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The paper presents a new four-level voltage source converter (VSC). Compared to conventional four-level converters, this proposed converter has fewer components and can be used for a higher power density system in low and medium voltage applications. Its principles and advantages are studied in this paper. The effect of various redundant switching states on the voltages of flying capacitors is analyzed...
The paper proposes a three phase nine level T-type neutral point clamped (9L-T-NPC) inverter for medium voltage induction motor drive. The primary objective of the proposed inverter is to improve the output voltage quality with reduced number of devices and passive components. The generation of nine levels in the output pole voltage is achieved using only ten switches per phase. Although the similar...
A capacitor voltage-balancing control strategy based on switching state redundancies is proposed for the hybrid stacked five-level converter. In order to obtain the balancing properties for flying capacitors, a hybrid model in state-space representation is established by considering the continuous and discrete variables. The proposed balancing strategy can control the flying capacitor voltages to...
Transformer-less single-phase grid-tied inverter is attractive due to low cost, high efficiency, and small size. However, leakage current and second-order ripple power have to be well dealt with. Because the leakage current is a potential threat for body safety and the ripple power will decrease overall efficiency and system reliability. Both issues become obstacles for practical applications. This...
This paper proposes two hybrid asymmetric cascaded multilevel inverters. Both inverters consist of the series connection of a three-level (3L) H-bridge cell and a nine-level (9L) H-bridge cell with an unequal dc voltage ratio of 1:8. The topologies of the 9L H-bridge cell are based on modular multilevel cascade converter (MMCC) with double-star chopper cells (DSCC). Both the proposed inverters can...
This paper investigates two five-level reduced hybrid inverters with split-wound coupled inductor and reduced number of components. The proposed inverters are composed of two legs, one of two levels and another of three-levels. Two types of three-level leg have been investigated: diode-clamped and flying capacitor. When compared with more conventional topologies consisting of two three-level legs,...
This paper proposes a 5-level single-phase multilevel inverter topology with reduced number of components. In order to validate the proposed structure, simulation and experimental results are presented. In addition, the proposed topology is compared with an existing counterpart structure in terms of number of levels and number of devices and value of power supply.
Ultra sparse matrix converter(USMC) is a derived form of Indirect matrix converter(IMC) having less no of switches. Though it has unidirectional power flow capability it is very useful for specific applications such as wind energy systems, electrohydrostatic actuator, variable speed drives etc. However its main limitation is lower gain for which various control strategies and topological changes had...
In recent years medium voltage direct-current (MVDC) grids have gained significant attention. This paper presents a new isolated modular multilevel converter (MMC)-based dc/dc converter for connecting such networks. The proposed converter can connect DC grids with different voltage levels and control power flow among them. The proposed isolated dc/dc converter has fewer components compared to conventional...
This paper introduces an asymmetric cascaded multilevel inverter consisting of series-connected two nine-level (9L) H-bridge cells, which are based on modular multilevel cascade converter (MMCC) with double-star chopper cells (DSCC). An unequal dc voltage ratio of 1:2 is used, so that the proposed topology can generate 25 output voltage levels. A modulation strategy for the inverter is proposed. A...
The star-configured modular multilevel converter is a promising topology for grid-connected storage as well as power-quality applications and motor drives. During operation, the ac output power generates substantial current pulsation at twice the output frequency in the modules, which causes additional loss and requires an increase of the module capacitance. This paper presents a common-mode voltage...
A quasi Z-source (QZS) network is coupled to the direct matrix converter (DMC) and a novel strategy of dual space vector modulation is proposed. It can effectively solve the defect of lower voltage transfer ratio of traditional matrix converter. The DMC which introduced the QZS can allow the three phase AC input side short circuit which defined shoot-through state. It can achieve the AC input voltage...
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...
A quasi single-stage power factor correction converter, which is composed of a three-level (TL) Boost converter and a DC-DC transformer (DCX), is presented and analyzed in this paper. The DC output load is connected to one of the dividing capacitors of the TL Boost converter, so that the load voltage can be lower than the peak amplitude of the AC line voltage and part of the AC input power can be...
A transformer-less Modular Multilevel DC-DC converter for High Voltage Direct Current (HVDC) applications is proposed in this paper. This topology is suitable for interfacing two HVDC links at different voltage levels using only conventional half bridge submodules. The uniqueness of the proposed converter is in its symmetry in performance in the event of reversal of polarity of one of the DC links...
With reliability and flexibility criteria surging, multi-level converters become of growing interest for high-power medium-voltage renewable energy applications. Specific objectives are met with specialized intelligent controls. The goal of this paper is to present a universal intelligent controller able to manage all degrees of freedom of multi-level power converters and any paradigm. To do so, a...
PFC converters are widely used in industrial drive systems. The modulation scheme and the topology of the converter have a considerable impact not only on the switching losses, but also on the volume of the passive components, i.e. the EMI filter (CM and DM) and the dC link capacitors. In order to evaluate this impact, different modulation schemes for 2L and 3L topologies are analysed in this paper...
This paper presents a seven level inverter utilizing switched-capacitor technique. Proposed topology employs two asymmetric DC voltage sources as input and generates a multilevel staircase output. The structure includes a front-end switched-capacitor based DC-DC converter cascaded by a back-end H-bridge inverter. The frontend SC DC-DC converter feeds three DC voltage levels to the H-bridge inverter...
Two Band-Pass (BP) Discrete Time (DT) ΔΣ modulators are proposed in this paper. In both cases, the drawback of high-speed power-hungry adder is tackled by proposing a modified unity signal transfer function (STF) adder-less feedforward structure. The first proposed BP DT ΔΣ modulator is a conventional adder-less multi-stage noise shaping (MASH) ΔΣ modulator, while the noise leakage problem, caused...
Performance of multilevel inverters (MLI) are distinguished because of their low harmonic waveform generation, low filtering requirements on AC side and high voltage application. Among different (MLI) topologies, cascaded multi-level inverters (CMLI) are easier to implement and are much more cost effective. The main drawback of multilevel inverters is requirement of more than one isolated DC source...
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