A Generalized Common-Mode Current Cancelation Approach for Power Converters

Chu, Yongbin; Wang, Shuo

doi:10.1109/tie.2014.2387335

Cited by 104 publications

(20 citation statements)

References 25 publications

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“…The

f_{c m 5}

is estimated to be 1.215 MHz and

f_{c m 6}

occurs at a lower frequency below 150 kHz frequency range. From the measured resonant frequencies, it can be observed that only Mode 1 contributes to CM noise as stated in the literature [19] (MOSFET is ON and diode is OFF). In Mode 2, the resonant frequencies

f_{c m 5}

and

f_{c m 6}

occur below 2 MHz.…”

Section: Analytical Formulationmentioning

confidence: 80%

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Mitigation of CM conducted EMI in flyback converter using balancing capacitors

Manjunath

Sudheer

2020

IET power electron.

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The offline Switched Mode Power Supply (SMPS) draw non-sinusoidal line current from the utility power supply, thereby introducing unwanted harmonics and also generate significant electromagnetic interference (EMI). Power factor correction (PFC) converters can be used to improve the power factor. But they also generate EMI in both Differential Mode (DM) and Common Mode (CM). In this paper, the EMI generated by the flyback PFC converter is addressed. A lumped circuit model for CM conducted EMI generated in a flyback converter, including the HF transformer's parasitics and the components, is considered. The parasitics of the HF transformer are calculated and measured experimentally. Using them, the resonant frequencies of the flyback converter are calculated for validation. A technique for determining the required balancing capacitor to mitigate CM conducted EMI is presented. A novel technique by splitting this balancing capacitor with their mid-point grounded for further reduction of this EMI is presented. This technique can eliminate the C y capacitors of the EMI line filter connected between line/neutral to the ground. Hence for the same amount of CM conducted EMI mitigation, the size and the cost of EMI line filters are reduced. Theoretical analysis, simulation results, and experimental verifications are presented.

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“…The

f_{c m 5}

is estimated to be 1.215 MHz and

f_{c m 6}

f_{c m 5}

and

f_{c m 6}

occur below 2 MHz.…”

Section: Analytical Formulationmentioning

confidence: 80%

“…The optimised selection of balanced capacitor (C z capacitor) value is necessary. To determine the C z capacitor value, the estimated parasitic capacitance is substituted into (19). Equation (19) is obtained by applying general parameters and considering e out is an open circuit as shown in Fig.…”

Section: Calculation Of Balancing Capacitor (C Z )mentioning

confidence: 99%

Mitigation of CM conducted EMI in flyback converter using balancing capacitors

Manjunath

Sudheer

2020

IET power electron.

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“…Then, the potential of each winding can be replaced by the average voltage of the entire winding. According to literature [25], the displacement current from the different primary windings to the secondary winding can be represented in (2).…”

Section: Displacement Current Modeling Of the Existingmentioning

confidence: 99%

An EMI‐Optimized Transformer for De‐Y Flyback Converter with Low Common‐Mode Noise

Wang

Shao

Liu

et al. 2021

IEEJ Transactions Elec Engng

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member Y-capacitors are widely used in flyback converters to suppress common-mode (CM) noise to comply with the strict electromagnetic interference (EMI) standards. However, Y-capacitors increase the leakage current between the primary and secondary side, which is not allowed in the applications with high safety requirements. In this paper, the displacement current models of two conventional De-Y methods are quantitatively established to analyze their limitations for the flyback converter. Then, a hybrid EMI-optimized transformer is proposed to improve the limitations. The proposed structure can completely balance the CM noise between the primary and secondary sides, making the flyback converter comply with the EMI standard under the conditions of no Y-capacitor. Compared with the traditional methods, the proposed method has a better capability for CM noise suppression, higher universality and the same cost. Finally, the simulation and experimental results verify that the CM noise of the new transformer structure decreases about 10 dB compared with that of the conventional one.

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“…Generally speaking, when the operating frequency is beyond megahertz, the PCB wingdings planer transformer is extensively adopted, due to its low leakage inductance and high-power density than conventional wire-wound transformer [36]. However, planar transformers have a relatively larger interwinding capacitance that provides the dominant path for the CM noise current travelling from the primary side to the secondary side [37,38]. Fortunately, the transformers with 200 kHz frequency are both implemented by conventional wire-wound transformers in two ACF converters.…”

Section: Experimental Verificationmentioning

confidence: 99%

A Comparative Study of GaN HEMT and Si MOSFET-Based Active Clamp Forward Converters

et al. 2020

Energies

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Compared with conventional forward converters, active clamp forward (ACF) converters have many advantages, including lower voltage stress on the primary power devices, the ability to switch at zero voltage, reduced EMI and duty cycle operation above 50%. Thus, it has been the most popular solution for the low bus voltage applications, such as 48 V and 28 V. However, because of the poor performance of Si MOSFETs, the efficiency of active clamp forward converters is difficult to further improved. Focusing on the bus voltage of 28 V with 18~36 V voltage range application, the Gallium Nitride high electron-mobility transistors (GaN HEMT) with ultralow on-resistance, low parasitic capacitances, and no reverse recovery, is incorporated into active clamp forward converters for achieving higher efficiency and power density, in this paper. Meanwhile, the comparative analysis is performed for Si MOSFET and GaN HEMT. In order to demonstrate the feasibility and validity of the proposed solution and comparative analysis, two 18~36 V input, 120 W/12 V output, synchronous rectification prototype with different power devices are built and compared in the lab. The experimental results show the GaN version can achieve the efficiency of 95.45%, which is around 1% higher than its counterpart under the whole load condition and the same power density of 2.2 W/cm3.

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A Generalized Common-Mode Current Cancelation Approach for Power Converters

Cited by 104 publications

References 25 publications

Mitigation of CM conducted EMI in flyback converter using balancing capacitors

Mitigation of CM conducted EMI in flyback converter using balancing capacitors

An EMI‐Optimized Transformer for De‐Y Flyback Converter with Low Common‐Mode Noise

A Comparative Study of GaN HEMT and Si MOSFET-Based Active Clamp Forward Converters

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