scholarly journals Analysis and Implementation of a Hybrid DC Converter with Wide Voltage Variation

2021 ◽  
Vol 11 (21) ◽  
pp. 10211
Author(s):  
Bor-Ren Lin ◽  
Yue-Ying Zhuang
Keyword(s):  
Power Flow ◽  
Low Voltage ◽  
Input Voltage ◽  
Pulse Frequency ◽  
Resonant Circuit ◽  
Bridge Structure ◽  
Pulse Frequency Modulation ◽  
Switching Losses ◽  
Voltage Variation ◽  
Bidirectional Power Flow

A new hybrid DC converter is proposed and implemented to have wide voltage variation operation and bidirectional power flow capability for photovoltaic power applications. The hybrid DC converter, including a half- or full-bridge resonant circuit, is adopted to realize the bidirectional power operation and low switching losses. To overcome the wide voltage variation problem (60 V–480 V) from photovoltaic panels due to sunlight intensity, the full-bridge structure or half-bridge structure resonant circuit is used in the presented converter to implement high or low voltage gain under a low or high input voltage condition. Using a pulse frequency modulation (PFM) scheme, the voltage transfer function of the resonant circuit is controlled to regulate the load voltage. Due to the symmetric circuit structures used on the primary and the secondary sides in the proposed converter, the bidirectional power flow can be achieved with the same circuit characteristics. Therefore, the proposed converter can be applied to battery stacks to achieve charger and discharger operations. Finally, a 400 W prototype is implemented, and the performance of the proposed hybrid DC converter is confirmed by the experiments.

Protection Scheme for DC Microgrid Distribution System

2012 ◽  
Vol 614-615 ◽  
pp. 1661-1665
Author(s):  
Ling Hui Deng ◽  
Zhi Xin Wang ◽  
Jian Min Duan
Keyword(s):  
Distribution System ◽  
Cost Efficiency ◽  
Power Flow ◽  
Low Voltage ◽  
Dc Microgrid ◽  
Protection Scheme ◽  
High Level ◽  
Bidirectional Power Flow ◽  
Efficiency And Reliability ◽  
Laboratory Prototype

The low voltage DC (LVDC) distribution system is a new concept and a promising technology to be used in the future smart distribution system having high level cost-efficiency and reliability. In this paper, a low-voltage (LV) DC microgrid protection system design is proposed. Usually, an LVDC microgrid must be connected to an ac grid through converters with bidirectional power flow and, therefore, a different protection scheme is needed. This paper describes practical protection solutions for the LVDC network and an LVDC system laboratory prototype is being experimentally tested by MATLAB/SIMULINK. The results show that it is possible to use available devices to protect such a system. But other problems may arise which needs further study.

scholarly journals A Bidirectional Double Uneven Power Converter Based DC–DC Converter for Solid-State Transformers

Electronics ◽  
2018 ◽  
Vol 7 (11) ◽  
pp. 334 ◽  
Author(s):  
Kiwoo Park ◽  
Kyo-Beum Lee
Keyword(s):  
Solid State ◽  
Distribution System ◽  
Power Flow ◽  
Power Converter ◽  
Small Scale ◽  
Power Semiconductor ◽  
Switching Losses ◽  
Zero Current Switching ◽  
Zero Current ◽  
Bidirectional Power Flow

This paper presents a novel bidirectional double uneven power (BiDUP) based dc-dc converter and its design and control methods. The proposed converter utilizes two dual active bridge (DAB) converters with different power ratings in a special way to realize zero current switching (ZCS), where both turn-on and turn-off switchings occur under the zero-current condition. A design example of the proposed BiDUP converter is presented for medium voltage (MV) and high-power solid-state transformer (SST) systems where both voltage transformation and bidirectional power flow are required. The main features of the proposed converter are to reduce both the switching losses in power semiconductor devices and the filter inductance requirement simultaneously. To verify the feasibility of the proposed converter, a simulation study on the BiDUP converter based SST in a distribution system is presented. Furthermore, to validate the operational principle of the proposed converter, an experimental study using a small-scale prototype is also presented.

scholarly journals Design and Implementation of 2.5kW IBFB-LLC DC/ DC Converter Using SiC Mosfet

2021 ◽  
Vol 31.2 (149) ◽  
pp. 7-14
Keyword(s):  
High Frequency ◽  
Power Flow ◽  
Input Voltage ◽  
Voltage Range ◽  
Zero Voltage Switching ◽  
Design And Implementation ◽  
Switching Losses ◽  
Power Switches ◽  
Isolation Transformer ◽  
Zero Voltage

