Design considerations for a high efficiency 3 kW LLC resonant DC/DC transformer

Wang, Qiong; Zhang, Xuning; Burgos, Rolando; Boroyevich, Dushan; White, A.; Kheraluwala, M.H.

doi:10.1109/ecce.2015.7310427

Cited by 11 publications

(5 citation statements)

References 5 publications

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“…Therefore the resonant inductor is usually integrated into the transformer by utilizing its leakage inductance to increase its power density and efficiency especially when LLC converter operates at high frequency [25]- [28]. Interleaved structure is often implemented to reduce AC resistance [21]- [24], but causing a small leakage inductance and a large inductance ratio and leading to reduced regulation capability. When the primary and secondary windings are not interleaved [25]- [26], the leakage inductance can be utilized to replace the resonant inductance.…”

Section: Introductionmentioning

confidence: 99%

High-Frequency <italic>LLC</italic> Resonant Converter With Magnetic Shunt Integrated Planar Transformer

Ouyang

Andersen

2019

IEEE Trans. Power Electron.

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Achieving high efficiency and high power density is emerging as a goal in many power electronics applications. LLC resonant converter has been proved as an excellent candidate to achieve this goal. To achieve smaller size of passive components, the resonant inductor in the LLC converter is usually integrated into the transformer by utilizing its leakage inductance. However, the leakage inductance of transformer is usually insufficient and thus the LLC converter has to be operated in a limited frequency range (this limits the input voltage range accordingly), otherwise the power efficiency will drop dramatically. Therefore, a larger resonant inductance in the LLC converter is expected to operate in a wider input voltage range. This paper proposes a new method to create a larger resonant inductance by using a magnetic shunt integrated into planar windings. The accurate leakage inductance modelling, calculation and optimal design guideline for LLC planar transformer, including optimal magnetic shunt selection and winding layout, are presented. A 280-380V input and output 48V-100W half bridge LLC resonant converter with 1MHz resonant frequency is built to verify the design methodology. A comparison is made between two converters with the same parameters, one using magnetic shunt integrated transformer and the others using traditional planar transformer and external inductor. Experimental result shows the proposed converter with magnetic shunt is capable to achieve comparable high efficiency and regulation capability with the other under a wide input voltage, which verify the optimal design methodology. Above all, this magnetics integration methodology reduces the whole converter's volume and thus increases the power density. Index Terms-magnetic shunt, LLC resonant converter, planar transformer, high frequency, wide input voltage.

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Section: Introductionmentioning

confidence: 99%

High-Frequency <italic>LLC</italic> Resonant Converter With Magnetic Shunt Integrated Planar Transformer

Ouyang

Andersen

2019

IEEE Trans. Power Electron.

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“…There is a difference between the efficiencies of a voltage boost LLC converter and a voltage drop LLC converter with the same power. A higher efficiency can be achieved with a voltage reducing LLC converter [14][15][16]. This is because their input voltage is higher, but the input current is lower.…”

Section: Efficiency Measurementsmentioning

confidence: 99%

Grid and PV Fed Uninterruptible Induction Motor Drive Implementation and Measurements

Boros

Bodnár

2022

Energies

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Motors powered directly from solar panels are becoming more and more popular in pump applications. However, solar panels can be the source of operational issues due to varying irradiance, ambient temperature, weather. This paper shows how it is worth expanding a solar induction motor drive to provide an uninterrupted flow of electricity to the motor. In addition, the main components of the uninterruptible induction motor drive are presented, including the LLC (inductor-inductor-capacitor) converter, the three-phase inverter, and the three-phase rectifier. LLC converters that can increase the voltage from 25–40 V to 330 V cannot be bought directly from manufacturers. Therefore, a custom LLC converter was made for the research. It was necessary to build a custom converter to avoid the use of solar panel strings. This way, solar panels connected in parallel can be used. A low-voltage (25–40 V) supply was implemented from the solar side, while the induction motor requires 230 V AC three-phase voltage in delta connection. For this reason, a voltage boost is required from the low voltage side. The grid feeds the universal DC link through the three-phase rectifier. This allows the motor to consume varying amounts of electricity from the grid or the solar panel. The study also presents in detail the LLC converter that performs the voltage boost. Measuring the entire motor drive, switching transients and efficiencies can be observed at different input voltages for different supplies as well as loads.

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“…Inversely, from t b to t c energy is delivered (Figure 7). The point t b corresponds to the zero crossing of vT r,sec (4), where all the capacitors C 5 to C 8 have an equal voltage.…”

Section: Measurement Of Q Oss Q Rr and Switching Lossmentioning

confidence: 99%

“…The main contributions to losses in the DCDC converter include the conduction, the auxiliary, the switching, the driving, and the core loss [3,4]. Most of these contributions to losses are, in some manner, frequency dependent, i.e., while the driving and the switching losses increase proportionally to the frequency, the core losses decrease proportionally to it (within the usable range of the specific material and considering a fixed geometry and number of turns, and therefore a decreasing magnitude of the magnetic field).…”

Section: Introductionmentioning

confidence: 99%

On the Practical Evaluation of the Switching Loss in the Secondary Side Rectifiers of LLC Converters

et al. 2021

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The switching loss of the secondary side rectifiers in LLC resonant converters can have a noticeable impact on the overall efficiency of the complete power supply and constrain the upper limit of the optimum switching frequencies of the converter. Two are the main contributions to the switching loss in the secondary side rectifiers: on the one hand, the reverse recovery loss (Qrr), most noticeably while operating above the series resonant frequency; and on the other hand, the output capacitance (Coss) hysteresis loss, not previously reported elsewhere, but present in all the operating modes of the converter (under and above the series resonant frequency). In this paper, a new technique is proposed for the measurement of the switching losses in the rectifiers of the LLC and other isolated converters. Moreover, two new circuits are introduced for the isolation and measurement of the Coss hysteresis loss, which can be applied to both high-voltage and low-voltage semiconductor devices. Finally, the analysis is experimentally demonstrated, characterizing the switching loss of the rectifiers in a 3 kW LLC converter (410 V input to 50 V output). Furthermore, the Coss hysteresis loss of several high-voltage and low-voltage devices is experimentally verified in the newly proposed measurement circuits.

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Design considerations for a high efficiency 3 kW LLC resonant DC/DC transformer

Cited by 11 publications

References 5 publications

High-Frequency <italic>LLC</italic> Resonant Converter With Magnetic Shunt Integrated Planar Transformer

High-Frequency <italic>LLC</italic> Resonant Converter With Magnetic Shunt Integrated Planar Transformer

Grid and PV Fed Uninterruptible Induction Motor Drive Implementation and Measurements

On the Practical Evaluation of the Switching Loss in the Secondary Side Rectifiers of LLC Converters

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