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The trends in power DC/DC conversion are not only size and weight reduction together with a good efficiency; EMI and mass production are a must as well. In this context, piezoelectric transformers seem to be the ideal solution, since they allow higher switching frequencies (size and weight reduction) while also providing high efficiencies. Additionally, they are not magnetic devices, which facilitates...
This paper presents an approach for upgrading droop control aimed to improve its performance when used for two parallel inverters. The proposed control ensures equal voltage for the two inverters when different power flowing through them which guarantee zero current circulation. To fulfill the voltage regulation, the second inverter (slave) regulates its voltage to follow the master inverter reference...
Micro-grid systems are based on distributed energy resources (DERs) for example wind, solar etc., energy storage devices and scattered loads that can perform islanded as well as grid-connected operation. The concept of micro-grid has brought a paradigm shift from large scale centralized power generation to Distributed Generation (DG). It has reduced the dependence on main electricity grid and enables...
This paper deals with modeling and control strategy for a dual active bridge (DAB) converter. The generalized average modeling method is used to obtain the state-space representation of the DAB, in which the DC and the fundamental harmonic in the Fourier series expansion of state variables are considered. Transfer functions from control-to-output are determined, which will be used to define two controllers...
The problems associated with the harmonics needs more attention as more number of distributed generators like PV and wind are integrated into a distribution system. Although the integration presents a lot of benefits, satisfying the needs of local load requirements by reducing the line losses and facilitating congestion management, the problems of power quality that impact the distribution system...
This paper proposed a single-phase to three-phase converter with APF in house-service power supply of traction substation. The single phase part of converter is controlled as the rectifier, with implement of the active power filter (APF). The three phase part of converter is used as an inverter. The experiment of the step-down prototype verified the control strategy of the converter.
Renewable energy sources can solve problems of decentralized power supply of remote consumers. This article is devoted to stabilization of output parameters of micro hydroelectric power plants (voltage amplitude and frequency) at variable load of comparable capacity. Research of an automatic balancing micro-HPP system is based on variable load control correlation. Stabilization conditions have been...
The Asgard subsea compression station has been in commercial operation for over a year and has been described as working like a Swiss watch. An essential part of the system is providing subsea control power to the station. This paper will describe the design, component qualification, fabrication, testing, installation and commissioning of the Control Power Distribution Units. These redundant units...
Nowadays the comfort in passenger transport system is very relevant. One source of noise and vibration is the torque ripple. Torque ripple can be generated by an inappropriate machine control tuning and by the inherent torque ripple of the machine. In permanent magnet machines, the inherent torque ripple is composed by three components: electromagnetic torque, reluctant torque, caused by the winding...
The paper is devoted to the problem of creation and development of effective and perspective control means and methods for correction of voltage and current level and harmonic spectrum by means of active and hybrid correction systems. The main types and topologies of active and hybrid correction systems on the base of active and passive filters are presented and analyzed. The advantages and disadvantages...
Harmonics is one of the important parameter which plays havoc in the successful operation of any equipment. Hence, this parameter has to be concentrated much. In this context, a Harmonic Elimination System (HES) using a novel type of PWM scheme is developed in the simulation environment. Design of harmonic suppression system is done. Simulations are performed & the results are obtained. The results...
Control of single-phase converters connected to the grid via an LCL filter is a demanding issue due to risk of oscillations. A linear-quadratic (LQ) controller enabling besides standard pure sine control also a multi-harmonic current reference is proposed in the paper. Such a design enables to control single-phase converters generating harmonic currents, e.g. shunt active filters, or converters operating...
This paper focuses on the determination of suitable carrier based pulse width modulation (PWM) switching and control methods for grid connected modular multilevel converters (MMCs). Characterization of various level-shifted and phase-shifted carrier based PWM methods are provided in terms of output voltage waveforms both for N+1 and 2N+1 level output phase voltages. Carrier based PWM method based...
Possibility of hybridization of switching strategies for modulated inverters of six-phase multi-inverter drive has been shown in this paper. Hybrid switching schemes can be used for control of power system with unequal voltages of dc-links. In this case the proposed combined PWM techniques of inverters insure equal magnitude of the fundamental harmonics of the phase voltages for different ratios between...
This paper focus on the control of the module capacitor voltages and the circulating current harmonics of the modular multilevel inverter (MMI). The harmonic elements of the circulating current and the capacitor voltages are analyzed with a single phase state equations of the system deduced in this paper. And then the three phase state equations are transformed into the double line-frequency negative-sequence...
This study proposes control algorithm for controlled single-phase current source. The power circuit of single-phase current source uses LCL type filter instead of a traditional L filter. The main advantage of LCL filter is lower current ripple, but it is necessary to use the advanced current control. Designed control algorithm combines model based (feedforward) control with a feedback direct current...
In recent years, Fuel Cells (FC) have gained interest as energy source for stand-alone and grid connected applications, because they are very high-efficiency and multi-fuel power generators that require neither the burning of conventional fuels nor the mechanical equipment of conventional power generators. When FC are used with inverters for supplying AC loads, harmonic distortion in the supply voltage...
Quasi Resonant (QR) converters are widely used as AC current generators for induction. These converters are particularly attractive because they use just one solid state switch and only one resonant capacitor to generate a variable frequency/variable amplitude current to feed the induction coil. When properly designed and matched with their load, these converters are known to operate in ZVS at turn...
DSP chips are widely used in automatic control, mage processing, communications technology and other fields. In this paper, the application of DSP in shunt active power filter (SAPF) was discussed. Taken a DSP as the core controller, the experimental study on the SAPF was carried out, and the results of experiment were analyzed. The experiment results show that the SAPF based on the DSP chips possesses...
This is a design of a stable and reliable control and drive system of IGBT, according to the requirement of the dynamic harmonic filter. This design is centrally controlled by a 89C52 MCU and it mainly consists of 89C52 MCU, FPGA, touch screen, alarm circuit, drive and protection circuit, intelligent electrical energy sensor. It has main functions of collection of harmonic parameters of the power...
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