Interleaved Boost Full Bridge integrated LLC resonant (IBFB- LLC) is an isolated DC/DC converter with directional power flow, which can cope with a wide input voltage range of PV applications. The main losses of the converter are switching losses of the power switches and transformers losses. This paper proposes a method to improve the efficiency of the IBFB converter due to zero voltage switching technique, in combination with employing new SiC MOSFET technology instead of the conventional Si MOSFET. In addition, Litz wire is also adopted to reduce the losses on the high frequency isolation transformer. Both numerical simulations and experiments with a prototype 2.5kW converter are implemented to verify the feasibility and effectiveness of the proposed solution.

scholarly journals Hybrid LLC Converter with Wide Range of Zero-Voltage Switching and Wide Input Voltage Operation

2020 ◽  
Vol 10 (22) ◽  
pp. 8250
Author(s):  
Bor-Ren Lin ◽  
Kun-Yi Chen
Keyword(s):  
Low Voltage ◽  
Input Voltage ◽  
Resonant Circuit ◽  
Zero Voltage Switching ◽  
Photovoltaic Energy Conversion ◽  
Wide Range ◽  
Input Side ◽  
Input Region ◽  
Output Side ◽  
Zero Voltage

A new hybrid inductor-inductor-capacitor (LLC) converter is investigated to have wide voltage input operation capability and zero-voltage turn-on characteristics. The presented circuit topology can be applied for consumer power units without power factor correction or with long hold-up time requirement, photovoltaic energy conversion and renewable energy power transfer. To overcome the weakness of narrow voltage gain of resonant converter, the hybrid LLC converter with different turns ratio of transformer is presented and the experimental investigation is provided to achieve wide voltage input capability (400 V–50 V). On the input-side, the converter can operate as full bridge resonant circuit or half bridge resonant circuit with input split capacitors for high or low voltage input region. On the output-side, the less or more winding turns is selected to overcome wide voltage input operation. According to the circuit structures and transformer turns ratio, the single stage LLC converter with wide voltage input operation capability (400 V–50 V) is accomplished. The laboratory prototype has been developed and the experimental waveforms are measured and demonstrated to investigate the effectiveness of the presented hybrid LLC converter.

Design and Simulation of a New ZVT Bi-directional DC-DC Converter for Electric Vehicles

2017 ◽  
Vol 7 (1) ◽  
pp. 75
Author(s):  
Rajesh Thumma ◽  
Veera Venkata Subrahmanya Kumar Bhajana ◽  
Pramo kumar Aylapogu
Keyword(s):  
Electric Vehicles ◽  
Power Flow ◽  
Low Voltage ◽  
Storage System ◽  
Energy Storage System ◽  
Switching Losses ◽  
Auxiliary Cell ◽  
Bidirectional Converter ◽  
Simulation Results ◽  
Zero Voltage

<p>This paper presents a new zero voltage transistion (ZVT) bi-directional DC-DCconverter for energy storage system in DC traction. This bidirectional converter can transfers the power flow from low voltage side to high voltage side and viceversa. The conventional hard-switched non-isolated converter improved with the additional auxiliary cell to obtain zero voltage transition for the IGBTs. The main advantages of this topology are reduced the switching losses and improved the efficiency as well.The main aim of this converter is to achieve the operation of zero voltage transition during the commutation of main switches from off to on by utilizing auxiliary cell, which consist active and passive elements.The boost and buck modes of operations are achieved with the zero voltage transistion, which reduce the IGBTs current stresses and switching losses.This paper mainly describes the operation principles and the evaluation of the simulation results with the aid of Matlab simulations.The obtained results were proved the expected assumptions of the theoretical analysis.</p>

A New Interleaved Bidirectional Zero Voltage Switching DC/DC Converter with High Conversion Ratio

2017 ◽  
Vol 26 (06) ◽  
pp. 1750105 ◽  
Author(s):  
Ebrahim Babaei ◽  
Zahra Saadatizadeh ◽  
Behnam Mohammadi Ivatloo
Keyword(s):  
Power Flow ◽  
Low Voltage ◽  
Zero Voltage Switching ◽  
Bidirectional Converters ◽  
Comprehensive Comparison ◽  
Step Down ◽  
High Conversion Ratio ◽  
Bidirectional Power Flow ◽  
Zero Voltage ◽  
Voltage Switching

In this paper, a new interleaved nonisolated bidirectional zero voltage switching (ZVS) dc–dc converter by using one three-windings coupled inductor is proposed. The proposed topology can provide high step-up and high step-down conversion ratios for boost and buck operations, respectively. Moreover, because of interleaving, the proposed converter has low input current ripple at low voltage side in both buck and boost operations. The proposed converter uses lower number of switches to have bidirectional power flow in comparison with other interleaved bidirectional converters. All used switches in the proposed converter are turned on under ZVS. The advantages of the proposed converter in comparison with the conventional interleaved converters are included in the capability of bidirectional power flow, ZVS operation for all switches and high step-up and high step-down voltage gain for boost and buck operations. In this paper, the proposed converter is analyzed completely and all equations of components are extracted as well as the ZVS conditions of all switches. Moreover, a comprehensive comparison between the proposed converter and conventional topologies is presented. To verify the accuracy performance of the proposed converter, the experimental results are given.

