Improvement of the generation power in micro-hydraulic turbines is shown in the range of low flow rate and low head using a new inverter generation system. The generation power can be obtained down ...to very low flow rate and head using the new inverter generation system with variable rotational speed control, where a water turbine connot produce the electric power in a normal constant-speed-control system. Experiments were carried out using a practical micro-hydraulic turbine with 2 kW output and variable rotational speed in a forest on the mountain, Mie University. The total efficiency is kept at a high value even in the very low partial load area. Compared with the constant speed control, the generation power is improved over 20 percent by varying the rotational speed.
The National Renewable Energy Laboratory (NREL) Phase II - IV wind turbine rotors 1 were used as the original research subjects in this article. In this paper, the numerical simulation method and ...business software FLUENT were used. The aerodynamic performances of different fixed-pitch, horizontal-axis wind turbine rotors were obtained through numerical computation. A rotational speed control model was given by direct calculation on the aerodynamic parameters of straight blades. As in the previous model, it required the wind turbine rotational speed be changed as little as possible in consideration of the life expectancy improvement and dynamo size reduction. Then, numerical simulation was used in one twisted wind turbine blade, three simple twist-oriented corrected models were acquired by flow-field analysis and simplified blade element theory application. Certain improvements in the wind turbine aerodynamic performances were obtained by contrasts of P-V curves and rotational speed model with original twisted wind turbine blade.
Rotational speed control of a hydraulic motor with a large inertia load has issues on stability and sometimes falls into unstable. In this paper, the discrete-time sliding mode control (SMC) is ...applied to rotational speed control of a hydraulic motor for improving its robustness. Modeling of the control components and design of the sliding surface (switching line) in the state space are discussed. Furthermore, one of the means attenuating chattering due to the SMC is presented. The control characteristics is evaluated by a testing apparatus which consists of the hydraulic motor of 28cm3/rev coupled to the large inertia load of 0.88kg·m2. The results of a theoretical and experimental study of the SMC show several benefits such as shorter settling time, lower sensitivity to disturbances and system parameter variations.
Weakly Damped Robot Arm Control Goldynia, J.W.; Hornischer, R.; Noisser, R.
IFAC Proceedings Volumes,
August 1994, 1994-08-00, Volume:
27, Issue:
9
Journal Article
Open access
A plant consisting of two rotating masses coupled with a leaf spring is driven by a dc motor. The task is to control the position of the second mass, where only its position and the motor current are ...measurable. It is shown that a control observer approach or Pi-control based on a reconstructed signal leads to better results for the overall performance than classic Pi-control, even under the influence of modelling uncertainties, friction and bounded values.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Systems to control the rotational speed of a Savonius-type wind turbine and to allow the Savonius rotor to stop the rotation in a strong wind are presented. It is known that the performances of a ...Savonius rotor changes greatly by varying the location of a deflecting plate which is placed in front of the rotor. Hence, in this work, the rotational speed of the Savonius rotor is controlled by turning the deflecting plate around the rotor.
This article deals with the control of variable displacement units connected to a constant pressure net. In particular the dynamical behaviour of two coupled secondary units in a speed- and torque ...control circuit is described and the decoupling of the two motors by the control technique is demonstrated. On this occasion results the possibility of recovering the energy into the hydraulic net. This onstellation is among other applications of special interest for power transmissions or testing benches, in case tension is applied to a traction mechanism or tape.
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