Capability Of Flow Control Research Articles

Flow-control capability of electronic-substrate-sized power supply for a plasma actuator

Plasma actuators, which are very thin, light and flexible, are attractive fluid control devices; however, they require high voltage power supplies for driving. Installation of a high-voltage generation system on vehicles, such as cars and airplanes, which are separated from the fixed ground coordinate, is a big problem. In this study, a small and light electronic-substrate-sized high-voltage power supply was introduced for mounting a plasma actuator system on a small vehicle like a UAV. This small power supply generates high voltage by an LC series transient resonance circuit and a transformer and can output at least 7.3 kVpp with a base frequency of 6000 Hz for a plasma actuator with a discharge length of 1000 mm. This study investigated the capability of flow control of the present small power supply by focusing on the output voltage waveform, induced flow velocity in static gas, and separation control around the airfoil model, Also the small power supply is compared with a conventional large power supply which has been used in typical laboratory-scale experiments. The results indicate that the substrate-sized power supply is powerful enough for flow control around a small UAV.

Power Flow Control in Multi-Terminal HVDC Grids Using a Serial-Parallel DC Power Flow Controller

Multi-terminal HVDC (MT-HVDC) grids have no capability of power flow control in a self-sufficient manner. To address this important issue, utilization of dc–dc high power and high-voltage converters is motivated. However, proposing suitable partial-rated dc–dc converters as well as their suitable modeling and control in both primary and secondary control layers as well as the stability analysis are the existing challenges that should be alleviated beforehand. This paper addresses the control of power flow problem through the application of a power converter with a different connection configuration, namely, serial parallel dc power flow controller (SPDC-PFC). The SPDC-PFC input is the transmission line voltage, and its output is transmission line current. Therefore, employing a full-power dc–dc converter is avoided as a merit. Additionally, in this paper, the common two-layer MT-HVDC grid control framework comprised of primary and secondary layers is efficiently modified in order to integrate the SPDC-PFC. A differential direct voltage versus active power droop control scheme is applied to the SPDC-PFC at the local control layer, guaranteeing dynamic stability, while an extended dc power-flow routine—integrating the SPDC-PFC—is developed at the secondary control layer to ensure the static stability of the entire MT-HVDC grid. The proposed control framework enables the SPDC-PFC to regulate the flow of current/power in the envisioned HVDC transmission line. From the static and dynamic simulation results conducted on the test CIGRE B4 MT-HVDC grid, successful operation of the proposed SPDC-PFC and control solutions are demonstrated by considering power flow control action. In more detail, the SPDC-PFC successfully regulates the compensated lines’ power to the desired reference both in static and dynamic simulations by introducing suitable compensation voltages. In addition, good dynamic performance under both SPDC-PFC power reference and wind power-infeed change is observed.

Iterative Learning Active Flow Control Applied to a Compressor Stator Cascade With Periodic Disturbances

This paper presents the capability of iterative learning active flow control to decrease the impact of periodic disturbances in an experimental compressor stator cascade with sidewall actuation. The periodic disturbances of the individual passage flows are generated by a damper flap device that is located downstream of the trailing edges of the blades. The device mimics the throttling effect of periodically closed combustion tubes in a pulsed detonation engine (PDE). For the purpose of rejecting this disturbance, the passage flow is manipulated by fluidic actuators that introduce an adjustable amount of pressurized air through slots in the sidewalls of the cascade. Pressure sensors that are mounted flush to the suction surface of the middle blade provide information on the current flow situation. These data are fed back in real-time to an optimization-based iterative learning controller (ILC). By learning from period to period, the controller modifies the actuation amplitude such that, eventually, a control command trajectory is calculated that reduces the impact of the periodic disturbance on the flow in an optimal manner.

