Electromagnetic interference issues are associated with high-speed switching of power converters. EMI modeling is an essential tool to study and control the EMI emission, enabling more efficient solutions. A comprehensive review and comparison of different modeling approaches for conducted emissions are provided in this paper, which can be used as a design guideline for engineers. For a motor drive application, common mode and differential mode conducted emissions are studied, and dominant noise production mechanisms are identified. Moreover, a review of various modeling techniques is presented for the main parasitic components of the system. Finally, time domain and frequency domain analysis approaches are explored along with the equivalent circuits which enable fast prediction of EMI emissions. This paper intends to help the reader develop an organized understanding of conducted emission modeling to assist them with a more efficient and electromagnetically-compatible design.

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Modeling of Conducted Emissions for EMI Analysis of Power Converters: State-of-the-Art Review

High voltage direct current (HVdc) transmission systems play an essential role in our modern power grids, not only providing bulk power transmission and asynchronous ac connection, but also enabling renewable energy integration into power grids. Renewable energy integration through HVdc transmission systems leads to the creation of multiterminal HVdc (MT-HVdc) grids. Recently, the idea of electrifying remote communities by HVdc transmission systems has emerged, and multi-terminal small-scale HVdc grids have been investigated in such applications. Despite numerous applications and significant potential of HVdc transmission systems, various technical and economic challenges in utilizing these systems still persist. In this article, an extensive literature review is conducted on HVdc transmission systems, particularly focusing on their role in renewable energy integration, and their potential application in remote communities. Future research directions are also recommended.

HVDC Transmission and its Potential Application in Remote Communities: Current Practice and Future Trend

High voltage direct current (HVdc) transmission systems play an essential role in our modern power grids, not only providing bulk power transmission and asynchronous ac connection, but also enabling renewable energy integration into power grids. Renewable energy integration through HVdc transmission systems leads to the creation of multiterminal HVdc (MT-HVdc) grids. Recently, the idea of electrifying remote communities by HVdc transmission systems has emerged, and multi-terminal small-scale HVdc grids have been investigated in such applications. Despite numerous applications and significant potential of HVdc transmission systems, various technical and economic challenges in utilizing these systems still persist. In this article, an extensive literature review is conducted on HVdc transmission systems, particularly focusing on their role in renewable energy integration, and their potential application in remote communities. Future research directions are also recommended. 

The bridgeless isolated power factor corrected (PFC) SEPIC converter based ceiling fan with DC link voltage of 48V, shows the better power quality and less power consumption. It consists of an electromagnetic interference (EMI) filter, high frequency isolation transformer in series with a voltage source inverter and a permanent magnet brushless DC (PMBLDC) motor. This topology is designed in discontinuous inductor current mode (DCIM) of operation with input power of 30W. This ceiling fan is taking power one third of a single phase induction motor. The power quality performances are found good for this topology based ceiling fan. This topology for the ceiling fan is simulated with simple voltage follower control technique. To control the speed of PMBLDC motor, DC link voltage is sensed and it varies up to 48V. The turn’s ratio of high frequency transformer and inductor are selected such a manner that the switch stress of the converter switches should be minimum. The MATLAB simulation results are shown to validate the design of a bridgeless isolated PFC SEPIC converter based ceiling fan.

BLDC Motor Ceiling Fan Using a Bridgeless Isolated PFC SEPIC Converter

This article proposes an active electromagnetic interference (EMI) filter (AEF) realized by a customized integrated circuit (IC) to reduce conducted emission noises. A fully transformer-isolated feedforward current-sense current-compensation structure is selected as a base topology of the AEF. To achieve the high reliability of the proposed AEF by using low-voltage IC devices, the injection transformer is added to protect IC devices from high-voltage hazards. The operation of the proposed AEF is theoretically demonstrated, and practical design guidelines for the IC part and nearby components are developed. The designed IC was fabricated by a 0.18 μ m bipolar-CMOS-DMOS process. The fabricated IC is implemented in a compact printed circuit board for application to a three-phase inverter motor system. The performance, stability, and surge immunity of the AEF are experimentally demonstrated. A designed 1stage AEF achieves better noise-attenuation performance than 2stage passive EMI filters (PEFs) over 6 dB at 150 kHz without critical resonance peak at the high-frequency range. Weak points of the conventional PEFs in both low and high frequencies are effectively improved by using the proposed 1stage AEF. In addition, the surge immunity of the designed IC within the AEF is validated under numerous 5 kV surge tests.

