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A hybrid modulation approach is proposed in this work, which allows to modulate the switches of the five level neutral point clamped inverter (5LANPC) with different switching frequencies. Some of the switches are controlled with a low switching frequency using six-step modulation and Optimized Pulse Patterns (OPPs), whereas the rest are modulated with a high switching frequency using Carrier-Based...
In this paper, a drive scheme generating 24-sided polygonal voltage space vector structure using an inverter topology with single DC source is proposed. A 24-sided structure eliminates dominant low order phase voltage harmonics including and up to seventeenth and nineteenth orders throughout the speed range including step operation. The power circuit has a two-level inverter and two low voltage cascaded...
The objective of this project is the performance optimization of an electrical drive system, which consists of a two-level Voltage Source Inverter (VSI) and a Permanent Magnet Synchronous Motor (PMSM) with high magnetic anisotropy. To this end, the concept of Synchronous Optimal Modulation (SOPWM) is employed for inverter control and the optimal inverter switching angles are defined for an isotropic...
This paper presents a boost switched-capacitor nine-level single-phase inverter, which utilizes flying capacitors and an H-bridge. Besides the boosting ability, the inverter is capable of producing redundant switching states that are used as a degree of freedom in controlling the voltage of DC link capacitor. A comprehensive study of the theoretical aspects of the proposed structure and its practical...
In this paper, the performance of three-phase five-level neutral-point-clamped inverter using different carrier waves namely trapezoidal (T) and trapezoidal triangular (TT) with different modulation techniques applying three different modulating signals is studied. In this study, three basic level-shifted multicarrier PWM strategies namely, alternative phase opposition disposition (APOD), phase opposition...
Selective Harmonic Elimination (SHE) is an established technique to eliminate unwanted harmonics that causes aliasing effect in communication systems and affects power quality in electrical systems. In this paper, an analytical approach for SHE is proposed for harmonic elimination in a multilevel inverter. Traditionally, numerical methods like Newton Raphson Algorithm are opted to solve the transcendental...
Five sorting-based methods for the modulation of modular multilevel converters are implemented on a test bench and evaluated regarding their switching frequency, voltage balancing capability, harmonics, voltage error, and computation time. In contrast to already published methods, the cells considered here can omit additional switch transitions when entering PWM mode. This reduces the switching frequency...
A fifth and seventh order harmonic elimination scheme for IM drive with a multilevel dodecagonal voltage space vector structure using a single DC source is proposed in this work. Single DC source requirement makes four quadrant operation of the drive system simpler compared to the multilevel do-decagonal structures presented in literatures before. The space vector structure consists of six concentric...
In this contribution, the switching frequency based active power will be presented as a new power definition. It combines the information of the instantaneous power, as product of voltage and current, and the conventional active power representing the mean value of the instantaneous power over the fundamental period. Under several theoretical conditions the switching frequency based active power is...
Conventional inverters rely on switching modulation to generate the alternating current (AC) output required by many loads, such as electric machines. Particularly in mass-produced electric vehicles (EV), inverters exclusively use pulse-width modulation (PWM) with fixed switching rates, resulting in strong though confined peaks in the output spectrum at the switching frequency, as well as its overtones...
Common mode voltage output is closely associated with switching states in three-phase three-wire neutral-point clamped inverter. Detailed analysis shows avoiding redundant states can effectively improve the common mode voltage, so this paper proposes a pulse width modulation (PWM) technique with zero redundant states to reduce the common mode voltage output, and evaluate their performance with the...
One of the basic problems in power conversion is the harmonic content at output level. Generally harmonics can be categorized as current and voltage harmonics. Harmonics can be minimized either by increasing the number of voltage levels or by using appropriate modulation techniques. In this paper both mechanisms are proposed. The proposed inverter is 7-level Cascaded Multilevel Inverter (CMLI). As...
Inverters form a major part of power electronic industry. The AC output of inverter is mainly controlled by pulse width modulation (PWM) technique. The PWM approaches are accompanied by harmonics due to the switched nature of power electronic devices. There are many ways to eliminate the harmonics such as selective harmonic elimination. Selective harmonic elimination is associated with tremendous...
This paper presents a simulation study for a built prototype of modular multi-level flying capacitor cascade converter as a STATCOM. The converter modulation scheme applied is based on Phase Shifted PWM and the two scenarios which require compensation are investigated to verify this topology. The two scenarios are PCC voltage regulation and unity power factor correction through reactive power compensation...
The Coupled Interleaved Multicellular Parallel (CIMP) topology is the subject of intense research because of its advantages in terms of systems integration, power density increase, low level of EMI emissions and dynamic performance. This paper evaluates the viability of application of switching frequency modulation techniques to CIMP topology.
This paper presents a new scheme of Pure Sinwave Inverters using Pic-18F4620 microcontroller to eliminate the most amount of current harmonics that flows through the whole circuit, and to obtain pure sinwave current at the output load side. The proposed inverter, with lossless harmonic power, gives pure sinusoidal output voltage and current. It is aimed to be used with AC machines, sensitive appliances...
This paper presents a novel control strategy of AC/DC power converters. The proposed control algorithm is based on Sliding Mode Control methodology. The basic idea is to apply feedback implementation of pulse-width modulation (PWM). The method exhibits low sensitivity to disturbances and fast dynamic performance in addition to the main converter properties. The proposed sliding mode control method...
Multilevel converter technology has emerged as a very important alternative in the area of high-power medium-voltage energy control. Several topologies for multilevel inverters have been proposed over the years, the most popular cascaded H-bridge apart from other multilevel inverters is the capability of utilizing different dc voltages on the individual H-bridge cells which results in splitting the...
Space vector pulse width modulation (SVPWM) technique has emerged as a most used modulation strategy for the voltage source inverter (VSI) fed AC motor drives. SVPWM is a method of pre-calculation of switching timing instants for various sections of target output which has options in terms of positioning vectors inside every sampling interval and has six possible patterns (variants) ofthe voltage...
The paper deals with the results of a study performed by RSE, in the frame of the Research Fund for the Italian Electrical System, and Politecnico di Milano focused on the evaluation of the harmonic impact in the distribution networks caused by the Distributed Generation, generally connected through Voltage Source Inverter (VSI). In particular the two-level three phase Pulse Width Modulation (PWM)...
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