Characteristics analysis of a new single‐phase π ‐type five‐level inverter

Abstract

The characteristics analysis of a new single-phase π-type five-level inverter using three-terminal switch-network is proposed in this study. The topology is the variant of three-level T-type topology or multi-level inverter using interleaved pulse width modulation (PWM) in a bridge-leg with coupled inductors. Moreover, the big merit of the new inverter is to apply only four active power switches to achieve five-level operations resulted in high efficiency and low harmonics. Furthermore, double-frequency operation of output inductors and equal division of the current that flows through power switches and filter inductor also can be achieved. These characteristics allow improvement of losses distribution, voltage and volume reduction of output filter inductor. The operation scenario with sinusoidal PWM is described in details. Meanwhile, the magnetic analysis and design, dc bias component evaluation in the magnetising current, stresses analyses and power losses calculation of power switches are studied and discussed. Finally, the simulation and prototype experiment demonstrate the advantages of the proposed topology.

A grid‐tied power conversion interface with a five‐level inverter

“…As compared with the conventional small-capacity distributed power generation system which is composed of an Hbridge inverter and a boost power converter to output two or three voltage levels, only an additional simple selection switch set is further involved in the proposed grid-tied power conversion to output five voltage levels. In the small-capacity distributed power generation system with conventional multi-level inverter, the boost power converter and the multi-level inverter are two independent circuits [4][5][6][7][8][9][10][11][12][13][14]. Since the boost power converter and the H-bridge inverter are merged by the selection switch set to output a multilevel voltage in the proposed grid-tied power conversion interface, the power circuit is effectively simplified.…”

“…However, a twin‐output DC–DC power converter must be used to generate two DC voltages with multiple relationships, which results in a complicated power circuit. A new single‐phase π‐type five‐level inverter is developed in [12]. It uses a couple inductor and the voltages of the capacitors for the DC bus of inverter must be equalised.…”