A Single-Switch HPF AC-to-DC Converter with Low Voltage Ripple

2013 ◽  
Vol 284-287 ◽  
pp. 2445-2449
Author(s):  
Hung Liang Cheng ◽  
Chien Hsuan Chang ◽  
Chun An Cheng ◽  
En Chih Chang ◽  
Li Ren Yu
Keyword(s):  
Power Factor ◽  
Low Voltage ◽  
Harmonic Distortion ◽  
Input Voltage ◽  
Boost Converter ◽  
Flyback Converter ◽  
Switching Losses ◽  
Voltage Ripple ◽  
Sinusoidal Waveform ◽  
Conduction Mode

This paper proposed a single-stage single-switch ac-to-dc converter which is derived by integrating a boost converter and a flyback converter. Only one active switch and simple control are required. The boost converter performs as a power-factor corrector (PFC) which is designed to operate at discontinue-conduction mode (DCM) to makes the input current be a sinusoidal waveform and in phase with the input voltage. High power factor and low total current harmonic distortion (THD) are ensured. The flyback converter further regulates the output voltage of the boost converter to provide an isolated dc voltage with low voltage ripple. The flyback converter is designed to operate at continue-conduction mode (CCM) to have the transformer current of a low peak value. It will be effectively reduce the switching stress and the switching losses of semiconductor components. The paper conducts the mathematical equations for the converter circuits, and then designing the circuit parameters. A prototype circuit designed for a 100 W output power was built and tested. Satisfactory results are obtained experimentally.

A Novel Energy Harvester in a Backpack via Precision Sensing of Back Electromotive Force

2020 ◽  
Author(s):  
W.-W. Yen ◽  
Paul C.-P. Chao
Keyword(s):  
Average Power ◽  
Input Voltage ◽  
Pulse Frequency ◽  
Oxide Semiconductor ◽  
Pulse Frequency Modulation ◽  
Peak Voltage ◽  
Adc Value ◽  
New Type ◽  
Conduction Mode ◽  
Boundary Conduction

Abstract In this paper, swop fly-back converter, a new type of fly-back converter, was proposed. It is controlled by constant-on time, a strategy of pulse frequency modulation with boundary conduction mode. Due to the structure of swop fly-back converter and the boundary conduction mode control strategy, the energy delivery to battery is proportional to the voltage of coupled capacitor of swop fly-back converter which changed the position of the metal-oxide-semiconductor field-effect transistor and the capacitor instead of measuring input voltage and input current. Thus, the energy was estimated by measuring the voltage of coupled capacitor. The previous test shows that the voltage of coupled capacitor sensing which is measured by 10-bit ADC is good. The peak voltage is 4.036 V, the ADC value is 1009 digi, and it induced average power 1.25W for striding and 2W for jogging.

Analysis and Performance Evaluation of Control Methods for LLC Resonant Converter

2018 ◽  
Vol 15 (2) ◽  
pp. 685-689
Author(s):  
Soundiraraj Nallasamy ◽  
Rajasekaran Vairamani
Keyword(s):  
Frequency Modulation ◽  
Short Circuit ◽  
Load Condition ◽  
Pulse Frequency ◽  
Open Loop ◽  
Resonant Circuit ◽  
Frequency Variation ◽  
Switching Frequency ◽  
Pulse Frequency Modulation ◽  
Tank Circuit

An LLC resonant dc to dc converter in the company of an LC ant resonant tank circuit for civilizing the act of pulse frequency modulation (PFM) is projected in this manuscript. The planned converter, known as LLC-LC converter, can expand a voltage guideline area below the unity gain with a lesser frequency variation of Pulse frequency modulation by the effect of the antiresonant tank. This beneficial possessions contribute for shielding over current in the case of the short-circuit load condition as well as the bring into being interval in the planned band of switching frequency. The circuit topology and working theory of the planned converter is described, subsequent to the design method of the working frequency and circuit parameters are offered. The performance of the soft switch and the steady-state pulse frequency modulation distinctiveness of the LLC-LC converter are evaluated underneath the open-loop control in conduct experiment of a 2.0-kiloWatts trial product, and its real effectiveness is compared with an LLC converter model. Intended for enlightening the usefulness of the LLC-LC resonant circuit, voltages and currents of the series and ant resonant tanks are analyzed, correspondingly, with state-plane trajectory based on computation and experimentation, where by the power and energy of resonant tank is verified. To conclude, the possibility of the projected converter is evaluate from the realistic point of vision.

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