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.