Non‐isolated single‐phase inverter based on an autotransformer for low‐power applications

Abstract

This work presents a non-isolated single-phase voltage-source inverter (VSI) topology using an autotransformer to provide an alternating current (AC) output voltage whose maximum peak value can be up to twice that obtained with the conventional half-bridge and full-bridge inverters. Prominent advantages include a simple structure with low component count, as well as the fact that both switches are connected to a same reference node, as there is no need for isolated driver circuitry. As a possible drawback, the maximum voltage across the switches is equal to twice the input voltage, but it is still reasonable to state that the topology is adequate for low-power, low-input-voltage applications. A thorough qualitative and quantitative analysis is presented, from which it is possible to derive a consistent design procedure. An experimental prototype with a rated power of 100 W, switching frequency of 20 kHz, direct current (DC) input voltage of 35 V, and rms output voltage of 37 V is developed to validate the theoretical assumptions.