Reconfiguration of a wind turbine with hydrostatic drivetrain to improve annual energy production

Deldar, Majid; Izadian, Afshin; Anwar, Sohel

doi:10.1109/ecce.2015.7310592

Cited by 14 publications

(5 citation statements)

References 9 publications

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“…Silva et al [17] compare different drive-train configurations including geared, direct-drive, and hydrostatic and conclude that a hydrostatic drive-train wind turbine generates higher annual energy. A similar conclusion is reached in [2], which assesses techniques to improve the overall efficiency of the hydrostatic drive-train.…”

Section: Introductionsupporting

confidence: 62%

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A decentralized multivariable controller for hydrostatic wind turbine drivetrain

Deldar

Izadian

Anwar

2019

Asian Journal of Control

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A hydrostatic drivetrain transmits wind turbine energy to a generator. One hydrostatic transmission system (HTS) configuration utilizes a fixed displacement pump and a variable displacement motor. The system dynamics are captured in a nonlinear multi-input multi-output mathematical model. This paper introduces a decentralized control configuration based on this model to achieve two desired objectives: maximizing the harvested energy without direct measurement of wind and regulating the frequency of the generator without using power electronic converters. To accomplish these objectives, suitable pairing of control actuators and system responses are identified through nonlinear relative gain arrays (RGA) analysis. The pairing also provides a strong decoupling of control loops. So maximum power point tracking (MPPT) is achieved independently while the generator speed is regulated to maintain the frequency of generated power at 60 Hz. Simulation results demonstrate robust performance of MPPT and frequency regulation in the presence of uncertainties in the turbine and HTS model. We also demonstrate that the RGA paired inputout control configuration offers superior performance over other possible input-output paired control configurations. KEYWORDSdecentralized multivariable control, frequency regulation, Hydrostatic pump and motors, maximum power point tracking, nonlinear relative gain array, power transmission

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Section: Introductionsupporting

confidence: 62%

“…IT is estimated that wind energy will have a significant share of the overall US energy demand by 2030 [1]. Improving the performance of wind turbines results in higher annual energy production [2]. Conventionally, a gearbox transmits the power from a high torque-low speed rotor to a low torque-high speed generator.…”

Section: Introductionmentioning

confidence: 99%

A decentralized multivariable controller for hydrostatic wind turbine drivetrain

Deldar

Izadian

Anwar

2019

Asian Journal of Control

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“…The result of [15] demonstrates the reduction of 35.5% in mass of the nacelle due to employing a hydraulic drivetrain and an average installed cost saving of 5.36-24.0% can occur for offshore wind. Despite the lower efficiency of HTS, which is about 85-88% [16,17], the HTS could reduce the overall cost of the system and lower the Levelized Cost of Energy (LCOE) by 3.92-18.8% [15], and improve the Capacity Factor (CF) of the wind turbine [18]. Given a tower structure, the rotor speed of a wind turbine with HTS could be restricted at a higher speed that results in harvesting about 17% more energy and can compensate for its losses [19].…”

Section: Introductionmentioning

confidence: 99%

Quasi Self-Excited DFIG-Based Wind Energy Conversion System

Akbari

Izadian

Weissbach

2021

IEEE Trans. on Ind. Applicat.

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This paper introduces a new configuration of the DFIG-based wind energy conversion system (WECS) employing only a reduced-size Rotor Side Converter (RSC) in tandem with a supercapacitor. In the proposed structure, the Grid Side Converter (GSC) utilized in conventional DFIG-based WECSs is successfully eliminated. This is accomplished by employing the hydraulic transmission system (HTS) as a continuously variable and shaft decoupling transmission unit. This transforms the conventional constant-ratio drives by providing an opportunity to control the power flow through the generator's rotor circuit regardless of the wind turbine's shaft speed. This feature of HTS can be utilized to control the RSC power and ultimately regulate the supercapacitor voltage without a need for GSC. The proposed system is investigated and simulated in MATLAB Simulink at various wind speeds to validate the results and demonstrate the dynamic performance of the system.

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“…Deldar et al [15] showed that improvement in hydrostatic efficiency can be achieved by optimal design of the full system, along with an appropriate rotor operational strategy. This can accomplish an annual energy production of hydrostatic wind turbines similar to that of conventional wind turbines.…”

Section: Introductionmentioning

confidence: 99%

Optimal Control of Hydrostatic Drive Wind Turbines for Improved Power Output in Low Wind-Speed Regions

2021

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World wind energy output is steadily increasing in both production scale and capacity of harvesting wind. Hydrostatic transmission systems (HTSs) have been used mostly in offshore wind turbine applications. However, their potential has not been fully utilized in onshore wind turbines, partially due to concerns related to hydraulic losses. In our prior work, it was shown that the annual energy production from a hydrostatic wind turbine can match or exceed that of a mechanical drive wind turbine with appropriate optimal control techniques. In this paper, we present an optimal control technique that can further improve energy production of a hydrostatic wind turbine, particularly in low speed regions. Here, the overall loss equation of the HTS is developed and used as a cost function to be minimized with respect to system model dynamics. The overall loss function includes the losses due to both the aerodynamic efficiencies and the hydrostatic efficiencies of the motor and pump. A nonlinear model of HST is considered for the drive train. Optimal control law was derived by minimizing the overall loss. Both unconstrained and constrained optimization using Pontryagin’s minimum principle were utilized to derive two distinct control laws for the motor displacement. Simulation results showed that both the controllers were able to increase power output with the unconstrained optimization offering better results for the HTS wind turbine in the low speed regions (3 m/s–8 m/s).

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Reconfiguration of a wind turbine with hydrostatic drivetrain to improve annual energy production

Cited by 14 publications

References 9 publications

A decentralized multivariable controller for hydrostatic wind turbine drivetrain

A decentralized multivariable controller for hydrostatic wind turbine drivetrain

Quasi Self-Excited DFIG-Based Wind Energy Conversion System

Optimal Control of Hydrostatic Drive Wind Turbines for Improved Power Output in Low Wind-Speed Regions

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