Combined Attitude and ThermalControlSystem (CATCS) was proposed for the implementation of an integrated solution for the satellite thermal and attitude control. This paper focuses on the CATCS numerical simulation of the Magnetohydrodynamic (MHD) driven flow of liquid metal within its channel. The numerical solution to the core mean velocity of liquid flowing through CATCS duct is obtained through the coupling of electric and magnetic fields towards an integrated solution in describing the MHD flow. The conventional Navier-Stokes equation is modified using Reynolds Averaging, yielding Reynolds Averaged Navier-Stokes (RANS) equation to solve the respective flow profile. Additional constraint is placed upon the flow in consideration of Hartmann layer effects. Simulation is also performed based on the variation of injected magnetic flux densities and induced thermoelectric currents to yield for different magnitudes of Lorentz forces that drive the liquid. Results show that the core mean velocity is mainly governed by the injected currents; whereas the flow profile shape is governed mainly by the magnetic fields.
In this paper, the stability analysis of thermalcontrolsystem with constant time-delay was used to analyze. In the analysis, PI controller is the essential part of the thermalcontrolsystem, time-invariant feedback loop delays and then new stability criteria was identified. First, the system was mathematically formulated as a linear retarded continuous-time delayed differential equation with incremental system variables (state variables). Subsequently, by using the stability criterion’s, maximum allowable bound of the network delay that the closed-loop system which can accommodate without losing stability, were computed for various subsets of the controller parameters (PI-controller). The obtained results are the more realistic operating condition in a real time temperature controlsystem. The effectiveness of the proposed result is validated on a benchmark thermalcontrolsystem.
A functional and high-performance thermalcontrolsystem with no power supply for a high-power micro-satellite: 100 W, 3 U has been proposed. To de- sign this system, a demonstration satellite which can absorb the solar heat of 100 W was proposed and the experiment of three phase changes of water was con- ducted as the testbed of 100 W thermalcontrolsystem. The basic design of the micro-satellite was divided into the payload design and the bus part design. The feasibility of the mission was proved by thermal mathematical model as follows: 1) the solar input to paddles could reach 180 W and the paddles can absorb the thermal energy up to 97 W; 2) the phase change of water led to a temperature change from −10˚C to 100˚C and reveals the possibility of the phase change test; and 3) the temperature of bus equipment was also within the allowable temper- ature range (0˚C - 40˚C). Furthermore, the thermal test model was built and the test results confirmed the operation of the functional thermalcontrolsystem with HSP, m-LHP and FRDR in the space environment testing, although the temperature fluctuation at the payload was not enough to satisfy the require- ment. In order to develop the functional thermalcontrol systems applied for high-power micro/nano-satellites, the future works are expected as follows: 1) a reduction of thermal resistance between the graphite sheet and water chamber, 2) a suppression of thermal radiation on the paddle, and 3) the optimization of FRDR and m-LHP toward the satellite.
Automatic Generation Control (AGC) or Load Frequency Control (LFC) is a very important issue in power systems for supplying reliable electric power with good quality [1, 2]. For successful operation of interconnected power system total generation should be equal to the total load demand plus system losses. A sudden load change in any area of interconnected power system causes the deviation of frequencies of all the areas. The main objectives of AGC are to maintain the megawatt output and the nominal frequency in an interconnected power system [3, 4]. Different types of control techniques such as classical control, variable structure control and robust control have been applied to the LFC problem . Conventional PI controller is simpler for implementation but its settling time is more and it produces large frequency deviation. As an alternative to conventional PI controller, Fuzzy Logic Controller has been widely used for nonlinear and complex systems. This paper presents the performance of two area interconnected thermal hydro system with conventional PI and FL Controllers. Simulation results show that the FLC greatly reduces the overshoot and settling time.
