scholarly journals Research on the Power Output Characteristics of a Coupling Transformer in D-FACTS

Energies ◽  
2019 ◽  
Vol 12 (24) ◽  
pp. 4709
Author(s):  
Zhimin He ◽  
Shuo Zhang ◽  
Yadong Liu ◽  
Fan Wu ◽  
Gehao Sheng ◽  
...  

The series coupling distributed flexible AC transmission system (D-FACTS) device couples the secondary side compensating reactance to the primary side based on the principle of transformer, thus realizing the goal of adjusting the transmission line parameters and controlling the distribution network flow. The coupling transformer is the most important power conversion part in the D-FACTS device but has different working principles of mutual inductor. The magnetizing current of the coupling transformer changes within a large range, which makes the traditional power output model of mutual inductor inapplicable. In this paper, the power output model of coupling transformer was constructed by viewing the coupling transformer as a constant current source. Moreover, the corresponding relationship between the output power of the transformer and related parameters, as well as between variations of reactive output power and active loss power with load changes, was analyzed. Some conclusions were drawn: (1) the output power characteristic curve of the coupling transformer was acquired; (2) given a constant line current, the maximum power was achieved when the system’s capacitive reactance and the internal resistance of the transformer matched, and the maximum power was unrelated to the number of turns of the coupling transformer; (3) the output power changed with the variation of the line current, and there was a proportional relationship between the maximum power and the square of the line current. Next, the relationship between the maximum output power and the air gap thickness of the magnetic core was discussed. Finally, these conclusions were proved accurate via experiments.

AVITEC ◽  
2019 ◽  
Vol 1 (1) ◽  
Author(s):  
Ernando Rizki Dalimunthe

Optimizing the output power value of a solar cell requires a tracker. The tracking is called the maximum power point tracking (MPPT) which will produce a maximum output power value. Each component in this system is modeled into Simulink. This simulation is designed to optimize the work of solar cells by searching maximum power points using perturb and observe (P & O) algorithms, then duty cycles are output  of the algorithms become Buck-Boost Converter inputs as switching so they can produce output power with better output  power. Simulation results show that MPPT can increase the average output power on changes in the value of sun irradiation, temperature and load than systems that do not use MPPT. The factor of the average difference in power is 37.82%.


Author(s):  
Amine Rachakh ◽  
Larbi El Abdellaoui ◽  
Jamal Zbitou ◽  
Ahmed Errkik ◽  
Abdelali Tajmouati ◽  
...  

Power Amplifiers (PA) are very indispensable components in the design of numerous types of communication transmitters employed in microwave technology. The methodology is exemplified through the design of a 2.45GHz microwave power Amplifier (PA) for the industrial, scientific and medical (ISM) applications using microstrip technology. The main design target is to get a maximum power gain while simultaneously achieving a maximum output power through presenting the optimum impedance which is characteristically carried out per adding a matching circuit between the source and the input of the power amplifier and between the load and the output of the power amplifier. A "T" matching technique is used at the input and the output sides of transistor for assure in band desired that this circuit without reflections and to obtain a maximum power gain. The proposed power amplifier for microwave ISM applications is designed, simulated and optimized by employing Advanced Design System (ADS) software by Agilent. The PA shows good performances in terms of return loss, output power, power gain and stability; the circuit has an input return loss of -38dB and an output return loss of -33.5dB. The 1-dB compression point is 8.69dBm and power gain of the PA is 19.4dBm. The Rollet's Stability measure B1 and the stability factor K of the amplifier is greater than 0 and 1 respectively, which shows that the circuit is unconditionally stable. The total chip size of the PA is 73.5× 36 mm2.


2021 ◽  
Vol 2 (2) ◽  
pp. 162-167
Author(s):  
Haris Masrepol ◽  
Muldi Yuhendri

Solar panels are a renewable energy power plant that uses sunlight as its main energy source. The power generated by solar panels are determined by the size of the solar panels, solar radiation and temperature. The power of the solar panels is also determined by the output voltage of the solar panels. To get the maximum output power at any time, it is necessary to adjust the output voltage of the solar panel. This study proposes controlling the maximum output power of solar panels, also known as maximum power point tracking (MPPT) by adjusting the output voltage of the solar panels using a buck converter. The buck converter output voltage regulation at the maximum power point of the solar panel is designed with the Perturbation and Observation (PO) algorithm which is implemented using an Arduino Mega 2560. This MPPT control system is applied to 4x50 Watt-Peak (WP) solar panels which are connected in parallel. The experimental results show that the proposed MPPT control system with the PO algorithm has worked well as expected. This can be seen from the output power generated by the solar panels already around the maximum power point at any change in solar radiation and temperature.


