Electromagnetic Interference Noise Research Articles

Enhancing the accuracy of low-cost thermocouple devices through deep-wavelet neural network calibration

Data collection using thermocouple sensors in low-cost data acquisition is prone to noise interference, which could reduce the data quality. Noise sources such as cold junction compensators, electromagnetic interference, and Johnson noise can significantly affect the reliability and accuracy of conventional measurements. This study aims to improve the quality of thermocouple sensor readings on low-cost data acquisition using calibration method based on deep learning and the denoising process using a wavelet transform. This taken approach successfully increase the accuracy value of 97.67% with a mean absolute error (MAE) of 0.2. The precision also increases of 262.7% as indicated by the result of signal-to-noise ratio (SNR) with a value of 105.29 dB. Comparative analysis was carried out against National Instruments® device and it was found that deep-wavelet method had a lower and higher of MAE and SNRdB values of 16.67% and 0.8% respectively. This study shows that the denoising-calibration method with deep-wavelet can improve the accuracy and reliability of data from low-cost thermocouple devices.

Optically controlled variable damping system based on PLZT ceramic/ERF in rectangular microchannel

Variable damping control technology based on intelligent materials of electromagnetic excitation has been widely used in the field of (semi-) active vibration control and fluid control. Unfortunately, a major drawback is the electromagnetic noise interference and low response speed. In this paper, a new optically controlled variable damping system based on PLZT ceramic/electrorheological fluid (ERF) is proposed. The mathematical models of the photovoltage generated by PLZT ceramics and the pressure difference between the two ends of the microchannel are established and verified by numerical simulation in COMSOL Multiphysics. Meanwhile, with the increase of light intensity, liquid flow rate and decrease of microchannel height and width, the pressure difference shows an uptrend. Optically controlled variable damping system based on PLZT ceramic/ERF is a control method with the advantages of a clean excitation source, remote control, no electromagnetic interference, and fast response speed, and has a good application prospect in the field of vibration control and fluid control.

Response of a novel all-solid-state sodium-based-electrolyte battery to quasi-static and dynamic stimuli

In response to growing environmental and economic concerns, developing new technologies prioritising safety, sustainability, and reliability has become imperative. In the energy sector, batteries play an increasingly significant role in applications such as powering electronic devices and vehicles. In this context, lithium-ion batteries have raised environmental concerns, driving the exploration of alternative technologies. Sodium-based batteries have emerged as an attractive option due to their environmental and economic advantages, as well as their potential for multi-functional applications. This study investigates a novel battery developed by a research team at the University of Porto, with a specific focus on its strain-sensing capabilities for potential applications in damage detection of structures. The battery under investigation is a novel all-solid-state design, comprised of a sodium-ion ferroelectric electrolyte and zinc and copper as the negative and positive electrodes, respectively. A series of quasi-static and dynamic tests are conducted to qualitatively assess the piezoelectric behaviour of the battery. The consistent findings show that the battery generates a difference in the electric potential in response to mechanical stimuli, thus confirming its piezoelectric nature. Furthermore, the results demonstrate the battery can accurately detect the operating frequencies of a shaker, despite encountering inherent electromagnetic interference noise from the electrical grid during testing. These promising outcomes highlight the substantial potential of this emerging technology for a wide range of applications, including but not limited to structural health monitoring systems. Given its novelty, this technology presents multi-functional capabilities for diverse practical future applications, such as energy harvesting that leads to self-powered structural health monitoring systems.