The model of AGC system is developed in MATLAB/SIMULINK to obtain dynamic response for a step load perturbation (SLP). As an interconnected power system is subjected to load disturbances, system frequency may get disturbed and oscillating, affecting the dynamic performance. To compensate for such load disturbances and stabilize the area frequency oscillations, the dynamic power flow control of SSSC or TCPS in coordination with SMES are examined in this work. A coordinated operation of SMES in both the areas, is also studied in a comparative manner. The effectiveness of frequency controllers are guaranteed by analyzing the transient performance of the system with varying load. The gains (K i ) of integral controller in AGC loop, SMES (K SMES , K Id ),
Pursuing M.Tech, Department of ECE, BVC Engg College, Vodalarevu, Andhra Pradesh, India 1 Assistant Professor, M.Tech, Department of ECE, BVC Engg College, Vodalarevu, Andhra Pradesh, India 2 Associate Professor, (Ph.D), HOD, Department of ECE, BVC Engg College, Vodalarevu, Andhra Pradesh, India 3 ABSTRACT: Due to harmful working environment and remote location of Thermal power plant sites, it is dangerous and time expensive to operate and maintenance. As the demand for power increases, increasing safety and reducing operating and maintenance cost plays a vital role in increasing the reliability of the power plant. As the Thermal power plant has to work for 24 hours and 365 days, it is not possible to monitor the parameters in site at each and every moment. So remote monitoring is also needed. This project develops a sensor network based interlock control and remote monitoring system. The system mainly consist Temperature sensor, Pressure sensor, Flow sensor, Level sensor, RPM sensor, PH sensor, Vibration sensor, Voltage sensor. All the sensors data is processed using ARM processor. Using this system we can control the operation of Thermal power plant in auto mode and monitor the parameters in work place. Also we can communicate the sensor data to other PCs in remote locations using GSM technology.
The conventional load-frequency controller may no longer be able to attenuate the large frequency oscillation due to the slow response of the governor. A fast-acting energy storage system in addition to the kinetic energy of the generator rotors provides adequate control to damp out the frequency oscillations. The problems like low discharge rate, increased time required for power flow reversal and less maintenance requirements have led to the evolution of Super Capacitor Energy Storage (SCES) or Ultra Capacitor Energy Storage (UCES) devices for their utilization as load frequency stabilizers. Super Capacitors are electrochemical type capacitor which offer large capacitances in the order of thousands of farads at a low voltage rating of about 2.5V [12, 13]and are used to store electrical energy during surplus generation and deliver high power within a short duration of time especially during the peak-load demand period [14, 15].The energy density of Super Capacitor(SC) is 100 times larger than the conventional electrolytic capacitor and their power density is 10 times larger than the lead-acid battery. Ultra capacitors possess a number of attractive properties like fast charge-discharge capability, longer life, no-maintenance and environmental friendliness. The effective specific energy for a prescribed load can be satisfied using various SC bank configurations. The SCES will, in addition to load levelling, a function conventionally assigned to them, have a wide range of applications such as power quality maintenance for decentralized power supplies. The SCES are excellent for short-time overload output and the response characteristics possessed in the particular. The effect of generation control and the absorption of power fluctuation required for power quality maintenance are expected. However, it will be difficult to locate the placement of SCES alone in every possible area in the interconnected system due to the economical reasons. In this paper SCES unit is located in area 1 of the two-area interconnected reheat thermal power system considering GDB and GRC nonlinearities.
A HEN synthesis problem, named H5SP1R, contains five process streams. It is generated from the commonly used test problem, problem 5SP1,  by imposing hypothetical disturbances on the stream source temperatures and heat capacity flowrates; the specifications for all streams data are shown in Table 20. Degree of intensity of disturbance, levels of control precision are shown in Table 21 and 22. In this pseudo-pinched problem, the pinch point is located at the temperature of 43.5°C according to the normal values of the source and target temperatures and heat capacity flow rates of all streams. Consequently, the minimum number of HTU’s under minimum energy requirements (MER), is equal to 5 including a heater. The MER is 884.6 kW. The grid diagrams for solutions are shown in Fig.6, 7, 8, 9 and 10.
