The necessity of preliminary estimation of the value of voltage dip arising at starting-up of asynchronous motor commensurate in power with operating diesel-generator sets as part of the ship electric power system is justified. The model of ship electric power system with a modified in real-time mode configuration is developed. The process of direct starting-up of asynchronous motor is simulated, and the values of voltage dips for various values of voltage and time of excitation boost of the synchronous generator are determined. It is established that there are optimum values of the magnitude and time of boosting of excitation voltage of the synchronous generator, where voltage dip in the network is minimal. The obtained results enable assessing in the process of monitoring and management of ship electric power system of the possible consequences of direct starting-up of asynchronous motor on the network voltage under current conditions, and based on them deciding on whether to connect the additional diesel generator to the network or disconnect the least essential consumers of electricity from the network to provide generated capacity reserve. Streszczenie. Zbadano możliwości zapadu napięcia w systemie okrętowtm generatora współpracującego z silnikiem diesla. Symulowano generator asynchroniczny podłączony do sieci dla różnych warunków startu. Określono optymalna wartość napięcia wspomagającego zapewniającą minimalne zapady napięcia. System wyprzedzający sterowania wzbudzeniem generatora synchronicznego umożliwiający zredukowanie zapadów napięcia podczas startu silnika asynchronicznego
In a wind energy conversion system (WECS), changing the pitch angle of the wind turbine blades is a typical practice to regulate the electrical power generation in the full-load regime. Due to the turbulent nature of the wind and the large variations of the mean wind speed during the day, the rotary elements of the WECS are subjected to significant mechanical stresses and fatigue, resulting in conceivably mechanical failures and higher maintenance costs. Consequently, it is imperative to design a control system capable of handling continuous wind changes. In this work, Linear Parameter Varying (LPV) H∞ controller is used to cope with wind variations and turbulent winds with a turbulence intensity greater than ± 10%. The proposed controller is designed to regulate the rotational rotor speed and generator torque, thus, regulating the output power via pitch angle manipulations. In addition, a PI-Fuzzy control system is designed to be compared with the proposed control system. The closed-loop simulations of both controllers established the robustness and stability of the suggested LPV controller under large wind velocity variations, with minute power fluctuations compared to the PI-Fuzzy controller. The results show that in the presence of turbulent wind speed variations, the proposed LPV controller achieves improved transient and steady-state performance along with reduced mechanical loads in the above-rated wind speed region.
One of the main tasks of information technology is to improve existing and develop new methods for formal recording of various dynamic logical operations of analog and digital signal conversion in electronic control systems, acquisition, and processing of information. The stage of formal recording of any signal transformation process must be presented in the form of analytic symbols, the sequence of which must form a fully functional mathematical model. The improved method of the signals conversion processes description based on a representation of the mathematical models of the electronic circuits’ components in the grapho-analytical form with the increased information content allows integrating the developed models of electronic circuit elements with object-oriented programming language in the form of functional structures. It opens the way to perform parametric analysis of circuits and other tasks, related to the modeling of electronic systems.
The paper suggests an improved method of active power distribution among the gas-diesel generators operating in parallel; the method involves the control of torque and the angular positions of their rotors. The use of the suggested approach to the solution of the active power distribution task in the presence of instability of drive motor speed provides the increase of autonomous power system operation efficacy and rising the power unit's performance. The authors analyzed the causes of generation of low-frequency fluctuations of generator drive engine speed; in autonomous electric power systems, gas diesel generators are increasingly used as such generator drive engines. It is suggested to use the developed method and structure of the optical device for control of rotation period and the measurement of the generator rotor angle position characterized with high accuracy, as the sensor. The authors developed a schematic diagram of active power distribution among the generators operating in parallel, which uses the cross feedback for gas-powered diesel engine shafts momentum and the generator rotor angle position. They obtained experimental results confirming the efficiency of the suggested active power distribution method and its practical implementation. Keywords-active load sharing, frequency instability, gaspowered diesel engine, optical sensor, rotor angular position I. INTRODUCTIONNE of the most important parameters of diesel autonomous power plants is the cost-effectiveness, which is determined by the ratio of the power generated to the fuel consumption per an operation hour. The fuel consumption reduction will provide the improvement of power efficiency of autonomous power systems (APS). The optimal diesel-generator load is the load proximal to 80% of their rated power [1]. When a dieselgenerator operates at lower loading, the specific fuel consumption increases with the development of carbonization effect caused by accumulation of incomplete combustion products, which produces a negative effect on the engine resource. The generator unit loading above 80% also results in significant performance reduction [1,2].The increase in the diesel fuel price results in the need to convert diesel vehicles to gas. Currently, gas-powered dieselgenerator sets (GDGS) are widely used to provide reliable power supplies at industrial facilities. Gas-powered dieselgenerator sets (GDGS) are increasingly used due to their cost
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