72 research outputs found
The Influence of Commercial PC Switched Mode Power Supply Interference on the PRIME PLC Performance
No full textIn the last few decades, the use of power converters is essential in the smart grid environment. Consequently, this leads to the presence of a high-level of conducted electromagnetic interference between the smart grid elements. This paper study the effect of two power converter modulation techniques: Normal convention modulation and spread-spectrum modulation, on the performance of the Power Line Communication (PLC) signal. The paper presents a practical implementation of the system and discusses the results for different operating scenarios
Electromagnetic Interference of Spread-Spectrum Modulated Power Converters in G3-PLC Power Line Communication Systems
No full textThe impact of spread-spectrum techniques used to mitigate EMI from power converters on Power Line Communication (PLC) systems is studied in this paper. A buck converter, utilizing a Random Carrier Frequency Modulation with Fixed Duty cycle (RCFMFD) based control is considered as a source of conducted EMI and a narrowband G3-PLC as the victim. It is shown that, although considered to be an EMI mitigating technique, the spread spectrum technique has a detrimental effect on the communication channel, which can be explained in the framework of Shannon’s information theory. Conventional emission evaluation methods are therefore incompatible with modern day’s technology
The Effect of EMI Generated from Spread-Spectrum-Modulated SiC-Based Buck Converter on the G3-PLC Channel
No full textPower line communication (PLC) is increasingly emerging as an important communication technology for the smart-grid environment. As PLC systems use the existing infrastructure, they are always exposed to conducted electromagnetic interference (EMI) from switching mode power converters, which need to be tightly controlled to meet EMC regulations and to ensure the proper operation of the PLC system. For this purpose, spread-spectrum modulation (SSM) techniques are widely adopted to decrease the amplitude of the generated EMI from the power converters so as to comply with EMC regulations. In this paper, the influence of a spread-spectrum-modulated SiC-based buck converter on the G3-PLC channel performance is described in terms of channel capacity reduction using the Shannon–Hartley equation. The experimental setup was implemented to emulate a specific coupling path between the power and communication circuits and the channel capacity reduction was evaluated by the Shannon–Hartley equation in several operating scenarios and compared with the measured frame error rate. Based on the obtained results, SSM provides the EMI spectral peak amplitude reduction required to pass the electromagnetic compatibility (EMC) tests, but results in increased EMI-induced channel capacity degradation and increased transmission error rate in PLC systems
Influence of Batch Cooling Crystallization on Mannitol Physical Properties and Drug Dispersion from Dry Powder Inhalers
No full textThis study provides, for the first time, an evaluation of the physicochemical properties of batch cooling crystallized mannitol particles combined with how these properties correlated with the inhalation performance from a dry powder inhaler (Aerolizer). The results showed that the type of polymorph changed from β-form (commercial mannitol) to mixtures of β- + δ-mannitol (cooling crystallized mannitol crystals). In comparison to mannitol particles, crystallized at a higher supersaturation degree, a lower degree of supersaturation favored the formation of mannitol crystals with a more regular and elongated habit, smoother surface, higher specific surface area, higher fine particle content, higher bulk density, and higher tap density. Cooling crystallized mannitol particles demonstrated considerably lower salbutamol sulfate–mannitol adhesion in comparison to commercial mannitol, with a linear reduction as surface roughness decreased and fines content increased. Also, mannitol crystals with smoother surfaces demonstrated a reduction in salbutamol sulfate content uniformity (expressed as %CV) within salbutamol sulfate–mannitol formulations. Despite the different physical properties, all mannitol products showed similar flow properties and similar emission of salbutamol sulfate upon inhalation. However, mannitol crystals grown from lower supersaturation (reduced roughness and increased fines) generated a finer aerodynamic size distribution and consequently deposited higher amounts of salbutamol sulfate on lower stages of the impactor. Regression analysis indicated linear relationships showing higher fine particle fraction of salbutamol sulfate in the case of mannitol particles having a more elongated shape, higher fines content, higher specific surface area, higher bulk density, and higher tap density. In conclusion, a cooling crystallization technique could be controlled to produce mannitol particles with controlled physical properties that could be used to influence aerosolization performance of a dry powder inhaler product
Influence of Random Modulated Power Converter on G3 Power Line Communication
No full textPower Line Communication (PLC) technologies are being used in many applications and offer the advantage of utilizing existing power cables for both power and data transmission, thus minimizing cost and complexity. Nevertheless, PLC technology requires further investigation to solve possible co-existence issues. Indeed, recent studies confirmed that alternative modulation schemes such as Random Pulse Width Modulation (RPWM), applied to switching-mode power converters to minimize conducted emissions, detrimentally interfere with the PLC system. This paper presents an experimental test campaign aimed at investigating the effects of RPWM on the G3-PLC system, with the final goal of understanding the conditions under which RPWM schemes can be considered as an effective alternative to conventional Pulse Width Modulation (PWM) in applications involving PLC systems. In details, the effects of different RPWM parameters such as switching frequency, modulation index, and Random Number Update Rate (RNUR) on the G3-PLC is investigated. In addition, different RPWM schemes such as Random Frequency Modulation (RFM) and Random Pulse Position Modulation (RPPM) are compared in terms of performance so as to highlight which RPWM is best suited to assure coexistence with PLC systems. The impact of RPWM on the communication channel is evaluated in terms of Frame Error Rate (FER), Channel Capacity, and Channel Capacity Loss metrics. Experimental results confirmed that randomly modulated converters with switching frequencies near the G3-PLC bandwidth cause more significant disturbance and possible coexistence issues than the switching frequencies out of this range. Results also show that the modulation index and the RNUR of RPWM have a direct effect on the communication channel. Moreover, a trade-off between Electromagnetic Interference (EMI) reduction and coexistence issues is observed: RFM, which is very effective for EMI reduction, is found to be very disruptive for G3-PLC, compared to alternative random modulation techniques such as RPPM
