scholarly journals Optimal Design of a Flyback Microinverter Operating under Discontinuous-Boundary Conduction Mode (DBCM)

Energies ◽  
2021 ◽  
Vol 14 (22) ◽  
pp. 7480
Author(s):  
Georgios Christidis ◽  
Anastasios Nanakos ◽  
Emmanuel Tatakis
Keyword(s):  
Power Loss ◽  
Design Procedure ◽  
Sinusoidal Wave ◽  
Flyback Converter ◽  
Loss Analysis ◽  
Discontinuous Boundary ◽  
Loss Models ◽  
Optimization Methodology ◽  
Conduction Mode ◽  
Selection Of

The flyback converter has been widely used in Photovoltaic microinverters, operating either in Discontinuous, Boundary, or Continuous Conduction Mode (DCM, BCM, CCM). The recently proposed hybrid DBCM operation inherits the merits of both DCM and BCM. In this work, the necessary analytical equations describing the converter operation for any given condition under DBCM are derived, and are needed due to the hybrid nature of the modulation strategy during each sinusoidal wave. Based on this analysis, a design optimization sequence used to maximize the weighted efficiency of the inverter under DBCM is then applied. The design procedure is based on a power loss analysis for each converter component and focuses on the appropriate selection of the converter parameters. To achieve this, accurate, fully parameterized loss models of the converter components are implemented. The power loss analysis is then validated by applying the optimization methodology to build an experimental prototype operating in DBCM.

scholarly journals Power Loss Analysis and a Control Strategy of an Active Cell Balancing System Based on a Bidirectional Flyback Converter

2020 ◽  
Vol 10 (12) ◽  
pp. 4380
Author(s):  
Yu-Lin Lee ◽  
Chang-Hua Lin ◽  
Shih-Jen Yang
Keyword(s):  
Metal Oxide ◽  
Control Strategy ◽  
Power Loss ◽  
Metal Oxide Semiconductor ◽  
Active Cell ◽  
Oxide Semiconductor ◽  
Flyback Converter ◽  
Loss Analysis ◽  
Loss Models ◽  
Cell Balancing

This research proposes a power loss analysis and a control strategy of an active cell balancing system based on a bidirectional flyback converter. The system aims to achieve an energy storage application with cells connected in 6 series and 1 parrarel (6S1P) design. To reduce the structural complexity, Metal-Oxide-Semiconductor Field Effect Transistor (MOSFET) array commonly used in balancing system is replaced with the photovoltaic Metal-Oxide-Semiconductor (photoMOS) array. Power loss analysis is utilized for the system operating in the proper current to reach higher efficiency. The proposed loss models are divided into conduction loss, switching loss, and copper and core loss of the transformer. Besides, the models are used to estimate the loss of converter operating in different balance conditions to evaluate the system efficiency and verified by the implemented balancing circuit. By way of the loss models, the balancing current can be determined to reach higher efficiency of the proposed system. For further improvement of the balancing process, the system has also applied a control strategy to enhance the balancing performance that reduces 50% maximum voltage difference than traditional cell-to-pack architecture, and 47% balancing duration than traditional pack-to-cell architecture.

Power Loss Analysis and the Selection of a Most Efficient Clutching Sequence Associated With an Automatic Transmission Mechanism

1997 ◽  
Author(s):  
Hsin-I Hsieh ◽  
Lung-Wen Tsai
Keyword(s):  
Power Loss ◽  
Automatic Transmission ◽  
Transmission Mechanism ◽  
Torque Distribution ◽  
Loss Analysis ◽  
Epicyclic Gear ◽  
Gear Mechanism ◽  
Selection Of

Abstract This paper presents a methodology for the identification of a most promising clutching sequence associated with an epicyclic-type automatic transmission mechanism. First, a methodology for the analysis of torque distribution on the links of an epicyclic gear mechanism is described. Then, the power loss relations associated with various clutching sequences of an epicyclic gear mechanism are derived. Finally, a procedure for the selection of a most efficient clutching sequence associated with a transmission mechanism is developed.

