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In series with each other, the cascaded H-bridge multilevel inverter (CHML) could apply same or different DC bus voltage. By modifying the isolated DC voltage supplies of a traditional 7-level 3H-bridge inverter with voltage ratio 4:2:1, the proposed inverter outputs a near-sinusoid, 15-level resoluted, stepped voltage with low distortion. The pros...
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Among various reasons, reduction of harmonic content is the major reason for which multilevel inverters has been chosen over the classical two-level converter The current rating or the voltage rating of the multilevel inverter becomes a compound of specific switches and thus the power rating of the inverter can surpass the limit executed by the ind...
Multilevel inverter is an effective and practical solution for increasing power demand and reducing harmonics of ac waveforms. Such inverters synthesize a desired output voltage from several levels of dc voltages as inputs. This paper analyzes the performance of five level cascaded H-bridge multilevel inverter with reduce number of power switches....
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... The low frequency control scheme possesses numerous significant features, which includes (a) highly efficient with low frequency to fundamental frequency proportion; (b) excellent voltage boosting and a wide converter capacity; (c) fewer filter demands; (d) complete omission of lower harmonics; (e) low switching losses with restricted harmonic regulation; and (f) additionally per-formance index is optimised for various superior aspects. Various modulation schemes for 15-level topology are presented [23,24]. The worth of utilizing a LF scheme than HF scheme are reduced switching losses, minimum stress on switches, improved device utilization factor, and enhanced converter efficiency. ...
... Analysis of various modulation schemes for distinct levels is offered under regulating loads, [17]. Hybrid PWM, Conventional PWM as well as stair case PWM are contrasted for the study of THD, switching losses, and lower order harmonic in the case of fifteen -level inverters, [18]. ...
Multi-Level Inverters (MLIs) are achieving broad popularity owing to the rapid development of power semiconductor devices. The capability of MLIs became recognized as a significant aspect of a system heavily reliant on Pulse Width Modulation(PWM) strategy. The conventional high frequency PWM techniques suffer from significant Total Harmonic Distortion (THD) along with power loss difficulties. This work recommends a hybrid PWM technique for lowering the THD and power loss of VSI adding the benefits of level-shift PWM and Phase-shift PWM. A novel form of carrier signals is employed in the proposed hybrid PWM technique. In contrast to existing PWM techniques, the proposed hybrid PWM technique minimizes switching and conduction power losses. In this work, the proposed PWM scheme is employed for asymmetric multilevel inverter. The proposed configuration is also examined using PLECS software to estimate losses and efficiency. The simulation work is done in the MATLAB/Simulink environment and the OPAL-RT(OP4510) test platform is employed to evaluate topology performance.
... Using the equation (1), the switching angle for a scheme can be calculated. [4] In the proposed modulation scheme, the number of levels (n) and the number of angles (i) of the MLI are defined. Using equation (1), the value of each angle is calculated depending on the number of angles. ...
... Using the equation (5), the switching angle for a NLM scheme can be calculated [16], ...
This paper proposes a nearest level modulation
(NLM) scheme for a Cross-Connected Sources (CCS) based MLI
topology. The proposed modulation scheme is found to facilitate a
reduction in the total harmonic distortion (THD) at the ac output
of the inverter. The modulation scheme employs low switching
frequency to operate the MLI. The paper presents an explanatory
description of the NLM scheme in order to help the upcoming
researchers for designing efficient MLI system. Simulation has
been implemented using the MATLAB/Simulink 2015b software
package. The simulation results indicate a significant reduction
in the voltage THD and current THD. Improvement in the other
output parameters of the inverter such as rms voltage, rms
current and output power is also seen.
