An integrated approach for the protection of series injection inverters

This paper presents an integrated scheme for protecting and controlling series injection voltage-source inverters used with electrical grid systems. The scheme uses a number of strategies to provide a continuous current path for current from the secondary winding of the injection transformer for both transient and longer term fault conditions. These strategies can also be used to provide a current path during normal operation of the external AC system, facilitating startup and shutdown of the series injection system, as well as recovery from a fault. Both simulation and experimental confirmation of the integrated protection scheme are presented.