Unified Power Flow Controller (UPFC) Integrated with Electromagnetic Energy Storage System for System Stability Enhancement

In this paper analysis the UPFC integrated with energy storage devices for improvement of system stability compensation. Before that, used traditional UPFC is to control all transmission line parameters simultaneously or selectively but don’t have appropriate control for throughout system. During large transients; traditional UPFC have restricted capability of power flow control. In this paper to do reduce or eliminate that negative aspect of established UPFC using substantial energy storage devices adapted with UPFC. In this proposed system Integration of Superconducting Magnetic Energy Storage (SMES) into UPFC is described. SMES is connected to UPFC through an interface with DC-DC chopper. UPFC with SMES system will inject or absorb real and reactive power to or from an influence system at really quick rate on a repetitive beginning of stability problem. Here Comparative Analysis of the two types, one is integration of electromagnetic energy storage into UPFC and another is integration of electrochemical energy storage into UPFC is done by means of MATLAB/SIMULINK software package.

Comparison of Sen Transformer and UPFC for congestion management in hybrid electricity markets

Congestion management (CM) is one of the most important and challenging tasks of the Independent System Operator (ISO) in the deregulated environment. Recently, Sen Transformer (ST) has emerged as an important power flow control device which has the capability of power flow control over a wide range like UPFC. This device with a conventional transformer and tap changers has the capability of bidirectional control of active and reactive power and can play a very important role in future markets for mitigating the congestion problems. In this paper, the capability of ST has been utilized to manage transmission line congestion for hybrid based electricity market model. The main contribution of the paper is: (i) to develop an optimal rescheduling of generators strategy for real time congestion management and impact of ST for congestion management, (ii) the comparison of ST with unified power flow controller (UPFC) for congestion management, (iii) the secure bilateral transactions determination in a hybrid market model and congestion management with both power flow controllers in combined pool and bilateral market model. The optimal location of ST and UPFC has been obtained solving mixed integer non-linear programming model of congestion management. The proposed model has been applied for results on IEEE 24-bus RTS test system.

A Lyapunov theory based UPFC controller for power flow control

Unified power flow controller (UPFC) is the most comprehensive multivariable device among the FACTS controllers. Capability of power flow control is the most important responsibility of UPFC. According to high importance of power flow control in transmission lines, the proper controller should be robust against uncertainty and disturbance and also have suitable settling time. For this purpose, a new controller is designed based on the Lyapunov theory and its stability is also evaluated. The Main goal of this paper is to design a controller which enables a power system to track reference signals precisely and to be robust in the presence of uncertainty of system parameters and disturbances. The performance of the proposed controller is simulated on a two bus test system and compared with a conventional PI controller. The simulation results show the power and accuracy of the proposed controller.

Active Power Flow Control for Generating a Quiet Zone in a Thin Plate (Feedback Control System Based on Cluster Control Method)

This paper addresses active power flow control of a distributed-parameter planar structure. From the viewpoint of wave propagation, this paper presents a novel power flow control employing vibration intensity as a criterion of vibration energy flow. It enables to generate a quiet zone where structural vibration is completely suppressed in the vibrating structure. Applying cluster feedback control approach, a control method generating a quiet zone on a designated area of the target panel is proposed. Finally, a numerical simulation and an experiment are conducted with a simply supported plate, demonstrating the capability of the active power flow control for generating a quiet zone.

A nL/min-Scale Valveless Flow Regulator for Integrated Micro Chemical Devices

A micro flow regulator with a capability of continuous volume flow control of a ultra-small volume flow rate liquid in nL/min scale is reported. A valveless principle based on the temperature dependence of liquid viscosity and the parylene-based freestanding micro channel structure enabled an extremely simple structure of the regulator element. This simplicity and the small footprint are advantageous over other mechanically movable regulation valves as the driving element for integrated chemical devices that require flexible control of liquid flow. A prototype device was fabricated with the surface micromachining technology. The experimantal results using de-ionized (DI) water as working fluid showed that the flow rate was continuously controlled in the range of 100-200% of that in the room temperature regardless of the applied pressure drop, successfully proofing the initial concept.