Due to the increasing of using wind turbines DFIG is desired to use and be stu- died. The DFIG stores the kinetic energy in its turbine blade. So the extraction of this kinetic energy depends on the inertia of the turbine. By controlling this in- ertia, the stored energy can be extracted from the blade. Under normal opera- tion, the convertor controllers of the DFIG keep the turbine at its optimal speed in order to extract the maximum power. Figure 3 shows the model used for ac- tive power control.
control areas. Area 1 consists of two reheat thermal power generation units and Area 2 comprises two non reheat thermal generation units. The frequency in the power syste m is being maintained by controlling the driving torques of the thermal turbine. The reheat turbine gives a fast response component due to the High Pressure (HP) stage and a much slower Low Pressure (LP) due to reheat delay. A Generation Rate Constraint (GRC) of 10 % p.u. MW/min and 3% p.u. MW/min for non-reheat and reheat thermal systems respectively [9,13]. GRCs are taken into account since the rapid power increase would draw out excessive stea m from boiler system to cause steam condensation due to adiabatic expansion. k11and k22 are the integral gain settings in area 1 and area 2 respectively. The nominal parameters of the system are given in Appendix-1.
The obtained results showed that the gained thermal power in the month January, February, November, and December is less than the rest eight months of the year due to low DNI and the high cosine effect. However, the four months, which have the lowest value of useful thermal power still has the significant potential to provide a thermal power to the system. The selecting solar irradiance around (500 ⁄ ) at design point to calculate the total area of collectors can give a great chance for these four months to contribute efficiently to supply a sufficient thermal power, despite a low value of average direct normal irradiance in the region that selected as a case study. In the same direction, the eight months, which have a higher DNI can be exploited to provide direct thermal power to MED and a surplus thermal power to a thermal storage system. Indeed, the optimal area of collectors and storage system capacity are based on the minimum total annual cost of the entire system that can be obtained through an optimization solution.
In this paper, a new control strategy of battery-ultracapacitor hybrid energy storage system (HESS) is proposed for hybrid electric drive vehicles (HEVs). Compared to the stand, alone battery system may not be sufficient to satisfy peak demand periods during transients in HEVs, the ultracapacitor pack can supply or recover the peak power and it can be used in high C-rates. However, the problem of battery-ultracapacitor hybrid energy storage system (HESS) is how to interconnect the battery and ultracapacitor and how to control the power distribution. This paper reviewed some battery-ultracapacitor hybrid energy storage system topology and investigated the advantages and disad- vantages, then proposed a new control strategy. The proposed control strategy can improve the system performance and ultracapacitor utilization, while also decreasing the battery pack size to avoid the thermal runaway problems and increase the life of the battery. The experiment results showed the proposed control strategy can improve 3% - 4% ultracapacitor utilization.
1 DESIGN DEVELOPMENT PROCESS The design procedure, which is to be carried out in the case of mechatronic systems, is very demanding - it is necessary that system engineering, within the field of mechanics, electronics and computer science, forms a completely integrated system. Hence, intelligent testing technologies, supported by CAE (Computer Aided Engineering), which provide numerical simulation models, are to be employed during component development and their qualification. An emphasis should be placed upon the interaction between computer aided system simulation and experimental testing techniques through intelligent information processing. CAE is a technology that enables computer analysis of the design, created within CAD (Computer Aided Design) technology. By the application of CAE technology it is now possible to have a much better linking of design, testing and design improvement, which are the development phases that have, so far, been almost separate. Fig. 1 shows a diagram of design development process . After theoretical modelling and experimental system identification, the future design steps are controlsystem analysis and model based controller design. The demands for efficient optimisation and testing include:
A controlsystem is the means by which any of interest in a machine, mechanism or equipment is maintained or altered in accordance Introduction of feedback into a controlsystem has the advantages of of system performance to internal variations in system parameters, improving transient response and minimizing the effects of disturbance signals. However, feedback ncreases the number of components, increases complexity, reduces gain and introduces the A system is stable if its response to a bounded input vanishes as time t approaches ∞. An any control task. A stable system with low damping is also not desirable. Therefore, a stable system must also meet the specifications on relative stability which is a quantitative measure of how fast the in the system. The oots of system’s characteristic equation determines the stability of the system [1 The roots of the system’s characteristic equation are the same as the poles of the closed-
In this study fuzzy gain scheduled proportional integral (FGSPI) controller is designed with five triangular membership functions instead of seven as used in [14-15, 20]. Using fuzzy logic, the integrator gain of FGSPI controller is so scheduled that it compromises between fast transient recovery and low overshoot in the dynamic response of the power system. The conventional PI controller and state feedback LQR controller were also implemented on the same two-area power system for comparative analysis. Comparative analysis of the results is carried out with other controllers reported in literature. As per reported literature, it has been gradually seen that superconducting magnetic energy storage (SMES) systems, because of their fast dynamics, high power, and high efficiency, have received considerable attention for their application as load-frequency stabilizers [23, 24]. In the AGC problem, the instantaneous mismatch between generation and consumption of real power can be reduced by the addition of fast acting SMES unit, and this in turn results in significant improvement in the transients of frequency and tie-line power deviations against small load disturbances. Therefore, in this study, the simulations are carried out with and without SMES units in both areas of the two-area power system. It is observed that the FGSPI controller along with an SMES unit in each area with a simple control scheme is sufficient for load frequency control of two-area thermal power system. The results obtained indicate the positive effect of SMES units on the improvement of the frequency and tie-line power oscillations due to step load perturbation.
