Comparative evaluation of three single-phase NPC inverters

Abstract

In this paper is presented a comparative evaluation in steady-state of three single-phase NPC multilevel inverters. The first is a five-level neutral point clamped (NPC) inverter based on multi-stage switching cell (MSSC); the second is also a five-level neutral point clamped (NPC) inverter based on interleaved cell (IC); and the third is a three-level neutral point clamped (NPC) inverter based on paralleled cell (PC). For this comparative purpose, the switching frequency is constant and the evaluated parameters are the volume of the heatsinks and the passive components, the total harmonic distortion (THD) of the output voltage, the power density and efficiency of each topology. Theoretical analyses, as well as simulation and experimental results obtained from 5kW prototype are presented.

Operation and Efficiency Analysis of a Five-Level Single-Phase Hybrid Si/SiC Active Neutral Point Clamped Converter

“…The same procedure can be performed to find the dc-link capacitors loss using equation (15). Instead of Rds-on, the equivalent series resistance (ESR) of the capacitor should be replaced.…”

“…A review of the literature reveals a focus on optimizing 5level single-phase converters to obtain high efficiency [11], [12], [15]- [20]. By comparing the symmetrical 5-level NPC, asymmetrical 5-level NPC (Fig.…”

“…1(e)) and asymmetrical 5-level ANPC, it has been concluded in [11] that the ANPC converter has greater efficiency over the whole range of output power. Another comparison between 5L-NPC converters with different communication cells at the output has been done in [15], in which the converter with uncoupled inductors has higher efficiency compared to the one with an autotransformer. The converter efficiency in [15] at full load (5kW) is 96.2%.…”

“…Another comparison between 5L-NPC converters with different communication cells at the output has been done in [15], in which the converter with uncoupled inductors has higher efficiency compared to the one with an autotransformer. The converter efficiency in [15] at full load (5kW) is 96.2%. In [18], an asymmetrical T-type transformer-less inverter for PV applications has been presented, where a 3-level T-type leg is combined with a 2-level half-bridge leg to create a 5-level converter.…”