Modeling 0.3 THz Coaxial Single-Mode Phase Shifter Designs in Liquid Crystals with Constitutive Loss Quantifications

This work proposes and examines the feasibility of next-generation 0.3 THz phase shifters realized with liquid crystals (LCs) as tunable dielectrics coaxially filled in the transmission line. The classic coaxial transmission line topology is robust to electromagnetic interference and environmental noise, but is susceptible to higher-order modes from microwave to millimeter-wave towards terahertz (THz) wavelength ranges, which impedes the low-insertion-loss phase-shifting functionality. This work thus focuses primarily on the suppression of the risky higher-order modes, particularly the first emerging TE11 mode impacting the dielectric loss and metal losses in diverse manners. Based on impedance matching baselines at diverse tuning states of LCs, this work analytically derives and models two design geometries; i.e., design 1 for the coaxial geometry matched at the isotopically referenced state of LC for 50 Ω, and design 2 for geometry matched at the saturated bias of LC with the maximally achievable permittivity. The Figure-of-Merit for design 1 and design 2 reports as 35.15°/dB and 34.73°/dB per unit length, respectively. We also propose a constitutive power analysis method for understanding the loss consumed by constitutive materials. Notably, for the 0.3 THz design, the isotropic LC state results in an LC dielectric loss of 63.5% of the total input power (assuming 100%), which becomes the primary constraint on achieving low-loss THz operations. The substantial difference in the LC dielectric loss between the isotropic LC state and saturated bias state for the 0.3 THz design (35.76% variation) as compared to that of our past 60 GHz design (13.5% variation) indicates that the LC dielectric loss’s escalating role is further enhanced with the rise in frequency, which is more pronounced than the conductor losses. Overall, the results from analytical and finite-element optimization in this work shape the direction and feasibility of the unconventional THz coaxial phase shifting technology with LCs, actioned as continuously tunable dielectrics.

A novel 4H–SiC IGBT with double gate PMOS for improving the switch controllability and FBSOA

In this work, a 4H–SiC insulated-gate bipolar transistor (IGBT) with double gate PMOS (DGPMOS) is proposed. In the on-state, DGPMOS IGBT can form a hole barrier, thus reducing the on-state voltage (VON). During the turn-on and turn-off transients, DGPMOS IGBT can form the extra hole extraction paths. This helps to reduce the turn-off loss (Eoff) and the gate displacement current (IG_dis). The simulation results show that compared with GS IGBT, the VON of DGPMOS IGBT is decreased by 58.04% under the same Eoff. Compared with PMOS IGBT, DGPMOS IGBT achieves better controllability in turn-on dIC/dt and peak turn-on current (Imax). At the same turn-on loss (Eon), the maximum reverse recovery dVKA/dt is lowered by 26.67%, and the electromagnetic interference (EMI) noise is suppressed. In addition, because DGPMOS IGBT has a small saturation current density (Jsat), its forward bias safe operating area (FBSOA) is greatly improved.

Research and analysis of electromagnetic interference of a motor drive control system based on PMSM with SiC MOSFET for new energy electric vehicles

Sustainable development in the 21st century faces significant challenges due to finite reserves of fossil fuels and environmental pollution. In the context of new energy electric vehicles (NEEVs), the wide-bandgap semiconductor known as the silicon carbide–metal oxide–semiconductor field-effect transistor (SiC MOSFET) and the permanent magnet synchronous motor (PMSM) have emerged as advantageous sources. However, the use of these components gives rise to electromagnetic interference (EMI) issues, which impede the achievement of electromagnetic compatibility (EMC) standards in the motor drive control system. This paper aims to elucidate the generation mechanism, propagation path, and test infrastructure of EMI. Furthermore, it proposes a system-level conducted EMI equivalent circuit model for the motor drive control system, encompassing the power battery pack, busbar cable, LISN, three-phase inverter, and PMSM. Building upon this foundation, the principles for suppressing and optimizing EMI noise are discussed. The paper concludes with the validation of simulations and experimental results, which demonstrate the effectiveness of the proposed approach. It is anticipated that professionals with an interest in the field of EMI/EMC will find this paper to be of both theoretical and practical importance.