Earlier the desalting plant in petroleum refinery is controlled using Programmable Logic Controller (PLC). It uses programmable memory to store instructions and specific functions that include ON/OFF control, timing, counting, sequencing, arithmetic, and data handling. Since PLC is a centralized controlsystem it has problems with flexibility, redundancy and reliability during desalting process control. Desalting facilities are often installed in crude oil production in order to minimize the occurrence of water and salt content in oil emulsions. The main objectives of installing DCS in desalting process are; maintaining production rate in a field, decreasing the flow of salt content to refinery distillation feed- stocks, reducing corrosion caused by inorganic salts. DCS is used because of its increased flexibility, redundancy and high performance capability in desalting process control than any other centralized systems. DCS ensures accurate process control condition and this in-turn means a better plant performance. The project work involves developing an interface card using CENTUM VP software, which is proprietary to Yokogawa. The need for DCS in desalting process is to increase the uptime, maintaining process safety, and reduction in process control operating costs. C. DCS control distribution in desalting process
The calorimetric measurements were conducted on a thermal activity monitor (TAM) 2277 isothermal calorimeter (Thermometric A/B, Järfälla, Sweden) equipped with an amplifier module enabling a resolution of the heat flow measurements extending into the nW range. The instrument has a total of four calorimetric channels, each of which consists of a sample cell and a reference cell mounted in a separate heat sink. This design allows independent measurement of the differential (sample – reference) heat flow in each channel, with the only restriction that the experimental temperature is the same (since all four heat sinks are in the same water bath). During measurement, the primary observable variable is simply the temperature difference between the sample and the reference; through appropriate calibration this translates into the sample-to-reference heat flow (in W). Details of a very similar, albeit less sensitive, version of this equipment have been published by its inventors (Suurkuusk and Wadsö, 1982). In the current application, one type 2250 perfusion module (Thermometric) with a 1·ml stainless steel cell, and one type 2250 RH module (4·ml stainless steel cell), were used in each trial according to the methodology below.
To prevent thermal radiation from affecting the Vision Camera, optical filters are used to block wavelengths that are thermally generated in significant amounts by the die. Choosing which optical filter to use requires establishing a maximum measurable temperature. The higher the maximum measurable temperature, the more of the camera’s spectrum that the filter must block. Intuitively, the filter must block the infrared region to which the CCD is sensitive. However, setting the maximum measurable temperature sufficiently high requires blocking some of the wavelengths in the visible spectrum. The maximum measurable temperature is chosen to be 600 ◦ C, since this is only about 50 ◦ C below the melting point of aluminum and magnesium, which are the most common materials used in die casting.
Typically flexibility as an integral factor in the physical education practice is evaluated by the ability to perform a tilt forward from a standing position. The expediency of using this test is due to the fact that from a practical point of view, the t important is the flexibility of a spine and it is believed that the "combined flexibility of the body" can be judged by bending forward. In addition, it is simple and accessible for measurements during mass examinations and does not require tions of conducting. At the same time, we should note that to provide standartisation of testing procedures by this method is almost impossible. This method of flexibility testing is characterized by the certain dependence of subjective mining the results of the exercise. The defined facts make impossible and difficult the obtaining of the reliable informative monitoring results due to a large number of uncontrolled variables and the absence of a certain registration system for test results. Hence, there is a need for a radically new approach to this issue.