Abstract
This paper proposes a model-based controller for a state-of-the-art isolated inverter, with the aim to provide a low THD true-sine wave (TSW) single-phase voltage to feed auxiliary loads in EV applications, which is a requirement of great relevance in the current market. The studied topology comprises two stages, namely an isolated DC-DC converter, and a TSW inverter. Isolation in the first stage is provided by means of a high-frequency transformer fed by an H-bridge converter, which creates a high-frequency switching alternating signal out of the EV DC-bus voltage. The transformer output is processed by a full-bridge rectifier and a filter to create a regulated DC voltage signal. In the second stage, an H-bridge converter followed by a second-order filter creates a TSW by inverting the regulated DC output of the DC-DC converter. The proposed controller comprises a proportional-integral-derivative (PID) solution to regulate the DC output voltage of the DC-DC isolated converter; and a proportional-resonant (PR) solution to guarantee a TSW output voltage with low THD in spite of the presence of non-linear distorting loads. In particular, the PR controller involves the measurement of the output capacitor current to incorporate