Attila Fodor

Parameter Sensitivity Analysis of a Synchronous Generator

A previously developed simple dynamic model of an industrial size synchronous generator is analyzed in this paper. The constructed state-space model consists of a nonlinear state equation and a bilinear output equation. It has been shown that the model is locally asymptotically stable with parameters obtained from the literature for a similar generator. The effect of load disturbances on the partially controlled generator has been analyzed by simulation using a PI controller. It has been found that the controlled system is stable and can follow the set-point changes in the effective power well. The sensitivity of the model for its parameters has also been investigated and parameter groups have been identified according to the system’s degree of sensitivity to them. This groups form the different candidates of parameters for subsequent parameter estimation. The ways of applying the developed methods to other generators used in the automotive industry are also outlined.

Multiple-Input–Multiple-Output Linear-Quadratic Control of the Energy Production of a Synchronous Generator in a Nuclear Power Plant

Abstract —A multiple-input–multiple-output linear-quadratic servo controller is proposed for a synchronous generator operating in a nuclear power plant that keeps the active power at the desired level and performs reactive power reference tracking using the reactive power demand from a central dispatch center. The controller design was based on the locally linearized version of a previous non-linear dynamical model of the synchronous electrical generator [1, 2], the parameters of which have been identified using measured data from Paks Nuclear Power Plant (Hungary). The method can easily be applied to any industrial power plant generator connected to the electrical grid after estimating its parameters. The proposed observer-based multiple-input–multiple-output state feedback controller is a linear-quadratic servo controller with very good reference tracking and disturbance rejection properties, which were confirmed by simulation experiments.

Stability and Parameter Sensitivity Analyses of an Induction Motor

A simple dynamical model of an induction motor is derived and analyzed in this paper based on engineering principles that describe the mechanical phenomena together with the electrical model. The used state space model consists of nonlinear state equations. The model has been verified under the usual controlled operating conditions when the speed is controlled. The effect of load on the controlled induction motor has been analyzed by simulation. The sensitivity analysis of the induction motor has been applied to determine the model parameters to be estimated.

Quasi-Polynomial Control of a Synchronous Generator

A simple dynamic model of permanent magnet synchronous generator, that is used for electrical energy generation is investigated in this work using a nonlinear technique based on the quasi-polynomial representation of the dynamical model. It is well known that dynamical systems with smooth nonlinearities can be embedded in a quasi-polynomial model. Quasipolynomial systems are good candidates for a general nonlinear system representation since their global stability analysis is equivalent to the feasibility of a LMI. Moreover, the stabilizing quasi-polynomial state feedback controller design problem is equivalent to the feasibility of a bilinear matrix inequality. The classical stabilizing state feedback problem for quasipolynomial systems has been extended in this work with the ability of tracking time-dependent reference signals. It is shown, that the stabilizing quasi-polynomial servo controller design is equivalent to a bilinear matrix inequality. The results are applied to the model of a synchronous generator.

MIMO LQ Control of the Energy Production of a Synchronous Generator in a Nuclear Power Plant

A multiple-input multiple-output (MIMO) LQ servo controller was proposed for an industrial size synchronous generator that keeps the active power at the desired level and performs reactive power reference tracking using the reactive power demand from the central dispatch center. The controller design was based on the locally linearized version of a previous dynamical model of the synchronous electrical generator (Anderson and Fouad, 1977, Fodor et al., 2012) the parameters of which have been identified using measured data from Paks Nuclear Power Plant, Hungary.

Effect of Domestic Power Plants to the Low Voltage Transformer Areas from the Nonlinear Distortion Point of View

A case study is presented in this work, where a 4 kW photovoltaic domestic power plant, located in Hungary, has been examined. Based on the measured voltage and current signals we examined the frequency domain behaviour of the power plant and the effect to the power quality, mainly the total harmonic distortion, of the low voltage transformer area. Evaluation of the measurement database suggests that this type of synchronous power injection has serious effect on the voltage distortion of the low voltage grid, and this effect highly depends on the ratio of the injected power magnitude related to the nominal power of the inverter part. The available hardware structure enables us not only to eliminate this phenomenon but also to improve the existing quality of the low voltage grid. It needs only a modified control structure that can be implemented in the inverter control device. It causes power loss reduction in the low voltage grid. This reduction helps lowering the power loss in the phase conductor, and more radically in the neutral conductor of the transportation line. In the case of electric power production from fossil sources, it lowers the greenhouse gas emission, to lower the environmental and social- welfare effects of the climate change. 1. Motivation and aim There is an ongoing discussion in the scientific and public society on the exhaustion of fossil fuel reserves and on how the climate change is affecting our planet. Current opinion says that the primarily emitted greenhouse gases (GHG) from natural and artificial sources are responsible for the effects of climate change. These effect the solar radiation, and thus act as key factors affecting the global weather. Nobody denies the constrained nature of fossil energy resources, but they use optimistic estimations of the quantity and availability of these energy resources, that may become available with the help of new scientific and technological developments. There is a huge literature about the prediction of fossil energy resources, and their effect on the CO2 concentration in the atmosphere, and as a result on further climate change impacts over the next 200 y period of time. The effects of fossil fuels depletion (Chiari and Zecca , 2011), economic growth (Nel and Cooper, 2009), the wind and solar energy production (Leggett and Ball, 2012) and the exploitation of methane hydrate deposits (Glasby, 2003) on global warming is predicted. The predicted CO2 concentration increases significantly, that result in rising average temperature values. The situation is getting worse by the global economic growth, and the extended use of newly available fossil energy sources (primarily deepwater oil and gas deposits) (Nel and Cooper, 2009). Without intervention, significant anthropogenic impacts should be expected in the 21st century. We must influence this process by all means in order to avoid the above described anthropogenic effects. We need to reduce the emissions by reducing the use of resources, which produce greenhouse gases. Surveys suggest that the economic sectors responsible for CO2 emission in the European Union are as follows (in descending order): energy and heat production (32 %), road transport (22 %), household