Quasi Cascaded H-Bridge Five-Level Boost Inverter

Abstract

Latterly, multilevel inverters have become more attractive for researchers due to low total harmonic distortion (THD) in the output voltage and low electromagnetic interference (EMI). This paper proposes a novel single-stage quasi-cascaded H-bridge five-level boost inverter (qCHB-FLBI). The proposed five-level inverter has the advantages over the cascaded H-bridge quasi-Z-source inverter (CHB-qZSI) in cutting down passive components. Consequently, size, cost, and weight of the proposed inverter are reduced. Additionally, the proposed qCHB-FLBI can work in the shoot-though state. A capacitor with low voltage rating is added to the proposed topology to remove an offset voltage of the output AC voltage when the input voltages of two modules are unbalanced. Besides, a simple PID controller is used to control the capacitor voltage of each module.

Existing System

Mitigation Technique.

Proposed System

A new single-phase single-stage CHB five-level inverter with boost voltage ability has been proposed in this paper. The proposed inverter has the following main features as: five-level output voltage, reduction in number of passive components and shoot-through immunity. With the simple PID controller, a constant capacitor voltage can be achieved with an excellent transient performance which enhances the rejection of disturbance, including the input voltage and load current variations. A quasi-switched boost (qSB) network is used to replace the qZS network. In comparison to the qZS network, the qSB network uses one less capacitor, one less inductor, one more diode and one more switch in front of the main H-bridge circuit. An isolated high step-up DC-DC converter is proposed based on the qSB network. In this paper, a new single-stage quasi-cascaded H-bridge five-level boost inverter (qCHB-FLBI) is proposed. In the proposed qCHB-FLBI, the qSB network is used in each module. The main features of the proposed qCHB-FLBI are five-level output voltage with boost voltage ability, reduction in a number of passive components and shoot-through immunity.

Architecture

Proposed qCHB-FLBI topology