A CLLC Resonant Converter Based Bidirectional EV Charger with Maximum Efficiency Tracking

2016 ◽  
Author(s):  
Chaohui Liu ◽  
B. Sen ◽  
Jiabin Wang ◽  
C. Gould ◽  
K. Colombage
Keyword(s):  
Maximum Efficiency ◽  
Resonant Converter

scholarly journals High-Frequency LLC Resonant Converter with GaN Devices and Integrated Magnetics

Energies ◽  
2019 ◽  
Vol 12 (9) ◽  
pp. 1781 ◽  
Author(s):  
Yu-Chen Liu ◽  
Chen Chen ◽  
Kai-De Chen ◽  
Yong-Long Syu ◽  
Meng-Chi Tsai
Keyword(s):  
High Frequency ◽  
High Efficiency ◽  
Power Converter ◽  
Maximum Efficiency ◽  
Switching Frequency ◽  
Resonant Converter ◽  
Leakage Inductance ◽  
Llc Resonant Converter ◽  
Resonant Inductor ◽  
Secondary Side

In this study, a light emitting diode (LED) driver containing an integrated transformer with adjustable leakage inductance in a high-frequency isolated LLC resonant converter was proposed as an LED lighting power converter. The primary- and secondary-side topological structures were analyzed from the perspectives of component loss and component stress, and a full-bridge structure was selected for both the primary- and secondary-side circuit architecture of the LLC resonant converter. Additionally, to achieve high power density and high efficiency, adjustable leakage inductance was achieved through an additional reluctance length, and the added resonant inductor was replaced with the transformer leakage inductance without increasing the amount of loss caused by the proximity effect. To optimize the transformer, the number of primary- and secondary-side windings that resulted in the lowest core loss and copper loss was selected, and the feasibility of the new core design was verified using ANSYS Maxwell software. Finally, this paper proposes an integrated transformer without any additional resonant inductor in the LLC resonant converter. Transformer loss is optimized by adjusting parameters of the core structure and the winding arrangement. An LLC resonant converter with a 400 V input voltage, 300 V output voltage, 1 kW output power, and 500 kHz switching frequency was created, and a maximum efficiency of 97.03% was achieved. The component with the highest temperature was the transformer winding, which reached 78.6 °C at full load.

Analysis of LC-LC2 Compensated Inductive Power Transfer for High Efficiency and Load Independent Voltage Gain

2018 ◽  
Author(s):  
Md Morshed Alam ◽  
Saad Mekhilef
Keyword(s):  
Output Power ◽  
High Efficiency ◽  
Domain Analysis ◽  
Air Gap ◽  
Maximum Efficiency ◽  
Voltage Gain ◽  
Resonant Converter ◽  
Power Transfer ◽  
Inductive Power Transfer ◽  
Inductive Power

This paper presents a novel LC-LC2 compensated resonant converter topology to achieve both high efficiency and good voltage gain controllability. An additional receiving side inductor working together with the receiving coil has the contribution to work with a large range of air gap distance. Due to this property, proposed compensation technique is effective for IPT based EV charging application. The frequency domain analysis of the proposed resonant converter provides the load independent voltage gain and ZPA of the input impedance. On the other hand, time domain analysis gives the circuit operation. A 500 W LC-LC2 compensated resonant converter prototype is built to testify the theoretical analysis. To perform the efficiency-comparison under different air gap, an S-SP compensated resonant converter with a similar amount of output power is also presented. In order to obtain the effectiveness, the proposed compensation method is verified by the experimental results. The maximum efficiency of the proposed compensated resonant converter is 93% at an output power of 500 W with a 140-mm air gap between the two sides of the IPT (inductive power transfer) transformer.

scholarly journals LLC Resonant Converter for LEV (Light Electric Vehicle) Fast Chargers

Electronics ◽  
2019 ◽  
Vol 8 (3) ◽  
pp. 362 ◽  
Author(s):  
Do-Hyun Kim ◽  
Min-Soo Kim ◽  
Sarvar Hussain Nengroo ◽  
Chang-Hee Kim ◽  
Hee-Je Kim
Keyword(s):  
Electric Vehicle ◽  
High Efficiency ◽  
Lithium Ion ◽  
Transient State ◽  
Constant Current ◽  
Maximum Efficiency ◽  
Resonant Converter ◽  
Switching Loss ◽  
Super Capacitor ◽  
Llc Resonant Converter

This paper presents a Light Electric Vehicle (LEV) fast charger with a Lithium-Ion Battery (LIB) and Super-Capacitor (SC). The LEV fast charger consists of an AC/DC rectifier and LLC (Inductor-Inductor-Capacitor) resonant Full bridge converter. The LLC resonant converter has high-efficiency and low switching loss because of Zero Voltage Switching (ZVS). So, it is used widely in the industry. In general, the fast charger algorithm uses the Constant Current (CC) mode and Constant Voltage (CV). The CC mode starts at first and then the CV mode finishes. However, there is a big control value gap between the CC mode and CV mode. Therefore, when changing from CC to CV, the transient state occurs. To compensate for the transient state, we propose a new control algorithm. By means of this algorithm, we can achieve a higher level of safety and stability. The fast charger with LIB of 800 Wh and SC of 50 Wh is analyzed and verified, and we obtain a maximum efficiency of 96.4%. The discussions are validated using the LLC resonant full bridge converter prototype at the laboratory level.

