The Infona portal uses cookies, i.e. strings of text saved by a browser on the user's device. The portal can access those files and use them to remember the user's data, such as their chosen settings (screen view, interface language, etc.), or their login data. By using the Infona portal the user accepts automatic saving and using this information for portal operation purposes. More information on the subject can be found in the Privacy Policy and Terms of Service. By closing this window the user confirms that they have read the information on cookie usage, and they accept the privacy policy and the way cookies are used by the portal. You can change the cookie settings in your browser.
This paper considers the stability and L2-gain for a class of switched neutral systems. Sufficient conditions for exponential stability criteria and L2-gain are developed for arbitrary switching signal with average dwell time.
In this paper, a class of linear switched systems with time delays is investigated. At the same time, the impulsive effects and parametric uncertainty assumed to be norm-bounded are considered. Some novel exponentially stable criteria are obtained by constructing appropriate Lyapunov-Krasovskii functional. The validity of the results is shown by one numerical example.
Forwarding system is one of key components for high-performance router. In this paper, the architecture of router is described first. Then, software system of centralized router and the process of a packet are analyzed. At the end, the performance bottleneck of centralized router is pointed out. To get better performance, we propose a fast-forwarding mechanism to increase the speed of packet, which...
In this paper, very low loss and high isolation single pole double throw (SPDT) switch design for millimeter wave applications using pseudomorphic high-electron mobility transistor (pHEMT) is presented. The MMIC switch design is developed using a commercial 0.15 mum GaAs pHEMT technology. At the operating frequency of 30 GHz, the SPDT switch has 1.948 dB insertion loss and 24.526 dB of isolation....
This paper introduces an optimized sync switching method of spring operating mechanism based vacuum circuit breaker (VCB), and the development of an actual control system using TI 2812 DSP. This optimized method could efficiently reduce the switching surges caused by VCB operation. In this paper, factors that drift operating times including control voltage and count of operations are analyzed. An...
Direct-drive wind power system needs a full-scale power converter to transmit the variable frequency electrical power to the grid. In order to improve the low voltage ride through (LVRT) capability, the grid-connected inverter (GCI) should work at a unity, a leading or a lagging power factor. Traditional control methods are complicated and output waveform is distorted by dead time. This paper introduces...
Design an electrical locomotive 110 V D.C. source with PFC based on the structure of two-stage switching converter. Discuss the design scheme of main circuit and control circuit. Expound the calculation method of the key parameters. The experiments indicate that the device gets good performance on output and reliability. The electric source is appropriate for electrical locomotive and the other similar...
The capacity and feature of a large-sized low-voltage switchgear laboratory are presented in this paper. A monitoring and control system is designed for the laboratory with industrial PC as upper computer and PLC as lower computer. The testing process and programming philosophy of switchgear testing are discussed in detail. WinCC configuration software with a human-machine interface (HMI) is used...
A novel control method for Permanent Magnet Synchronous Motor (PMSM) position servo systems is presented, which can greatly improve the dynamic performance of servo systems. In this method, the maximum reaching velocity control is introduced to reconstruct the conventional three closed-loop PID regulators. Under the new velocity and position control modes (two-segment modes), the PMSM servo systems...
This paper presents a high performance direct torque control (DTC) theme for the induction motor (IM). To solve those problems associated with conventional DTC, such as high current, flux and torque ripple, variable switching frequency, the space vector modulation (SVM) is implemented in the DTC to guarantee the constant switching frequency of the inverter. Meanwhile, the design of a robust speed...
This paper presents a three-level rectifier with reduced number of power switches based on one-cycle control. Only six power switches with voltage rating of half DC-link are adopted in this multilevel rectifier. A nonlinear control method, one-cycle control, is used to control the rectifier. The controller is composed of some integrators with reset, flip-flops, comparators and linear components, which...
Five-level inverter has been applied to industry and railway traction to solve the difficulty in applying low-voltage or medium-voltage switch devices to high-voltage system. The basic principle of diode-clamped five-level inverter is analysed in this paper. Based on the analysis of diode-clamped three-level inverter, single pulse control method, pulse width modulation(PWM) control methods and a novel...
To solve the problems of torque ripple and inconstant switch frequency of inverter in the conventional direct torque control (DTC) for permanent magnet synchronous motor (PMSM) drive, a novel DTC method using space vector pulse width modulation (SVM) is proposed based on analysis of PMSM mathematical model. In this novel DTC system of PMSM , traditional torque hysteresis controller and flux hysteresis...
Based on the working conditions and development trend of operating mechanism of high-voltage circuit breaker, this paper presented a high-load adjustment rate of portable high-frequency switching power supply designed for high-voltage circuit breakers test. The main circuit topological structure is analysed in detail, which uses the fullbridge circuit and IGBTs (insulated gate bipolar transistor)...
The conventional methods used in the isolation of the UPQC are add a isolation transformer in the point, in which series unit or parallel connection unit access the system, but owing to the non-linear of the transformer, this isolation method shall bring many baleful ingredients. In order to avoid the baleful influence of the conventional isolation transformer, the text introduces a sort of new-style...
Z-Source inverters have recently been proposed as new power conversion concept as they have both voltage buck and boost features. A unique impedance network between the power source and converter circuit provides both voltage buck and boost properties, which cannot be achieved with conventional voltage-source and current-source inverters. This paper presents a neural network control system that control...
Multilevel converters have excellent performance in power application, especially in high-power medium voltage fields. To find an effective and general strategy for multilevel and multiphase system is a challenge attracting many researchers. This paper analyses the basic analytical meaning of PWM strategy, which is to implement an analog continuous reference value by means of several available discrete...
Double modes inverters, as the interface devices between the microgrid system and public grid, plays an important role in the distributed generation system. In order to realize the connection and disconnection between double modes inverter and public grid, an intelligent switch is necessary. The switch is used to detect the status of grid and inverter, adjust the frequency, amplitude and phase of...
According to the basic characteristics of air plasma cutting inverter, the cutting inverter with sliding mode control (SMC) is researched and designed. Unlike the traditional PI control with the contradictory between the small voltage overshoot and the fast response time, SMC has not only effectively solved the voltage overshoot during the cutting process, but also realized a faster voltage response...
Through analyzing the shortcomings of the control system on the traditional cutting inverter, this paper presents the double close loop control system based on pole assignment for cutting inverter, which based on phase shift full bridge zero voltage switched (PS-FB-ZVS). This paper builds the small signal mode of PS-FB-ZVS PWM converter, and assigns the double close loop PI parameters by pole assignment...
Set the date range to filter the displayed results. You can set a starting date, ending date or both. You can enter the dates manually or choose them from the calendar.