Comparative Analysis of Hybrid NPP and NPC Seven-Level Inverter With Switched-Capacitor

Abstract

In this work, the general structure of a hybrid NPP/NPC seven-level inverter is derived from a dual-T-type inverter. Compared with the original structure, the general structure is more flexible as there are four specific circuit configurations to meet different applications. In addition to self-balanced capacitor voltages and boost capability, various commercial NPP and NPC modules can be used to speed up the design process. Circuit description, operation principle, modulation and simulation results are analyzed comparatively. Theoretical analysis and simulation comparison indicate that the four configurations of the hybrid NPP/NPC inverter have their own merits and demerits. Especially, except for a bidirectional switch, all switching components of the NPP+NPC configuration have the same voltage stress as the dc input voltage making it is better in the aspect of component selection, and it is more suitable for high voltage applications. The performance of the NPP+NPC inverter is experimentally demonstrated by an 1kW prototype and its efficiency is closed to 96%. Multilevel inverter, neutral-point-piloted, neutral-point-clamped, switched-capacitor. INDEX TERMS

Control Scheme Influence on the Performance of Shunt Active Power Filter based on Five-level NPC Inverter in Steady and Transient Conditions

“…The waveforms of source voltage with source current after compensation are simultaneously shown in Fig (11). Through visualization Figures (8) , (11) and (12), we are able to conclude that the operation of the proposed shunt active based on five-level (NPC) inverter is successful. Before the application of shunt active power filter, the source current is equal to non-linear load current; highly distorted and rich in harmonic.…”

“…The corresponding harmonic spectrum is shown in Figure (7). The harmonic spectrum of the source current after compensation using shunt APF based on five-level (NPC) inverters is shown in Figures (8). Before compensation, the source current is much distorted with high Total Harmonic Distortion (THDi) value equal to 28.27%, after compensation the THDi is decreased to 3.43% using conventional SPWM controller and to 2.80% using fuzzy control scheme.…”

“…Several multilevel inverter topologies are being used for shunt active filter applications, but some practical problems like power circuit packaging, switching circuit complexity and dynamic voltage stress have restricted the number of inverter levels to 3 or 5 [7]. Topologies with very high number of voltage levels were also proposed [8]. In general, the more voltage levels of converter can decrease the harmonic in the output.…”

Seventeen-Level Inverter Based on Switched-Capacitor and Flying-Capacitor-Fed T-type Unit

“…As illustrated in Fig. 5(b), an inductor can be inserted into the double-mode SC unit to limit the charging current variation di/dt, as described in [24]. To ensure that the energy stored in the inductor can be quickly dissipated at switching VOLUME 10, 2022 instants, its inductance should be very small, so that it can be realized by utilizing the stray inductance of the PCB board and wires [25].…”

A Novel Control Approach to Hybrid Multilevel Inverter for High-Power Applications

“…The inverter topology and stability of the proposed control method have been validated through simulation and experimental results. A comparative analysis of the proposed inverter with existing topologies such as NPC [21,22], HNPC with H-bridge [23,24], HNPC with cascaded module [25,26], and PWM voltage source inverter [27] is conducted to illustrate the advantages of the proposed work.…”