Study on the Modes of Operation of a Multi-Machine Installations with Mechanical Reduction

2019 ◽  
pp. 12-22
Author(s):  
A. M. Oleynikov ◽  
L. N. Kanov
Keyword(s):  
Mathematical Description ◽  
Reactive Power ◽  
Maximum Efficiency ◽  
Wind Flow ◽  
System Of Equations ◽  
Mechanical Equilibrium ◽  
Synchronous Generators ◽  
Electromagnetic Excitation ◽  
Number Of Generators ◽  
Wide Range

The paper gives the description of the original wind electrical installation with mechanical reduction in which the output of vertical axis wind turbine with rather low rotation speed over multiplicator is distributed to a certain number of generators. The number of acting generators is determined by the output of actual operating wind stream at each moment. According to this constructive scheme, it is possible to provide effective and with maximum efficiency installation work in a wide range of wind speeds and under any schedule issued to the consumer of electricity. As there are no any experience in using such complexes, mathematical description of its main elements is given, namely windwheels, generators with electromagnetic excitation of magnetic electrical type, then their interaction with windwheel, and also the results of mathematical modeling of work system regimes under using the offered system of equations. The basis for the mathematical description of the main elements of the installation – synchronous generators – are the system of equations of electrical and mechanical equilibrium in relative units in rotating coordinates without considering saturation of the magnetic circuit. The equation of mechanical equilibrium systems includes torque and brake windwheel electromagnetic moments of generators with taking into account the reduction coefficients and friction. In addition, we specify the alternator rotor dynamics resulting from continuous torque of windwheel fluctuations under the influence of unsteady wind flow and wind speed serving as the original variable is modeled by a set of sinusoids. Model simplification is achieved by equivalization of similar generators and by disregarding these transitions with a small time constant. Calculation the installation with synchronous generators of two types of small and medium capacity taking into account the operational factors allowed us to demonstrate the logic of interactions in the main elements of the reported complex in the process of converting wind flow into the generated active and reactive power. We have shown the possibility of stable system work under changeable wind stream condition by regulating of the plant blade angle and with simultaneous varying of generator number of different types. All these are in great interest for project organizations and power producers.

Sustaining Job Performance through Technology Acceptance with Usage of Whatsapp Mobile Application

2020 ◽  
Vol 5 (1) ◽  
pp. 123
Author(s):  
Nor Hayati Kassim ◽  
Norlina Mohamed Noor ◽  
Jati Kasuma ◽  
Juliza Saleh ◽  
Ceaser Dealwis ◽  
...  
Keyword(s):  
Job Performance ◽  
Technology Acceptance ◽  
Mobile Applications ◽  
Mobile Application ◽  
Ease Of Use ◽  
Perceived Usefulness ◽  
Maximum Efficiency ◽  
Perceived Ease Of Use ◽  
Positive Attitudes ◽  
Willingness To Use

Companies are now recognizing that their employees require a spectrum of mobile applications in order to achieve maximum efficiency at the workplace. Mobile applications such as WeChat, Twitter and WhatsApp via smartphones have become influential tools and extensively used by employees at the workplace. This state-of-the-art technology in communication has penetrated various fields, including routine administrative jobs at the workplace. The objective of this research is toinvestigate the acceptance of the WhatsApp mobile application for formal use among support staff at The Commission of the City of Kuching North, Sarawak (DBKU). Perceived usefulness, perceived ease of use and behavioral intention of the users in using WhatsApp are the variables measured for job performance. The researchers utilized convenience sampling, whereby a total of 105 employees from two departments participated in the investigation. Data was collected using a set of selfadministered questionnaires which was adapted from Davis. The findings revealed that perceived usefulness and perceived ease of use of WhatsApp as a means of communication were significant for job performance at DBKU. The employees felt more competent during their formal interaction at the workplace as less effort was needed while using WhatsApp. The existence of features which were user-friendly and easy operational functions helped to create positive attitudes when utilizing the application. Faster feedback, ease of use, and convenience were some of the reasons for the employees’ willingness to use WhatsApp for communication at the workplace.

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