Results in Journal Journal of Energy Systems: 57
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Journal of Energy Systems, Volume 4, pp 71-87; doi:10.30521/jes.727975
Model predictive control has been widely used in the industry. This can control the multivariable system with constraints on input and output variables but it needs online computation solver, and creates the non-convex solution in nonlinear plant due to the parameter uncertainties. The online computational problem and non-convex solution of the model predictive control are achieved via neural network model predictive control. The paper explores the speed control of permanent magnet synchronous motor (PMSM) by using neural network model predictive control (NNMPC) technique. The multi-layer artificial neural network is used to identify the dynamics of PMSM. The set point speed tracking control of PMSM is identified by using neural network model predictive control strategy. By using the set of input and output data obtained from the system, the multi input-output feed-forward neural network model is created. Levenberg-Marquardt algorithm is used to train the process models of the PMSM. That provides future plant output for control optimization of the predictive control. The overall system is developed and tested in the MATLAB/Simulink. To evaluate the efficiency of the controller proposed, it is compared with a constrained model predictive controller through the studies of simulation. The overshoot and settling time of the speed response of the PMSM are measured and analyzed for NNMPC and constrained MPC.
Journal of Energy Systems, Volume 4, pp 32-47; doi:10.30521/jes.690997
Direct drive gearless axial flux permanent magnet synchronous generators (AFPMSG) are designed as multi-pole for use in vertical axis wind turbines. In particular, there are multi-pole core/coreless stator structures with axial flux for use in vertical axis wind turbines (WT) that can be designed in a compact structure at low wind speeds. In this study, the parametric simulation studies have been carried out according to rotor mechanical speeds with certain linear steps depending on different wind speed scenarios for an AFPMSG designed with 16-pole and cored stator for 5 kVA rated power with the finite element analysis (FEA) software. According to the analysis results obtained, the performance of the generator is reported and current, voltage, power losses and flux distribution are investigated. In addition, the DC bus voltage at the output of the DC-DC boost converter circuit due to wind speed changes is adaptively controlled for AFPMSG, which is co-simulated with the power electronics interface used at the generator output. Thus, both power electronics circuit performance and generator side have been simulated simultaneously with electromagnetic modeling. Therefore, the performance of the designed AFPMSG, which is modeled in three dimensions (3D) before the prototype stage, can be determined under more realistic conditions.
Journal of Energy Systems, Volume 4, pp 58-70; doi:10.30521/jes.740587
The very high annual heat demand of greenhouses is the most critical factor that increases production costs. Conventional methods are generally used to obtain the optimum temperature required for greenhouses. In these systems, greenhouse air is heated by a boiler and pipe networks are connected to it, and in this way, most of the heat energy is transferred from the greenhouse ceiling to the atmosphere. In addition, in the greenhouse, not only the air but also the soil should be heated in order not to spoil the roots of the plants. The objective of this research is to provide sustainable heating for greenhouse applications. For this purpose, an innovative heating system has been designed for greenhouse heating by using of solar energy and heat pump technologies. In this study, a new approach was presented by designing a novelty heat pump flow for the heat required in the greenhouse. With this design, not only greenhouse air but also the soil will be heated and the best conditions for the development of plants will be provided. In the system, an ethylene glycol water mixture was used to prevent damage caused by freezing. In addition, it is designed to provide sustainability with an auxiliary heater when solar radiation is insufficient. It is highly recommended to apply this presented system for all greenhouse types.
Journal of Energy Systems, Volume 4, pp 48-57; doi:10.30521/jes.724207
Nowadays the advancement of technology and equipment to monitor the operating performance of power transformer has achieved a high level. So, the monitoring system enables the continued investigation of the operational work of power transformer parameters as well as the prevention of failures and enhance reliability. However, the monitoring of power transformers is of unquestionable value for the electrical power systems and consumers to have more reliability in supplying. Therefore, given that monitoring involves a considerable number of parameters and elements of transformers, in the present case the overview of the monitoring of some of the most important parameters has been taken into account. Thus, the paper includes the monitoring parameters such as; partial discharges, oil and winding temperatures, bushing currents, tap changer, moisture and dissolved gas analysis. Also, in the paper are presented data for the operation of these parameters in different periods as well as with different loading regimes. The reports of events that correspond to the operational performance of the transformer, which are a good cause for diagnosis and preliminary actions in transformers, are also presented.
Journal of Energy Systems, Volume 4, pp 22-31; doi:10.30521/jes.703313
Journal of Energy Systems, Volume 4, pp 12-21; doi:10.30521/jes.690717
Renewable energy resources are safe and easy to access giving solution to the problems caused by non-renewable energy resources (fossil fuels etc.) and can balance the increasing demand of the electricity generation in Pakistan. The aim of this study was to utilize PVGIS module to estimate the solar electricity generation at six districts (such as Dir, Mansehra, Peshawar, Buner, Dera Ismail Khan (DIK) and Chitral) of Khyber Pakhtunkhwa province of Pakistan. PVGIS is a web based interactive GIS system provided database (based on meteorological geostationary satellites e.g., Meteosat & GOES) which include monthly and yearly average values of the global solar irradiation on horizontal and inclined surfaces, as well as climatic parameters (i.e.; Linke atmospheric turbidity, the ratio of diffuse to global irradiation). Based on the PVGIS module, monthly averages of global irradiation were utilized to estimate the solar electricity generation at six locations of Khyber Pakhtunkhwa. The results showed that the daily as well as monthly electricity production (Ed and Em) and global irradiance (Hd and Hm) for all the districts are maximum in the months of March until October and minimum during January, February, November and December. The acquired results of the estimated electricity production (kWh) and the estimated irradiations (kwh/m2) per year from a PV system for the six districts exhibited that Dera Ismail Khan (DIK) district has highest estimated electricity production as well as estimated irradiations followed by Buner, Dir and Peshawar districts. It is concluded that PVGIS datasets can be used for the estimation of solar electricity generation and as a support system for the policy-making in the region.
Journal of Energy Systems, Volume 4, pp 1-11; doi:10.30521/jes.635582
Journal of Energy Systems, Volume 3, pp 168-182; doi:10.30521/jes.623285
Journal of Energy Systems, Volume 3, pp 183-187; doi:10.30521/jes.659237
Journal of Energy Systems, Volume 3, pp 158-167; doi:10.30521/jes.616982