A new half-bridge based inverter with the reduced-capacity DC capacitors for DC micro-grid

This paper proposes a new half-bridge based inverter for the DC micro-grid. The proposed topology consists of a three-leg inverter, which can be constructed by an intelligent power module (IPM). Using the IPM gives cost-effective inverters for the dc micro-grid. In the proposed half-bridge based topology with a three-leg inverter, two legs are used for two single-phase half-bridge inverters, where the neutral line is grounded. The third leg performs a power de-coupler balancing the mean value of two dc capacitor voltages. This power de-coupler exchanges the energies between two dc capacitors connected to two single-phase half-bridge inverters. Thus the capacity of the dc capacitors of the half-bridge inverters can be dramatically reduced as compared to those of the previously proposed half-bridge inverters for the dc micro-grid. The basic principle of the proposed half-bridge based inverter is discussed in detail, and then confirmed by digital computer simulation using PSIM software. Simulation results demonstrate that the capacity of the dc capacitors is reduced by one fortieth as compared to those of the previously proposed half-bridge based inverter used in the dc micro-grid.