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Profile of the FIN-MP airfoil was used as the basic section of vertical axis wind rotor blade. Emphasis was placed on the aerodynamic performance of the wind rotors with different length? of blade chord, while the blade height, rotor diameter and blade's spiral angle are respectively uniform for the studied rotors. Three-dimensional and unsteady simulation was carried out for the flow field around...
There are two configuration modes of the FGD booster fan in thermal power plants. One is to install booster fan behind induced draft fan, called the separation mode; the other is to integrate the two kinds of fans, that is to cut off booster fan, but install a bigger induced draft fan which can support the pressure head for the whole system, called the integration mode. Through detailed analysis,...
A method based on the D-S (Dempster-Shafer) evidential theory is presented and applied to diagnose the broken rotor bars of induction motors. Wavelet packets decomposition of the three-phase stator current is performed based on the frequency partition characteristics of the wavelet packets transformation; The faults characteristic vector (evidence) of the broken rotor bars is established by the RMS...
Through the analysis of the electromagnetic properties for the rotor coil of turbine generator, we obtained the main magnetic field variation characteristics for the rotor winding and put forward the short circuit fault between rotor inter-turns causing the potential difference and circulation between the parallel branches of generation stator winding spectral method was applied on the spectrum analysis...
A new gain-scheduling sliding mode controller for permanent magnet synchronous motor (PMSM) was designed to achieve position tracing control and robust control. The sliding mode position controller is designed to ensure the tracing and robust performance of the PMSM servo system firstly, and then the gain-scheduling based on fuzzy logic theory is adopted to reduce chattering of sliding mode controller...
Vibration faults frequently occurring to the feed water pump in large-scale power plants are diagnosed by the integrated neural network based on MATLAB. The integrated neural network for fault diagnosis is established from individual neural network and on the basis of information fusion. The strategies and principles for the realization and formation of integrated neural network are analyzed and a...
The DFIG is excited by converter which is connected rotor. The performance of wind turbine is depended on the matching conditions of the DFIG and converter. And the DFIG equivalent circuit parameter will influence the generator electromagnetic design. Based on the equivalent circuit and the test data, this paper put forward a kind of theory and calculation method to separate the equivalent circuit...
A maximum power point tracking (MPPT) controller for variable speed wind energy conversion system (WECS) is proposed. The proposed method, without requiring the knowledge of air density, wind speed and turbine parameters, generates at its output the optimum speed command for speed control loop of rotor flux oriented vector controlled grid side inverter control system using only the instantaneous active...
In existing load flow model of induction generators, the magnetizing path is moved to the stator terminal, parallel to the shunt capacitor, yielding the same stator and rotor currents. The power output is equal to the mechanical power input. The stator resistance and the machine loss are ignored. It can not provide the initial condition for the dynamic and control schemes requiring the exact stator...
Oscillating water column wave energy converter is widely used in the world. The impulse turbine is recently employed for the bi-directional mechanical air power into electricity power. The 2D and 3D numerical model is established in the present paper to investigation the operating performance. The proper mesh style, turbulence model and numerical solutions are employed to study the velocity and air...
The labyrinth seal belongs to the category of complex structure labyrinth seal, which is widely applied in engineering for its better leakage control due to its multiple throttle mechanism which guarantees a more satisfactory energy dissipation. By using Fluent, the flow and the leakage in labyrinth seal were predicted by employing two-dimensional steady flow model, the κ-ε turbulence model and numerically...
A novel field modulated magnetic gear (FMMG) with concentric configuration is proposed and introduced to the drive train for a wind turbine system, which eliminates the vibration, noise and lubrication problems of mechanical gearbox and avoids the size and weight issues of directly-driven wind turbines The efficiency and reliability are improved simultaneously. Based on the static field computations...
An accurate model of large scale wind farm is demanded for researches about the impacts on the power grid. The total number of wind energy generators is so large that the detailed model of wind farm is computationally prohibitive. Dynamic equivalence can significantly reduce system order with the major characteristics retained. So the aggregation of large scale wind farm is inevitable. An overview...
This paper implement an online training of dynamic neural networks (NNs) for identification and control of permanent magnet synchronous motor (PMSM) servo system. Utilizing two multilayer feed-forward NNs, it makes no such assumptions. The two networks work in tandem to simultaneously achieve system identification and adaptive control. The proposed control system is designed and its effectiveness...
Rotor earth fault protection is used to detect earth faults in the excitation circuit of synchronous machines, ping pong type and injecting-step-voltage rotor earth fault protection are both used in Three Gorges Hydropower Plant. This article analyzes both the principle and application of the two types of protections, together with the operation on giant generating set, advantages and disadvantages...
This paper suggests a hybrid, vertical configuration of multi-bladed and multi-stage (multi-S) Savonius rotors for capturing and storing wind energy. The intended hybrid design is expected to provide small- or near-medium-sized wind turbine of unique design in terms of the gained energy and speed factors. The whole system is dedicated for stand-alone power plants. Integration of wind power into electricity...
In the variable frequency driver system of induction motor, the DC-side current of converters and the AC-side current of rectifiers are analytically analyzed using switching functions of converters and rectifiers when induction motors would be in fault state. The transmission rules of faults characteristic information in driver system were derived, and the fault features frequency components corresponding...
In case of three-phase short circuit fault occurring at the terminal of a doubly-fed induction generator (DFIG), the rotor current characters of DFIG are analyzed from the viewpoint of the flux linkage, and the expression of the rotor current is deduced together with the estimated expression of the maximum rotor current. Based on above analysis, the max rotor currents and their appearing times with...
The traditional control strategies of the permanent magnet synchronous generator (PMSG) based on rotor flux orientation have unconquerable drawbacks, such as the reactive power exchange by the id=0 control and the complicated calculation by the unity power factor (UPF) control. A novel UPF control strategy of the PMSG using stator flux orientation is proposed in this paper. The simulation results...
The fault ride-through ability of doubly fed wind generators (DFIG) has got more and more attention. New grid codes for interconnection of wind turbines required that wind turbines remain connected to the grid and actively contribute to the system stability during and after grid faults. Uninterrupted excitation of DFIG can both avoid running over-speed of wind turbines during grid faults and accelerate...
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