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This paper proposes a mixed-integer quadratic programming (MIQP) model for optimal day-ahead distribution networks dispatch considering Wind Generators (WGs) and topology reconfiguration. Firstly, linearized current injection model is introduced for generators by a series of approximations. Then the day-ahead Switching Operations (SOs) of reconfiguration could be calculated in a linear form based...
In this paper a new method is presented to achieve economic exploitation and proper usage of network capacity by exerting controlling actions over flexible loads and energy storage (ES) equipment. Multi-objective planning for demand response programs (DRP) and battery management policies is carried out by considering energy not supplied (ENS). In order to achieve an optimal scheduling, charge/discharge...
Microgrids have become an alternative to increase the controlability and resilience of the electrical system due to the local and efficient energy management they provide. Additionally, when the microgrid has a main DC bus it does not require synchronization hence the control scheme is simplified allowing to improve the dynamics of currents and voltages. These DC microgrids are usually controlled...
The paper proposes a hybrid droop control strategy to enhance the stability and increase maximum constant power loads (CPLs) capability of DC microgrids in a realistic scenario. By capturing the detailed model of inner control loops and hybrid droop control and general dc MG topology, a thorough comparative study is conducted between traditional droop control and hybrid droop control. Enhanced control...
The penetration of electric vehicles (EVs) has attracted growing research interests in its impact on both power and traffic networks. With the expansion of EVs' range as well as the development of fast charging technology and related infrastructure, large-scale EVs are involved in intercity transportation systems and power transmission systems. We propose a traffic-power integrated network model and...
Non-inverting Buck Boost converters (NIBB) have been utilized as interfacing converters for energy storage, due to the high steady-state efficiency offered by the asynchronous control. However, classical asynchronous control has inherent poor dynamic performance when the input and output voltages are near. To solve the problem, concept of “dynamic mode switching” is first proposed in this paper. Instead...
An energy management system of a microgrid (MG) has several basic objectives; e.g. to maximize the utilization of renewable energy resources (RES), to protect the internal components from overloading, and to ensure that the MG operates reliably under any operating conditions. Although many control techniques are available in the literature to monitor and control the energy flows among distributed...
Cascaded H-bridge converters based islanded microgrids are applied to integrate the distributed generators (DGs). The accurate load sharing is an important task for the research of microgrids. Due to the characteristics of series connection, all DGs share a single common current. In this paper, the power factor of each DG is assigned to be consistent via regulating both the frequency and voltage....
Designing a control system for an induction motor (IM) is a generally twofold task: (1) controller synthesis and, (2) assessment of its stability. When using the full fifth order dq-frame model, with incomplete state information and unknown disturbances, the controller design and the proof of stability are not trivial tasks. In this paper, we propose a speed controller for the IM using a reduced-order...
This paper proposed a modified MPP-Locus method. Compared to the other MPPT methods, the MPP-Locus method is relatively simple to implemented into the PV system. Furthermore, this method does not require the designer's knowledge on the PV characteristic or the FLC rules. However, the conventional MPP-Locus method generally has some drawbacks, such as additional circuits required and less tracking...
To manage the microgrid effectively, it is important to get the power information among multiple distributed generation (DG) units. However, when the droop control method is adopted, as the corresponding DG units cannot be simply modeled as VF or PQ buses, the conventional power flow algorithm may become inapplicable. To solve this issue, a time domain iteration (TDI) based power flow algorithm is...
In these years, the wind power integration capacity has increased a lot, and the issue of wind curtailment has become more serious for lack of adequate flexible energy sources. To find out whether the nuclear power plant (NPP) in the present power system can solve this issue, this paper proposes a joint operational optimization model that includes the NPP, wind power plant, thermal units and pumped-storage...
The hybrid power system consisting of new energy inverters and diesel generators has become a typical case of independent power systems in remote areas. Aiming at the problem of generator overload caused by sudden load applying in such systems, this paper proposes a novel emergency control strategy which increases the inverter output power according to the changing rate of system frequency. This control...
Microgrids rely on energy management levels to optimally schedule their components. Conventionally, the research in this field has been focused on the optimal formulation of the generation or the demand side management separately without considering real case scenarios and validated only by simulation. This paper presents the power scheduling of a real site microgrid under a price-based demand response...
In micro-grids, energy storage systems (ESSs) have provided a feasible option in mitigating load mismatch as well as facilitating integration of renewable distributed generations. However, due to the high construction cost of ESSs, proper mechanisms are needed for the optimization of their sizing. In this paper, owing to the temporal and spatial disparities of different types of loads, a mathematical...
This paper proposes a stochastic programming approach based on Conditional Value at Risk (CVaR) to measure the impact of prediction errors brought about by the renewable energy and load on DC-linked multi-microgrids coalition in the distribution network so that the system scheduling operator can achieve the lowest day-ahead scheduling cost at a certain risk. Due to the prediction errors of the renewable...
Electro-hydrostatic actuators (EHAs) are said to have potential as actuators for robotic systems because they have high power-to-weight ratio, compact, and energy saving systems compared to general hydraulic systems. However, modeling approaches and analyses on dynamic characteristics have not been quite concrete yet. In order to expand EHAs' potential to be used for robots, further studies of their...
The dual-driving feed system is widely used in highspeed/high-precision CNC machine tools due to its high rigidity. However, when the column moves along the beam, the load parameters of the dual-driving two axes will change, which results in non-synchronous error and affects the machining accuracy. For this problem, an adaptive synchronization tracking control (ASTC) strategy of dual-driving feed...
Uncertainties including matched and unmatched disturbances are the obstacles of developing advanced controllers for electro-hydraulic servo systems. This article presents a dual extended state observer (ESO) with full state to estimate the matched and unmatched disturbances and a robust controller to compensate them. Firstly, the nonlinear mathematical model of the considered single-rod hydraulic...
Rampant power theft at the low voltage consumer end is a growing concern for the power distribution companies. This paper proposes an effective method for detection of power theft at low voltage consumer end. The proposed method is designed to reliably detect hooking in service line cable and bypassing of electric energy meter. In this method, a low magnitude, high-frequency, non-interfering signal...
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