摘要 :
In Multilevel Inverters, Cascaded H bridge converters are considered to be the most preferred form of converters. But in these converters as the number of staircase levels in output voltage increases the dc source requirement also...
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In Multilevel Inverters, Cascaded H bridge converters are considered to be the most preferred form of converters. But in these converters as the number of staircase levels in output voltage increases the dc source requirement also increases, thereby limiting its application. This paper tries to address the above mentioned problem by developing a Modified version of Cascaded Multilevel Converters which require reduced number of dc voltage source for increased levels in output voltage as compared to conventional cascaded converters. The spectral quality analysis of output voltage obtained for different loads is also shown signifying the merits of modified converters. Due to these advantages the drawback in the implementation of conventional cascaded converters in electric vehicles or in industrial applications is overcome by modified cascaded inverters. In this paper, the developed Modified Cascaded Converters are simulated in MATLAB/ SIMULINK and the THD of different output voltage levels are compared for different loads.
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摘要 :
In Multilevel Inverters, Cascaded H bridge converters are considered to be the most preferred form of converters. But in these converters as the number of staircase levels in output voltage increases the dc source requirement also...
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In Multilevel Inverters, Cascaded H bridge converters are considered to be the most preferred form of converters. But in these converters as the number of staircase levels in output voltage increases the dc source requirement also increases, thereby limiting its application. This paper tries to address the above mentioned problem by developing a Modified version of Cascaded Multilevel Converters which require reduced number of dc voltage source for increased levels in output voltage as compared to conventional cascaded converters. The spectral quality analysis of output voltage obtained for different loads is also shown signifying the merits of modified converters. Due to these advantages the drawback in the implementation of conventional cascaded converters in electric vehicles or in industrial applications is overcome by modified cascaded inverters. In this paper, the developed Modified Cascaded Converters are simulated in MATLAB/ SIMULINK and the THD of different output voltage levels are compared for different loads.
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Multi-level Cascaded H-bridge (CHB) converters are ideal for implementing large scale photovoltaic systems. The improved quality of the voltage waveforms, high efficiency and ability to employ multiple Maximum Power Point Tracking...
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Multi-level Cascaded H-bridge (CHB) converters are ideal for implementing large scale photovoltaic systems. The improved quality of the voltage waveforms, high efficiency and ability to employ multiple Maximum Power Point Tracking (MPPT) algorithms are just some of the advantages. In this paper a three-phase CHB converter supplied with photovoltaic arrays is considered. A control and modulation structure based on Model Predictive Control (MPC) is described. The scheme inherently controls the DC link voltages while also providing the ability to modify any of those voltages to meet MPPT requirements. This avoids the cost and added complexity of extra DC/DC converters that are typically required to keep the DC link voltages uniform. Simulation and experimental results are presented that confirm the correct operation of the proposed approach.
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A single-phase cascaded H-bridge multilevel inverter for a grid-connected photovoltaic (PV) system with nonactive power compensation is presented in this paper. To maximize the solar energy extraction of each PV string, an individ...
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A single-phase cascaded H-bridge multilevel inverter for a grid-connected photovoltaic (PV) system with nonactive power compensation is presented in this paper. To maximize the solar energy extraction of each PV string, an individual maximum power point tracking (MPPT) control scheme is applied, which allows the independent control of each dc-link voltage. A generalized nonactive power theory is applied to generate the nonactive current reference. Within the inverter's capability, the local consumption of nonactive power is provided to realize power factor correction. A single-phase modular cascaded multilevel inverter prototype has been built. Each H-bridge is connected to a 195 W solar panel. Simulation and experimental results are presented to validate the proposed ideas.
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The multilevel inverter technology has gained a tremendous significance in the research area. This paper proposed a new controller for generating the switching sequence of power devices used in multilevel inverter to produce the d...
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The multilevel inverter technology has gained a tremendous significance in the research area. This paper proposed a new controller for generating the switching sequence of power devices used in multilevel inverter to produce the desired output. An embedded code has been developed to control the switching states of different IGBT switches. To validate the effectiveness of the proposed technique to control the multilevel inverter switching states MATLAB simulation of 3-level, 5-level and 17-level using cascaded H bridge topology of multi-level inverter is presented in this paper. Each multilevel inverter configuration presented in this paper is explained by the corresponding schematic diagram, operating principle, and simulation results.
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Cascaded H-Bridge, CHB, is one of the most widely used topologies in medium voltage drive applications. Recently, regenerative capability has been required to several loads such as laminators, downhill conveyors, and mill drives. ...
