This paper deals with transient stability in interconnected micro-grids. The main contribution involves i) robust classification of transient dynamics for different intervals of the micro-grid parameters (synchronizat...
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Two typical load shaping stabilization methods, stabilization via amplitude compensation (SAC) and stabilization via phase compensation (SPC), are firstly analysed and compared in this paper. It is shown that, though ...
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ISBN:
(纸本)9781467386180
Two typical load shaping stabilization methods, stabilization via amplitude compensation (SAC) and stabilization via phase compensation (SPC), are firstly analysed and compared in this paper. It is shown that, though both SAC and SPC can stabilize the cascaded system, the system utilizing the SAC is unconditionally stable but conditionally stable when utilizing the SPC. Therefore, the cascaded system with SAC is more stable than that with SPC. In addition, considering the SAC can be realized by both the parallel-virtual-impedance (PVI) and series-virtual-impedance (SVI) control strategies, the PVI / SVI control strategies are also compared in this paper. The results shows that, the PVI control strategy has inevitable limitation when realizing the SAC during the whole load and input voltage range of the load converter, however the SVI control strategy does not have limitation. Therefore, compared to the PVI control strategy, the SVI control strategy is more suitable for the SAC. Moreover, in order to stably connect the load converter to different source converters without changing its internal structure, an adaptive SVI control strategy has been further proposed in this paper. Finally, the adaptive SVI strategy has been experimentally verified on an actual 100 W cascaded system.
For cascaded system, interactions among individually designed power subsystems may cause the instability of the whole system. It has been shown recently that the series-virtual-impedance (SVI) control strategy can sta...
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ISBN:
(纸本)9781509007387
For cascaded system, interactions among individually designed power subsystems may cause the instability of the whole system. It has been shown recently that the series-virtual-impedance (SVI) control strategy can stabilize the cascaded system via shaping the load input impedance in a very small frequency to minimize its impact on the original load converter. In this paper, a further investigation of the SVI control strategy is carried out by two-port network analysis. Firstly, it is pointed out that, though the impact of the SVI control strategy is limited in a very small frequency, it still deteriorates the performance of the original load converter. In order to overcome this drawback, this paper proposes source-side series-virtual-impedance (SSVI) control strategy, which move the series-virtual-impedance of the traditional SVI control strategy from load side to source side by changing the control of the source converter instead of the load converter. With the proposed SSVI control strategy, the cascaded system not only can solve its instability problem, but also can improve the performance of its source converter. Finally, a 100W 48V-32V-24V experimental system is fabricated to validate the SSVI control strategy.
In this paper, a cascaded control scheme for single-phase inverters connected to a load is proposed to improve the power quality and shape the output impedance. The proposed strategy consists of a proportional control...
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ISBN:
(纸本)9781467386180
In this paper, a cascaded control scheme for single-phase inverters connected to a load is proposed to improve the power quality and shape the output impedance. The proposed strategy consists of a proportional controller in the inner loop and the Uncertainty and Disturbance Estimator (UDE) in the outer loop. An advanced modulation method is adopted to minimize the control implementation delay and both the current and the voltage control loops are analytically investigated. Simulation and experimental results are presented to validate the theory.
Due to problems caused by variable switching frequency a modulated model based predictive control was proposed for different topologies and their applications. However, for cascade H-bridge multilevel converters, ther...
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ISBN:
(纸本)9781509053278
Due to problems caused by variable switching frequency a modulated model based predictive control was proposed for different topologies and their applications. However, for cascade H-bridge multilevel converters, there is another problem, the imbalance in the dc-link voltages. This paper proposes extend the modulated model based predictive control to a cascade H-bridge 7-level STATCOM, further including a switcher of redundant states to solve the imbalance voltage issue. Simulation results show improvements in terms of mean squared error, total harmonic distortion and balance voltages in the dc-links.
A fundamental challenge in multiagent systems is to design local control algorithms to ensure a desirable collective behaviour. The information available to the agents, gathered either through communication or sensing...
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A fundamental challenge in multiagent systems is to design local control algorithms to ensure a desirable collective behaviour. The information available to the agents, gathered either through communication or sensing, defines the structure of the admissible control laws and naturally restricts the achievable performance. Hence, it is fundamental to identify what piece of information can be used to produce a significant performance enhancement. This paper studies, within a class of resource allocation problems, the case when such information is uncertain or inaccessible and pinpoints a fundamental risk-reward tradeoff faced by the system designer.
In the paper, a six phase interleaved noninverting buck-boost converter is presented and compared with a single phase one. The results are presented in simulation and experimental environment. Each leg of the converte...
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ISBN:
(纸本)9781538617519
In the paper, a six phase interleaved noninverting buck-boost converter is presented and compared with a single phase one. The results are presented in simulation and experimental environment. Each leg of the converter is operating in parallel. The topology of multiphase buck-boost converter is suitable for many applications where high power with low interference is needed. Both single phase and multiphase converters are controlled with an ARM (Advanced RISC Machine) microcontroller in an experimental environment. Same electrical components are used for achieving valid results. From simulation and experimental results, it is possible to see that the multiphase converter is more suitable where lower current ripple with relatively cheap components is required.
The prediction method based on the partition of weather types has been widely used in photovoltaic prediction. Here, the temporal characteristics of PV data is studied, the physical meaning of the sequential differenc...
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The prediction method based on the partition of weather types has been widely used in photovoltaic prediction. Here, the temporal characteristics of PV data is studied, the physical meaning of the sequential difference sequences is analysed, and a characteristic index system including sequential characteristics index is proposed. The weather types are partitioned based on self-organising map neural network algorithm. Case study shows that the partition method is helpful to improve the discrimination of weather types and to improve prediction accuracy.
We propose a novel approach to input design for identification of nonlinear state space models. The optimal input sequence is obtained by maximizing a scalar cost function of the Fisher information matrix. Since the F...
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