Design and Performance Evaluation of a High Power-Density EMI Filter for PWM Inverter-Fed Induction-Motor Drives

This paper presents the design of an electromagnetic interference (EMI) filter for a low-voltage high-current induction-motor drives supplied by dc power grids. In order to effectively design the EMI filter, a suitable common-mode/differential-mode (CM/DM) separation technique has been used. Due to the high operating currents, the software-based separation technique using time-domain measurements has been applied. The proposed technique allows the CM and DM sections of the EMI filter to be properly selected in a more economical way, i.e., without the need of a dedicated hardware or costly radio frequency (RF) instrumentation. The design has been done according to a power-density criterion. The effectiveness of the proposed CM/DM separation technique and the EMI filter features/performance has been assessed by experimental tests, carried out with an 1.1-kW pulsewidth modulation (PWM) inverter-fed induction-motor drive, supplied by a 48-V dc power grid

COMMON MODE VOLTAGE ELIMINATION IN THREE-PHASE FOUR-LEG INVERTERS UTILIZING PULSE DENSITY MODULATION

Common mode (CM) electromagnetic interference (EMI) is a phenomenon that negatively affects power electronics to include voltage source inverters. Typically, CM EMI reduction is achieved through passive measures such as CM chokes and passive filters. This thesis research explores removing the need for these passive devices in three-phase, four-leg grid-following inverters by eliminating CM EMI using pulse density modulation (PDM) in conjunction with model predictive control (MPC) and delta modulation. A physics-based model of the equipment under test (EUT), utilizing state-space modeling, was analyzed using computer simulations and a laboratory prototype, utilizing SiC switching devices, was designed to validate the model. The physics-based model of the proposed control system was converted to Verilog, a hardware description language (HDL) utilizing MATLAB HDL coder in order to control the laboratory prototype via a field-programmable gate array (FPGA). Simulated and experimental results demonstrate that both the unbalanced load requirements in MIL-STD-1399 and the conducted emission limits in MIL-STD-461G are met with the proposed controller, while the grid-following converter supplies a desired current to the load.Office of Naval Research, Arlington VA 22203-1995Outstanding ThesisLieutenant, United States NavyApproved for public release. Distribution is unlimited

Elimination of CM Noise from SMPS Circuit using EMI Filter

The electronic devices are exposed to external electromagnetic signals that produce an unwanted signal called noise in the circuit, which causes electromagnetic interference [EMI] problems. It occurs in two modes: radiated mode and conducted mode. In the radiation mode, the shielding technique is used for radiation mode, in conduction mode filtering technique is used. The design of an EMI filter depends upon the type of noise generated by the Switched Mode Power supply circuit [SMPS]. The SMPS circuit used in this paper is a DC-DC power converter, the Boost converter is a step-up converter and Buck converter is step down converter are considered as equipment for generation of noise, the Line Impedance Stabilization Network [LISN]is used for generating the common output impedance to the power converters, the EMI filters are designed to eliminate noise generated by the circuits. There noise generated by this power converters is Common Mode [CM] noise and Differential Mode [DM] noise. The separation of noise from the equipment is done by using a noise separator. In this paper, CM noise generated by these power converters is eliminated by designing an EMI filter called an inductor filter and a PI filter. The comparison between the LC inductor filter and the PI filter for the boost and buck converters is observed. The PI filter has better performance characteristics when compared to the inductor filter for both SMPS circuits as per the Comité International Special des Perturbations Radioélectriques [CISPR] standards. This standard gives the conducted emission range for different electronic devices

Improved methodology for conducted EMI assessment of power electronics and line impedance measurement

