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The comparisons of the new offered optimum three-segment and the previously considered five-segment variants of the space vectors switching sequence are continued in values of the first three orders of the n-order integral voltage harmonics factors and in values of the first three orders of some unified indices, the so-called n-order aggregate switchings and integrated voltage harmonics factors. The...
The ordinary Voltage source inverter (VSI) has two output levels +VDC/2 and -VDC/2. For medium and high power applications, multi-stage VSI (series and/or parallel combinations) with suitable filter (for obtaining near sinusoidal waveform at the output) may be a solution but there are problems in matching of different stages, selection of bulky transformer and proper filter. The quality of both the...
In this study, a modified carrier is proposed to generate PWM gating signal. Proposed PWM method reduces total harmonic distortion (THD) of the output voltage of inverter up to 5.8% than the traditional triangular carrier based PWM. Major harmonic components in output voltage are less in magnitude when proposed PWM technique is applied to inverter. Fundamental component of output voltage is also higher...
This paper presents a dual output PFC converter for switched reluctance motor (SRM) drive. Here, a modified SEPIC converter is proposed for wide range of speed control and to achieve power factor correction at AC mains. To regulate the DC link voltage, a single voltage sensor is used which output is used to drive the midpoint converter fed SRM. The switching frequency of the converter is considered...
Diode and thyristor based solid state converters are preferred because of their high reliability in applications for bulk power conversion. These converters generally use Power diodes or SCR (silicon controlled rectifiers) which has non-linear characteristics. Due to this reason such converters generate highly non-sinusoidal currents at the power supply utility. As a result of distorted currents the...
This paper presents the design of a modified Vienna rectifier for single phase power factor correction (PFC) under RL load. This research proposes a newly developed scheme consist of a modified Vienna rectifier for converting AC to DC, a simple control circuit for controlling single phase modified Vienna rectifier switching, a single phase inverter (H-bridge) for converting power from DC to AC, a...
Specific odd harmonics can be mitigated by operating the simeconductor switches in H-bridge inverters at optimized switching angles of the PWM signals. These switching angles can be achieved by calculating a set of nonlinear equations using Selective Harmonic Elimination Pulse Width Modulation (SHE PWM) technique. Modulation index (m) is a significant parameter used to control the amplitude of the...
This paper presents a simulation and experimental study on one of the most common control strategy, direct power control (DPC), for three phase shunt active power filter. The main aims of the proposed strategy are to minimize or eliminate the impacts of the unwanted harmonics, and compensate the reactive power derived by the non-linear loads. The simulation and the experimental results obtained in...
A voltage-controlled, single-phase, five-level inverter for photovoltaic systems using semiconductor power devices is proposed. Use of a unique, multilevel voltage source configuration allows the production of high voltage, low harmonic distortion AC outputs without using transformers or series-associated synchronized switching devices. The typical role of multi-level inverters is to generate the...
A design method for three-phase grid tied inverters is discussed. Four-leg topology is used to cater for unbalance voltage of the grid. A LCL filter is designed to restraint harmonic distortion. Based on three-dimensional space vector control method, voltage feed-forward control strategy is proposed for standalone model of the inverter, and a current wave tracking controller is designed for gird tied...
Recently, Development and the utilization of single phase based multilevel inverters has been increased. This paper proposes concept based new topology based seven level inverter with less number of power electronics switches with utility grid connection. This proposed multilevel inverter operates with only eight power electronics switches at their fundamental frequency. This inverter produces seven...
In today's commercial world, multilevel inverters is playing a significant role from power failure. Harmonics is a major problem in power systems that have become serious recently owing to the wide use of power electronics related equipment. In this process, there is a possibility of generation of harmonic peaks because majority of the power utilities are non-linear loads. A high performance multilevel...
The major drawback of an inverter are Total Harmonic Distortion (THD) and Harmonics. The study of harmonics and THD are carried out in this work. The cascaded multilevel inverter topology is incorporated to suppress the harmonics produced by the inverter at its output. The cascaded multilevel inverter is most effective with fuel cells or battery stored power. The cells have low voltage ratings, the...
In this paper an improved switched mode telecom rectifier for a 12kW telecommunication system is presented. An improved telecom rectifier is a combination of phase-shift transformer based ac-dc converter and passive high pass filter. The phase-shift transformer and high pass filter is realized with a fractional magnetic rating of the load. The supply current is almost sinusoidal with low total harmonic...
In this paper, a cascade multilevel inverter using a single Dc source is considered. Switching angles are obtained using a smart technique to remove the selected harmonics. Changing voltage of DC-link has been employed to change the output voltage rather than the change of the switching modulation. Problems due to the change of the modulation switching (e.g. changes of THD value and undesirability...
Due to the increase in load and use of heavy machines in the industries, the demand for multilevel inverter has been increased to a large extent. This paper investigates the effect of increase in Levels from 3 to 33 levels, using a simplified technique in Separate Source Cascaded Multilevel Inverter (CMlI) on the Total Harmonic Distortion (THD) for 1-Phase and 3-Phase Inverter without using any filters,...
This paper presents the sinusoidal pulse width modulation technique based switching strategy for three level H-bridge inverter for single phase shunt active power filter applications. The H-bridge voltage source inverters are extensively used in active filtering inverter products. Sinusoidal Pulse Width Modulation (SPWM) technique has fixed switching frequency and provides advantage over others. Power...
Switching power supply in computers and motor drive systems operate by rectifying the input AC line voltage using diodes and filtering it with large electrolytic capacitors. This results in distortion of input current waveform which is highly peaky in nature. The reduction of input current harmonics and improved power factor operation are important from the energy saving point of view and also to...
This work deals with a new hybrid multilevel inverter with Z-source converter fed induction motor drive which focuses on asymmetrical topologies. This work approximates the reduction of total harmonic distortion and selective harmonic minimization using new model asymmetric cascaded multilevel inverter by PWM technique using MATLAB/SIMULINK. The switching angles are mathematically calculated. This...
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