scholarly journals Buck-Boost Single-Stage Microinverter for Building Integrated Photovoltaic Systems

Energies ◽  
2021 ◽  
Vol 14 (23) ◽  
pp. 7854
Author(s):  
Derick Mathew ◽  
Mohamed Emad Farrag ◽  
Rani Chinnappa Naidu ◽  
Rajesh Kumar Muthu ◽  
A Sivaprakasam ◽  
...  

Microinverters for Building Integrated Photovoltaic (BIPV) systems must have had a small number of components, be efficient, and be reliable. In this context, a single-phase Buck-Boost Single-stage Microinverter (BBSM) for grid-connected BIPV systems is presented. The concept of topology is extracted from the buck-boost converter. The leakage current in the system is kept under control. It uses an optimal number of active and passive components to function at a high-efficiency level. The suggested topology provides a high level of reliability due to the absence of shoot-through problems. To validate the findings, a simulation in combination with an experimental system for a 70 W system is developed with the design approach. The efficiency of the microinverter, total harmonic distortion of the grid current are measured as 96.4% and 4.09% respectively. Finally, a comparison study has indicated the advantages and disadvantages of the suggested inverter.

Author(s):  
L. S. Pioro ◽  
I. L. Pioro

It is well known that high-level radioactive wastes (HLRAW) are usually vitrified inside electric furnaces. Disadvantages of electric furnaces are their low melting capacity and restrictions on charge preparation. Therefore, a new concept for a high efficiency combined aggregate – submerged combustion melter (SCM)–electric furnace was developed for vitrification of HLRAW. The main idea of this concept is to use the SCM as the primary high-capacity melting unit with direct melt drainage into an electric furnace. The SCM employs a single-stage method for vitrification of HLRAW. The method includes concentration (evaporation), calcination, and vitrification of HLRAW in a single-stage process inside a melting chamber of the SCM. Specific to the melting process is the use of a gas-air or gas-oxygen-air mixture with direct combustion inside a melt. Located inside the melt are high-temperature zones with increased reactivity of the gas phase, the existence of a developed interface surface, and intensive mixing, leading to intensification of the charge melting and vitrification process. The electric furnace clarifies molten glass, thus preparing the high-quality melt for subsequent melt pouring into containers for final storage.


Energies ◽  
2020 ◽  
Vol 13 (12) ◽  
pp. 3069
Author(s):  
Yahui Li ◽  
Pu Deng ◽  
Jing Zhang ◽  
Donghang Liu ◽  
Zhenghang Hao

Real-time online simulation based on a real-time workshop (RTW) plays a vital role in the study and application of power electronics. However, restricted by the performance of equipment and hardware, the simulators so far available in the market mainly support simulation steps over 50 μs, while large step simulation may result in the action delay of pulse-width modulating (PWM), numerical oscillation and high-level non-characteristic harmonic distortion. In view of these problems, this paper puts forward a modeling method based on integral prediction and interpolation compensation. First of all, prediction is performed one step in advance by the implicit trapezoidal method to find out the accurate time when the triangle carrier wave intersects with the modulation wave. At the same time, a mathematic model is built for the insulated gate bipolar transistor (IGBT) to output equivalent voltage waveform according to the principle of area equivalent. Next, in MATLAB/Simulink, offline simulation is performed with the three-phase AC-DC-AC converter as the subject. By comparing the control accuracy, the content of harmonic wave and the simulation time, the simulation effects of the 50 μs fixed-step interpolation prediction model are the same as that for a 5 μs fixed-step standard model. Finally, the effectiveness and high efficiency of this algorithm are verified on a real-time simulator, marking the application of offline models on real-time simulators.


Author(s):  
Santhi Mary Antony ◽  
Godwin Immanuel

Now day’s the power factor has become a major problem in power system to improve the power quality of the grid, as power factor is affected on the grid due to the nonlinear loads connected to it. Single phase bridgeless AC/DC power factor correction (PFC) topology to improve the power factor as well as the total harmonic distortion (THD) of the utility grid is proposed. By removing the input bridge in conventional PFC converters, the control circuit is simplified; the total harmonics distortion (THD) and power factor (PF) are improved. The PI controller operates in two loops one is the outer control loop which calculates the reference current through LC filter and signal processing. Inner current loop generates PWM switching signals through the PI controller. The output of the proposed PFC topology is verified for prototype using MATLAB circuit simulations. The experimental system is developed, and the simulation results are obtained.


2013 ◽  
Vol 16 (3) ◽  
pp. 29-40
Author(s):  
Phuong Minh Le ◽  
Dzung Quoc Phan ◽  
Huy Minh Nguyen ◽  
Phong Hoai Nguyen

This paper presents an implementation of the DC/DC push–pull converter for an uninterruptible power supply (UPS). Some classical DC/DC converters are presented and analyzed for pointing out their advantages and drawbacks. Besides, an original system based on a push-pull converter associated with a dynamic modulation control is chosen. The main advantage is the possibility to control the delivered electric power in a wide range from very low level to high level of voltage within the same basic architecture. It can reduce the switching power losses and increase the power conversion efficiency. This paper proposed a new control scheme of the DC/DC converter and DC/AC inverter. The suggested system consists of a high efficiency DC/DC converter and a singlephase DC/AC inverter has been simulated using Matlab/Simulink and designed basing on the DSP TMS320F28027. Both results show high performances of the DC link and AC load voltages, when load changes from zero to rated. The performance of the proposed system has been verified through a 1kW prototype of the system for a 50 Hz/220-230 VAC load sourcing by two series connected batteries of 12V. The proposed DC/DC converter achieves a high efficiency of 93.0%. The system including the DC/DC converter and DC/AC inverter achieves an efficiency of 91.2% and Total Harmonic Distortion (THD) of AC load voltage reached 1.9%.