Electromagnetic Interference (EMI), primarily common mode (CM), is problematic in a wide range of electronic circuits due to its propensity to radiate, particularly in high power applications. It is routine for much effort and resources to be dedicated to its characterization and reduction as EMI compliance is a requirement for most electronic systems and devices, including power electronics. Many well-known factors contribute to a system’s EMI performance including intentional coupling from system components as well as unintentional coupling from parasitics. Sources of intentional coupling may include Y-capacitors intended to mitigate EMI as part of a filter. Unintentional coupling is more elusive and can exist throughout the system in PCB layout, cabling, load construction, and internal to components such as inverter bridges. Lesser-known contributions to EMI performance irregularities can be EMI filter asymmetries, switching asymmetries, line impedance variances, and galvanic coupling from the metrology intended to measure EMI. It is critical to understand these contributors to facilitate designs with optimal EMI performance. EMI filters are often added to designs with no consideration to asymmetries in construction and component tolerances. This proposal evaluates the impact to CM currents in cases of coupling or leakage inductance imbalances of a CM choke. Similarly, CM currents are also evaluated for cases when EMI filter Y-capacitor imbalances span the components tolerance band. Also analyzed are switching asymmetries in a typical converter topology to understand EMI impact and evaluate potential benefits if intentional asymmetric switching is applied. A practical method is introduced to measure line impedance upstream of devices under test as line impedance variation can impact the performance of EMI filter design. However, few documented practices exist to measure line impedance without specialized instrumentation. Finally, this work proposes a streamlined method for conducted emissions evaluation employing an oscilloscope, differential voltage probes, and post-processing software implemented in MATLAB. This method eliminates unintended metrology ground coupling that can significantly impact EMI measurements and minimizes risk of instrumentation damage particularly in high power systems

A high-frequency modeling of AC motor in a frequency range from 40 Hz to 110 MHz

Introduction. Most electromagnetic compatibility models developed for the study of three-phase induction machines are generally valid for low and medium frequencies (<< 1 MHz). This frequency limit seems to be too restrictive for the overall study of conducted electromagnetic interference. In this paper, the model is using the proposed model and compared with experimental results in low and medium frequency. And then, the high-frequency modeling of induction motor is presented new method based on transfer function model. The proposed methodology is verified on an experimental and simulation, it’s suitable for prediction of the terminal overvoltage analysis and electromagnetic interference problems and common-mode and differential-mode currents. The novelty of the work consists to develop an improved high-frequency motor model based on transfer function to represent the motor high-frequency behavior for frequency-domain analyses in the frequency range from 40 Hz up to 110 MHz .The purpose of this work is to study the common-mode impedance and the differential-mode impedance of AC motor. The determination of these impedances is done for firstly both common and differential modes at low and medium frequency, and then common-mode and differential-mode characteristics at high frequency. Methods. For the study of the path of common-mode and differential-mode currents in typical AC motor (0.25 kW, 50 Hz) an identification method in high frequency for induction motor has been proposed based on the transfer function in differential-mode and common-mode configuration. The low and medium frequency model were presented in the first time based on equivalent circuit of electrical motor. Then, the common-mode and differential-mode impedances were defined in high frequency using asymptotic approach. This motor was studied by MATLAB Software for simulation and also experimental measurements. Results. All the simulations were performed using the mathematical model and the results obtained are validated by experimental measurements performed in the University of the Federal Armed Forces Hamburg in Germany. The obtained results of common-mode and differential-mode at low frequency, medium and high frequency are compared between simulation and experiment.Вступ. Більшість моделей електромагнітної сумісності, розроблених для дослідження трифазних асинхронних машин, загалом застосовні для низьких та середніх частот (<<1 МГц). Ця частотна межа здається надто суворою для загального вивчення кондуктивних електромагнітних перешкод. У цій статті запропонована модель використовується і порівнюється з експериментальними результатами за низької та середньої частоти. Потім представлений новий метод високочастотного моделювання асинхронного двигуна, що базується на моделі передавальної функції. Запропонована методологія перевірена експериментально та за допомогою моделювання, вона придатна для прогнозування аналізу перенапруг на клемах та проблем електромагнітних перешкод, а також синфазних та диференціальних струмів. Новизна запропонованої роботи полягає у розробці вдосконаленої моделі високочастотного двигуна на основі передавальної функції для представлення високочастотної поведінки двигуна для аналізу частотної області в діапазоні частот від 40 Гц до 110 МГц. Мета роботи полягає у вивченні синфазного імпедансу та диференціального імпедансу двигуна змінного струму. Визначення цих імпедансів виконується спочатку для синфазних та диференціальних мод на низькій та середній частоті, а потім для синфазних та диференціальних характеристик на високій частоті. Методи. Для дослідження шляху синфазних та диференціальних струмів у типовому двигуні змінного струму (0,25 кВт, 50 Гц) було запропоновано метод ідентифікації на високій частоті для асинхронного двигуна, заснований на передавальній функції у конфігураціях диференціального та синфазного режимів. Вперше представлена низько- та середньочастотна модель на основі схеми заміщення електродвигуна. Потім синфазний та диференціальний імпеданси визначені на високій частоті з використанням асимптотичного підходу. Цей двигун був вивчений програмним забезпеченням MATLAB для моделювання та експериментальних вимірювань. Результати. Все моделювання виконано з використанням математичної моделі, а отримані результати підтверджені експериментальними вимірами, проведеними в Університеті федеральних збройних сил у Гамбурзі, Німеччина. Отримані результати синфазного та диференціального режиму на низькій частоті, середній та високій частоті порівнюються між моделюванням та експериментом

