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In order to shorten the response times of aperiodic tasks in mixed task sets in real-time systems, this paper proposes an adaptive total bandwidth server (ATBS) algorithm based on aperiodic tasks with varying executing times. This method of reducing response times of aperiodic execution by using predictive execution times instead of worst-case execution times for deadline calculations in the total...
Increasing use of online backup services, as well as the popularity of user-generated content, has increased the demand for bandwidth. However, traffic generated by these applications can impact on the responsiveness of delay-sensitive applications if they receive a 'fair-share' of the available bandwidth. Less-than-Best-Effort TCP congestion control mechanisms aim to allow lower-priority applications...
High frequency power electronic converters require lossless, accurate and isolated current measurement. High frequency currents through a Printed Circuit Board (PCB) trace generates a non-uniform magnetic field around the trace. The non-uniform magnetic fields can be normalized by means of utilizing Magnetic Field Concentrators (MCON) using conductive materials. In this work, the effect of different...
Current-controlled LCL-filtered inverters are usually paralleled together for interconnecting the renewable energy resources into the grid. When the inverter output impedance is not well designed, the harmonic circulating currents out of the control bandwidth may be easily aroused. To reveal this resonant phenomenon and to enhance the stability of the parallel system, this paper builds the parallel...
A variety of wireless communication links today, such as HSPA+ access in high speed trains, balloon-based aerial wireless networks and satellite Internet connections have high loss rates. In such environments, Multipath TCP (MPTCP) offers a robust solution compared to regular TCP. However, MPTCP and existing schedulers suffer from performance degradation for both constant bit rate (CBR) and bulk traffic...
Existence of several application specific network technologies like Sensor Networks, Cloud, Personal Area Networks (WPANs), Vehicular Networks (VANETs), Content Delivery Networks and Wifi operating oblivious to each other in the same ISM band creates numerous problems like contention for the same bandwidth leading to excessive collisions and hence lower throughput. This calls for a hybrid mesh framework...
High fluctuation of signal strength is evident in wireless channel under mobile environment. IEEE 802.11n and IEEE 802.11ac based wireless technologies experience a challenge for selecting link configuration parameters, like number of spatial streams, channel bonding, advanced modulation and coding schemes, frame aggregation etc., dynamically under mobility. Selection of the best possible data rate...
The paper presents a 24 V chopper offset-stabilized operational amplifier with symmetrical RC notch filters, having a 4–24 V supply range, and being realized using a 0.25 ßm BCD process. The amplifier has a typical offset voltage of 1.2 μV, a minimum PSRR of 128 dB, a minimum CMRR of 120 dB, a minimum open-loop gain of 134dB, a noise PSD of 30 nV/√Hz, 1.8 MHz unity gain bandwidth, and THD + noise...
This work proposes a control linearization technique for a single phase 3 level-flying capacitor multi-level (FCML) inverter with multiple modulation strategies along the line period, based on the plant inversion. Multiple modulation strategies are used along the line cycle so that the overall size and efficiency of the converter are optimized. This benefit from the point of view of the energy processing...
In view of LCL-type grid-connected inverter system, traditional methods can hardly realize multigoal analysis and optimization, thus, a research is carried out on the visualization method based on D-partition method. In consideration of the discrete characteristic of digital control, this paper infers the establishment conditions of D-partition method in z domain, and compares it with D-partition...
Recently, an LCL-filter-based dual “Buck-Boost” AC/DC converter for DC Nano-grid with three terminal outputs was proposed. Since it is a high order filter based single-phase converter, a RC damper is adopted to keep the system stable. This converter has two work modes: “Boost” and “Buck”. During the “Buck” mode, the control-to-grid current transfer function of this dual “Buck-Boost” AC/DC converter...
This paper deals with the self-commissioning of synchronous reluctance motors. Previous work has demonstrated that the motor flux maps can be accurately identified at standstill by exciting the machine with square-wave voltage pulses of large amplitude, of the same order of the machine nominal voltage. This was made without the need of rotor locking and without using position sensors. The knowledge...
A battery-assisted qZSI features buck/boost characteristic by introducing shoot-through states. It makes full use of the fluctuant power, which generated from photovoltaic or fuel cell, by the energy-stored battery paralleled to the quasi-Z-source capacitor. Previous studies discussed the steady state performance and energy storage management for batteries. However, the dynamic tracking performance...
Application areas such as electric vehicles, data centers and microgrids increasingly rely on power electronic converters and electric motor drives to control loads. These tightly regulated converters act as Constant Power Loads (CPLs) in the context of the entire system. The negative incremental impedance of a CPL causes inherent instability which may lead to a grid collapse. This paper reviews the...
This paper proposes a DC link controller based on H∞ method for robust and reliable operation of a single-phase grid-connected inverter with an LCL-filter in photovoltaic (PV) applications. The H∞ DC link controller minimizes the bus voltage fluctuations caused by the power variations of PV system. Also, the controller ensures system robustness against such power variations, which conventional controllers...
Conventional resonant controllers (RCs) are commonly used in the current control of grid-tied converters with LCL filter due to their advantages, such as zero steady-state error at both fundamental sequences, easy design process, and straightforward implementation. Nevertheless, these traditional solutions do not permit to place the closed-loop poles of the system in convenient locations when dealing...
In order to quickly identify the noise sources in power electronics converters for EMI/EMC applications, a galvanic isolated voltage probe is developed and optimized to achieve adequate measurement bandwidth and high common-mode rejection ratio (CMRR). Several structures of the voltage probes are proposed. The prototypes are built and the performances are evaluated through testing. The experimental...
Modular medium voltage power converters have gained increasing attention in context of Smart Transformers (STs) in the electrical distribution grid. A possible ST architecture can be built by a Cascaded H-Bridge (CHB) converter in the Medium Voltage side and Dual Active Bridges (DABs) in the isolation stage. One of the main issues in the CHB control is represented by the voltage balancing. This work...
A novel angular independent dual-band FSS for multi-frequency communication is discussed in this letter. The proposed FSS with closely spaced response is consist of improved cross-shaped metal strips and a dielectric substrate. The unit cell size of the proposed FSS is 0.13λ×0.13λ where λ corresponds to the wavelength of the first resonant frequency. The proposed FSS exhibits dual stop band characteristics...
In this paper, the bandwidth enlargement method of the conventional λ/4 monopole antenna on finite ground plane is investigated for utilization in IFF (Identification friend or foe) of the secondary radar the operating frequency 1.03–1.09 GHz. For the initial study, we have proposed the structure of the resonant holes on the surface of a sector of metallic cylinders covering such the monopole that...
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