A Customized Integrated Circuit for Active EMI Filter With High Reliability and Scalability

It is widely believed that hybrid electromagnetic interference (EMI) filter (HEF) is one of the most optimized solutions for EMI elimination. Nevertheless, the desire for a smaller and lighter filtering method has never stopped. To further reduce the size and weight of a hybrid EMI filter, this paper proposes a multi-function common mode choke (MCMC) used in HEF. It differs from the traditional common mode (CM) choke in that two functions of (1) CM signal sensing and (2) CM noise suppression are integrated into one choke. In such a proposed MCMC design, the traditional current transformer (CT) is eliminated in the hybrid filter topology. This technique could reduce the size, weight, and cost of the filter to a great extent. Based on the MCMC, a novel CM filter is proposed to achieve high-performance noise suppression. System model and stability feature of the new filter are developed and investigated in detail. A filter prototype based on the proposed MCMC is constructed. It is tested on a 100-W commercial ac/dc converter. The experimental results show that the proposed CM filter can provide better EMI noise suppression with a smaller size. The insertion loss could reach 50 dB at low frequencies and 40 dB at high frequencies.

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A Multi-Function Common Mode Choke Based on Active CM EMI Filters for AC/DC Power Converters

Hybrid EMI filters, which consist of an active filter and a passive filter (i.e., common mode choke), have been proposed to effectively reduce the size and weight of traditional passive EMI filters in literatures. However, the active filter topology current controlled current source (CCCS) that has good performance to attenuate CM noise employs a current transformer (CT), which will take up additional space, of course, cost more. To cope with this, this paper proposes a novel multifunction common mode choke (MCMC) based on active EMI filters for CM noise suppression. The proposed multi-function common mode choke can act as the CM choke and CM noise current sensing at the same time. This results in elimination of a CT and a reduction in the number of magnetic components. Both simulations and experiments are conducted to verified the developed model of proposed MCMC and performance of the new CM EMI filter.

Design of Active EMI Filters With the Integrated Passive Component

The acoustic noise generated by filter capacitors in a high voltage direct current (HVDC) converter station will have a serious negative impact on the residents' lives and the ecological environment. Though accurate enough, traditional modeling methods based on either boundary element method (BEM) or finite element method (FEM) are almost impossible to reconstruct sound field for whole HVDC station filter array because of their extremely high demand for computing resources. To deal with this problem, this paper proposes a novel Tikhonov Regularization Equivalent Source Method (TRESM)-based filter capacitor acoustic model. By constructing multiple point-sound source models, the acoustic characteristics of the actual filter capacitor are simulated and the original sound field is reconstructed. The accuracy of the proposed model is verified by the experimental results and the sound field distribution characteristics of the three-phase filter capacitor array are observed and analyzed using the proposed model.

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Modeling of Acoustic Emission Generated by Filter Capacitors in HVDC Converter Station

This paper focuses on the problem of conducted electromagnetic interference (EMI) in multi-load magnetic resonant wireless power transfer (WPT) system. A high frequency equivalent model is established to analyze the common mode (CM) and the differential mode (DM) conducted EMI by simulations in Saber. The comparison of CM interference has been made when the number of loads changing and the load impedances becoming unbalanced at the primary side. The circulation of the CM interference at the load side between two loads by coupling capacitors of resonant coils have been discussed. Filtering methods are put forward for multi-load magnetic resonant WPT system to reduce the CM interference. Both simulations and experimental results verify the complexity of EMI conditions and the significant effect of the filter.

Conducted EMI Modeling and Filtering for Multi-load Magnetic Resonant WPT System

The noise from the converter station will have a negative impact on the residents’ lives and the ecological environment. It is currently known that the main sources are filter capacitors and reactors. Taking a filter capacitor as an example, a large number of tests are required to predict the capacitor noise based on a traditional capacitor analysis modeling method, and the simulation calculation requires a huge amount of calculation power. This paper proposes an equivalent source method(ESM) based on the Huygens principle. By constructing multiple point sound source models, the acoustic characteristics of the actual capacitor are simulated and the original sound field is reconstructed. Comparison between the proposed model and the traditional boundary element method(BEM) model has been made through physical testing and simulation, and the accuracy of this method is verified.

Rui Wang

Papers

A Multi-Function Common Mode Choke Based on Active CM EMI Filters for AC/DC Power Converters

Design of Active EMI Filters With the Integrated Passive Component

Modeling of Acoustic Emission Generated by Filter Capacitors in HVDC Converter Station

Conducted EMI Modeling and Filtering for Multi-load Magnetic Resonant WPT System

Filter Capacitor Acoustic Noise Prediction Based on ESM for HVDC Converter Stations