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This work presents a back to back converter topology with the ability to connect two power systems of different voltages and frequencies for the exchange of power. By utilizing indirect AC to AC conversion decoupling is achieved between the power systems with one of three phase, two level voltage source converters performing the AC to DC conversion that maintains the required DC bus voltage level...
Driven by economic and environmental concerns, countries around the world are demanding renewable energy resources (RES). Among the available renewable resource; wind and solar energy are promising resources. Recent energy regulations in Jordan have allowed the customers to install their own Photovoltaics generation (PVs) to cover their full energy consumption. This paper investigates the impact of...
In order to analyze non-sinusoidal modes of power supply systems, an accurate determination of parameters for these modes is required. Effective values of currents and voltages are among these parameters. The work is based on the wavelet transform, which allows the values for these parameters depending on each harmonic component to be accurately defined without losing data in the time domain. The...
The aim of the paper is to calculate the maximum magnetic induction value of the transformer's core which provides a specified value of current distortion. To solve this problem, an experimental study was made on the dependence of the magnetic induction on Total Harmonic Distortion for current. The processing of the measurement results was carried out using Fourier series, harmonic analysis and interpolation...
X-band power performance of N-polar GaN HEMTs is reported, including 2-tone results at 10GHz that demonstrate an OIP3/PDC linearity figure of merit of 12dB at a drain voltage of 20V, utilizing tuning of fundamental, second and third harmonic terminations. Compared to available linearity results of GaN HEMTs at 10GHz, the device technology presented here demonstrates the best such ratio reported at...
The high-frequency characteristics of power cables are very important in many application situations, especially the current distributions of power cables in the high frequency band. This paper mainly presents two important integral equation methods, volume integral equation (VIE) and surface integral equation (SIE), which can be applied to arbitrary shape of cross section of cables. This paper also...
A novel control strategy is proposed for a bidirectional multiport single phase two stage microinverter without electrolytic capacitor. The application of this converter is for power factor correction under non-linear grid tied load. The converter is composed of a triple active bridge series-resonant DC/DC converter cascaded with a voltage source inverter where a film capacitor is used in the DC-Link...
Grid synchronization of distributed generation (DG) plays an important role for effective power transfer from DG units to the utility grid. Usually, the synchronous reference frame based phase-locked loop (PLL) is a common technique. However, there is a compromise between steady-state accuracy and dynamic performance of PLL especially when the grid voltages contain harmonics and /or unbalances. In...
The modular multilevel converter (MMC), is widely adopted in high voltage applications because of its simplicity and modularity. However, the current and power flow is very complicated. As a result, methods proposed for capacitor reduction, which is required to stored line frequency related circulating energy, all went through complicated mathematical derivation. C. Li proposed a state plane analysis...
This paper analyzes the advantages of a selective retrofit of the drives in a hot rolling mill plant. More specifically, three cycloconverter-based drives of the finishing rolling mill in the plant are proposed to be replaced by back-to-back converters, thus enabling an efficient management of the active and reactive power flows and improving the control of harmonic emissions. Three-level converters...
Grid-tied Photovoltaic (PV) inverters are required to have harmonics mitigation control to reduce harmonics distortion on the output current caused by the impact of grid background harmonics. In this paper, a decentralized control strategy for reduction of the impact of distorted grid voltage on the AC-stacked PV inverter architecture is proposed. Two control schemes with the selective harmonics mitigation...
Harmonic and interharmonic distortions are considered as the main power quality issues especially in the distribution networks. The double-stage Adjustable Speed Drives (ASDs) in which the front-end diode rectifier is connected to a rear-end inverter through an intermediate DC-link filter may inject significant amount of harmonics and interharmonics into the grid and consequently degrade the grid...
Problems with power quality in the grid have gained a lot of attention recently due to rapid increase in the amount of grid-connected power converters. The converter should produce sinusoidal currents also during abnormal conditions, such as unbalanced grid voltages. Several methods, like the delayed signal cancellation-based method (DSC), have been proposed to alleviate the detrimental effect of...
As the penetration of renewable energy sources (RES) increases, variation of system impedance seen from grid-connected converters becomes much larger than expected. In this situation, stable operation of converter becomes more challenging. One of the issues caused by system impedance is resonance harmonic problem. Typically active damping control is used and designed based on the known conditions...
Power quality of ac bus voltage is a key issue for microgrids. A model-predictive-control (MPC)-based distributed bus voltage compensation methods using inverter-interfaced distributed generators (DGs) connected to the concerned bus is proposed. The presented method can compensate bus voltage unbalance and harmonics and share the compensated current between inverters autonomously, with neither communication...
This paper proposes an adaptive DC-bus stabilizer for single-phase grid-connected voltage source converter (VSC) with small-scale renewable energy integration. To enhance converter's power density, the conventional active power decoupling (APD) techniques were adopted to reduce the DC capacitance by compensating the inherent second-order harmonic power ripples in the single-phase VSC. However, it...
In this paper, an improved grid voltage modulated control (GVM) with power compensation is proposed for grid-connected voltage inverters when the grid voltage is unbalanced. The objective of the proposed control is to remove the power ripple and to improve current quality. Three power compensation objectives are selected to eliminate the negative sequence components of currents. The modified GVM method...
This paper proposes a new control scheme for harmonic power sharing and PCC voltage harmonics compensation in islanded microgrids by adopting virtual harmonic impedance method. Firstly, a droop relationship between the equivalent harmonic impedance of distributed generation (DG) units and their remaining power capacities (ZDG_h_eq-SDG_remaining droop relationship) is put forward. Then, a virtual harmonic...
In this work, it is proposed, through mathematical and computational modeling, to simulate the electrical interactions between a synchronous generator of protruding poles with its field winding being fed by a DC component to a common bus in the permanent regime, subject to a nonlinear loads. Next, sine-wave voltage components with multiple frequencies of the fundamental are inserted in order to promote...
A robust sliding mode controller (SMC) for a grid-connected photovoltaic inverter is proposed in this paper. The objective of the control is to force both the output voltage of the PV source and the grid power factor at the inverter output to follow a certain trajectory reference. The robust sliding mode controller is applied directly to the nonlinear state model of the system composed by the PV source...
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