Efficiency Optimized Design Procedure of low-Q LLC Resonant Converter for Wide Input Voltage and Load Range Application

Awasthi, Abhishek; Bagawade, Snehal; Kumar, Amit; Jain, Praveen

doi:10.1109/apec39645.2020.9124557

Cited by 5 publications

(4 citation statements)

References 20 publications

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“…The output voltage is gradually increased to prevent the circuit components from being subjected to the surge current generated during sudden start-up. Usually, the control frequency of the switch tube during LLC soft start is higher than the resonance frequency fr2 [6]. In this design, the frequency during soft start is set to the maximum output frequency, and the reference value in the PI control algorithm is gradually changed to make the output voltage slowly reach the rated 12 V. After soft start, the system enters the FV mode for closed-loop control and simultaneously detects the input voltage.…”

Section: Software Designmentioning

confidence: 99%

“…The power battery generally consists of lithium battery cell modules [4,5]. The range of output voltage changes greatly for different types of batteries, and the DC/DC converter of the subsequent stage should also have the ability to work within a wide voltage range to ensure stable onboard power supply, as the battery may experience low voltage problems after excessive discharge [6][7][8].…”

Section: Introductionmentioning

confidence: 99%

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Wide‐Range Mode Variable Strategy Design and Switching Process Optimization for LLC Resonant Converter

Lin,

Jin,

Xie

et al. 2023

IEEJ Transactions Elec Engng

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In response to the demand for new energy applications and wide‐range DC/DC converters, this study focuses on the LLC resonant converter. The traditional LLC working range is not wide enough, so this paper investigates variable mode control to increase the LLC working range without changing the topology. Different control strategies are selected for different modes, and simulation studies are conducted on variable mode control strategies such as full‐bridge frequency conversion, full‐bridge phase shifting, and half‐bridge frequency conversion. The LLC operates in full‐bridge frequency conversion mode at low input voltage, half‐bridge frequency conversion mode at high input voltage, and full‐bridge phase shifting mode at intermediate voltage. The transient process of mode switching is optimized to greatly improve the stability of the converter and reduce voltage fluctuations. Based on the simulation and analysis, the system design of software and hardware is completed, an LLC resonant converter prototype is made, and experimental verification is carried out, confirming the effectiveness of the variable mode strategy. © 2023 Institute of Electrical Engineer of Japan and Wiley Periodicals LLC.

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Section: Software Designmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Wide‐Range Mode Variable Strategy Design and Switching Process Optimization for LLC Resonant Converter

Lin,

Jin,

Xie

et al. 2023

IEEJ Transactions Elec Engng

View full text Add to dashboard Cite

show abstract

“…PON and PN cannot guarantee that the switch tube achieves ZVS. OPO mode will produce high circulation conduction loss [7]. A detailed analysis of each mode was carried out in [8], indicating the connection between each mode and the boundary of PO is OPO and PON.…”

Section: Introductionmentioning

confidence: 99%

LLC resonant converter analysis in PO mode

Mao,

2024

J. Phys.: Conf. Ser.

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The PO mode under time-domain analysis is a kind of discontinuous conduction mode (DCM) which is beneficial to reduce the switching loss of the converter, but the calculation of the gain and frequency characteristics of the converter in this mode is cumbersome and difficult to be solved. Based on the analysis method of time domain approximation, the PO operating mode characteristics of the LLC resonant converter are analyzed, and a simple and accurate voltage gain calculation formula is theoretically deduced. Simple analytical expressions for the PO mode power boundary conditions are given based on the voltage variations of the magnetizing inductance and capacitance. A simulation model of the studied converter is established, and the simulation can prove that the proposed voltage gain formula and PO mode boundary conditions are correct.

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“…Albeit using additional circuits may widen the soft-switching range, [30]- [33], but it leads to higher components count and cost. Resonant-type full-bridge converters can realize softswitching operation by using resonant tank on the primary side, which can improve the efficiency by eliminating MOSFET-based [28], [34] and IGBT-based [35] converters turn-on and turn-off switching losses, respectively.…”

Section: Introductionmentioning

confidence: 99%

A High Step-Up Interleaved Current-Fed Resonant Converter for High-Voltage Applications

et al. 2022

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A current-fed LLC resonant converter is proposed for high-voltage and high-power applications. Here, a two-phase interleaved structure is used in the input stage under the continuous conduction mode (CCM) to effectively reduce the input current and output voltage ripple values and the input filter and the output capacitors volumes. Due to the expandable structure and high voltage gain, the proposed configuration is suitable for high voltage applications since low voltage stresses are applied across its components. In fact, voltage stresses across the power semiconductors, i.e., MOSFETs and output diodes, along with the output capacitors, are almost one-third of the output voltage in the implemented three-stage configuration of the proposed converter. Here, the switching frequency is chosen close to, but less than, the converter series resonant frequency to reduce its different components' current stresses and perform softswitching operation for all power devices under wide input voltage and output power variations. Therefore, conduction and switching losses, and EMI noises are effectively reduced. Consequently, efficiency is improved and high-frequency operation is possible, which reduces the volume of passive components to achieve high-power density. The given topology is thoroughly analyzed mathematically. Also, a 1 kW prototype converter has been implemented to validate the given simulations and analyses. Here, wide input voltage (100 V-200 V) and output power (100 W-1000 W) variations are applied, and an asymmetric pulse width modulation (APWM) technique is used at 143 kHz switching frequency to regulate the output voltage at 1 kV. The obtained maximum efficiency value is 95.3%.INDEX TERMS Asymmetric pulse width modulation (APWM), current-fed converter, interleaved technique, LLC resonant converter, multi-winding transformer.

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Efficiency Optimized Design Procedure of low-Q LLC Resonant Converter for Wide Input Voltage and Load Range Application

Cited by 5 publications

References 20 publications

Wide‐Range Mode Variable Strategy Design and Switching Process Optimization for LLC Resonant Converter

Wide‐Range Mode Variable Strategy Design and Switching Process Optimization for LLC Resonant Converter

LLC resonant converter analysis in PO mode

A High Step-Up Interleaved Current-Fed Resonant Converter for High-Voltage Applications

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