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Network Function Virtualization (NFV) shed new light for the design, deployment, and management of cloud networks. Many network functions such as firewalls, load balancers, and intrusion detection systems can be virtualized by servers. However, network operators often have to sacrifice programmability to achieve high throughput, especially at networks' edge where complex network functions are required...
This paper studies the stability and stabilization of switched Boolean networks (SBNs) with impulsive effects. The dynamics of SBNs with impulsive effects is converted to an algebraic form, based on which, some criteria are presented for the stability of SBNs with impulsive effects. These conditions include the arbitrary switching signal case and the state feedback switching signal case. In addition,...
Networked teleoperation with haptic feedback is a prime example for the emerging Tactile Internet, which requires a careful orchestration of haptic communication and control. One major challenge in this context is how to maximize the user's quality-of-experience (QoE) while ensuring at the same time the stability of the global control loop in the presence of communication delay. In this paper, we...
This paper presents a full-order equivalent circuit model of Dual Active Bridge (DAB) converter. The proposed equivalent circuit facilitates the in-depth knowledge on the physical insight of DAB converter and can precisely retain both the steady state and dynamic behavior of the original system. This equivalent circuit can be divided into two parts: ac branch and dc branch. Both ac branch and dc branch...
Modular multilevel converter (MMC) is a promising topology of Voltage Source Converter based High voltage Direct Current (VSC-HVDC) system with many outstanding advantages such as low switching frequency, low voltage distortion and harmonics. Pre-charge process is one of the core issues of MMC based system, especially for the MMC with DC fault blocking capability. In this paper, considering a novel...
In this paper, the energy conservation law in physics is introduced into the control prototype of boost converters. Firstly, the input and output energy and the energy changes in the reactive components in each switching cycle are analysed. Then an energy balance control (EBC) method is designed based on the energy conservation law, which is independent of converter work modes, continuous conduction...
Multilevel current source converter (MCSC) is an effective way to increase the power rating of conventional current source-fed motor drive, especially its current rating. However, there are still several challenges existing in this configuration, which mainly focus on its modulation and control techniques, and the inherent DC current imbalance issue. In this paper, a model predictive control (MPC)...
This paper proposes and designs a switching cell using paralleled gallium nitride (GaN) high-electron-mobility transistor (HEMTs) in the minimized, symmetric power and gate loops. Based on the design, 1Ω gate resistor was successfully applied to speed up the switching transient. The switching cell can be easy to replace on the mother board thanks to the pluggable connector and the cell owns unique...
A capacitor voltage-balancing control strategy based on switching state redundancies is proposed for the hybrid stacked five-level converter. In order to obtain the balancing properties for flying capacitors, a hybrid model in state-space representation is established by considering the continuous and discrete variables. The proposed balancing strategy can control the flying capacitor voltages to...
This paper presents an analytical model to provide a rapid estimation of the steady-state averaged power loss of a T-type STATCOM with Virtual Zero level Modulation (VZM) to balance the neutral point voltage. A case study is then conducted on a 54kVA rated T-type STATCOM system to investigate the power loss distribution over power devices and variations over switching frequency. A comparison is made...
The high frequency high voltage (HFHV) transformer is one of the biggest contributors for conducted electromagnetic interference (EMI) emission of switching power supply. The transformer technologies for reducing conducted EMI emission focus on the shielding and changing the winding structures. However, for suppressing conducted EMI, the suppression capability of shielding is limited; current methods...
The four-level Hybrid Clamped Converter (4L-HCC) is emerging as a promising DC/AC converter topology for high-efficiency medium-voltage drives. However, without proper control, the voltage fluctuation of the DC-link capacitors will be excessive, resulting in distorted AC current and stability issue in low frequency operation. In reality, the distorted current makes it impractical for motor drive during...
In order to reduce the size of high-voltage flying capacitors in the five-level hybrid-clamped inverter, an improved modulation strategy based on phase-shifted PWM (PSPWM) is proposed in this paper. The four carrier waves are redistributed and the charge/discharge time of the high voltage capacitor can be largely reduced. The only disadvantage of this PWM scheme is that the harmonic characteristic...
A three phase power block based on novel 1.7 kV/450 A SiC-MOSFET is designed and tested. To benchmark the performance of the power block, a through comparison is done with currently standardized 1.7 kV/450 A Si-IGBT based three phase power block. Key performance indices, including power rating curves at different switching frequencies and power factors; temperature ripple at different fundamental...
Inverters are widely applied in industrial fields. To acquire the analytical solution of sinusoidal pulse width modulation (SPWM) Single-phase inverters, a traditional harmonic balance based method is extended, in which the double Fourier transform is used to describe the nonlinear switching function of the converter. Thus the steady-state periodic solution of the inverter can be obtained by our approach...
Sub-harmonic oscillation is a key factor causing instability for current-mode controlled single-inductor dual-output (SIDO) Buck converter. To inhibit the sub-harmonic oscillation of the converter and to extend its stable operating range, the ramp compensation technique is introduced in this paper. The discrete iterative map model of current-mode controlled SIDO Buck converter with ramp compensation...
The pump back test is widely adopted in the industry for characterizing and qualifying the high-power converters. One popular pump back test mode is to tie the DC link of two converters together and circulate the current through the inductor connected between the AC terminals. In this mode, one of converter operates in voltage mode to generate the virtual grid and another converter regulates the circulating...
This paper proposes a new modular multilevel converter with symmetric bidirectional DC fault blocking capability for high voltage direct current transmission systems. The new modular multilevel converter is composed of novel submodules, which is developed from a three-level T-type converter combined with some clamp circuits. The proposed novel submodule can output three voltage levels with six IGBTs,...
Long transactions, high concurrency, and frequent activity situations occur in many areas. The intermediate process of long transactions in the process of execution is more, in the process, therefore, can not avoid frequent access to the data, the system overhead of the data access process is relatively large, which reduces the efficiency of the system and increase the pressure of the server. The...
With regard to the pulse width modulation (PWM) of seven-phase motor system if the three-phase space vector pulse width modulation (SVPWM) is simply extended to the seven phase motor system that is the seven phase of the traditional SVPWM it will produce a great harmonic current. In order to restrain the harmonic content of phase current the voltage vector synthesized in the 3rd harmonic subspace...
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