• Title, Summary, Keyword: Multilevel inverter

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Improvement of the Performance of the Cascaded Multilevel Inverters Using Power Cells with Two Series Legs

  • Babaei, Ebrahim;Dehqan, Ali;Sabahi, Mehran
    • Journal of Power Electronics
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    • v.13 no.2
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    • pp.223-231
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    • 2013
  • A modular three-phase multilevel inverter especially suitable for electrical drive applications has been previously presented. This topology is based on series connection of power cells in which each cell comprised of two inverter legs in series. In this paper, in order to generate the maximum number of voltage levels with reduced number of switches, three algorithms are proposed for determination of the magnitudes of dc voltage sources. In addition, a new hybrid multilevel inverter is proposed that is composed of series connection of the previously presented multilevel inverter and some H-bridges. The proposed topology has been compared with some other presented multilevel inverters. The performance of the proposed multilevel inverter has been verified by simulation and experimental results of a single-phase 39-level multilevel inverter.

Single-Phase Multilevel PWM Inverter Based on H-bridge and its Harmonics Analysis

  • Choi, Woo-Seok;Nam, Hae-Kon;Park, Sung-Jun
    • Journal of Power Electronics
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    • v.15 no.5
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    • pp.1227-1234
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    • 2015
  • The efficient electric power demand management in electric power supply industry is currently being changed by distributed generation. Meanwhile, small-scale distributed generation systems using renewable energy are being constructed worldwide. Several small-scale renewable distributed generation systems, which can supply electricity to the grid at peak load of the grid as per policy such as demand response programs, could help in the stability of the electric power demand management. In this case, the power quality of the small-scale renewable distributed generation system is more significant. Low prices of power semiconductors and multilevel inverters with high power quality have been recently investigated. However, the conventional multilevel inverter topology is unsuitable for the small-scale renewable distributed generation system, because the number of devices of such topology increases with increasing output voltage level. In this paper, a single-phase multilevel inverter based on H-bridge, with DC_Link divided by bi-directional switches, is proposed. The proposed topology has almost half the number of devices of the conventional multilevel inverter topology when these inverters have the same output voltage level. Double Fourier series solution is mainly used when comparing PWM output harmonic components of various inverter topologies. Harmonic components of the proposed multilevel inverter, which have been analyzed by double Fourier series, are compared with those of the conventional multilevel inverter. An inverter prototype is then developed to verify the validity of the theoretical analysis.

A New Topology of Multilevel Voltage Source Inverter to Minimize the Number of Circuit Devices and Maximize the Number of Output Voltage Levels

  • Ajami, Ali;Mokhberdoran, Ataollah;Oskuee, Mohammad Reza Jannati
    • Journal of Electrical Engineering and Technology
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    • v.8 no.6
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    • pp.1328-1336
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    • 2013
  • Nowadays multilevel inverters are developing generally due to reduced voltage stress on power switches and low total harmonic distortion (THD) in output voltage. However, for increasing the output voltage levels the number of circuit devices are increased and it results in increasing the cost of converter. In this paper, a novel multilevel inverter is proposed. The suggested topology uses less number of power switches and related gate drive circuits to generate the same level in output voltage with comparison to traditional cascaded multilevel inverter. With the proposed topology all levels in output voltage can be realized. As an illustration, a symmetric 13-level and asymmetric 29-level proposed inverters have been simulated and implemented. The total peak inverse (PIV) and power losses of presented inverter are calculated and compared with conventional cascaded multilevel inverter. The presented analyses show that the power losses in the suggested multilevel inverter are less than the traditional inverters. Presented simulation and experimental results demonstrate the feasibility and applicability of the proposed inverter to obtain the maximum number of levels with less number of switches.

