A novel single-stage PWM microinverter topology using two-power switches

Abstract

This paper presents a novel single-stage Microinverter topology using only two-power switches. The number of components count are directly proportional to the power losses, weight, cost and complexity of the design. Nowadays, conventional Microinverter without transformer having minimum of six power switches, while only three power switches involved in a Microinverter structure with the presence of a transformer. Thus, this paper proposed a novel Microinverter topology with only two-power switches to convert DC-voltage from Photovoltaic (PV) module to an AC-output. Modes of operation and current flow during each cycle are being explained. Variation of modulation index, irradiance and temperature of the PV module, the switching frequency and harmonic content of the proposed Microinverter are being analysed. A simulated model of Microinverter topology, employed only two power switches with a standard Unipolar Sinusoidal Pulse Width Modulation (SPWM) having 0.85% harmonic percentage; able to inject current to the load; have been successfully built and demonstrated through simulation based on MATLAB/Simulink, thus provide theoretical validation for further research.

An Overview on Multi-Level Inverter Topologies for Grid-Tied PV System

“…By considering these things, the NASCMLI [67][68][69] and ACHBI [19,55] topologies are most preferable in this category of MLI topologies. In highvoltage topologies, the SSLI [16,77,78], SMSI [79][80][81], NHGSCMLI [21,22,85,86], NAMLI [26,99,100], SUS-CMLI [101][102][103][104], RSCHMLI [109,110], 19LAMLI [111][112][113], NRCAMLI [114][115][116], 25LACMLI [79,117], and SP35LAMLI [118][119][120] topologies have the allowable THD value of less than 5%. Te number of components required to generate one output voltage level in these MLI topologies is 2, 1.41, 3, 2.66, 1.82, 1.53, 1.31, 1.42, 1.12, and 0.8, respectively.…”

“…Te SMSI topology has a THD value of 22.09% for the 5-level output. While generating 31-level output, this topology contains a proper acceptable THD value of 4.54% [79][80][81]. Te NHGSCMLI topology has a low THD value of 1.04% when generating the 11-level output.…”

“…Tis topology is structured with a new switched source confguration, so it is known as switched multi- source inverter (SMSI), and it is shown in Figure 21 with the help of IGBT switches [79]. Tis topology's basic circuit can generate a 7-level output voltage, and the cascaded structure can generate a 31-level output voltage with asymmetric source confgurations [80]. Te advantages of this topology are fewer components, high THD, and high switching frequency.…”

A new multilevel inverter topology based on switched-capacitor technique

“…Moreover, they generally employ more power switches, gate drives and resulting in more power losses. These issues motivate researchers to develop new inverter topologies, and to date, many inverter structures addressing those issues have been introduced in the literature [5]- [15].…”

“…Recent MLI topologies [5]- [15] tend to focus on increasing the efficiency and modularity of the MLIs. Hence, most of them have a more straightforward structure [3], but they are buck-type MLIs.…”