A Bidirectional Direct AC-AC Resonant SCC

A direct ac-ac resonant switched-capacitor converter (SCC) for both noninverting and inverting output voltages is proposed here, which is suitable for bidirectional power transmission including different applications such as dynamic voltage restorer (DVR), constant voltage regulator (CVR), and constant current regulator (CCR). Zero voltage switching (ZVS) and zero current switching (ZCS) operation conditions are easily realized for its power switches, which effectively reduce the switching losses, as well as the electromagnetic interference (EMI) noise. Consequently, high-frequency operation is possible, which improves the converter power density, in practice. Continuous voltage-gain, transformerless connection of the converter output port to the gird, no commutation problems without using extra components, and improving the electrical specifications are some other advantages of the given resonant SCC. The converter operation principles, its key waveforms and different operational states, its mathematical analysis and normalized state-plane trajectories, simulation results, as well as its design procedure, are also given here, in detail. To verify the given theoretical analyses and simulation results, a 500 W prototype converter for a 2 kW DVR with 220 V <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">rms</sub> nominal output voltage has been implemented successfully, which realizes 96.55% efficiency at its rating power value.

Magnetic integration of a symmetrical LCL filter in the grid‐tied inverter with reduced EMI noise

AbstractHarmonics and electromagnetic interference (EMI) pose serious threats to the safety and efficiency of grid‐tied inverters. Although the inductor‐capacitor‐inductor (LCL) filter offers commendable harmonic suppression, it does not sufficiently mitigate leakage current and EMI caused by high‐frequency pulse‐width modulation (PWM). This paper examines the use of a symmetrical LCL filter to reduce the AC side leakage current in grid‐tied inverters. The symmetrical structure bolsters the conducted EMI suppression capability of the LCL filter. A magnetic integration scheme for symmetric LCL filters is introduced, and through thoughtful structural design, it achieves filter inductance integration on the EIE magnetic core. An experimental platform, equipped with a high‐frequency SiC‐MOSFET voltage source inverter with a 600 W output, is utilized. The LCL filter, symmetric LCL filter, and magnetic integrated symmetric LCL filter are contrasted, proving the effectiveness and feasibility of the proposed scheme. Furthermore, the experimental results demonstrate that the proposed magnetic integration scheme significantly reduces the filter's volume and weight, thereby enhancing the power density of the grid‐tied inverter system.

Investigation of a Low-Speed Commutation Voltage Shock Problem in Three-Level ANPC Inverter with Hybrid Modulation Mode

With the development of the photovoltaic industry; there will be an increasing demand for efficient, high-power density, and low-cost grid interface converters. Compared with two-level inverters, multilevel inverters have the following advantages: (1) lower device voltage ratings; (2) better output filtering spectrum; (3) lower electromagnetic interference (EMI) noise; and (4) higher switching speed capability. However, the complex switching circuit of the multilevel inverter will bring more parasitic inductance, resulting in severe switching overvoltage (ringing). Especially in order to reduce the cost of the inverter, using the long-loop modulation mode, the commutation loop will introduce more parasitic inductance, which will make the overvoltage more serious. Consider that commonly used overvoltage absorption schemes are effective only for overvoltage or suppression of oscillations. Therefore, a new overvoltage absorption circuit is proposed in this paper, which can not only alleviate the overvoltage and ringing phenomena but also suppress the effect of voltage jumps during low-frequency switching on high-frequency input voltage. This overvoltage absorption circuit is characterized by low overvoltage, fast ringing damping, and minimum capacitance. Experiments and simulations are conducted to verify the effectiveness of this overvoltage absorption circuit using a three-level ANPC inverter as a prototype. The results show that the proposed overvoltage absorption circuit can significantly reduce the overvoltage level, shorten the oscillation time, and reduce the voltage difference between the upper and lower DC bus capacitors.