2018 ◽  
Vol 173 ◽  
pp. 02041
Author(s):  
Lin Chunxu ◽  
Zhou Chunhua ◽  
Li Wei ◽  
Chen Rui

In order to reduce the total harmonic distortion (THD) of the grid-connected current caused by the high-frequency switching of the inverter, this paper combines the high efficiency single-phase H6-type inverter with LCL filter. The double closed-loop control method that consists of grid-connected current outer loop and capacitor current inner loop is put forward, by which a resonance peak of a low damping LCL filter is eliminated. In the grid-connected current outer loop, quasi proportion resonant (QPR) controller is adopted to overcome the steady-state error and weak anti-jamming capability in traditional PI controller. Finally, a simulation model is built in SIMULINK to verify the research. The simulation results show that, based on the single-phase H6-type inverter and LCL filter, the double closed-loop QPR control strategy can achieve the static error free tracking control of grid-connected current, which makes the system more stable and reduces the THD of grid-connected current effectively.


The paper presents a compact AC-AC single phase voltage regulator based on Impedance network. The proposed topology has ability to perform buck and boost operation in a single stage .The circuit is simple, highly efficient and more importantly reduced manufacturing cost due to its minimal number of active and passive components. The Impedance network has dual function of boosting and filtering. The proposed topology employs two bidirectional switches operating at high frequency PWM pulses. The high frequency switching reduces the size of the Impedance network. The gain of the system is controlled by controlling the duty cycle of the bidirectional switches. The operating mechanism of the proposed topology along with simulation and experimental results are presented.


2022 ◽  
Vol 13 (1) ◽  
pp. 18
Author(s):  
Tianran He ◽  
Ziqiang Zhu ◽  
Fred Eastham ◽  
Yu Wang ◽  
Hong Bin ◽  
...  

This paper overviews high-speed permanent magnet (HSPM) machines, accounting for stator structures, winding configurations, rotor constructions, and parasitic effects. Firstly, single-phase and three-phase PM machines are introduced for high-speed applications. Secondly, for three-phase HSPM machines, applications, advantages, and disadvantages of slotted/slotless stator structures, non-overlapping/overlapping winding configurations, different rotor constructions, i.e., interior PM (IPM), surface-mounted PM (SPM), and solid PM, are summarised in detail. Thirdly, parasitic effects due to high-speed operation are presented, including various loss components, rotor dynamic and vibration, and thermal aspects. Overall, three-phase PM machines have no self-starting issues, and exhibit high power density, high efficiency, high critical speed, together with low vibration and noise, which make them a preferred choice for high-performance, high-speed applications.


Author(s):  
Ye Dai ◽  
Wan-Jian Wen ◽  
Li-Yu Xuan ◽  
Xiao-Yang Yu ◽  
Gang Wang

Background: The motorized spindle preload technology is one of the motorized spindle key technologies, and adjusting the preload according to the working conditions can effectively improve the dynamic performance of the motorized spindle and enhance the machining accuracy. Objectives: Review the preload mechanism development, introduce various preload mechanisms, and show research status in recent years. Then to explore and predict the future development of preload technology through the analysis of the overall preload mechanism. Methods: Search for different kinds of patents and literature about spindle preload structure in recent years. Through structural research and comparison with the traditional preload mechanism, to review the structure principle of various preload mechanisms at the present stage, then shown the advantages and disadvantages of each structure. Result: According to the patents and research of the preload mechanism in recent years, classification introduced the piezoelectric ceramic preload device, electromagnetic preload device, and hydraulic preload device, and so on. Introduce their advantages and existing problems in detail, then comprehensively compare the advantages and disadvantages of various mechanisms in control and mechanism. Finally, discuss the prospects and development directions of preload technology. Conclusion: With the further development of technology, high-precision products have higher requirements for machine tools, such as low latency, low heat generation, high efficiency, and long life. People use electromagnetic force, air pressure, hydraulic pressure, and other methods, to control the magnitude of the preload, maintain the performance of the motorized spindle at a high level. Compared with the traditional quantitative preload, their applicable working conditions are more extensive and accuracy is higher. However, various new preload methods still have certain shortcomings and need further improvement.


2014 ◽  
Vol 573 ◽  
pp. 72-77 ◽  
Author(s):  
J. Gnana Vadivel ◽  
A. Aswini ◽  
N. Senthil Kumar ◽  
S.T. Jaya Christa

This paper proposes the single phase ac-dc three-level boost converter with controller circuit such as sliding mode controller, proportional integral controller and employs three-level pulse width modulation technique. Solid state switched mode three-level boost converter along with the control methods achieve unity power factor, high efficiency, precisely regulated dc output in boost converter, reduced output voltage ripple and less than 5% of total harmonic distortion with unidirectional power flow. The outstanding feature of proposed control scheme is line current is driven to follow sinusoidal reference current command which is in phase with sinusoidal input voltage and guaranteeing dc-link capacitor voltage balance in every switching cycle. Comparative analysis of PI controller and sliding mode controller is carried out. The performances of converter under load variation, unbalanced load condition and sudden change in load condition for various control strategies were verified.


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