Development Of Multilevel Inverters Research Articles

Development of multilevel inverter with reduced switch counts and limited sources for electric vehicles

A new topology with a reduced number of switches with minimum cost, less switching complexity, and adaptable to different dc source voltage ratios of 1:2 (binary) and 1:3 (trinary), with reliable and extended/cascaded operation in both symmetric and asymmetric mode, has been developed for EV applications. Pulses are generated for the proposed configuration using Nearest Level Control. The proposed inverter is compared with another recent topologies based on various factors, such as total switches, number of gate drivers, and total standing voltage. An asymmetrical multilevel inverter of type II configuration selects dc sources based on binary and trinary algorithms. To increase the stepped output levels, the basic unit is extended by three different structures: series, cascading, and packed unit cell connections. The dc-link capacitor voltage is boosted with the help of bidirectional multilevel-boost converter with a low input dc source, which is commonly used in electric vehicle applications. In addition to the simulation of the proposed configuration using MATLAB, it has also been validated with an experimental setup developed.

Thermal analysis and reliability evaluation of cascaded H‐bridge MLPVI for grid‐connected applications

Nowadays, great progress has been made in the development of multilevel inverters (MLIs) in grid-connected photovoltaic (PV) energy systems, because of the advantages such as reduced voltage stress on the power semiconductor switches and having higher efficiency. Since the multilevel PV inverter (MLPVI) has been a critical part within the failures of a PV energy system, so it becomes important to predict the lifetime of the components and the MLPVI system. In this paper, a five-level modular cascaded H-bridge MLI is analyzed based on grid-connected application for PV energy system, and an independent dc-link voltage controller for each H-bridge is implemented by taking the reference value generated from the maximum power point tracking algorithm of each PV module. The loss and thermal distributions of the different power devices in the MLPVI system are investigated and illustrated for various pulse-width modulation (PWM) controllers. The junction temperature and power losses of the components in the MLPVI are simulated by MATLAB/Simulink and Piecewise Linear Electrical Circuit Simulation (PLECS) blockset, which validate the theoretical analysis. The reliability of the MLPVI is evaluated using parts stress method. It shows that the MLPVI has a good reliability when phase shift PWM control technique is used.

Development of LabVIEW-based multilevel inverter with reduced number of switches

In the present scenario, the development of multilevel inverter is becoming popular for industrial applications and higher scale renewable green power technologies such as fuel cell, PV cell and wind turbine systems connected to the load. But the traditional multilevel topologies have large components and complex Pulse Width Modulation (PWM) controller leading to reduced harmonics and voltage stress on the load. Therefore, a new topology of a cascaded multilevel inverter employing less number of switches with reduced gate driver circuits and simple control scheme is presented in this paper. A comprehensive MATLAB/Simulink model of a seven-level inverter and the generation of control pulses using multi-carrier-based PWM is evolved and discussed. With the aid of LabVIEW, an experimental prototype is developed and their results are compared with simulation results.