The solar photovoltaic (PV) system is emerging energetically in meeting the present energy demands. A rise in PV module temperature reduces the electrical efficiency, which fails to meet the expected energy demand. The main objective of this research was to study the nature of OM29, which is an organic phase change material (PCM) used for PV module cooling during the summer season. A heat transfer network was developed to minimize the experimental difficulties and represent the working model as an electrical resistance circuit. Most existing PV module temperature (T_PV) reduction technology fails to achieve the effective heat transfer from the PV module to PCM because there is an intermediate layer between the PV module and PCM. In this proposed method, liquid PCM is filled directly on the back surface of the PV module to overcome the conduction barrier and PCM attains the thermal energy directly from the PV module. Further, the rear side of the PCM is enclosed by tin combined with aluminium to avoid any leakages during phase change. Experimental results show that the PV module temperature decreased by a maximum of 1.2 °C using OM29 until 08:30. However, after 09:00, the OM29 PCM was unable to lower the T_PV because OM29 is not capable of maintaining the latent heat property for a longer time and total amount of the PCM experimented in this study was not sufficient to store the PV module generated thermal energy for an entire day. The inability of the presented PCM to lower the temperature of the PV panel was attributed to the lower melting point of OM29. PCM back sheet was incapable of dissipating the stored PCM’s thermal energy to the ambient, and this makes the experimented PCM unsuitable for the selected location during summer.

A high number of research work is being carried out in the field of DC-DC converters to improve the performance of microgrid operation. The DC microgrid has a high level of acceptance because of the integration of renewable energy sources. In DC Microgrid, there is a need for improved DC-DC converter topologies which offer high gain, small size, enhanced efficiency, reduced voltage stress and reduced component count etc. A new Triple-Mode Active-Passive Parallel Intermediate Links (TM-A2P-IL) converter is proposed in the paper. The A2P-IL is designed by a combination of an inductor, capacitor, diode, and control switch. The proposed converter is derived by inserting A2P-IL in conventional boost converter. The proposed TM-A2P-IL converter operates in three modes and provides a high voltage gain without using a transformer, voltage multiplier stages, coupled inductor, switched inductor/capacitor circuitry. The other benefits of the proposed TM-A2P-IL converters are flexibility in the selection of duty cycles, reduced voltage stress of devices, small reactive components, single-stage power conversion. The proposed converter circuit, operating principle, steady-state analysis is studied for both CCM and DCM, discussed. The comparison between available similar type converters and the proposed converter is provided. The operation and performance of the proposed A2P-IL converter are validated through simulation and experimental work.

Calculation of firing angles for the efficient operation of multilevel inverter is very important. This paper gives a simple guide to calculate the firing angles for the operation of multilevel inverter. The firing angles are calculated for Nearest Level Modulation and Selective Harmonics Elimination which are the two very popular low switching frequency modulation schemes. The modulation schemes are implemented on a Multilevel DC-link inverter to generate a nine level output. The simulation is carried out using Matlab/Simulink software. The Matlab code to calculate the THD is also presented. Hardware result is shown to validate the simulation results. The code to execute the firing pulse in Atmega32 AVR microcontroller is also presented.

The switching angles play a vital role in varying the total harmonics distortion in the operation of a multilevel inverter. This paper proposes a modified nearest level modulation scheme to be employed on multilevel inverter for the electrical engineering students in power electronics course. Compared to the conventional nearest level modulation scheme, the proposed modulation scheme is found to facilitate a reduction in the total harmonics distortion at the output of the inverter. An algorithm has been designed for this purpose. The algorithm not only provides an easy approach in calculating the total harmonics distortion but also to reduce the total harmonics distortion. Since the algorithm is applicable to multilevel inverter of any level output, it gives the students a deeper understanding of operation of various multilevel inverter topologies. The proposed scheme is also compared with three other conventional schemes in order to thoroughly understand the importance of total harmonics distortion. Validation of the modified nearest level modulation and nearest level modulation has been done on a cascaded H-bridge inverter for 11 different types of configuration. Simulation has been implemented using the MATLAB/Simulink 2015b software package. A hardware prototype with a specification similar to that of simulation is also presented. With the proper understanding of the algorithm presented, it is very easy to teach multilevel inverter topics under the field of power electronics.

The advent of high power and medium power appliances has given substantial importance to Multilevel Inverters (MLI) in recent times. The MLI is widely used in driving AC loads which requires to be operated with low harmonics. In this paper, the various MLI topologies and the modulation techniques implemented on MLIs are reviewed. While reviewing the various MLI topologies, they are categorized into symmetrical type and asymmetrical type. All the existing MLIs topologies and those that are developed in future can be categorized into one of these two categories. A comprehensive review is done of these topologies to examine the various performance parameters. The modulation techniques are also classified into fundamental switching frequency (FSF) modulation techniques and high switching frequency (HSF) modulation techniques. This classification provides an easy understanding of the concepts that are conveyed by MLI. This paper also gives a broad understanding of the various features of each modulation technique.