Papers by Keyword: Inverter

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Authors: Ying Li Zhang, Yi Chen, Wei Hua Chen
Abstract: Wind turbine system (WTS) is a representative distributed power generation (DG). Establishment of WTS model and control strategies is of important practical significance. One critical field is the research of inverter system. It should be operated in stand-alone (SA) or grid-connected (GC) mode. The purpose of this thesis is to establish simulation platform of WTS inverter control model in Matlab/Simulink environment, which includes two typical DG control strategies, PQ and V/f. The wind fluctuation makes inverter output power harder to follow wind turbine (WT) power. In GC mode, PQ strategy was adopted to balance inverter output power and WT generated power. In SA mode, V/f strategy was applied to keep emergency load voltage stable. The bidirectional smooth transitions between SA and GC mode were well accomplished. Simulation proves the model can survive grid failures or load shedding. The study can be used in research of DG operation control.
Authors: Jun Yuan, Wei Wang
Abstract: This paper presents a time-to-digital converter (TDC) based built-in self-test (BIST) scheme for operational amplifier (Op Amp). The propagation delay exiting in the transient response of the Op Amp is monitored by the inverter based TDC, and converted into a digital code based on the referenced delay interval of the inverter used in the TDC, as a result, the digital code is finally employed to determine the test rsults. The circuit-level simualtion results of the proposed BIST syetem for a two-stage Op Amp are presented to demonstrated the feasility of the proposed BIST scheme with high fault coverage.
Authors: Yoshitaka Sugawara
Abstract: To achieve large current capability in spite of present small SiC devices that are limited by various crystal defects, focus was placed on SiC GTO thyristor and SICGT have been developed as an advanced SiC GTO. SICGTs with current capability of 1.6-100 A and blocking voltage of 3-12.7 kV and a 3 phase PWM SICGT inverter with output power of 35 kVA have been successfully developed. Furthermore, application of the SiC inverter aimed to a load leveling system was demonstrated.
Authors: Yang Xia, Hai Liang Tao, Ning Zhang
Abstract: Hysteresis current controllers are widely used in PV inverters. The main drawback of conventional hysteresis current control is that the switching frequency is variable, as the hysteresis band is fixed. In this paper an adaptive band hysteresis control algorithm with no derivative calculation is presented. As it will be shown, this algorithm can limit the switching frequency variation within a small range and the algorithm itself is simple and easy to be implemented. The performance of this algorithm, together with the one [10] and conventional hysteresis control has been evaluated by means of simulations performed with PSIM and SIMULINK. Simulation results show the effectiveness of the suggested hysteresis current controller.
Authors: Da Lu Guan, Fang Yang
Abstract: The paper introduces an electrical design to dilute heavy crude oil. The design is based on the feedback principle and includes detection part, control part and actuator part. The practice proves the design is reliable and accurate to realize the proportion between the crude oil flow and dilution liquid flow.
Authors: Ji Hong Zhang, Zhi Yong He, Chuan Li
Abstract: This paper proposes an improved droop control strategy. Its principle is an introduction of feed-forward bias currents based on conventional droop control, which makes the inverter work as grid supporting sources in the grid connected mode. When the main grid voltage suffers any variation, the inverter will respond with variation of active power and reactive power, so that it can restore the main grid voltage and frequency and increase stability of the main grid. In the island mode, the proposed control method can allocate load power proportionally as expected and make soft changes between island mode and grid connected mode. At last, verify the effectiveness and reasonableness of the proposed control strategy through simulation.
Authors: Chen Xin Li, Qi Ping Yuan
Abstract: Islanding detection is a very essential function for a photovoltaic grid-connected system. Islanding phenomenons not only damage to equipment, but also endanger to the safety of the maintenance personnel. Passive islanding detection methods that use alone have considerable non-detection zone (NDZ); active islanding detection methods that use alone are that join disturbance to system, but the disturbance will cause system instability [1]. In this paper, an over/under voltage and over/under frequency detection method combines with an improved active power perturbation detection method are proposed. The photovoltaic system can be reduced non-detection zone (NDZ) with improved the power quality and reduced the total harmonic distortion (THD) through this method.
Authors: M.Z. Aihsan, R.B. Ali, M. Othman, N.A. Rahman, L.S. Sing
Abstract: This paper presents a new selective switching strategy for single phase SPWM Inverter that can reduce the power loss and total harmonic distortion. Power loss is always a command issue for inverter system. Power loss occurs during the switching of the inverter. This new selective switching strategy is modified from the typical switching strategy and has been proven to reduce the power loss and harmonics. This project had already been tested on direct power source and also from the solar PV module. This project is focusing on 100W inverter system.
Authors: Zhao Gang Wei
Abstract: This passage introduces using inverters to achieve high efficiency and energy conservation, and using distributed remote data collection system to achieve anti-interfering, intelligent and energy-saving combined pumping station. The passage emphatically analyzes pump station system's structure, the energy-saving profits of inverter application, and the anti-interference of remote data collection. This system has been put into operation in several industrial corporations, and the reliability and energy conservation of it have been fully affirmed; therefore, it can be used as reference for other similar systems.
Authors: Yang Tian, Ru Cheng Han, Chen Li
Abstract: With increasing concern of global warming, many are looking at sustainable energy solutions to protect the earth for the future generations.. This paper presents a new inverter which can be used in hybrid wind/photovoltaic grid-connected power system. This inverter allows the two sources to work separately or simultaneously depending on the availability of the energy sources. Harmonic content is detrimental for the Grid security. The introduction of the inverter can effectively reduce the harmonics generated by the system. Operational analysis of the proposed system will be discussed in this paper. Simulation results are given to highlight the merits of the proposed inverter.
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