Electromagnetic interference in balanced converters

M.Ing. (Electrical And Electronic Engineering)In this dissertation, an investigation into reducing Electromagnetic Interference (EMI) through design is presented. Root generation mechanisms of Electromagnetic Interference are often neglected during the design process and later treated symptomatically. Mitigation of Electromagnetic Interference at source often reduces cost and physical size of electronics. This dissertation demonstrates the process and results by which schematic balance mitigates EMI. In addition, the introduction of Geometric Balance and physically designing circuits to be Geometrically Symmetrical are presented and tested to determine whether the design produces mitigating EMI results. Multiple Printed Circuit Boards (PCB’s) were developed and tested against each other to demonstrate schematic balance and other EMI generation mechanisms. The final PCB was designed to be Geometrically Symmetrical and the test results compared. The results illustrate the varying performance of each PCB due to their differing design. The Geometrically Symmetrical PCB presented the best results due to various improvements which include physical layout size and semiconductor placement. An additional important phenomenon discovered was the amount of EMI generated during MOSFET Driver operation. This contributed to a significant amount of EMI during the no-load phase of testing

Phone virtual environment for RC assistive robot

Robotic systems nowadays are all around us and interact in many aspects such as homeowners use robotic vacuums in their homes. However, a push needed to make these systems more and more interactive with humans. The complexity of the robot controller might be one of the boundaries between the robot interactions with human. An assistive robot with an Android phone controller needed since smart phones nowadays are used almost by everyone. This assistive robot controller does not require much effort from the user, just needs moving a finger to control them. This project uses SolidWorks and Processing in the software development phase. The IOIO board has been applied as a main controller to run the system as an embedded system, and integrate the android application with the assistive robot. The communication has been established using the standard 0 dBm radio Bluetooth with range of 10 meters radius. The joint have a good desired tracking with less than 1% error. Finally the aim of this project, which is a user friendly smart phone application to monitor and control the assistive robot has been developed

Modeling and Optimization Algorithm for SiC-based Three-phase Motor Drive System

More electric aircraft (MEA) and electrified aircraft propulsion (EAP) becomes the important topics in the area of transportation electrifications, expecting remarkable environmental and economic benefits. However, they bring the urgent challenges for the power electronics design since the new power architecture in the electrified aircraft requires many benchmark designs and comparisons. Also, a large number of power electronics converter designs with different specifications and system-level configurations need to be conducted in MEA and EAP, which demands huge design efforts and costs. Moreover, the long debugging and testing process increases the time to market because of gaps between the paper design and implementation. To address these issues, this dissertation covers the modeling and optimization algorithms for SiC-based three-phase motor drive systems in aviation applications. The improved models can help reduce the gaps between the paper design and implementation, and the implemented optimization algorithms can reduce the required execution time of the design program. The models related to magnetic core based inductors, geometry layouts, switching behaviors, device loss, and cooling design have been explored and improved, and several modeling techniques like analytical, numerical, and curve-fitting methods are applied. With the developed models, more physics characteristics of power electronics components are incorporated, and the design accuracy can be improved. To improve the design efficiency and to reduce the design time, optimization schemes for the filter design, device selection combined with cooling design, and system-level optimization are studied and implemented. For filter design, two optimization schemes including Ap based weight prediction and particle swarm optimization are adopted to reduce searching efforts. For device selection and related cooling design, a design iteration considering practical layouts and switching speed is proposed. For system-level optimization, the design algorithm enables the evaluation of different topologies, modulation schemes, switching frequencies, filter configurations, cooling methods, and paralleled converter structure. To reduce the execution time of system-level optimization, a switching function based simulation and waveform synthesis method are adopted. Furthermore, combined with the concept of design automation, software integrated with the developed models, optimization algorithms, and simulations is developed to enable visualization of the design configurations, database management, and design results