Deep-ultraviolet light communication in sunlight using 275-nm LEDs

Emerging deep-ultraviolet (DUV) light communication with attractive features fulfills the increasing demand for novel wireless communication without electromagnetic interference or solar noise influence. Here, we propose, manufacture, and characterize a solar-blind full-duplex light communication system using 275-nm DUV light-emitting diodes (LEDs). Four DUV LEDs connected in series form a unit, and the transmitter consists of an array of three independent units, which can be synchronously controlled using a main processing unit to modulate the emitted light. A solar-blind filter is inserted in front of the receiver due to the lack of an ultraviolet photodetector. Both the transmitter and receiver are encapsulated together to manufacture a full-duplex DUV light communication system, which can independently transmit and receive data with a maximal communication distance of 7 m at the same time. All users within a 46 m2 area of the system have access to the DUV communication network through an integrated wireless module. Real-time video is demonstrated and different types of files could be shared. Based on Transmission Control Protocol/Internet Protocol (TCP/IP), the system is finally performed in sunlight with a transmission rate of 10 Mbps and a packet loss rate of 1.28%.

Adaptive Neural Control of Flight-Style AUV for Subsea Cable Tracking Under Electromagnetic Localization Guidance

This article focuses on an industrial system for the intelligent inspection of subsea cables based on a flight-style autonomous underwater vehicle (AUV) that tracks the route of subsea cable guided by electromagnetic localization signals. The intelligent inspection system consists of electromagnetic localization and autonomous tracking control modules. The electromagnetic localization algorithm for subsea cable is geometrically derived based on the electromagnetic sequences measured with two triaxial sensors that are symmetrically mounted on the forewings of a flight-style AUV. The argument results on the singularity, sensitivity, and consistency of the localization algorithm provide guidelines for designing the cable-tracking AUV prototypes and planning the near-bottom cable-tracking tasks. Subsequently, the cable-tracking control schemes for decoupled AUV heading and diving subsystems are developed by using the localization results. Particularly, the vector field guidance based on the localization results is designed to overcome the challenges, including underactuation and the lack of cable-tracking error dynamics. To minimize the electromagnetic noise interference and to relax the dependence on the accurate AUV hydrodynamics, the kinematic virtual control signals are filtered with low-pass filters, and neural networks are applied to approximate dynamics. Finally, an integrated simulation study is presented to demonstrate the effectiveness and robustness of the proposed electromagnetic localization-guided autonomous cable-tracking system.

Suggesting a Non-Unity Turn Ratio Two-Winding Coupled Inductor for Filtering CM EMI Noise in an SRC

Switched-mode power supplies (SMPS) are the source of both conducted and radiated electromagnetic interference (EMI) noise. Resonant converters are popular due to the possibility of switching loss reduction using zero voltage switching (ZVS) or zero current switching (ZCS) and also attenuating conducted EMI noise. Conventionally, a common-mode (CM) choke with a single core and two identical windings is used to suppress the CM noise in an EMI filter. This paper introduces an effective and cost-efficient method for mitigating the CM EMI noise in SRCs. The proposed method benefits a two-winding coupled inductor instead of the simple resonant inductor in the SRC. While a unity turn ratio does not meet the desired resonance inductance, the suggested two windings coupled inductor with an unequal number of turns deals with the EMI noise as well as the normal operation of an inductor in the resonant tank. Applying the proposed method significantly achieves up to 20 dB attenuation in the noise amplitude both at the input and output terminals of the converter. Simulations are used for investigating the analysis of the method. Moreover, a series resonant converter is designed and implemented to verify both analysis and simulations.

Conducted electromagnetic interference mitigation in super-lift Luo-converter for electric vehicle applications

In this article, a digital chaotic pulse width modulation (DCPWM)-dependent electromagnetic interference (EMI) noise attenuating procedure has been implemented. With the aid of a field programmable gate array (FPGA), a randomized carrier frequency modulation with a fixed duty cycle has been generated through chaotic carrier frequency, and this process is called DCPWM. Conducted EMI suppression is achieved in a 200 kHz, 40 W elementary positive output super lift Luo (EPOSLL) converter using the DCPWM technique. The results are compared and validated with periodic PWM over DCPWM in simulation and hardware with electromagnetic compatibility (EMC) standards. Besides, 9 dBV (2.81 V) of conducted EMI noise has been minimized in the DCPWM approach against periodic pulse width modulation method for the EPOSLL converter in electric vehicles applications.

