Design and implementation of a paralleled inverter system with failure isolation and hot-swap features

This paper presents design and implementation of a paralleled inverter system with failure isolation and hot-swap features. The system is controlled with a system control unit (SCU) to achieve output voltage regulation, inverter synchronization and the above-mentioned features. By incorporating a current weighting distribution control, the system allows inverters with different power ratings connected in parallel. The failure isolation feature is achieved with a scanning circuit associated with R-C circuits, which are also used in achieving the hot-swap one. To release a reset signal tentatively during start-up transient, another R-C circuit and transistors are introduced into each inverter module. This design can help achieve a hot-swap feature. Thus, system power capability can be expanded readily and inverter failure disturbance can be correspondingly reduced. Experimental results obtained from a two-inverter system with equal or different power ratings have demonstrated its feasibility. Additionally, the discussed failure isolation and hot-swap features have improved reliability and stability of the paralleled inverter system.