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This paper presents the design and analysis of both the active and reactive power control of a single-phase voltage source inverter (VSI) for grid-connected photovoltaic (PV) system. The proposed method is based on vector control of power by decoupling control of the active and reactive current components to feed the active and reactive power to the grid. The aim of this research is to control power...
Model Predictive Direct Torque Control (MPDTC) is a recent computational control methodology that combines the merits of Model Predictive Control (MPC) with the ones of Direct Torque Control (DTC). Specifically, with respect to standard DTC, the converter's switching frequency and/or losses are considerably reduced, while at the same time the Total Harmonic Distortion (THD) levels of the phase currents...
This paper applies the selective harmonic elimination technique to 5-phase, 2-level inverters to assess the ability of the technique to eliminate specific harmonics. Whilst the technique is well-known, there is little information on its application to five-phase drives, where there are specific and important differences to three-phase counterparts. This includes the need to eliminate different harmonics,...
This paper presents the analysis, modelling and control model of the electric part of a grid connected photovoltaic generation system. The model contains a detailed representation of the main components of the system that are the solar array, and the grid side multilevel neutral point clamped (NPC) voltage source inverter (VSI). In order to extract the maximum amount of from the photovoltaic generator,...
Multilevel inverters introduce harmonic to the network, beside their enormous advantages. THD is one of the most important indexes to evaluate harmonic contents of waveforms. Conventional method of line voltage THD calculation gives approximate answers but its accurate value is important. In this paper, a series of analytical formula is found to calculate line voltage THD of 5-level inverter with...
Inverters are power devices used for many industrial applications such as power conversion, the speed control of induction motors etc. When a magnetic device is energized by an inverter power supply, its magnetic core is subjected to additional core losses due to harmonic contents. One solution to this problem may be the selective harmonic elimination based on the simultaneous solution of non-linear...
It is difficult to obtain a more precise mathematical model of parallel-inverter system with a nonlinear load. Nonlinear load is the general factor which affects output voltage total harmonic distortion (THD) and current sharing. But fuzzy controller can control well without a precise mathematical model. Master-slave control is used to control the parallel-inverter system in this paper. The voltage...
In this paper, the elimination of harmonics in a cascade multilevel inverter by considering the nonequality of separated dc sources by using particle swarm optimization is presented. Solving a nonlinear transcendental equation set describing the harmonic-elimination problem with nonequal dc sources reaches the limitation of contemporary computer algebra software tools using the resultant method. The...
In this paper, a new digital switching technique for cascaded H bridge multilevel inverter (CMLI) for the purpose of power quality improvement is proposed in order to ensure an efficient voltage utilization and better harmonic spectrum. The method presented shows a topology to control cascaded multilevel inverter that is implemented with multiple DC sources to get 2n+1-1 levels. Whereas a standard...
Constant frequency One Cycle Control (OCC), as proposed by Smedley, is a powerful method for controlling switching power converters. The dimensioning of this control method for two level AC output converters is not of common knowledge. This paper describes OCC for two level switched power converters. Its instability problems and solutions are analysed and dimensioning equations are deducted. This...
Grid-connected inverters are widely used in the distribution generation (DG) systems for the conversion of renewable energies. These inverters are usually connected to the utility grid through LCL filter to reduce the current harmonics injected to the grid. A LCL network, which can achieve reduced levels of harmonic distortion at low switching frequencies with less inductance, is a good alternative...
This paper presents three-phased inverter with three identical step voltage levels. The main application is for embedded systems where the DC input voltage is stored in accumulator batteries. The input DC voltage is assumed to be a three identical series connection of accumulator batteries. The chosen inverter structure leads to minimise the necessary power switches. The voltage step levels and the...
A direct torque control strategy of a three-level neutral point clamped inverter-fed induction machine is presented. Three-level inverters are an emerging technology and are commonly applied to high power motion drives instead of the standard two-level voltage source inverters (VSI). In three-level inverters the blocking voltage of each switch is half of the DC bus voltage, lower dV/dt is generated...
One of the major problems in electric power quality is the harmonic contents. There are several methods of indicating the quantity of harmonic contents. The most widely used measure is the total harmonic distortion (THD). This paper compares the two harmonic optimization techniques, optimal minimization of the total harmonic distortion (OMTHD) technique and optimized harmonic stepped-waveform (OHSW)...
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