Design and Implementation of a Flyback-Assisted Wide-Range Fully Soft-Switched T-Type Inverter

A novel soft-switched three-level T-type inverter (3LT <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> I) is proposed in this paper. The proposed inverter provides turning-on by zero voltage transition (ZVT) and turning-off by zero voltage switching (ZVS) for main switches without any voltage or current stresses. The switching energies are transferred to the snubber capacitors, so the turning-off process of the main switches is improved by these snubber capacitors. Besides, the auxiliary switches are turned on by zero current switching (ZCS) and turned off by ZVS. Furthermore, all snubber diodes are operated by soft switching (SS), and the proposed SS snubber cell decreases the electromagnetic interference (EMI) noises. The novel snubber cell has a simple structure, ease of application, common-ground switches, and low-cost features. The theoretical analysis of the inverter is clarified, and the operating modes for steady-state analysis are presented in detail. The experimental results rated 1 kW output power and 100 kHz switching frequency are provided to justify the theoretical analysis. The proposed unique snubber cell can be easily implemented in other three-level inverters (3LIs), and the practice is demonstrated in the paper.

MHz‐driven snubberless zero‐current soft‐switching high step‐up DC‐DC converter with a multi‐resonant tank

AbstractA novel high step‐up DC‐DC converter suitable for the power interface of fuel cells (FC) is presented in this paper. The proposed converter features a multi‐resonant tank for achieving high‐step up ratio under zero current soft switching (ZCS) without any snubber circuits. The simple and minimized‐component topology is beneficial for megahertz driving of gallium nitride (GaN) power transistors with effective reductions of switching loss, electromagnetic emission interference (EMI) noise, and ripple‐free DC input current. Mode‐transitional power stages are described in detail, following that the high step‐up principle is revealed by means of frequency‐domain analysis. The essential performances of the proposed circuit topology are demonstrated by simulation and experiment of 1.8 MHz‐120W prototype whereby effectiveness of the snubberless and multi‐resonant topology are verified from the practical point of view.

A Selective Common Mode Noise Mitigation Method Using Phase-Shifted Modulation for Four-Switch Buck–Boost DC/DC Converter

Wide bandgap (WBG) power devices can work at higher switching frequencies compared to silicon competitors. It helps reduce the volume of passive components but brings more serious electromagnetic interference (EMI) noise issue. The increased noise filtering requirements may restrict the power density improvement. This study discusses the conducted EMI issue and noise filtering in the four-switch buck-boost DC/DC converter (FSBB). The differential mode (DM) and common mode (CM) noise model embedded with noise sources features are derived and analyzed. It is found that modifying the spectral distribution of the CM noise is a challenge when the duty cycles are fixed by voltage gain. Inspired by the CM model, a phase-shifted modulation method is proposed to achieve selective CM noise mitigation. The recommended operating range and the implementation process are presented. The theoretical modeling and the proposed method are verified through a FSBB converter with 48V input and 100kHz switching frequency. And experimental results validate that the proposed method can achieve 30% volume reduction of the CM filter.

Full Electromagnetic Integration of Impedance-Balanced EMI Filters for Single-Phase Power Converters

Utilizing passive electromagnetic interference (EMI) filters is the most widely used approach to restrain the conducted emissions from power converters. However, the introduction of these filters will significantly raise the weight and size of the systems. Using the emerging flexible multi-layer foil (FMLF) technique, this paper investigates a complete electromagnetically integrated design concept of single-phase EMI filters based on EE-type cores, which can be applicable to engineering application scenarios with different EMI noise attenuation requirements. Two types of integrated structures are constructed with different well-designed FMLF-windings and terminal configurations. One is a common-mode (CM) choke with controllable leakage inductances, which is able to realize the integration design of CM inductor, CM capacitors and differential-mode (DM) inductors. The other is an EMI choke with integrating the CM and DM inductances & capacitances, which achieves electromagnetic integration of all the CM and DM filtering components. Compared to the existing UU-type core based integration methods, the proposed methods can ameliorate the noise suppression performance while reducing filter's weight and volume. Theoretical analyses for modeling and design of the EMI chokes is presented. Then prototypes of different FMLFs based EMI filters have been built for a 500W 100kHz SiC-MOSFET inverter, experiments demonstrate the feasibility and validity of the proposed structures.