scholarly journals Analysis of Radial Inflow Turbine Losses Operating with Supercritical Carbon Dioxide

Energies ◽  
2021 ◽  
Vol 14 (12) ◽  
pp. 3561
Author(s):  
Antti Uusitalo ◽  
Aki Grönman
Keyword(s):  
Fluid Dynamic ◽  
Dynamic Simulations ◽  
Average Deviation ◽  
Loss Analysis ◽  
Specific Speed ◽  
Loss Models ◽  
Rotor Losses ◽  
Radial Turbines ◽  
Design Power ◽  
Good Agreement

The losses of supercritical CO2 radial turbines with design power scales of about 1 MW were investigated by using computational fluid dynamic simulations. The simulation results were compared with loss predictions from enthalpy loss correlations. The aim of the study was to investigate how the expansion losses are divided between the stator and rotor as well as to compare the loss predictions obtained with the different methods for turbine designs with varying specific speeds. It was observed that a reasonably good agreement between the 1D loss correlations and computational fluid dynamics results can be obtained by using a suitable set of loss correlations. The use of different passage loss models led to high deviations in the predicted rotor losses, especially with turbine designs having the highest or lowest specific speeds. The best agreement in respect to CFD results with the average deviation of less than 10% was found when using the CETI passage loss model. In addition, the other investigated passage loss models provided relatively good agreement for some of the analyzed turbine designs, but the deviations were higher when considering the full specific speed range that was investigated. The stator loss analysis revealed that despite some differences in the predicted losses between the methods, a similar trend in the development of the losses was observed as the turbine specific speed was changed.

scholarly journals Evolutionary Multitasking-Based Multiobjective Optimization Algorithm for Channel Selection in Hybrid Brain Computer Interfacing Systems

2021 ◽  
Vol 15 ◽  
Author(s):  
Tianyu Liu ◽  
Zhixiong Xu ◽  
Lei Cao ◽  
Guowei Tan
Keyword(s):  
Multiobjective Optimization ◽  
Real Life ◽  
Channel Selection ◽  
Research Field ◽  
Neural Engineering ◽  
Computer Interfaces ◽  
Classification Tasks ◽  
Optimization Methodology ◽  
Brain Computer Interfacing ◽  
Selection Of

Hybrid-modality brain-computer Interfaces (BCIs), which combine motor imagery (MI) bio-signals and steady-state visual evoked potentials (SSVEPs), has attracted wide attention in the research field of neural engineering. The number of channels should be as small as possible for real-life applications. However, most of recent works about channel selection only focus on either the performance of classification task or the effectiveness of device control. Few works conduct channel selection for MI and SSVEP classification tasks simultaneously. In this paper, a multitasking-based multiobjective evolutionary algorithm (EMMOA) was proposed to select appropriate channels for these two classification tasks at the same time. Moreover, a two-stage framework was introduced to balance the number of selected channels and the classification accuracy in the proposed algorithm. The experimental results verified the feasibility of multiobjective optimization methodology for channel selection of hybrid BCI tasks.

scholarly journals An Unified Design Procedure for Flying Machining Operations

2012 ◽  
Author(s):  
Roberto Strada ◽  
Bruno Zappa ◽  
Hermes Giberti
Keyword(s):  
Design Procedure ◽  
Point Of View ◽  
Drive System ◽  
General Validity ◽  
The Subject ◽  
Machining Operations ◽  
Selection Of ◽  
Unified Design

“Flying machining” represents synchronization of an axis (slave) with a master axis in motion. One of the most important aspects of the design of “flying machining” operation is the choice of the proper law of motion of the slave axis. In literature, technical reports and papers can be found concerning this subject, but they deal with specific problems and the solutions or suggestions proposed are specific as well, suitable for those cases. In order to try to overcome this limitation, in this paper we analyze the subject of the flying machining operations from a wider point of view. We propose a unified design procedure with general validity, suitable for the choice of the slave axis’ law of motion for whatever “flying machining” operation. Furthermore methodologies for the selection of the drive system will be proposed. The procedure is described applying it on a cross sealing operation, typical of wrapping machine.

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