2021 ◽  
Vol 4 (2) ◽  
pp. 49-55
Author(s):  
Rao Muhammad Asif ◽  
Muhammad Abu Bakar Siddique ◽  
Ateeq Ur Rehman ◽  
Muhammad Tariq Sadiq ◽  
Adeel Asad

Photovoltaic energy is considered highly favorable due to the environment's pleasant nature. After analyzing different maximum power point tracking (MPPT) algorithms, an effective control scheme is proposed to obtain stabilized maximum output power throughout the PV system. Therefore, this article presents an efficient control algorithm for the extraction of maximum power through a PV system under severe climatic drifts. The modified fuzzy logic controller sustains the maximum output power of the system by defining fuzzy rules to control the duty cycle appropriately. A DC-DC boost converter is also modeled to stabilize and maintain output power under variant climatic uncertainties. Furthermore, charging management control is also implemented on lead-acid battery bank to store PV energy for backup usage. It defines charging-discharging time and state of charge for keeping the battery bank healthier.


2005 ◽  
Vol 3 (2) ◽  
pp. 131-136 ◽  
Author(s):  
G. Q. Lu ◽  
C. Y. Wang

A silicon-based micro direct methanol fuel cell (μDMFC) for portable applications has been fabricated and its electrochemical characterization carried out. A membrane-electrode assembly (MEA) was specially fabricated to mitigate methanol crossover. The cell with active area of 1.625cm2 demonstrated a maximum power density of 50mW∕cm2 at 60°C. Since the silicon wafer is too fragile to compress for sealing, and a thicker layer of gold has to be coated on the silicon wafer to reduce contact resistance, further development of micro DMFCs for high power application was carried out using stainless steel as bipolar plate in which flow channels were fabricated by photochemical etching technology. The maximum power density of the micro DMFC reaches 62.5mW∕cm2 at 40°C and 100mW∕cm2 at 60°C with atmospheric pressure. An 8-cell air-breathing DMFC stack has been developed. Mass transport phenomena such as water transport and oxygen transport were investigated. By using a water management technique, cathode flooding was avoided in our air-breathing DMFC stack. Furthermore, it was found that oxygen transport in the air-breathing cathode is still very efficient. The DMFC stack produced a maximum output power of 1.33W at 2.21V at room temperature, corresponding to a power density of 33.3mW∕cm2. A passive DMFC using pure methanol was demonstrated with steady-state output power of 20-25mW∕cm2 over more than 10h without heat management.


2011 ◽  
Vol 148-149 ◽  
pp. 169-172 ◽  
Author(s):  
Hong Yan Wang ◽  
Xiao Biao Shan ◽  
Tao Xie

The impedance matching and the optimization of power from a circular piezoelectric energy harvester with a central-attached mass are studied. A finite element model is constructed to analyze the electrical equivalent impedance of the circular piezoelectric energy harvester. Furthermore, the complex conjugate matching load is used to extract the maximum output power of the energy harvester. The power output from complex conjugate matching load is compared with the power output from the resistive matching load and a constant resistance, separately. The results suggest that the complex conjugate matching can result in a significant increase of the output power for all frequencies. The effective bandwidth of the piezoelectric energy harvester is extended significantly.


Author(s):  
Wentao Sui ◽  
Huirong Zhang ◽  
Chongqiu Yang ◽  
Dan Zhang ◽  
Rujun Song ◽  
...  

This paper presents a magnetically coupling bending-torsion piezoelectric energy harvester based on vortex-induced vibration from low-speed wind. The theoretical model of the energy harvester was formulated and validated by wind tunnel experiments. Numerical and experimental results showed that the power output and bandwidth of the proposed harvester are improved about 180% and 230% respectively compared with the nonmagnetic coupling harvester. Furthermore, the effects of cylinder, piezoelectric layer, load resistance, and magnetic nonlinear parameters on the harvester were investigated based on the distributed parameter model. The results showed that the length of cylinder hardly affect output power, but the diameter of cylinder presented complicated influences. The width of piezoelectric beam was negatively correlated with the torsion angle. With increasing the length of piezoelectric layer, an optimal wind velocity and load resistance can be obtained for the maximum output power. With decreasing of the distance between two magnets, the resonant bandwidth, the optimal power output, and torsion angle can be enhanced, respectively. Besides, the magnetic potential energy increased owing to the magnetically coupling, which led to the improvement of onset speed for the energy harvester. This study provides a guideline on improving the performance of bending-torsion vibration piezoelectric energy harvester.