Integrated Common-Mode Filter for GaN Power Module With Improved High-Frequency EMI Performance

While the employment of wide bandgap (WBG) devices in high-frequency and high-voltage applications brings benefits such as reduced system size and improved efficiency, it aggravates the electromagnetic interference (EMI) issue due to fast switching. High-frequency EMI noise suppression relies mainly on the filter design, where the filter's performance is strongly affected by parasitics. Through analyzing the common-mode (CM) equivalent circuit of a half-bridge power module, this letter identifies the key parasitics that dominate the performance of a common-mode filter (CMF) at high frequencies. To minimize the parasitics, the concept of integrating the CMF inside the WBG power module package is developed to improve the noise attenuation. A π-type CMF is integrated with a half-bridge GaN-based power module as a prototype to validate the concept. Experiments are conducted by measuring the CM noise spectrum received by the line impedance stabilization networks (LISNs) from the hard switching of the designed power module under 70 V and 80 kHz. Comparing the measured results of the integrated CMF to the externally-added CMF, up to 50 dBμV more attenuation is achieved by the integrated CMF in the frequency range of 10 MHz to 100 MHz, verifying the theoretical analysis and the established CM equivalent circuit.

A comparison statement on DCPWM based conducted EMI noise mitigation process in DC-DC converters for EV

Fast switching techniques at high frequencies are employed for quick charging and energy conversion in electric vehicle (EV) power converters. Electromagnetic interference (EMI) noise is produced due to the fast-switching process, which may result in malfunctioning and degraded EV performance. In this work, a digital chaotic pulse width modulation (DCPWM) technique-based EMI noise mitigation process has been applied to elementary positive output super lift Luo (EPOSLL), two-stage cascaded boost (TSCB), and ultra-lift Luo (ULL) converters, and a comparison study has been conducted with EMI reduction levels as per electromagnetic compatibility (EMC) standards. The duty cycle is varied from 0.5 to 0.67 to get the desired output voltage as an input of 10V to achieve the power ratings of 40 W to 80 W for various load conditions. A total of 4 dBV (3 V) to 15 dBV (10 V) of conducted EMI noise has been mitigated for the above-said converters. Simulation results based on power spectrum density and hardware results based on fast fourier transform (FFT) of output voltages are analyzed. According to the findings, the ULL converter is more acceptable for electromagnetic compatibility in EV applications than EPOSLL and TSCB DC-DC converters.

An Integrated Gate Driver Based on SiC MOSFETs Adaptive Multi-Level Control Technique

In HV (high-voltage) and HF (high-frequency) applications, SiC (silicon carbide) MOSFET is widely used for its small parasitic characteristics and fast switching speed. Using discrete devices on PCB, the active gate driver is usually adopted to restrict EMI (electromagnetic interference) noise. This method could achieve a limited switching performance improvement, and many disadvantages still exist. In this paper, the integrated adaptive multi-level gate driver is presented to improve the switching performance of SiC MOSFET in HV and HF applications. The proposed gate driver is realized on the chip using critical techniques such as <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">dV/dt</i> noise attenuation, high-speed circuit, and anti-false triggering mechanism. Then, the proposed gate drive is fabricated in a 0.18 <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\mu$</tex-math> </inline-formula> m BCD process and occupies a 4.16 mm <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$^{2}$</tex-math> </inline-formula> active area. The experimental results show that SiC MOSFET can achieve a 200 ns switching time, 0.8 mJ energy losses, no more than 15 V/ns average <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">dV/dt</i> noises, and 1.5 A/ns average <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">di/dt</i> noises under a 600 V power supply and a 33 A load. SiC MOSFET can also realize the excellent switching performance at different load currents from 15 A to 90 A by using the proposed adaptive multi-level gate driver.