A Two-Level Hysteresis-Based Sliding Mode Control for Three-Level Single-Phase Inverters

This paper presents a single-phase inverter controlled by a three-level sliding mode control. A simple first order sliding mode is designed to regulate the output voltage and it is implemented through a symmetrical two-level hysteresis band comparator. The hysteresis band of the comparator is dynamically adjusted to bound the switching frequency of the inverter. As a result, the desired voltage tracking is achieved and no average error is induced at the output. The article includes numerical simulation and experimental results carried out in a 1.2 kW prototype that confirm the good performance of the designed control in terms of tracking error and harmonic distortion of the output voltage. The proposal has been tested with input voltage variations, transients of resistive loads and with a non-linear load showing the expected robustness