The Neutral Point Clamped (NPC) Multi-Level Inverters (MLI) have been ruling the power electronics industries for the past two decades. The Multi-Carrier Pulse Width Modulation (MCPWM) is common PWM techniques which are widely used in NPC-MLI applications. However, MCPWM is not having a good impact on the balancing of DC-link voltages, Common Mode Voltage (CMV) and limiting the Total Harmonics Distortion (THD). The Selective Harmonic Elimination (SHE) technique is introduced for reducing the THD, however all the switching angles should be maintained less than π/2 to keep the eliminated harmonics at constant level which narrows down the modulation index range. Hence, in recent days Space Vector Modulation (SVM) technique is widely used in NPC-MLI, which gives better DC-link voltage balancing, self-neutral point balancing, near-zero CMV reduction, better-quality harmonics profile and switching loss minimization. Hence, it is a preferred solution for the majority of electrical conversion applications such as electric traction, high power industrial drives, renewable power generation, and grid-connected inverters, etc. The paper gives a comprehensive review of the SVM for NPC-MLI. First, this paper deliberates the state of art for two-level SVM and extends it to three-level (3L) SVM. Also compares the 3L SVM performance with other MCPWM techniques. Followed by the various modified MLI SVM techniques in terms of their implementations, DC-link capacitor balancing, and reduction of CMV. Further, the review of MLI SVM is widened to open-end winding Inverters and multiphase MLIs. The final part of this paper discussed the future trends and research directions on MLI SVM techniques and its applications.

The use of hybrid renewable energy systems among household consumers in sub-Sahara Africa (SSA) is increasingly gaining attention. This is due to low electrification rates in many of the countries in SSA. A hybrid energy system for power generation combines various energy systems, either renewable or a combination of renewable and fossil-powered sources for optimal power extraction and operation. In the era of decarbonization of the electricity grid through the use of renewable energy, hybridization of sources is an essential condition for the production of electricity. Based on current quest for renewable energy (RE) expansion in the global energy mix, optimum conditions for the production and adoption of hybrid renewable energy systems (HRES) at micro-levels are indispensable and must be advocated for. This can be justified based on the perpetually rising cost of energy for socio-economic development. This paper presents a survey of major issues regarding the motivations and specific benefits behind the adoption of HRES. Also presented, is a discussion on different renewable energy sources that can be adopted for HRES application for both grid and off-grid consumers. Furthermore, a discussion on the important issues as it pertains to the design and implementation of HRES is also presented. Finally, a policy discussion on the affordability of HRES in a low-income household is presented.