90 research outputs found
Mixed Voltage Angle and Frequency Droop Control for Transient Stability of Interconnected Microgrids with Loss of PMU Measurements
We consider the problem of guaranteeing transient stability of a network of
interconnected angle droop controlled microgrids, where voltage phase angle
measurements from phasor measurement units (PMUs) may be lost, leading to poor
performance and instability. In this paper, we propose a novel mixed voltage
angle and frequency droop control (MAFD) framework to improve the reliability
of such angle droop controlled microgrid interconnections. In this framework,
when the phase angle measurement is lost at a microgrid, conventional frequency
droop control is temporarily used for primary control in place of angle droop
control. We model the network of interconnected microgrids with the MAFD
architecture as a nonlinear switched system. We then propose a
dissipativity-based distributed secondary control design to guarantee transient
stability of this network under arbitrary switching between angle droop and
frequency droop controllers. We demonstrate the performance of this control
framework by simulation on a test 123-feeder distribution network.Comment: American Control Conference (ACC), 202
Experimental application of Takagi-Sugeno observers and controllers in a nonlinear electromechanical system
[EN] In this paper, a systematic methodology to design fuzzy Takagi-Sugeno observers and controllers will be used to estimate the angular positions and speeds, as well as to stabilise an experimental mechanical system with 3 degrees of freedom (fixed quadrotor). Takagi-Sugeno observers and controllers are compared to observers and controllers based on the linearized model, both designed with the same optimization criteria and design parameters. Experimental results confirm that Takagi-Sugeno models and observers behave similarly to linear ones around the linearization point, but have a better performance over a larger operating range, as intuitively expected.The work of Zs. Lendek was supported by a grant of the Romanian National Authority for Scientific Research, CNCS UEFISCDI, project number PN-II-RU-TE-2011-3-0043, contract number 74/05.10.2011. Spanish authors are grateful to grants DPI2011-27845-C02-01 (A. Sala), DPI2011-27845-C02-02 (R. Sanchis), DPI2011-28507-C02-01 (P. Garcia) from Spanish Government, and PROMETEOII/2013/004 (A. Sala, P. Garcia) from Generalitat Valenciana.Lendek, Z.; Sala, A.; García Gil, PJ.; Sanchis Llopis, R. (2013). Experimental application of Takagi-Sugeno observers and controllers in a nonlinear electromechanical system. Control Engineering and Applied Informatics. 15(4):3-14. http://hdl.handle.net/10251/150453S31415
Adaptive neural network cascade control system with entropy-based design
A neural network (NN) based cascade control system is developed, in which the primary PID controller is constructed by NN. A new entropy-based measure, named the centred error entropy (CEE) index, which is a weighted combination of the error cross correntropy (ECC) criterion and the error entropy criterion (EEC), is proposed to tune the NN-PID controller. The purpose of introducing CEE in controller design is to ensure that the uncertainty in the tracking error is minimised and also the peak value of the error probability density function (PDF) being controlled towards zero. The NN-controller design based on this new performance function is developed and the convergent conditions are. During the control process, the CEE index is estimated by a Gaussian kernel function. Adaptive rules are developed to update the kernel size in order to achieve more accurate estimation of the CEE index. This NN cascade control approach is applied to superheated steam temperature control of a simulated power plant system, from which the effectiveness and strength of the proposed strategy are discussed by comparison with NN-PID controllers tuned with EEC and ECC criterions
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