Performance of a High-Speed Motor Drive System Using a Novel Multilevel Inverter Topology

Abstract

The performance of a novel multilevel six-switch (SS) three-phase inverter drive is examined for low-voltage high-speed motor applications. The switching losses of hard-switched voltagesource-inverter topologies place limits on the maximum feasible switching frequency. When operating at higher fundamental frequencies, this results in low-frequency modulation ratios and either high load harmonic currents that cause excessive rotor heating or larger than desired output reactors with a large fundamental voltage drop. The multilevel inverter structure examined offers an increased number of output pulsewidth-modulated (PWM) voltage levels, higher frequency PWM output waveforms, reduced dead-time effects, and a significant reduction in harmonic content. These features reduce the total losses in the motor load when compared to the standard SS three-phase inverter. The harmonic reduction provided by the multilevel topology relative to the standard inverter is experimentally demonstrated with a 15-hp 18 000-r/min induction machine.

Design and Implementation of a Highly Efficient Three-Level T-Type Converter for Low-Voltage Applications

“…Compared to the three-level NPC topology [4], the Ttype employs an active bidirectional switch to the dc-link voltage midpoint and gets along with two diodes less per bridge leg. It is an alternative to more complex three-level topologies such as active neutral point clamped converters [9]- [11] or split-inductor converters [12], [13]. The 3LT 2 C basically combines the positive aspects of the two-level converter such as low conduction losses, small part count and a simple operation principle with the advantages of the three-level converter such as low switching losses and superior output voltage quality.…”

Comparison of reduced part count multilevel inverters (RPC-MLIs) for integration to the grid

“…The topologies, which are being proposed and accounted to reduce the number of counts in the multilevel inverters are called as ''reduce part count multilevel inverters (RPC-MLIs)". The topologies are not included here which are specific application oriented not reduced part count oriented such as: MMC highly popular for HVDC applications [14], multilevel matrix converter for ac-ac applications [15,16], coupled inductor NPC topology for low-voltage high-speed motor applications [17] and cascaded multilevel boost inverter for hybrid electric vehicle application [18]. Daher et al multilevel inverter topology for standalone PV systems [19].…”

Optimised active harmonic elimination technique for three‐level T‐type inverters

“…1b. Contrary to three-level NPC topology, the efficiency of the three-level T-type converter (3 L-T2C) is outstanding for low switching frequencies ( < 20 kHz) because of lower conduction losses and needs only three additional isolated gate drive power supplies compared with the two-level converter [6]. The main reasons for the small acceptance of three-level split inductor converter are the increased losses and costs because of the bulky and expensive bridge leg inductors [1,7].…”