<p>Usage of high power and medium voltage applications in domestic and industrial purpose has been increased in the recent years. Also, the penetration of renewable energy sources is increasing rapidly. To make use the renewable energy sources there is a need of using inverters. The basic inverter is conventional two level inverter which produces the square wave output voltage. The major drawback of conventional inverter is it contains more harmonics. Therefore, multilevel inverters have been introduced with staircase output voltage waveform. Lot of multilevel inverter topologies have been developed and cascaded H bridge type is the more frequently used. But, it requires more number of switches for higher output voltage level. In this paper, a novel 7 level asymmetrical multilevel inverter topology is proposed with less number of switches. This proposed topology is compared with already existing topology. The simulation of circuit and result analysis of the circuit is carried out by using Matlab/simulink software. The comparison between existing topology and proposed topology is given. The results are discussed and presented.</p>

This paper attempts to come up with a proposed configuration of Multilevel inverters with a lesser number of switches that are smaller in size, lesser in cost and with a higher efficiency. Designing an inverter topology with a lesser number of switches and proper control technique is the major challenge. cascaded H-Bridge (CHB) topology are more popular among the existing configurations of multilevel inverters (MLI). Even though it can produce more levels, it needs to accommodate a huge number of switches for higher levels. The focus of this paper is to reduce the number of components for the same voltage level of cascaded H- Bridge configuration. In addition to that, generating the gating pulses for the switches is difficult when there is an asymmetry in the switches. A new symmetrical series/parallel configuration is proposed with reduced switch count and the pulse width modulation (PWM) technique is implemented with digital logic to generate the required gating pulses for the switches. The total harmonic distortion (THDI) of the output current is reduced with this PWM technique. The simulation has been carried out in MATLAB/Simulink software for both R (resistive) and R-L (resistive -inductive) loads.

Power generation using renewable energy sources is becoming popular in current scenario due to their capability of reduction in carbon emission as well as reliable power supply to consumers. However, power generation from a single renewable energy source cannot able to provide stable power. Hence, integration of renewable energy sources-based power generations needs to be established for providing continuous power supply to consumers. Solar energy and wind power are two major available sources on earth, hence, photovoltaic (PV) and permanent magnet synchronous generator (PMSG) based wind power generation system is considered in this paper. On the other hand, many loads are AC loads that required conversion from DC to AC such as inverters. Generally, multilevel inverters can able to provide quality supply to loads than normal inverters. However, the number of switches used in the multilevel inverter is more and also increasing size and complexity by increasing the level of the inverter. Therefore, an aligned multilevel inverter is implemented for a PV-Wind-based stand-alone system that has a smaller number of switches. Both solar irradiance and wind speed are depending on weather conditions and are unstable, hence a battery bank is incorporated with the help of a bidirectional DC to DC converter to provide an uninterrupted power supply to loads. A novel controller for 7 levels aligned inverter is implemented in this paper to supply quality power to loads under various scenarios. The proposed Aligned Multilevel Inverter needs half of the switches when compared to existing multilevel inverters as diode-clamped, flying-capacitor, and cascaded H-Bridge topologies. The hardware-in-loop is developed with OPAL-RT to present results under various case studies.

Grid connected hybrid renewable energy sources (RES) are main challenges nowadays. Interconnecting of two or more RES is called hybrid system and battery is optional in this kind of systems where grid is in active. The normal inverters are unable to produce sinusoidal voltages and this will cause many problems in grid connected system. Hence, many topologies of multilevel inverters are proposed which can able to produce sinusoidal output voltage. However, the cost and operational complexity will increase due to increasing number of switches. In order to reduce total number of switches, an Aligned Multilevel Inverter (AMI) configuration of three phase is implemented in this paper. Wind energy-based electrical power generation system and solar energy based electrical power generation systems are considered for interconnection. Energy storage devices such as batteries are not incorporated to system since considered grid is in active mode. Maximum power point tracker (MPPT) devices are available to extract maximum power from photovoltaic arrays and wind turbines, hence a boost converter is considered as MPPT converter for wind turbine and proposed AMI also works as MPPT converter for PV by using proposed controller. Hence extra DC–DC converters are not essential for PV system for MPPT, resulting in reduction of overall system cost. Also, the modified invasive weed optimization (MIWO) based algorithm is proposed for PV system to harvest maximum energy under partial shading conditions. The proposed MIWO is compared with particle swarm optimization (PSO) and grey wolf optimization (GWO) to enhance the performance of proposed algorithm. Extensive results are validated with Hardware-in-Loop (HIL) designed on OPAL-RT platform.