A Three-Level DC-Link Quasi-Switch Boost T-Type Inverter with Voltage Stress Reduction

Abstract

In recent years, the three-level T-Type inverter has been considered the best choice for many low and medium power applications. Nevertheless, this topology is known as a buck converter. Therefore, in this paper, a new topology incorporating the dc-link type quasi-switched boost network with the traditional three-level T-type inverter is proposed to overcome the limit of traditional three-level T-Type inverter. The space vector pulse width modulation scheme is considered to control this topology, which provides some benefits such as enhancing modulation index and reducing the magnitude of common-mode voltage. For this scheme, the zero, medium, and large vectors are utilized to generate the output voltage. The shoot-through state which is adopted by turning on all power switches of inverter leg is inserted into zero vector to boost the dc-link voltage. As a result, there is no distortion at the output waveform. The control signal of intermediate network power switches is also detailed to improve the boost factor and voltage gain. As a result, the voltage stress on power devices like capacitors, diodes, and switches is decreased significantly. To demonstrate the outstanding of proposed structure and its control strategy, some comparisons between the proposed method and other ones are performed. Simulation and experimental prototype results are conducted to verify the accuracy of the theory and effectiveness of the inverter.

Keywords

• quasi-switched boost inverter
• three-level T-type inverter
• shoot-through
• three-level inverter
• intermediate network
• dc-link type