Author(s):  
Guoqiang Lu ◽  
Chao-Yang Wang

A silicon-based micro direct methanol fuel cell (μDMFC) for portable applications has been fabricated and its electrochemical characterization carried out. A membrane-electrode assembly (MEA) was specially fabricated to mitigate methanol crossover. The cell with the active area of 1.625 cm2 demonstrated a maximum power density of 50 mW/cm2 at 60°C. Since silicon wafer is too fragile to compress for sealing, and a thicker layer of gold has to be coated on the silicon wafer to reduce contact resistance, further development of micro DMFCs for high power application was carried out using stainless steel plate as bipolar plate in which flow channels were fabricated by photochemical etching technology. The maximum power density of the micro DMFC reaches 62.5 mW/cm2 at 40 °C and 100 mW/cm2 at 60°C with atmospheric pressure. An 8-cell air-breathing DMFC stack has been developed. Mass transport phenomena such as water transport, and oxygen transport were investigated. By using a water management technique, cathode flooding was avoided in our air-breathing DMFC stack. Furthermore, it was found that oxygen transport in the air-breathing cathode is still very efficient. The DMFC stack produced a maximum output power of 1.33 W at 2.21 V at room temperature, corresponding to a power density of 33.3 mW/cm2. A passive DMFC using pure methanol was demonstrated with steady-state output power of 20–25 mW/cm2 over more than 10 hours without heat management.


Author(s):  
Siddharth Ramachandran ◽  
Naveen Kumar ◽  
Mallina Venkata Timmaraju

Abstract A pragmatic approach is adopted to investigate irreversible thermodynamic combined cycle devices. The finite-time thermodynamic model of combined Stirling-organic Rankine cycle is formulated and evaluated for maximum output power and thermal efficiency. The influence of effectiveness of heat exchangers, heat capacitance of external fluids, and, inlet temperatures of heat exchangers at heat source, heat recovery unit and heat sink on the performance of Stirling-organic Rankine cycle are investigated to get their corresponding optimum. The maximum allowable heat capacitance of external fluids of heat source and heat recovery units are about 1.1 kW/K and 1.4 KW/K, respectively for the operating conditions considered in the present study. The maximum power output is achieved only when the effectiveness of heat exchangers is ideal. The overall performance of Stirling-organic Rankine cycle combination will be higher than either of the performances of individual cycles provided that the isothermal heat rejection from Stirling cycle takes place at temperature above 540 K. Further, a 0.2 increase in the internal irreversibility parameter from an ideal/reversible condition reduced the maximum output power and the corresponding thermal efficiency of Stirling-organic Rankine cycle by 16.1 kW and 24%, respectively.


Sensors ◽  
2021 ◽  
Vol 21 (11) ◽  
pp. 3861
Author(s):  
Jie Mei ◽  
Qiong Fan ◽  
Lijie Li ◽  
Dingfang Chen ◽  
Lin Xu ◽  
...  

With the rapid development of wearable electronics, novel power solutions are required to adapt to flexible surfaces for widespread applications, thus flexible energy harvesters have been extensively studied for their flexibility and stretchability. However, poor power output and insufficient sensitivity to environmental changes limit its widespread application in engineering practice. A doubly clamped flexible piezoelectric energy harvester (FPEH) with axial excitation is therefore proposed for higher power output in a low-frequency vibration environment. Combining the Euler–Bernoulli beam theory and the D’Alembert principle, the differential dynamic equation of the doubly clamped energy harvester is derived, in which the excitation mode of axial load with pre-deformation is considered. A numerical solution of voltage amplitude and average power is obtained using the Rayleigh–Ritz method. Output power of 22.5 μW at 27.1 Hz, with the optimal load resistance being 1 MΩ, is determined by the frequency sweeping analysis. In order to power electronic devices, the converted alternating electric energy should be rectified into direct current energy. By connecting to the MDA2500 standard rectified electric bridge, a rectified DC output voltage across the 1 MΩ load resistor is characterized to be 2.39 V. For further validation of the mechanical-electrical dynamical model of the doubly clamped flexible piezoelectric energy harvester, its output performances, including both its frequency response and resistance load matching performances, are experimentally characterized. From the experimental results, the maximum output power is 1.38 μW, with a load resistance of 5.7 MΩ at 27 Hz, and the rectified DC output voltage reaches 1.84 V, which shows coincidence with simulation results and is proved to be sufficient for powering LED electronics.


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