A simplified structure for three‐phase 4‐level inverter employing fundamental frequency switching technique

Abstract

This study describes the design and control of simplified structure of three-phase 4-level inverter. A 4-level dc-link derived from three symmetrical dc voltage supplies and two controlled switches is connected to a three-phase 3-level neutral point clamped (3-level NPC) bridge inverter. By employing the fundamental frequency switching technique, the simplified 4-level inverter can have two distinct modes of operation: 4-level and 2-level. Compared to the well-known three-phase 4-level NPC inverter, the proposed inverter topology comes with series of features including a minimum number of power components, high quality voltage waveform, lower losses and higher efficiency. To ensure the feasibility of the proposed topology with its suggested modulation technique, the prototype of the proposed 4-level inverter is built and the experimental results are given.

A new single‐phase cascaded multilevel inverter topology with reduced number of switches and voltage stress

“…IGBT TOSHIBA GT50J325 is used as a switch to realize the proposed topology. As shown in Figure 15A, the voltage stress across switches S 1 , S 3 , and S 5 are 60, 30, and 120 V, respectively, as given in (3), (4), and (5). As the voltage magnitude of gate signals generated from dSPACE is of low voltage and not sufficient to drive the IGBTs, a gate driver circuit made up of an IC NXP 74HCNIC74 with an optocoupler A3120.…”

“…The output voltage has a peak value of 240 V, which has eight voltage steps of 30 V. The voltage stress across the switch is shown in Figure 15A,B. As shown in Figure 15A, the voltage stress across switches S 1 , S 3 , and S 5 are 60, 30, and 120 V, respectively, as given in (3), (4), and (5). Similarly, the voltage stress across switches S 7 and S 9 is 90 and 120 V, respectively, as given by (6) and (7) and shown in Figure 14B.…”

“…[1][2][3][4][5][6][7] Figure 1A to C shows the recently proposed AMO-based MLIs. MLIs have been extensively researched and find application in almost all sector of power industry like industrial drives, applications related to renewable energy, power system applications including high voltage dc transmission (HVDC) and flexible ac transmission systems (FACTS).…”

“…Most of these topologies have been developed to eliminate or mitigate the demerits of the classical topologies. [1][2][3][4][5][6][7] Figure 1A to C shows the recently proposed AMO-based MLIs. [8][9][10] In Figure 1A to C, all the topologies have a similar structure with different placement of bidirectional switches.…”

High‐efficiency three‐phase bidirectional dc–ac converter for energy storage systems

“…To overcome these drawbacks, multi-level converters have become an attractive topology for interfacing batteries to the grid. Compared with traditional two-level topologies, multi-level topologies have several advantages, including reduced voltage stress on switches, lower power losses, and higher grid power quality [5][6][7]. These properties also make multi-level topologies appealing for use with ESSs.…”