Loss Minimization Control for Doubly-Fed Induction Generators in Variable Speed Wind Turbines

This paper reviews and compares the performance of reactive power dispatch strategies for the loss minimization of Doubly Fed Induction Generator (DFIG)-based Wind Farms (WFs). Twelve possible combinations of three WF level reactive power dispatch strategies and four Wind Turbine (WT) level reactive power control strategies are investigated. All of the combined strategies are formulated based on the comprehensive loss models of WFs, including the loss models of DFIGs, converters, filters, transformers, and cables of the collection system. Optimization problems are solved by a Modified Particle Swarm Optimization (MPSO) algorithm. The effectiveness of these strategies is evaluated by simulations on a carefully designed WF under a series of cases with different wind speeds and reactive power requirements of the WF. The wind speed at each WT inside the WF is calculated using the Jensen wake model. The results show that the best reactive power dispatch strategy for loss minimization comes when the WF level strategy and WT level control are coordinated and the losses from each device in the WF are considered in the objective.

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“…The copper loss minimizing strategy is proposed in [33,34]. This method regulates reactive power using both the RSC and the GSC.…”

Section: Strategy 3: Minimum Copper Loss Controlmentioning

confidence: 99%

Review of Reactive Power Dispatch Strategies for Loss Minimization in a DFIG-based Wind Farm

Zhang

Hou

et al. 2017

Energies

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“…This method needs to know the empirical formula in advance, and the calculation is normally done according to the Finite Element Method (FEM). Alternatively, iron losses can be estimated from the electrical point of view [19], [20]. In other words, it can be expressed by the equivalent iron resistance R i in parallel with the magnetizing inductance as shown in Fig.…”

Section: Loss Breakdown Of Dfig Systemmentioning

confidence: 99%

Reduced cost of reactive power in doubly fed induction generator wind turbine system with optimized grid filter

Zhou

Blaabjerg

Franke

et al. 2014

2014 IEEE Energy Conversion Congress and Exposition (ECCE)

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The modern grid requirement has caused that the wind power system behaves more like conventional rotating generators and it is able to support certain amount of the reactive power. For a typical doubly-fed induction generator wind turbine system, the reactive power can be supported either through the rotor-side converter or the grid-side converter. This paper firstly compares the current ripples and supportive reactive power ranges between the conventional L and optimized LCL filter, if the reactive power is injected from the grid-side converter. Then, the loss distribution is evaluated both for the generator and the wind power converter in terms of the reactive power done by the rotor-side converter or the grid-side converter with various grid filters. Afterwards, the annual energy loss is also estimated based on yearly wind profile. Finally, experimental results of the loss distribution are performed in a down-scaled DFIG system. It is concluded that over-excited reactive power injected from the grid-side converter has lower energy loss per year compared to the overexcited reactive power covered by the rotor-side converter. Furthermore, it is also found that the annual energy loss could even become lower with the optimized filter and thereby more energy production for the wind turbine. I.978-1-4799-5776-7/14/$31.00 ©2014 IEEE

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“…The major eroding mechanisms in these capacitors are the leakage and deterioration of the electrolyte by vapor diffusion through the seals. Such Energies 2019, 12, 2369 3 of 11 deterioration causes a fluctuation of the capacitor's internal ESR [10][11][12][13]. Several methods to estimate the deterioration status of the electrolytic capacitor have been proposed in the literature [14,15].…”

Section: Introductionmentioning

confidence: 99%

Real-Time Reliability Monitoring of DC-Link Capacitors in Back-to-Back Converters

et al. 2019

Self Cite

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Electrolytic capacitors have large capacity, low price, and fast charge/discharge characteristics. Therefore, they are widely used in various power conversion devices. These electrolytic capacitors are mainly used for temporary storage and voltage stabilization of DC energy and have recently been used in the renewable energy field for linking AC/DC voltage and buffering charge/discharge energy. However, electrolytic capacitors continue to be disadvantageous in their reliability due to their structural weaknesses due to the use of electrolytes and very thin oxide and dielectric materials. Most capacitors are considered a failure when the capacitance has changed by 25% of its initial value. Accurate and fast monitoring or estimation techniques are essential to be used with low cost and no extra hardware. In order to achieve these objectives, an online, reliable, and high-quality technique that continuously monitors the DC-link capacitor condition in a three-phase back-to-back converter is proposed. In this paper, the particle swarm optimization (PSO)-based support vector regression (PSO-SVR) approach is employed for online capacitance estimation based on sensing or deriving the capacitor current. Because the SVR performance alone severely depends on the tuning of its parameters, the PSO algorithm is used, which enables a fast online-based approach with high-parameter estimation accuracy. Experimental results are provided to verify the validity of the method.Energies 2019, 12, 2369 2 of 11 increases and rushes evaporation of the capacitor's electrolyte. Therefore, the volume of the electrolyte is reduced so that the etched tunnels are not fully filled due to the electrolyte evaporation. Hence, the capacitance decreases as a result of the electrolyte volume reduction. The evaporation process will be higher whenever the ambient temperature increases; then, the capacitance value decreases and the lifetime deteriorated more.can be made thick, and as a result, the capacity per unit volume of the capacitor can be increased. Also shown also in Figure 2 is an oxide layer is formed on the cathode surface through a natural chemical reaction between the electrolyte and aluminum. Compared to the thickness of the anode surface oxidation layer formed by the manufacturing process, the capacitance on the cathode side is larger than that on the anode side. Therefore, since the anode and cathode capacitors can be regarded as connected in series, the total capacitance becomes similar to the capacitance value of the anode. Equivalent series resistance (Rs) represents the sum of all the resistances of the electrolyte, oxide layer, electrode, lead, and connection. The equivalent inductance (Ls) is the inductance formed by winding the coil in a cylindrical shape, which can usually be ignored in the frequency range of the power converter. Thus, the equivalent circuit can be simplified in the form of a series connection of the resistor and the capacitor.

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Loss Minimization Control for Doubly-Fed Induction Generators in Variable Speed Wind Turbines

Cited by 17 publications

References 10 publications

Review of Reactive Power Dispatch Strategies for Loss Minimization in a DFIG-based Wind Farm

Review of Reactive Power Dispatch Strategies for Loss Minimization in a DFIG-based Wind Farm

Reduced cost of reactive power in doubly fed induction generator wind turbine system with optimized grid filter

Real-Time Reliability Monitoring of DC-Link Capacitors in Back-to-Back Converters

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