Hydraulic Control Systems

Manring, Noah D.; Fales, Roger

doi:10.1002/9781119418528

Cited by 195 publications

(205 citation statements)

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“…Physically, high volume hydraulic circuitries can have intrinsic dampening characteristics [31,32]. For this HTSWT configuration, the pump is coupled with rotor on the nacelle while the motor is located at the ground level, thus the pressure lines with large volume of the fluid effectively dampen pressure transients resulting in smooth response.…”

Section: Tuning Of Generator Speed Controller's (Pi) Gainmentioning

confidence: 99%

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: Tuning Of Generator Speed Controller's (Pi) Gainmentioning

confidence: 99%

A decentralized multivariable controller for hydrostatic wind turbine drivetrain

Deldar

Izadian

Anwar

2019

Asian Journal of Control

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“…The dynamic behavior of hydraulic pipelines is well described by a set of partial differential equations (PDE). For detailed discussion of the mathematical modeling of these components see, e.g., [6]. This discretization, however, results in a high number of states and is therefore not well suited for a model-based controller design.…”

Section: Optimal Feedforward Controlmentioning

confidence: 99%

“…The valve dynamics is modeled by an additional state, where the time derivative of the valve position serves as the (virtual) control input for the controller design. For detailed discussion of the mathematical modeling of these components see, e.g., [6]. In total, the system is described by a set of 29 nonlinear ordinary differential equations (ODE).…”

Section: Optimal Feedforward Controlmentioning

confidence: 99%

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Optimal feedforward control of hydraulic drive systems with long pipelines

Pietschnig

Marko

Kemmetmüller

et al. 2019

Proc Appl Math and Mech

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Hydraulic drives are used in many technical systems, ranging from automotive and aerospace applications to industrial production systems. They provide high forces and torques at a compact design. The typical setup of hydraulic drive systems comprises a valve which controls a hydraulic cylinder or motor. In many practical applications, the valve is connected to the hydraulic cylinder via hydraulic pipelines, whose length can amount to several meters. Typically, the distributed-parameter characteristics of these pipelines is not considered in the controller design. For very fast operation scenarios, wave effects can be excited which may cause a significant reduction of the control accuracy or even lead to instability of the closed-loop system. In this paper, a model-based control strategy is proposed which allows to systematically account for long pipelines. One main element is the spatial discretization of the partial differential equations of the pipelines by means of the spectral elemental method (SEM), which yields a low-dimensional, but yet accurate model. Based on this model, an optimal feedforward control strategy is developed, which also enables to take into account actuator constraints. The resulting optimal control problem is efficiently solved on a moving horizon, resulting in a real-time capable moving horizon trajectory planning strategy. An observer is added to account for uncertain model parameters. The high potential of the proposed approach is demonstrated in simulation by applying the method to the actuation system of a looper in a hot strip rolling mill.

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“…Traditional hydraulic control systems are of two basic types: pump control and valve control [1]. Valve control systems respond quickly to valve and load inputs but are less efficient due to throttling and overflow losses [2,3].…”

Section: Introductionmentioning

confidence: 99%

The Influence of Valve-Pump Weight Ratios on the Dynamic Response of Leaking Valve-Pump Parallel Control Hydraulic Systems

et al. 2018

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A new leaking valve-pump parallel control (LVPC) oil hydraulic system is proposed to improve the performance of dynamic response of present variable speed pump control (VSPC) system, which is an oil hydraulic control system with saving energy. In the LVPC, a control valve is operating at leaking status, together with a variable speed pump, to regulate the system flow of hydraulic oil simultaneously. Therefore, the degree of valve control and pump control can be adjusted by regulating the valve-pump weight ratio. The LVPC system design, mathematical model development, system parameter and control performance analysis are carried out systematically followed by an experimental for validation process. Results have shown that after introducing the valve control, the total leakage coefficient increases significantly over a wide range with the operating point and this further increases damping ratios and reduces the velocity stiffness. As the valve-pump weight ratio determines the flow distribution between the valve and the pump and the weight factors of the valve and/or the pump controls determines the response speed of the LVPC system, thus if the weight factors are constrained properly, the LVPC system will eventually have a large synthetic open-loop gain and it will respond faster than the VSPC system. The LVPC will enrich the control schemes of oil hydraulic system and has potential value in application requiring of fast response.

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Hydraulic Control Systems

Cited by 195 publications

References 0 publications

A decentralized multivariable controller for hydrostatic wind turbine drivetrain

A decentralized multivariable controller for hydrostatic wind turbine drivetrain

Optimal feedforward control of hydraulic drive systems with long pipelines

The Influence of Valve-Pump Weight Ratios on the Dynamic Response of Leaking Valve-Pump Parallel Control Hydraulic Systems

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