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.
Neutral-point (NP) voltage oscillation amplitude, THD of output voltage and the switching frequency of the inverter are the three key performance indices in three-level neutral-point-clamped (NPC) inverter. Every element connects with each other and restricts each other, which indicates that to keep the three key performance indices balanced is the research focus of the modulation strategy for three-level...
The smart transformer, a solid-state transformer with control and communication functionalities should provide services to the grid. This paper proposes to use a different frequency respect to the fundamental frequency, to provide such services to the distribution grid. The approach has the main benefit to transfer energy from point to point of the grid, exploiting the lower impedance path that multi-frequency...
The growing availability of high power semiconductor devices and the increasing necessity of high power converters in power systems and industry applications demand the use of multilevel converters topologies, such as the 3-level neutral point clamped voltage source converter. The tradeoff in designing this kind of converter is between switching losses and fast dynamic control. The size and cost of...
Smart grid applications, renewable energy utilization and electric vehicles (EVs) are attracting researchers due to their importance nowadays as well as in the future. An efficient power electronic converter is a main and common topic for research in this area. In this paper, a prototype of the electrical part of a power-train for EVs using an advanced multilevel converter topology is introduced,...
Multilevel converters are widely used in medium voltage applications. One of the most popular topologies in this field is the 18 pulses diode rectifier, which uses a mu Iti pu I so transformer that realizes a current harmonics cancelation that are generated by the three phase diode rectifiers. In this work an efficiency comparison of the aforementioned topology and a Multi-Cell Active-Front-End (AFE)...
Optimal Pulse Patterns (OPPs) permit setting the switching frequency of power converters to a low value without compromising on Total Harmonic Distortion (THD). This paper presents the algorithm of calculating OPPs for Medium Voltage converters. The calculation procedure is explained in detail. Results are discussed and an efficient method is proposed to speed up and simplify calculations.
This work presents a comparison between two adaptive filters applied to harmonic and reactive power detection in power electronics conditioners. The objective is to demonstrate their ability of tracking the signal variations without the use of synchronization techniques, with fast dynamic response and low computational burden. The algorithms are simulated and implemented in DSP TMS320F2812 for power...
In this paper, an active power filter (APF) based on a modified one-cycle control is proposed. This control method can be applied in a three-level three-phase four-wire system. By adding an additional current sensor to detect the fundamental component of the output current, the proposed APF is capable of compensating harmonic components independently from the VAR compensation so that the capacity...
The paper presents an analytical approach to find switching angles for an optimal PWM signal. The solution is in closed form that eliminates the need for numerical solution to find the transition angles. The disadvantage in iterative computation is overhead in computational effort as it requires a PC with expensive software and solution time can be a problem in real-time operation. Such an approach...
In this paper, a three-phase four-wire shunt active power filter (APF) is studied. In order to reduce voltage stress of power devices and improve the performance and practicality of APF in high voltage and capacity occasions, a hybrid cascade H-bridge seven-level converter is adopted as the main circuit of the APF. In system control, DC-link total voltage control is realized by transferring active...
A deterministic algorithm aiming at reduction of harmonic content in three phase, five-level cascaded inverters is proposed. The procedure starts from a non-linear system consisting of disequations and, using Chebyshev polynomials and Waring's formula, for any assigned modulation index computes those switching angles α1 and α2 reducing harmonics amplitude such as to fulfill grid code specifications...
Power hardware-in-the-loop (PHIL) is an important tool for testing and verifying various aspects of systems level research. It provides a realistic assessment of how a device will interact under various conditions and environments, allowing the testing process to truly vet the apparatuses before full scale deployment. Crucial to the PHIL concept, is the hardware-in-the-loop interface. Interfaces must...
This paper presents low computation algorithms for single phase integration of permanent magnet generators associated with a wind turbine emulator test-rig. The grid synchronisation and grid side control are performed by Second Order Generalised Integrators (SOGI). A SOGI-FLL (frequency locked loop) was used for robust, accurate and low computation single phase grid synchronisation. Proportional-Resonant...
This paper deals on control strategy and analyzing power flow between home integrated photovoltaic system (PVS), plug-in hybrid electric vehicle (PHEV) and distribution network The neutral point clamp (NPC) multilevel inverter is the main element that allows interfacing between the different energy sources and receptors. The combination of synchronous reference frames (SRF) and indirect control algorithms...
The steady state operating curves of three design variants of a five-phase induction machine are assessed and compared to a standard three-phase induction machine of the same size which is taken as the basis for the comparison. The performance in terms of torque, power factor, stator current and efficiency are analyzed for different load conditions. The operating curves are determined by means of...
This paper describes novel adaptive multiplicative general parameter finite impulse response filter with real coefficients (MGP-FIR). The MGP-FIR is adaptive, predictive digital FIR filter for fundamental harmonic estimation of distorted signal with small frequency fluctuations without phase shift (time delay). This property is necessary for high quality control of power converters connected to the...
An obvious obstacle to a wider utilization of electric vehicles (EVs) is the absence of a widely available charging network. Direct charging of EV batteries with dc voltage in charging stations requires deployment of expensive power electronics equipment. On the other hand, placing the same equipment on-board an EV would enable access to any three-phase grid outlet, but would substantially increase...
Repetitive schemes are composed by the interconnection of delay lines. These schemes are usually implemented in a digital way, where delay lines are replaced by discrete delays. Each discrete delay is obtained as the ratio between the required delay time in continuous time and the sampling period. A problem arises whenever the delay time of the controller is not an integer multiple of the sampling...
This paper addresses the harmonic compensation error problem existing with parallel connected inverter in the same grid interface conditions by means of impedance-based analysis and modeling. Unlike the single grid connected inverter, it is found that multiple parallel connected inverters and grid impedance can make influence to each other if they each have a harmonic compensation function. The analysis...
Renewable resources power generation systems are mainly constituted by power converters. These converters can be controlled in several ways to execute different functions inside microgrids. Some of the converters cannot operate on isolated grids, that is, without connection to the electrical grid. Therefore, there are converters whose purpose is to provide a voltage reference so that other converters...
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.