Analysis of Cascaded H-Bridge Multilevel Inverter in DTC-SVM Induction Motor Drive for FCEV

  • Gholinezhad, Javad;Noroozian, Reza
    • Journal of Electrical Engineering and Technology
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    • v.8 no.2
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    • pp.304-315
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    • 2013
  • In this paper, analysis of cascaded H-bridge multilevel inverter in DTC-SVM (Direct Torque Control-Space Vector Modulation) based induction motor drive for FCEV (Fuel Cell Electric Vehicle) is presented. Cascaded H-bridge multilevel inverter uses multiple series units of H-bridge power cells to achieve medium-voltage operation and low harmonic distortion. In FCEV, a fuel cell stack is used as the major source of electric power moreover the battery and/or ultra-capacitor is used to assist the fuel cell. These sources are suitable for utilizing in cascaded H-bridge multilevel inverter. The drive control strategy is based on DTC-SVM technique. In this scheme, first, stator voltage vector is calculated and then realized by SVM method. Contribution of multilevel inverter to the DTC-SVM scheme is led to achieve high performance motor drive. Simulations are carried out in Matlab-Simulink. Five-level and nine-level inverters are applied in 3hp FCEV induction motor drive for analysis the multilevel inverter. Each H-bridge is implemented using one fuel cell and battery. Good dynamic control and low ripple in the torque and the flux as well as distortion decrease in voltage and current profiles, demonstrate the great performance of multilevel inverter in DTC-SVM induction motor drive for vehicle application.

A New Single Phase Multilevel Inverter Topology with Two-step Voltage Boosting Capability

  • Roy, Tapas;Sadhu, Pradip Kumar;Dasgupta, Abhijit
    • Journal of Power Electronics
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    • v.17 no.5
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    • pp.1173-1185
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    • 2017
  • In this paper, a new single phase multilevel inverter topology with a single DC source is presented. The proposed topology is developed based on the concepts of the L-Z source inverter and the switched capacitor multilevel inverter. The input voltage to the proposed inverter is boosted by two steps: the first step by an impedance network and the second step by switched capacitor units. Compared to other existing topologies, the presented topology can produce a higher boosted multilevel output voltage while using a smaller number of components. In addition, it provides more flexibility to control boosting factor, size, cost and complexity of the inverter. The proposed inverter possesses all the advantages of the L-Z source inverter and the switched capacitor multilevel inverter like controlling the start-up inrush current and capacitor voltage balancing using a simple switching strategy. The operating principle and general expression for the different parameters of the proposed topology are presented in detail. A phase disposition pulse width modulation strategy has been developed to switch the inverter. The effectiveness of the topology is verified by extensive simulation and experimental studies on a 7-level inverter structure.

A Cascaded Hybrid Multilevel Inverter Incorporating a Reconfiguration Technique for Low Voltage DC Distribution Applications

  • Khomfoi, Surin
    • Journal of Power Electronics
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    • v.16 no.1
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    • pp.340-350
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    • 2016
  • A cascaded hybrid multilevel inverter including a reconfiguration technique for low voltage dc distribution applications is proposed in this paper. A PWM generation fault detection and reconfiguration paradigm after an inverter cell fault are developed by using only a single-chip controller. The proposed PWM technique is also modified to reduce switching losses. In addition, the proposed topology can reduce the number of required power switches compared to the conventional cascaded multilevel inverter. The proposed technique is validated by using a 3-kVA prototype. The switching losses of the proposed multilevel inverter are also investigated. The experimental results show that the proposed hybrid inverter can improve system efficiency, reliability and cost effectiveness. The efficiency of proposed system is 97.45% under the tested conditions. The proposed hybrid inverter topology is a promising method for low voltage dc distribution and can be applied for the multiple loads which are required in a data center or telecommunication building.

