism for mass are different from those for stiffness. For the stiffness experimental substructure case, the instability results from the inherent mode because of an obvious negative damping effect of the delay. For the mass case, the delay introduces an equivalent positive damping into the inherent mode, and instability occurs at an added high frequency mode. Then, the compound stability condition is investigated for a general case and the results show that the mass ratio may have both upper and lower limits to remain stable. Finally, a high-emulational virtual shaking table model is built to validate the stability conclusions.展开更多
针对具有固定转动惯量的常规光伏储能虚拟同步发电机并网发电系统容易出现功率振荡以及频率超调等问题,提出光储并网系统的虚拟同步发电机(virtual synchronous generator,VSG)自适应控制策略。首先,搭建虚拟同步发电机控制的光伏储能...针对具有固定转动惯量的常规光伏储能虚拟同步发电机并网发电系统容易出现功率振荡以及频率超调等问题,提出光储并网系统的虚拟同步发电机(virtual synchronous generator,VSG)自适应控制策略。首先,搭建虚拟同步发电机控制的光伏储能并网发电系统模型,系统前级采用光伏最大功率点跟踪(maximum power point tracking,MTTP)控制以及储能控制策略;然后,根据功角特性和转子角频率特性曲线分析转动惯量对VSG动态特性的影响,将RBF神经网络应用到VSG中,对转动惯量进行自适应调整,同时,在固定阻尼比的基础上,随着转动惯量的变化自适应调整阻尼系数;在MATLAB/SIMULINK上建立光储并网系统的VSG自适应控制仿真模型,验证此控制策略的可行性;最后,将自适应转动惯量阻尼控制策略与其他控制策略进行对比,仿真结果表明:采用此控制策略能够使光储并网系统的有功功率振荡得到抑制,改善转子角频率超调。展开更多
The development of regional integrated electric-thermal energy systems(RIETES) is considered a promising direction for modern energy supply systems. These systems provide a significant potential to enhance the compreh...The development of regional integrated electric-thermal energy systems(RIETES) is considered a promising direction for modern energy supply systems. These systems provide a significant potential to enhance the comprehensive utilization and efficient management of energy resources. Therein, the real-time power balance between supply and demand has emerged as one pressing concern for system stability operation. However, current methods focus more on minute-level and hour-level power optimal scheduling methods applied in RIETES. To achieve real-time power balance, this paper proposes one virtual asynchronous machine(VAM) control using heat with large inertia and electricity with fast response speed. First, the coupling timescale model is developed that considers the dynamic response time scales of both electric and thermal energy systems. Second, a real-time power balance strategy based on VAM control can be adopted to the load power variation and enhance the dynamic frequency response. Then, an adaptive inertia control method based on temperature variation is proposed, and the unified expression is further established. In addition, the small-signal stability of the proposed control strategy is validated. Finally, the effectiveness of this control strategy is confirmed through MATLAB/Simulink and HIL(Hardware-in-the-Loop) experiments.展开更多
基金State Key Laboratory of Hydroscience and Engineering Under Grant No.2008-TC-2National Natural Science Foundation of China Under Grant No.90510018,50779021 and 90715041
文摘It is well-recognized that a transfer system response delay that reduces the test stability inevitably exists in real-time dynamic hybrid testing （RTDHT）. This paper focuses on the delay-dependent stability and added damping of SDOF systems in RTDHT. The exponential delay term is transferred into a rational fraction by the Pad6 approximation, and the delay-dependent stability conditions and instability mechanism of SDOF RTDHT systems are investigated by the root locus technique. First, the stability conditions are discussed separately for the cases of stiffness, mass, and damping experimental substructure. The use of root locus plots shows that the added damping effect and instability mechanism for mass are different from those for stiffness. For the stiffness experimental substructure case, the instability results from the inherent mode because of an obvious negative damping effect of the delay. For the mass case, the delay introduces an equivalent positive damping into the inherent mode, and instability occurs at an added high frequency mode. Then, the compound stability condition is investigated for a general case and the results show that the mass ratio may have both upper and lower limits to remain stable. Finally, a high-emulational virtual shaking table model is built to validate the stability conclusions.
文摘针对具有固定转动惯量的常规光伏储能虚拟同步发电机并网发电系统容易出现功率振荡以及频率超调等问题,提出光储并网系统的虚拟同步发电机(virtual synchronous generator,VSG)自适应控制策略。首先,搭建虚拟同步发电机控制的光伏储能并网发电系统模型,系统前级采用光伏最大功率点跟踪(maximum power point tracking,MTTP)控制以及储能控制策略;然后,根据功角特性和转子角频率特性曲线分析转动惯量对VSG动态特性的影响,将RBF神经网络应用到VSG中,对转动惯量进行自适应调整,同时,在固定阻尼比的基础上,随着转动惯量的变化自适应调整阻尼系数;在MATLAB/SIMULINK上建立光储并网系统的VSG自适应控制仿真模型,验证此控制策略的可行性;最后,将自适应转动惯量阻尼控制策略与其他控制策略进行对比,仿真结果表明:采用此控制策略能够使光储并网系统的有功功率振荡得到抑制,改善转子角频率超调。
基金supported by the National Key R&D Program of China (Grant No. 2022YFB3304001)the Major Program of the National Natural Science Foundation of China (Grant No. 52293413)。
文摘The development of regional integrated electric-thermal energy systems(RIETES) is considered a promising direction for modern energy supply systems. These systems provide a significant potential to enhance the comprehensive utilization and efficient management of energy resources. Therein, the real-time power balance between supply and demand has emerged as one pressing concern for system stability operation. However, current methods focus more on minute-level and hour-level power optimal scheduling methods applied in RIETES. To achieve real-time power balance, this paper proposes one virtual asynchronous machine(VAM) control using heat with large inertia and electricity with fast response speed. First, the coupling timescale model is developed that considers the dynamic response time scales of both electric and thermal energy systems. Second, a real-time power balance strategy based on VAM control can be adopted to the load power variation and enhance the dynamic frequency response. Then, an adaptive inertia control method based on temperature variation is proposed, and the unified expression is further established. In addition, the small-signal stability of the proposed control strategy is validated. Finally, the effectiveness of this control strategy is confirmed through MATLAB/Simulink and HIL(Hardware-in-the-Loop) experiments.
文摘传统虚拟同步发电机(virtual synchronous generator,VSG)的动态响应过程存在超调量与调节时间相矛盾的情况,且虚拟同步发电机控制参数选取时往往将储能侧视为理想电源,导致系统参数与储能系统的特性不相匹配。针对这种情况,结合模糊理论提出一种考虑储能系统约束的虚拟同步发电机参数协调模糊自适应控制方法,分析不同阻尼状态下虚拟同步发电机系统的动态响应,将储能系统的荷电状态(state of charge,SOC)和运行功率约束转化为转动惯量约束范围,通过模糊控制器自适应控制惯量变化,并根据合适的阻尼比协调调节虚拟阻尼,使得系统动态响应过程中系统阻尼比合理变化,从而改善传统虚拟同步发电机系统超调量与调节时间相矛盾的情况,使系统参数与储能系统特性相匹配。Matlab/Simulink仿真结果验证了所提控制策略的可行性与有效性。