Effects of the Switching Frequency of Random Modulated Power Converter on the G3 Power Line Communication System
No full textPower Line Communication (PLC) technologies utilize existing power cables for both power and data transmission which minimizes cost and complexity. However, recent studies show that alternative modulation schemes such as Random Pulse Width Modulation (RPWM), applied to power converter to minimize conducted emissions, have possible side effects on the PLC system. In this work, the effects of the switching frequency of randomly modulated power converter on the G3-PLC system is investigated. To this end, a range of switching frequencies from 10 kHz-100 kHz is applied to a randomly modulated DC-DC converter and its potential effect on the G3-PLC is studied. Experimental results confirmed that switching frequencies near the bandwidth of the G3-PLC caused significant disturbance and possible coexistence issue compared to the frequencies out of this range. Moreover, there is a tradeoff between Electromagnetic Interference (EMI) reduction and coexistence issue that is Random Frequency Modulation, which is very effective for EMI reduction, is found to be very disruptive for G3-PLC, compared to alternative random modulation techniques like Random Pulse Position Modulation
Electromagnetic Interference of Power Converter with Random Modulation on the Power Line Communication System
No full textRandom Pulse Width Modulation (RPWM) allows controlling the switching signal of power converters in order to reduce the harmonic peaks by spreading the noise spectrum. Currently, many manufacturers of power converters are deploying this modulation scheme in order to comply with Electromagnetic Compatibility (EMC) test requirements. However, when the converters coexist with Power Line Communication (PLC) systems, such as in Smart Grid (SG) applications, resorting to RPWM needs further investigations since it potentially affects the communication channel by increasing the bit error rate. This possible detrimental effect is investigated in this work, by considering a PLC system for automatic meter reading (AMR) implemented in a SG application. To this end, the model of a complete PLC system is implemented in SIMULINK, and Quadrature Phase Shift Keying (QPSK) modulation is used to model the PLC modems in the communication channel. Results show that, even if the deployment of RPWM techniques may lead to an appreciable reduction/spreading of the peaks in the noise spectrum, it may also lead to an increase of the bit error rate on the PLC system
The effect of EMI generated from spread-spectrum modulated converters on the power line communication systems
No full textOver the last few years, the smart grid and renewable energy environment have attracted heightened interest and relevance from governments and investors for the purpose of decreasing their dependency on fossil fuels as a source of energy. Consequently, the dependency on the power converters and the communication systems continues to rise in order to link the grid elements with each other, thereby creating a complex environment. As such, one of the challenges resulting from this ‘complex’ environment is the Electromagnetic Compatibility (EMC) between the smart grid devices. In most cases, the power converter’s modulation is the main source of emissions in the smart grid. Thus, the focus of this thesis remains only on the conducted emissions in the low-frequency range. The EMC standards deal with managing the amplitude of the emissions generated from the devices at any given frequency range. A great many studies have been interested in the use of Spread-Spectrum modulation (SSM) as an Electromagnetic Interference (EMI) amplitude mitigation tool. Notably, the communication systems operating in the smart grid are the main victim, as most of the power converters switching modulation frequencies lay in the same frequency range as the communication systems.The SSM works to distribute the signal power by randomizing the modulation parameters. The PLC system works by the OFDM modulation, which works also by distributing the communication signal to several sub-carriers. To meet the research needs, a proposed testbed is implemented to couple both the power and the communication circuit. The performance of the communication system is analysed under several various operating scenarios using two approaches to assure the robustness of the results— (1) measuring the Frame Error Rate (FER) throughout the communication channel, and; (2) calculating the channel capacity of the used channel by the Shannon Hartley equation. In conclusion, the purpose of the thesis is to assure the robustness of the power line communication data transmission capability by controlling the modulation parameters of power electronic converters working in nearby electromagnetic environments
Fault Diagnosis of PMSG Stator Inter-Turn Fault Using Extended Kalman Filter and Unscented Kalman Filter
No full textSince the permeant magnet synchronous generator (PMSG) has many applications in particular safety-critical applications, enhancing PMSG availability has become essential. An effective tool for enhancing PMSG availability and reliability is continuous monitoring and diagnosis of the machine. Therefore, designing a robust fault diagnosis (FD) and fault tolerant system (FTS) of PMSG is essential for such applications. This paper describes an FD method that monitors online stator winding partial inter-turn faults in PMSGs. The fault appears in the direct and quadrature (dq)-frame equations of the machine. The extended Kalman filter (EKF) and unscented Kalman filter (UKF) were used to detect the percentage and the place of the fault. The proposed techniques have been simulated for different fault scenarios using Matlab®/Simulink®. The results of the EKF estimation responses simulation were validated with the practical implementation results of tests that were performed with a prototype PMSG used in the Arab Academy For Science and Technology (AAST) machine lab. The results showed impressive responses with different operating conditions when exposed to different fault states to prevent the development of complete failure
The Influence of Spread-Spectrum Modulation on the G3-PLC Performance
No full textThe smart grid is a fertile ground for conducted Electromagnetic Interference (EMI) between the power and the communication circuits. This paper shows the detrimental effect of spreading the switching spectrum (Spread-Spectrum modulation) on the performance of G3-PLC, which is counterintuitive to be a mitigation technique. An experimental setup is built to emulate an in-situ coupling situation between both circuits. Finally, tests are performed with different operating scenarios, and the results are discussed in the Electromagnetic Compatibility (EMC) framework. </p
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