An Improved Carrier-based SVPWM Method By the Redistribution of Carrier-wave Using Leg Voltage Redundancies in Generalized Cascaded Multilevel Inverter

  • Kang, Dae-Wook;Lee, Yo-Han;Suh, Bum-Seok;Park, Chang-Ho;Hyun, Dong-Seok
    • Journal of Power Electronics
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    • v.1 no.1
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    • pp.36-47
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    • 2001
  • The carrier-based space vector pulse width modulation(SVPWM), which is considered as highly simple and efficient PWM technology, can be also used in multilevel inverters. The method was originally designed for the two-level inverter and developed to the diode clamped multilevel inverter structure. however it may be noted that it also cause bad switch utilization in cascaded multilevel inverter. This paper introduces an improved carrier-based SVPWM scheme, which is fully suitable for cascaded multilevel inverter topologies because it can achieve the optimized switch utilization through the redistribution of the triangular carrier waves considering leg voltage redundancies while having the advantages of the conventional carrier-based SVPWM. Using simulation and experimental results, the superior performance of new PWM method is shown.

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A New Basic Unit for Cascaded Multilevel Inverters with the Capability of Reducing the Number of Switches

  • Laali, Sara;Babaei, Ebrahim;Sharifian, Mohammad Bagher Bannae
    • Journal of Power Electronics
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    • v.14 no.4
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    • pp.671-677
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    • 2014
  • In this paper, a new basic unit is proposed. Then, a cascaded multilevel inverter basded on the series connection of n number of these new basic units is proposed. In order to generate all of the voltage levels (even and odd) at the output, three different algorithms to determine the magnitude of the dc voltage source are proposed. Reductions in the number of power switches, driver circuits and dc voltage sources in addition to increases in the numbr of output voltage levels are some of the advantages of the proposed cascaded multilevel inverter. These results are obtained through a comparison of the proposed inverter and its algorithms with an H-bridge cascaded multilevel inverter from the point of view of the number of power electronic devices. Finally, the capability of the proposed topology with its proposed algorithms in generating all of the voltage levels is verified through experimental results on a laboratorary prototype of a 49-level inverter.

Development of a Switched Diode Asymmetric Multilevel Inverter Topology

  • Karthikeyan, D.;Krishnasamy, Vijayakumar;Sathik, Mohd. Ali Jagabar
    • Journal of Power Electronics
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    • v.18 no.2
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    • pp.418-431
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    • 2018
  • This paper presents a new asymmetrical multilevel inverter with a reduced number of power electronic components. The proposed multilevel inverter is analyzed using two different configurations: i) First Configuration (with a switched diode) and ii) Second Configuration (without a switched diode). The presented topologies are compared with recent multilevel inverter topologies in terms of number of switches, gate driver circuits and blocking voltages. The proposed topologies can be cascaded to generate the maximum number of output voltage levels and they are suitable for high voltage applications. Various power quality issues are addressed for both of the configurations. The proposed 11-level inverter configuration is simulated using MATLAB and it is validated with a laboratory based experimental setup.

Hybrid Cascaded MLI topology using Ternary Voltage Progression Technique with Multicarrier Strategy

  • Venugopal, Jamuna;Subarnan, Gayathri Monicka
    • Journal of Electrical Engineering and Technology
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    • v.10 no.4
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    • pp.1610-1620
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    • 2015
  • A major problem in conventional multilevel inverter is that an increase in power semiconductor switches causes an increase in cost and switching losses of the inverter. The multicarrier strategy adopted for the multilevel inverters has become more popular due to reduced cost, lower harmonic distortion, and higher voltage capability than the conventional switching strategy applied to inverters. Various topologies and modulation strategies have been reported for utility and drive applications. Level shifted based pulse width modulation techniques are proposed to investigate the performance of the multilevel inverter. The proposed work focuses on reducing the utilized switches so that the cost and the switching losses of the inverter do not go up and the consistent efficiency could be achieved. This paper presents the detailed analysis of these topologies. The analysis is based on the number of switches, DC sources, output level, maximum voltage, and the efficiency. As an illustration, single phase cascaded multilevel inverter topologies are simulated using MATLAB/SIMULINK and the experimental results demonstrate the viability of these inverters.