Multilevel converters for large electric drives

Abstract

This paper presents transformerless multilevel converters as an application for high-power and/or high-voltage electric motor drives. Multilevel converters: 1) can generate nearsinusoidal voltages with only fundamental frequency switching; 2) have almost no electromagnetic interference or common-mode voltage; and 3) are suitable for large voltampere-rated motor drives and high voltages. The cascade inverter is a natural fit for large automotive all-electric drives because it uses several levels of dc voltage sources, which would be available from batteries or fuel cells. The back-to-back diode-clamped converter is ideal where a source of ac voltage is available, such as in a hybrid electric vehicle. Simulation and experimental results show the superiority of these two converters over two-level pulsewidthmodulation-based drives. Index Terms-Cascade inverter, common-mode voltage, diodeclamped inverter, electric vehicle, motor drive, multilevel converter, multilevel inverter.

Ac Five-Phase Drive Systems Based on Cascade Converters and Open-End Winding Five Phase Machine

“…-Step 2: a) determine v * sxj min and v * sxj max from (19) and (20); b) choose μ * sxj ; c) determine v * sxj from (26); and d) determine the ten pole voltages v * sa10a to v * sb50 b from (17).…”

“…Another solution to achieve medium to high power drive systems, instead of using power switches with high voltage and high current characteristics [18], [19] is the use of multilevel converters [20], mainly neutral point clamped configurations and cascade configurations [21][22][23][24]. Another possible multilevel configuration in AC drive is the open windings configurations, first reported in [25] and widely explored since then [26][27][28][29][30][31].…”

Space vector PWM technique for a three-level six-phase drive

“…The NPC inverter topology was proposed in-order to reduce the magnitude of harmonics which cause losses and pulsating torque in medium power drives while also allowing controllability of the output voltage fundamental [2]. As the number of inverter output voltage levels increases, the output voltage waveform approximates towards a sinusoidal waveform, thus, reducing the total harmonic distortion (THD) [3]. Furthermore, a multilevel topology can sustain a higher dc-link voltage compared to a two-level inverter using power semiconductors of the same rating.…”

SPWM Control Strategy for Multilevel Inverter Fed an Induction Motor Drive

“…Thus it is admitted that the harmonics decrease proportionately to the inverter level. For these reasons, the multilevel inverters are preferred for high power applications [6][7]. However, there is no shortage of disadvantages.…”