Model Predictive-Based Voltage Balancing Control for Single-Phase Three-Level Inverters

Neutral-point voltage balance is critical for safe operation of single-phase three-level inverters. This issue can be overcome by selecting proper redundant small vectors. However, two voltage sensors are usually required to sample the split dc-link voltages. This letter proposes a model predictive-based voltage balancing method to reduce the usage of the voltage sensors (saving one voltage sensor). The required voltage information, which is essential for selecting the appropriate small vector, is obtained by comparing the current tracking errors. Consequently, the cost is reduced and the reliability is improved. A prototype is finally built to validate the feasibility and effectiveness of the proposed control method.