Modular bidirectional current-fed three-phase inverter for microgrid application

A modular bidirectional current-fed three-phase 6-pack inverter is proposed to integrate the low-voltage high-current source, i.e., solar, fuel cells, storage, or low voltage dc grid to interface to ac grid or load. The 3-phase 6-switch or 3-leg module can be employed with dedicated driver board to design and develop the converter for high power application. It offers scalability and reliability. Front-end dc/dc converter achieves zero current commutation and natural voltage clamping of current-fed devices. It also attains soft-switching of all semiconductor devices. Load connected 6-pack inverter is modulated using symmetric space vector modulation (SVM). Detailed steady-state operation and analysis are reported. Experimental results are demonstrated on a proof-of-concept hardware prototype rated at 1kW to validate the claims. Overall inverter system efficiency is 93% and light load efficiency is 88%.