Improved Three-Phase Micro-Inverter Using Dynamic Dead Time Optimization and Phase-Skipping Control Techniques

This paper introduces two efficiency improvement techniques for a grid-tied micro-inverter with current mode control zero voltage switching (ZVS) output stages. The first technique is dynamic dead time optimization wherein PWM dead times are dynamically adjusted as a function of load current. The second method is advanced phase-skipping control which distributes power on individual phases depending on the available input power from PV source. Neither of the techniques require any additional components and both can be easily implemented in the digital controller firmware. The two techniques were designed and implemented in a 400W three-phase micro-inverter prototype and the experimental results confirm practical implementation of these techniques and demonstrate that significant efficiency improvement can be achieved.