1,721,781 research outputs found
Single-Stage NPC-Type Dual-Port Inverter for Integrated Wind/Battery Hybrid System
No full textWind power is inherently intermittent and poses challenges to the stable integration of wind turbines (WTs) into a power system. Battery energy storage systems (BESSs) are often used to mitigate wind power fluctuations, charging and discharging batteries depending on wind conditions. Like every multisource system, the WT-BESS hybrid system requires power electronic converters to control the dc and ac power flows. Multiple dc-dc and dc-ac power conversion stages enable high control flexibility, but have a low energy conversion efficiency and require several bulky passive filters. Single-stage multiport inverters (MPIs) that connect multiple sources to the ac grid in a single conversion stage have been increasingly investigated in recent years as a potential alternative. This paper examines the performance of the NPC-type Dual-Port Inverter (DPI) for a wind energy system based on a permanent magnet synchronous generator and battery storage device. The modulation of the DPI and the integrated BESS and WT maximum power point tracking control are presented and discussed. As proved by numerical simulations, the single-stage DPI can inject smooth electrical power into the grid at a unity power factor under highly variable speed conditions while always extracting the maximum power from the turbine
Compact Integration of Battery Storage System for a Micro Wind Turbine Generator
No full textAs wind turbine (WT) power fluctuates due to the intermittent nature of the wind, batteries can help smooth out this variation. Traditionally, multiple conversion stages are used to manage the power flow between the wind source and the storage device. This paper investigates the feasibility of a dual-port inverter (DPI) as single conversion stage to connect a battery and a micro-WT and shows how the DPI can be controlled to ensure that the most power possible is harvested from the wind turbine. Numerical simulations demonstrate that the DPI has the capability to deliver power to the grid with a unity power factor, even under conditions of highly variable speed, while always extracting maximum power from the WT. The simple DPI-based configuration enables smoothing wind power variations with the battery without employing multiple dc-dc and dc-ac conversion stages
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No full textOptimal Torque Curve Tracking for Wind Turbine Generators Using Adaptive Extremum Seeking
No full textOptimal torque control is a common technique for tracking the maximum power point of wind energy systems without direct wind measurements. However, it relies on the precise knowledge of the turbine's aerodynamic characteristics and air density. Since these parameters can significantly differ from their nominal value due to variable ambient conditions and turbine aging, suboptimal operation of the wind generator can occur. In this paper, a sensorless and model-free Adaptive Extremum Seeking (ES) parameter optimization is considered to track in real-time the optimal torque trajectory and achieve maximum wind energy harvesting. Differently from the conventional approach, adaptive ES is here used to drive the generator torque toward its optimal trajectory rather than to define a variable speed setpoint for the turbine. By doing so, maximum power operation can be reached with reduced oscillations of electrical power. Simulations on a 1.5 MW wind energy system are reported to demonstrate the effectiveness of the technique
A Comparison between Habituation and Conscience mechanism in Self–Organizing Maps
No full textIn this letter, a preliminary study of habituation in self-organizing networks is reported. The habituation model implemented allows us to obtain a faster learning process and better clustering performances. The habituable neuron is a generalization of the typical neuron and can be used in many self-organizing network models. The habituation mechanism is implemented in a SOM and the clustering performances of the network are compared to the conscience learning mechanism that follows roughly the same principle but is less sophisticated
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