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In order to solve the distribution of voltage quality problems, this paper presents a new voltage regulation control strategy of distribution network based on switched affine model. By establishing the state space equation of the controllable series voltage regulation device, using the method of Lyapunov function and quadratic stability theory, according to the convex combination stability theory,...
The study of AC-DC matrix converter under unbalanced power grid is mostly focused on the suppression of the two harmonic of output voltage. In this paper, the voltage type AC-DC matrix converter under unbalanced power network is studied, focusing on the control of the three-phase current in the grid side and the predictive unbalance control strategy with negative sequence voltage compensation is proposed...
IR-drop values of power grid can be reduced through inserting on-chip low-dropout voltage regulators (LDO). In this paper, we explore the optimization of LDOs to meet the IR-drop constraint, where the maximum IR-drop value is less than 10% of power supply. With Cholesky direct solver and SPICE, we propose a method to simulate power grid with LDOs. Based on the simulation method, we develop an efficient...
Power storage system using battery and super-capacitor are more and more popular in renewable energy, smart grid and electrical vehicles. But the voltage and current of the basic battery cells and super-capacitor are limited. So in practical applications, a large number of cells are connected in seriously or parallel to improve the output voltage and current ability. Due to the differences between...
In this paper, a plug and play type autonomous-micro-grid system is considered. Multiple distributed generating sources (DGs) and loads interactions are considered pertaining to the stability of the micro-grid. The proposed method enables communication-less operation of each of the elements of the micro-grid system. Master-slave control of the distributed generating sources is considered in a decentralized...
To satisfy the demand for high-quality and uninterrupted electricity service increases, advanced automatic voltage control systems of distribution power grid are highly required. Based on the hybrid control method of power systems, a new automatic voltage control system named as D-HAVC is proposed in this work. To handle fast changing daily load, the D-HAVC system adopts the switching control method...
When voltage upgrading, lightning-, switching- ice-and pollution performance of the insulators and airgaps in the overhead line play a very important role. The dimensioning procedure is different and technically more challenging from the one used for new lines. Amongst others, the margins available in voltage upgrading are much smaller and therefore the engineering needs to be done more precise. To...
Voltage pulsations in the DC bus may develop if the voltage-source inverter is fed from an unbalanced voltage supply. Negative effects on the connected electric machine and on the power grid usually result from such operation. It is possible to entirely eliminate or at least minimize such negative effects by suitable control of the active front end of the inverter. The control range of the active...
For future all-electric ships, one possibility is a DC grid fed by converter-controlled generators and loaded by converter-controlled components. The consumers can be categorized by their power demand - mainly constant or pulsed operation. Especially pulsed power is a major challenge in the scope of grid stability and, therefore, has to be analyzed and assessed in the early conceptual-design phase...
Extracting as much as wind energy as possible and feeding the grid with high quality power are the two main targets for the grid connected wind turbine system. This paper proposes the design of an efficient controller for the 3.2KW wind turbine which grabs the maximum power from the available wind. The 3.2 KW wind turbine system provides a variable frequency AC voltage and this variable frequency...
Based on the discuss and the analyse of the domestic and international study of self excitation over voltage and switching over voltage in 1000kV ultra high voltage long distance transmission line, the main point of the study of these problems is proposed . The first point is the precise production condition of the self excitation over voltage. Besides, the possibility of simultaneity and superposition...
In this paper, a high gain single-stage buck-boost grid-connected system is proposed. The proposed system consists of a high voltage gain - high efficiency - switched inductor buck-boost converter (SIBBC) and a folded cascade H-bridge inverter. The proposed converter switch is derived with a sinusoidal modulation, so that the converter output voltage is a rectified sine wave which requires only a...
This paper presents a software-based adaptive dead-time compensation technique for single-phase grid-connected photovoltaic (PV) inverter system. To prevent a short circuit in the dc-link, a switching delay time is needed to be inserted in Pulse Width Modulation (PWM) signals. This causes the dead-time effect which is harmful to the system performance. To improve the mitigation of dead-time effect...
In this paper, some of the aspects related to the design and implementation of grid connected DC microgrids are investigated. A prototype system has been designed and implemented to address these aspects. The described system is dependent mainly on sustainable energy sources. Hence, a special care has been given to dealing with these kinds of sources while designing different components of the system...
This paper proposes the Fuzzy Direct Power Control (F-DPC), a new control approach applied to three phase PWM converters. The F-DPC controller regulates the DC-link voltage, active and reactive power-flows of the grid-connected converter. The principle of this control is based in fuzzy controller. The steady state and dynamic behavior of DPC and F-DPC are presented that illustrate the operation and...
The power source in micro-grid (MG) is either atmosphere dependent source (e.g. wind generator, solar etc.) or it will be small hydro or diesel turbine. This introduces power quality concerns in MG. It is because of small power number (MW per Hz.) due to limited size of the system and limited resources for system stability. In this paper, a new application of the UPFC is introduced. The slightly modified...
This paper discusses modeling of a micro-grid with PV-Wind-Diesel generator hybrid system and its operations. The PV system is modeled with a DC/AC inverter with a pre-defined Maximum Power Point Tracking (MPPT) control. Fixed speed induction generator based wind turbines are used to model the wind farm. The diesel generator controls are modeled with droop governor and automatic voltage regulator...
The increasing penetration of generation power plants based on renewable energies in the electrical networks has boosted the number of systems connected to the grid. In this scenario the microgrid, providing advanced functionalities to improve the stability and operation of the network, have become very popular. In this paper a control strategy for the microgrid management is presented. The proposed...
This paper analyzes Henan power circuit breakers with closing resistors operation. Selecting a typical substation as the research object, switching overvoltage and surge arrester energy absorption were simulated without the closing resistor. Measured through the field test verified the accuracy of the simulation. The relations between line length and over-voltage level was also analyzed. The result...
Stand-alone photovoltaic (SAPV) system is more favourable than grid connected photovoltaic (PV) system in areas where extension of power grid is impracticable. However, the high set up cost of a SAPV system requires cost efficient solar energy harvesting methods. To improve the energy harvesting efficiency of a PV system, a large, centrally controlled PV array can be rearranged into smaller PV modules...
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