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Cascaded H-Bridge, CHB, is one of the most widely used topologies in medium voltage drive applications. Recently, regenerative capability has been required to several loads such as laminators, downhill conveyors, and mill drives. Therefore, topologies for Active Front End (AFE)-CHB had been proposed and implemented. In this paper, PWM strategy for AFE 5 Level Cascaded H-Bridge is developed. Conventional PWMs, Phase Shift PWM and Level Shift PWM are analyzed in terms of current harmonics, switching loss, loss distribution, DC-link voltages ripple, and balancing DC-link voltages. To overcome the demerits of the conventional PWM methods, in this paper a novel PWM strategy is proposed. Through the proposed PWM method, the switching loss can be evenly distributed between legs, and THD can be reduced to 60% compared with THD of the conventional method.
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摘要 :
Multilevel converters are well suited for medium and high power applications because of its characteristic of synthesizing a sinusoidal voltage on several DC levels. They give good quality output resulting with lower harmonic dist...
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Multilevel converters are well suited for medium and high power applications because of its characteristic of synthesizing a sinusoidal voltage on several DC levels. They give good quality output resulting with lower harmonic distortion in the output and lower commutation losses. The main disadvantage is their complex circuit configurations, requiring a great number of power devices and passive components, and a complex control circuitry. A new topology of multilevel inverter for 5-level using the Conventional H-Bridge is proposed in this paper. The proposed topology is referred as new TCHB has the feature like boost output voltage capability along with capacitor voltage balancing. The proposed multilevel inverter uses four auxillary switches and transistor clamped H-bridge (TCHB) with an bidirectional switch. The single cell of conventional H-bridge produces three-level output voltage similar to input DC voltage but the single cell of proposed topology produces five-level output with output voltage double the input DC voltage. The proposed new TCHB and old TCHB 5-level inverter are modeled and simulated on matlab / simulink and compared in terms of the output voltage, total harmonic distortion (THD), No. of switching devices used etc. From the results the proposed inverter provides more output voltage with less harmonics in the output voltage.
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摘要 :
Multilevel converters are well suited for medium and high power applications because of its characteristic of synthesizing a sinusoidal voltage on several DC levels. They give good quality output resulting with lower harmonic dist...
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Multilevel converters are well suited for medium and high power applications because of its characteristic of synthesizing a sinusoidal voltage on several DC levels. They give good quality output resulting with lower harmonic distortion in the output and lower commutation losses. The main disadvantage is their complex circuit configurations, requiring a great number of power devices and passive components, and a complex control circuitry. A new topology of multilevel inverter for 5-level using the Conventional H-Bridge is proposed in this paper. The proposed topology is referred as new TCHB has the feature like boost output voltage capability along with capacitor voltage balancing. The proposed multilevel inverter uses four auxillary switches and transistor clamped H-bridge (TCHB) with an bidirectional switch. The single cell of conventional H-bridge produces three-level output voltage similar to input DC voltage but the single cell of proposed topology produces five-level output with output voltage double the input DC voltage. The proposed new TCHB and old TCHB 5-level inverter are modeled and simulated on matlab / simulink and compared in terms of the output voltage, total harmonic distortion (THD), No. of switching devices used etc. From the results the proposed inverter provides more output voltage with less harmonics in the output voltage.
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摘要 :
Recently introduced topologies achieve higher number of output voltage with less number of semiconductor devices, dc sources. Reduction of switch count and DC voltage sources reduces the size, cost, complexity and enhances overall...
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Recently introduced topologies achieve higher number of output voltage with less number of semiconductor devices, dc sources. Reduction of switch count and DC voltage sources reduces the size, cost, complexity and enhances overall performance. Enhanced topology is capable of producing 7, 9 and 11 levels of output voltage with seven switches only. Moreover, significant reduction in voltage stress across the switches can be achieved. A comparative analysis of enhanced topology with the conventional topology and recently published topologies has been made in terms of controlled switches, power diodes, driver circuit requirement, DC voltage sources and blocking voltage. Multi-carrier pulse-width modulation strategy is adopted for generating the switching pulses. Simulation study of the enhanced topology has been carried out using Mat lab/Simulink.
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This paper investigated different carrier based modulation schemes for the proper modulation of 3-phase 9-level cascaded H-bridge modular multilevel converter (MMC). In this article, modulations are performed in terms of modulatin...
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This paper investigated different carrier based modulation schemes for the proper modulation of 3-phase 9-level cascaded H-bridge modular multilevel converter (MMC). In this article, modulations are performed in terms of modulating or reference signals and carrier signals (triangular or sinusoidal). Performance evaluation is done on the basis of percentage of total harmonic distortion (THD) of the converter output voltages, as well as suppression of lower order harmonics and efficient utilization of dc voltages. Modulation signals generation and application are shown with the harmonic profiles of respective modulated output voltages. All the simulation works are carried out in commercially available software environment MATLAB/Simulink.
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