There are several interesting topics for further research:
■ The implemented controller does not take into account that the inverter output voltage can present a DC-level if the inverter feeds unsymmetrical loads, such as half-wave loads. Future implementations must include a mechanism to monitor and eliminate any possible output voltage DC-level.
■ The implemented controller adjusts the output voltage amplitude by only changing the number of output levels. Future implementations might include fine adjustment of the output voltage amplitude by also altering the output voltage waveform shape.
■ In this work, the correction of transformer-unbalancing was investigated only at steady-state level. Future work might study the transformer dynamics and should consider it on the controller design.
■ Regarding inverter efficiency characteristic, it might be interesting to design the transformer according to a typical load profile. Also, future work should consider that no-load consumption can be even more decreased through individual optimization of auxiliary power supplies, control/measurement circuits, drivers and snubber circuits.
■ Finally, it might be interesting to extend the proposed inverter operation to the connection with mini-grid systems.