Common-Mode Noise Cancellation in Switching-Mode Power Supplies Using an Equipotential Transformer Modeling Technique

Chan, Yick Po; Pong, M.H.; Poon, N.K.; Liu, J. C. P.

doi:10.1109/temc.2011.2166270

Cited by 26 publications

(13 citation statements)

References 10 publications

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“…The terminal B, E and C are corresponding terminals. The winding to core capacitors can be neglected because its capacitance is too small and the primary winding inner layers capacitors can also be neglected because they do not contribute to CM noise [8]. And it is assumed that all the winding layers cover the whole window width and there is 2 layer taps between different layers.…”

Section: Proposed Topology With Balanced Windingmentioning

confidence: 99%

“…Up to now, few studies have been done to reduce CM noise without the help of Y-cap [4][5][6][7][8]. In [1][2][3], the Y-cap is used to bypass the CM noise from the propagation path.…”

Section: Introductionmentioning

confidence: 99%

“…But the Y-cap is unacceptable in those applications. In [1], [4], [5], [8], an additional balanced winding is added to cancel the CM current goes through parasitic capacitance between transformer primary side and secondary side. In [1], [6], a shield winding is added in series of a compensation capacitor to cancel the CM current goes through inter-winding capacitance.…”

Section: Introductionmentioning

confidence: 99%

“…Moreover, it requires accurately control of parasitic capacitance, which is not only very difficult but also time consuming in mass production. In [8][9], new topologies are proposed to reduce the CM noise at the expense of cost and complexity. Although these methods are effective in reducing EMI, there is a lack of manuscript that investigating the No Y-cap EMI design method from topology optimization viewpoint.…”

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

A novel balanced winding topology to mitigate EMI without the need for a Y-capacitor

Bai

Yang

et al. 2016

2016 IEEE Applied Power Electronics Conference and Exposition (APEC)

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Due to the interaction between human and the power supply equipment, more and more Switch-mode power supplies (SMPS) require lower leakage current. In the AC-DC SMPS, the leakage current is mainly caused by the Y-capacitors. It is better to remove the Y-caps in this situation. But connecting Y-caps between the primary return line terminal and the secondary return line terminal is a very common method in EMI design. Certain works should be done to acquire good EMI design without the help of Y-cap. In this paper, a novel balanced winding topology is proposed to mitigate EMI noise without the need for Y-cap. To have a better understanding of the operational principle, the EMI noise transmission path with and without Y-cap are analyzed. The design procedure of the proposed topology is discussed in detail. The experimental results demonstrated the prototype has excellent EMI performance without the help of Y-cap. It also can simplify the transformer design and be easy to implement mass production.

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Section: Proposed Topology With Balanced Windingmentioning

confidence: 99%

“…Up to now, few studies have been done to reduce CM noise without the help of Y-cap [4][5][6][7][8]. In [1][2][3], the Y-cap is used to bypass the CM noise from the propagation path.…”

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

A novel balanced winding topology to mitigate EMI without the need for a Y-capacitor

Bai

Yang

et al. 2016

2016 IEEE Applied Power Electronics Conference and Exposition (APEC)

View full text Add to dashboard Cite

show abstract

“…Usually, the attenuation of common mode (CM) current in 2-wires AC input SMPS is more difficult than those 3-wires SMPS [5], [10]. So, for these 2-wire isolated SMPS, a big Y-capacitor is an essential component to reduce the common mode current [7][8].…”

Section: Introductionmentioning

confidence: 99%

EMI noise cancelation by optimizing transformer design without need for the traditional Y-capacitor

Bai

Chen

et al. 2016

2016 IEEE Applied Power Electronics Conference and Exposition (APEC)

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At present, Y capacitor is widely adopted inside an isolated switched mode power supply to pass EMI tests. However, to meet certain safety standard, engineers are trying to reduce the Y-cap in such equipment as cell phone and pad chargers, medical instruments, handheld and portable equipment. As we know, the removal of Y-cap offers a big challenge for the EMI design. To solve the problem, this paper proposed an optimized transformer design method. By means of this method, the EMI noise can be reduced without the need of the traditional Y-cap. Analysis of the transformer architecture as well as the auxiliary winding has been carried out. The experiment results demonstrated the effectiveness and feasibility of the proposed method.

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CM Conducted EMI mitigation in flyback PFC converter

Ashritha

Sudheer

2019

Electr Eng

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The switched mode power supplies offer many advantages in power conversion. But they offer low power factor and generate electromagnetic interference (EMI). The low power factor can be improved by a front-end power factor correction (PFC) unit. However, they also generate EMI in both differential mode and common mode (CM). The interwinding capacitance of the transformer and parasitic capacitance between the heat sink and ground are major contributors to CM noise. The traditional method to minimize the CM noise by using a line filter consists of CM choke and Y capacitor. But, CM noise causes leakage current to flow to the ground through the Y capacitor. This leakage current has to be restricted as per the standards for commercially used equipment and medical instruments. The technique proposed here reduces the values of Y capacitor thereby reducing the leakage current. This can be reduced by minimizing the predominant parasitic capacitances of the HF transformer used in the PFC converter. This paper presents a technique for reducing these parasitic capacitances by incorporating an additional parasitic capacitance noise cancellation winding (PCW). A flyback transformer winding capacitance model depicting the parasitic capacitances is considered, and a novel method to determine this parasitic capacitance is presented. Using this model, the CM Conducted EMI in a flyback PFC is determined by simulation and experimentation. These simulation and experimentation results are used to design an EMI line filter to reduce the Conducted CM noise to complaint levels. The value of Y capacitor now is reduced due to the addition of PCW thereby reducing the size and cost of the filter. This technique has been validated experimentally on a 30-W power factor correction flyback converter working in critical conduction mode.

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Common-Mode Noise Cancellation in Switching-Mode Power Supplies Using an Equipotential Transformer Modeling Technique

Cited by 26 publications

References 10 publications

A novel balanced winding topology to mitigate EMI without the need for a Y-capacitor

A novel balanced winding topology to mitigate EMI without the need for a Y-capacitor

EMI noise cancelation by optimizing transformer design without need for the traditional Y-capacitor

CM Conducted EMI mitigation in flyback PFC converter

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