Development of a New Pseudo-DC Link Type DC-Decoupled Transformerless Inverter

Abstract

This paper proposes a pseudo-DC link type DC-decoupled transformerless inverter. The variation of common mode voltage is the primary reason for the flow of common-mode leakage current in the transformerless inverter. The proposed topology uses the DC-decoupling method to mitigate the common-mode leakage current. In contrast to two-stage inverters, the proposed topology’s pseudo-DC link structure avoids the necessity for a DC-link capacitor and associated charging diode between the boosting and inverter stages. The proposed inverter’s excellent boosting ability allows it to work with a wide input voltage range. The modulation strategy used here avoids the need for dead time and the problem of shoot-through. The MATLAB simulation model directly confirms the feasibility and efficacy of the proposed topology and its modulation strategy. The loss calculation and thermal analysis of the inverter made of three different materials are compared in PLECS platform. The thermal analysis helps to decide the heat sink size and thermal protection of switches.

Keywords

• transformerless inverter
• leakage current
• loss analysis
• thermal analysis